Section

[Code of Federal Regulations]

[Title 33, Volume 3]

[Revised as of July 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 33CFR222.6]

[Page 257-311]

TITLE 33--NAVIGATION AND NAVIGABLE WATERS

CHAPTER II--CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF

DEFENSE

PART 222_ENGINEERING AND DESIGN--Table of Contents

Sec. 222.6 National Program for Inspection of Non-Federal Dams.

(a) Purpose. This regulation states objectives, assigns

responsibilities and prescribes procedures for implementation of a

National Program for Inspection of Non-Federal Dams.

(b) Applicability. This regulation is applicable to all Divisions

and Districts having Civil Works functions.

8 August 1972.

(2) Freedom of Information Act, Pub. L. 87-487, 4 July 1967.

(3) ER 500-1-1.

(d) Authority. The National Dam Inspection Act, Public Law 92-367, 8

August 1972 authorizes the Secretary of the Army, acting through the

Chief of Engineers, to carry out a national program of inspection of

non-Federal dams for the purpose of protecting human life and property.

(e) Scope. The program provides for:

(1) An update of the National Inventory of Dams.

(2) Inspection of the following non-Federal dams (the indicated

hazard potential categories are based upon the location of the dams

relative to developed areas):

(i) Dams which are in the high hazard potential category (located on

Federal and non-Federal lands).

(ii) Dams in the significant hazard potential category believed by

the State to represent an immediate danger to the public safety due to

the actual condition of the dam.

(iii) Dams in the significant hazard potential category located on

Federal lands.

(iv) Specifically excluded from the national inspection program are:

(A) Dams under the jurisdiction of the Bureau of Reclamation, the

Tennessee Valley Authority, the International Boundary and Water

Commission and the Corps of Engineers and

(B) Dams which have been constructed pursuant to licenses issued

under the authority of the Federal Power Act, and

immediately prior to the enactment of this act by a State agency and

which the Governor of such State requests be excluded from inspection.

(f) Objectives. The objectives of the program are:

(1) To update the National Inventory of Dams by 30 September 1980.

(2) To perform the initial technical inspection and evaluation of

the non-Federal dams described in paragraph 222.8(e) of this section to

identify conditions which constitute a danger to human life or property

as a means of expediting the correction of hazardous conditions by non-

Federal interests. The inspection and evaluation is to be completed by

30 September 1981.

(3) To obtain additional information and experience that may be

useful in determining if further Federal actions are necessary to assure

national dam safety.

(4) Encourage the States to establish effective dam safety programs

for non-Federal dams by 30 September 1981 and assist the States in the

development of the technical capability to carry out such a program.

(g) Program execution--(1) Responsibilities. (i) The owner has the

basic legal responsibility for potential hazards created by their

dam(s). Phase II studies, as described in Chapter 4, Appendix D, and

remedial actions are the owner's responsibility.

(ii) The State has the basic responsibility for the protection of

the life and property of its citizens. Once a dam has been determined to

be unsafe, it is the State's responsibility to see that timely remedial

actions are taken.

(iii) The Corps of Engineers has the responsibility for executing

the national program. The Federal program for inspection of dams does

not modify the basic responsibilities of the States or dam owners. The

Engineering Division of the Civil Works Directorate is responsible for

overall program goals, guidance, technical criteria for inspections and

inventory and headquarters level coordination with other agencies. The

Water Resources Support Center (WRSC) located at Kingman Building, Fort

Belvoir, Virginia 22060 is responsible for:

(A) Program Coordination of both the inventory and inspection

programs.

[[Page 258]]

(B) Developing and defining functional tasks to achieve program

objectives.

(D) Compiling and disseminating progress reports.

(E) Monitoring and evaluating program progress and recommending

corrective measures as needed.

(F) Collecting and evaluating data pertaining to inspection reports,

dam owners' responses to inspection report recommendations, attitudes

and capabilities of State officials, State dam safety legislation,

Architect-Engineer performance, etc., for defining a comprehensive

national dam safety program.

(G) Responding to Congressional, media, scientific and engineering

organization and general public inquiries.

Division and District offices are responsible for executing the program

at the State level. Assignment of Division reponsibilities for States is

shown in Appendix A.

(2) State participation. Where State capability exists, every effort

should be made to encourage the State to execute the inspection program

either with State personnel or with Architect-Engineer (A-E) contracts

under State supervision. If the State does not have the capability to

carry out the inspection program, the program will be managed by the

Corps of Engineers utilizing Corps employees or contracts with A-E firm.

(h) Update of National Inventory of Dams. (RCS-DAEN-CWE-17/OMB No.

49-RO421)

(1) The National Inventory of Dams should be updated and verified to

include all Federal and non-Federal dams covered by the Act. Those dams

are defined as all artificial barriers together with appurtenant works

which impound or divert water and which: (1) Are twenty-five feet or

more in height or (2) have an impounding capacity of fifty acre-feet or

more. Barriers which are six feet or less in height, regardless of

storage capacity or barriers which have a storage capacity at maximum

water storage elevation of fifteen acre-feet or less regardless of

height are not included.

(2) Inventory data for all dams shall be provided in accordance with

Appendix B.

(3) The hazard potential classification shall be in accordance with

paragraph 2.1.2 Hazard Potential of the Recommended Guideline for Safety

Inspection of Dams (Appendix D to this section).

Table 2--Hazard Potential Classification

----------------------------------------------------------------------------------------------------------------

Category Urban development Economic loss

----------------------------------------------------------------------------------------------------------------

Low.................................... No permanent structure for human Minimal (Undeveloped to occasional

habitation. structures or agriculture).

Significant............................ No urban development and no more Appreciable (Notable agriculture,

than a small number of habitable industry or structures).

structures.

High................................... Urban development with more than a Excessive (Extensive community,

small number of habitable industry or agriculture).

structures.

----------------------------------------------------------------------------------------------------------------

(4) As in the original development of the inventory, the States

should be encouraged to participate in the work of completing, verifying

and updating the inventory. Also, when available, personnel of other

appropriate Federal agencies should be utilized for the inventory work

on a reimbursable basis. Work in any State may be accomplished:

(i) Under State supervision utilizing State personnel or Architect-

Engineers contracts.

(ii) Under Corps supervision utilizing Corps employees, employees of

other Federal agencies or Architect-Engineer contracts.

(5) A minimum staff should be assigned in Districts and Divisions to

administer and monitor the inventory activities. Generally, the work

should be accomplished by architect-engineers or other Federal agency

personnel under State or Corps supervision. Corps personnel should

participate in the inventory only to the extent needed to assure that

accurate data are collected.

[[Page 259]]

(6) The National Inventory of Dams computerized data base in stored

on the Boeing Computer Services (BCS) EKS computer system in Seattle,

Washington. The data base uses Data Base Management System 2000 and is

accessible for query by all Corps offices.

(7) Appendix B indicates details on accessing and updating inventory

data.

(8) Appendix I describes the procedure for using NASA Land Satellite

(LANDSAT) Multispectral Scanner data along with NASA's Surface Water

Detection and Mapping (DAM) computer program to assist in updating and

verifying and National Inventory of Dams.

(9) All inventory data for dams will be completed and verified

utilizing all available sources of information (including LANDSAT

overlay maps) and will include site visitation if required. It is the

responsibility of the District Engineer to insure that the inventory of

each State within his area of responsibility is accurate and contains

the information required by the General Instructions for completing the

forms for each Federal and non-Federal dam.

(i) [Reserved]

(j) Inspection Program. (RCS-DAEN-CWE-17 and OMB No. 49-RO421)

(1) Scheduling of inspections. The Governor of each State or his

designee will continue to be involved in the selection and scheduling of

the dams to be inspected. Priority will be given to inspection of those

dams considered to offer the greatest potential threat to public safety.

(i) No inspection of a dam should be initiated until the hazard

potential classification of the dam has been verified to the

satisfaction of the Corps. Dams in the significant hazard category

should be inspected only if requested by the State and only then if the

State can provide information to show that the dam has deficiencies that

pose an immediate danger to the public safety. Guidance for the

selection of significant category non-Federal dams on Federal lands will

be given in the near future.

(ii) Selection for inspection of non-Federal dams located on Federal

lands or non-Federal dams designed and constructed under the

jurisdiction of some Federal agency, should be coordinated with the

responsible Federal agency. The appropriate State or regional

representative of the Federal agency also should be contacted to obtain

all available data on the dam. Representatives of the agency may

participate in the inspection if they desire and should be given the

opportunity to review and comment on the findings and recommendations in

the inspection report prior to submission to the Governor and the dam

owner. Examples of such dams are: non-Federal dams built on lands

managed by National Forest Service, Bureau of Land Management, Fish and

Wildlife Service, etc.; non-Federal dams designed and constructed by the

Soil Conservation Service of the U.S. Department of Agriculture; high

hazard mine tailings and coal mine waste dams under the jurisdiction of

the Mine Safety and Health Administration, Department of Labor.

(iii) Indian-owned dams on trust lands are considered to be non-

Federal dams. All dams in the high hazard potential category will be

inspected. Privately-owned dams located on Indian lands are to be

included in the program, however BIA-owned dams on Indian lands are

Federal dams and are exempt.

(2) Procedures. The Division Engineer is responsible for the quality

of inspections and reports prepared by the District Engineer. Close

liaison between the District Engineer and the State agency or A-E firm

responsible for the inspections will be required in order to obtain a

dependable result. To avoid undesirable delays in the evaluation of

safety of individual dams, contracts with A-E's or agreements with

States which are managing the program will provide that reports be

completed and furnished to the District Engineer within a specified time

after completion of the on-site inspection of the dam.

(i) Inspection guidelines. The inspection should be conducted in

accordance with the Recommended Guidelines for Safety Inspection of Dams

(Appendix D to this section). Expanded Guidance for Hydrologic and

Hydraulic Assessment of Dams is provided in Appendix C. The criteria in

the recommended guidelines are screening criteria to be used only

[[Page 260]]

for initial determinations of the adequacy of the dam. Conditions found

during the investigation which do not meet the guideline recommendations

should be assessed as to their importance from the standpoint of the

degree of risk involved.

(ii) Coordinators. Experience has shown that coordination and

communications among technical disciplines, Public Affairs Office,

emergency officials, training officers, operations personnel, State

representatives and A-E firms has been best in those districts where one

person was delegated the responsiblity for coordinating the actions of

all involved elements. Each district should evaluate its overall

coordination procedures to insure that all involved elements have the

best possible access to necessary data.

(iii) Field investigations should be carried out in a systematic

manner. A detailed checklist or inspection form should be developed and

used for each dam inspection and appended to the inspection report. The

size of the field inspection team should be as small as practicable,

generally consisting of only one representative of each required

discipline in order to control the costs of the inspection without

sacrificing the quality of the inspection. The inspection team for the

smaller less complex dams should be limited to two or three

representatives from appropriate technical areas with additional

specialists used only as special conditions warrant. The larger more

complex projects may require inspection teams of three or four

specialists. Performance of overly detailed and precise surveys and

mapping should be avoided. Necessary measurement of spillway, dam

slopes, etc. can generally be made with measuring tapes and hand levels.

(iv) Additional engineering studies. Dam inspections should be

limited to Phase I investigations as outlined in Chapter 3 of Appendix

D. However, if recommended by the investigating engineer and approved by

the District Engineer, some additional inexpensive investigations may be

performed when a reasonable judgment on the safety of the dam cannot be

made without additional investigation. Any further Phase II

investigation needed to prove or disprove the findings of the District

Engineer or to devise remedial measures to correct deficiencies are the

responsibility of the owner and will not be undertaken by the Corps of

Engineers.

(v) Assessment of the investigation. (A) The findings of the visual

inspection and review of existing engineering data for a dam shall be

assessed to determine its general condition. Dams assessed to be in

generally good condition should be so described in the inspection

report. Deficiencies found in a dam should be described and assessed as

to the degree of risk they present. The degree of risk should consider

only loss of life and/or property damage resulting from flooding due to

dam failure. Loss of project benefits i.e., municipal water supply,

etc., should not be considered. If deficiencies are assessed to be of

such a nature that, if not corrected, they could result in the failure

of the dam with subsequent loss of life and/or substantial property

damage, the dam should be assessed as ``Unsafe.'' If the probable

failure of an ``Unsafe'' dam is judged to be imminent and immediate

action is required to reduce or eliminate the hazard, the ``unsafe''

condition of the dam should be considered an ``emergency.'' If the

probable failure is judged not to be imminent, the ``unsafe'' condition

should be considered a ``non-emergency.''

(B) Adequacy of spillway. The ``Recommended Guidelines for Safety

Inspection of Dams,'' Appendix D, provide current, acceptable inspection

standards for spillway capacity. Any spillway capacity that does not

meet the criteria in the ``Guidelines'' is considered inadequate. When a

spillway's capacity is so deficient that it is seriously inadequate, the

project must be considered unsafe. If all of the following conditions

prevail, the Governor of the State shall be informed that such project

is unsafe:

(1) There is high hazard to loss of life from large flows downstream

of the dam.

(2) Dam failure resulting from overtopping would significantly

increase the hazard to loss of life downstream from the dam over that

which would exist just before overtopping failure.

[[Page 261]]

(3) The spillway is not capable of passing one-half of the probable

maximum flood without overtopping the dam and causing failure.

Classification of dams with seriously inadequate spillways as ``unsafe,

non-emergency'' is generally a proper designation of the urgency of the

unsafe condition. However, there may be cases where the spillway

capacity is unusually small and the consequences of dam overtopping and

failure would be catastrophic. In such cases, the unsafe dam should be

classified as an emergency situation.

(vi) All inspection reports will receive one level of independent

review by the Corps. If the reports are prepared by the Corps, the

independent review may be performed internally within the district

office. However, in cases which involve significant economic, social or

political impacts and technical uncertainties in evaluating the dams,

advice may be obtained from the staffs of the Division Engineer and the

Office, Chief of Engineers.

(3) Reports--(i) Preparation. A written report on the condition of

each dam should be prepared as soon as possible after the completion of

the field inspection and assessment. A suggested report format is

attached as Appendix E. It is important that the inspection report be

completed in a timely manner. For inspections being done by Corps

employees, it is suggested that once an inspection team has been

assigned to a dam inspection it be allowed to complete the inspection

and report without interruption by other work.

(ii) Review and approval. The coordinating engineer should determine

which disciplines should review the report and establish a procedure to

accomplish the review in a timely manner. A review panel, made up of the

appropriate Division and Branch Chiefs has worked well in some

districts. Use of a review panel should be seriously considered by all

districts. All inspection reports shall be approved by the District

Engineer who will maintain a complete file of final approved reports.

Any State or Federal agency having jurisdiction over the dam or the land

on which the dam is built should be given the opportunity to review and

comment on the report prior to submission to the Governor or dam owner.

The District Engineer will transmit final approved reports to the

Governor of the State and the dam owner (or the Governor only, when

requested in writing by State officials). If the report is initially

furnished to the Governor only, a period of up to ten days may be

allowed before the report is furnished to the dam owner. If the Governor

or the owner indicates additional technical information is available

that might affect the assessment of the dam's condition, the District

Engineer will furnish the proposed final report to the Governor and the

owner and establish a definite time period for comments to be furnished

to the District Engineer prior to report approval.

(iii) In general the Governor will be responsible for public release

of an inspection report and for initiating any public Statements.

However, an approved report must be treated as any other document

subject to release upon request under the Freedom of Information Act.

The letters of transmittal to the Governor and owner should indicate

that under the provisions of the Freedom of Information Act, the

documents will be subject to release upon request after receipt by the

Governor. Proposed final reports will be considered as internal working

papers not subject to release under the Freedom of Information Act.

Corps personnel, A-E contractor personnel and others working under

supervision of the Corps will be cautioned to avoid public statements

about the condition of the dam until after the District Engineer has

approved the report. The Corps will respond fully to inquiries after the

Governor has received the approved report or been notified of an unsafe

dam. An information copy of the report should be sent to the District

office normally having jurisdiction if other than the District

responsible for the inspection.

(iv) Follow-up action. A Federal investment of the magnitude

anticipated for this inspection program makes it desirable that a

reporting system be established to keep the District Engineer abreast of

the implementation of the recommendations in the inspection reports. The

letters of transmittal to the Governor and owner will request that

[[Page 262]]

the District Engineer be informed of the actions taken on the

recommendations in the inspection reports. However, the National Dam

Inspection Act only authorizes the initial inspection of certain dams;

therefore, once a report is completed no reinspection will be

undertaken.

(4) Unsafe dams. The investigating engineer will be required to

immediately notify the District Engineer when a dam is assessed as being

unsafe. He will also indicate if probable failure of the unsafe dam is

judged to be imminent and immediate action is required to reduce or

eliminate the threat. The District Engineer will evaluate the findings

of the investigating team and will immediately notify the Governor and

the owner if the findings are Unsafe Non-Emergency or Unsafe-Emergency.

The appropriate State agency and the Corps of Engineers officials having

emergency operation responsibility for the area in which the dam is

located will also be notified. The information provided in the unsafe

dam notice shall be as indicated in Appendix F. Any emergency procedures

or remedial actions deemed necessary by the District Engineer will be

recommended to the Governor who has the responsibility for any

corrective actions. As provided in ER 500-1-1, Corps assistance under

Pub. L. 84-99 ``Advance Measures,'' may be made available to complement

the owner's and Governor's action under certain conditions and subject

to the approval of the Director of Civil Works. The District Engineer's

Emergency Operation Officer will coordinate the advance measures request

in accordance with existing procedures. Coordination will be maintained

between the District responsible for emergency action under Pub. L. 84-

90 and the District responsible for the inspection.

(5) Emergency action plans. An emergency action plan should be

available for every dam in the high and significant hazard category.

Such plans should outline actions to be taken by the operator to

minimize downstream effects of an emergency and should include an

effective warning system. If an emergency action plan has not been

developed, the inspection report should recommend that the owner develop

such an action plan. However, the Corps has no authority to require an

emergency action plan.

(k) Progress reports. Progress reports should be submitted monthly

by the Division Engineer to WRSC. The reports shall include progress

through the last Saturday of the month and should be mailed by the

following Monday. The reports shall contain the information and be

typewritten in the format shown in Appendix G. Copies of Unsafe Dam Data

Sheets will be submitted with the progress report. Copies of the

completed inspection report for Dams in the Unsafe-Emergency category

will be submitted also. (RCS-DAEN-CWE-19)

(l) Contracts--(1) Corps of Engineers supervision. Contracts for

performing inventory and inspection activities under supervision of the

Corps of Engineers shall be Fixed-Price Architect Engineer Contracts for

Services. A sample scope of work setting forth requirements is provided

in Appendix H. Experience has shown that costs for individual dam

inspection have been lower when multiple inspections are included in one

contract. Therefore, each A-E contract should include multiple dam

inspections where practicable. Corps participation in A-E inspections

should be held to a minimum. Corps representatives should participate in

only enough A-E inspections to assure the equality of the inspections.

(2) State supervision. Contracts with States for performing

inventory and inspection activities under State supervision may be

either a Cost-Reimbursement type A-E Contract for Services or a Fixed-

Price type contract. The selection of Architect-Engineers by the State

should require approval of the Corps of Engineers Contracting Officer.

The negotiated price for A-E services under cost-reimbursement type

contracts with States will also require approval by the Contracting

Officer. Contracts with States should require timely submission of the

inspection reports to the District Engineer for review and approval. The

contract provisions should also prevent public release of or public

comment on the inspection report until the District Engineer has

reviewed and approved the report. Corps

[[Page 263]]

of Engineers participation in State inspections should be limited to

occasional selected inspections to assure the quality of the State

program.

(m) Training. As indicated in paragraph (f) of this section, one

objective of the inspection program for non-Federal Dams is to prepare

the States to provide effective dam safety programs. In many States this

will require training of personnel of State agencies in the technical

aspects of dam inspections. The Office, Chief of Engineers is studying

the need for and content of a comprehensive Corps-sponsored training

program in dam inspection technology. Pending the possible adoption of

such a comprehensive plan, division and district Engineers are

encouraged to take advantage of suitable opportunities to provide needed

training in dam safety activities to qualified employees of State

agencies and, when appropriate, to employees of architect-engineer firms

engaged in the program. The following general considerations should be

observed in providing such training:

(1) Priority must be placed on inspection of dams and updating the

national dam inventory; hence, diversion of resources to training

activities should not deter or delay these principle program functions.

(2) Salaries, per diem and travel expenses relating to training

activities of State employees will be a State expense. There will be no

tuition charge for State employees.

(3) Architect-Engineer firms will be required to pay expenses and

tuition costs for their employees participating in Corps-sponsored

training activities.

(4) Corps-sponsored training will require that each trainee is a

qualified engineer or geologist and will concentrate on engineering

technology related directly to dam safety. (This may require screening

of proposed candidates for training.)

(5) Under this program, the Corps will not sponsor training that is

intended primarily to satisfy requirements for a degree.

(6) Training by participation in actual dam inspections and/or

management of the inspection program should be encouraged.

Appendix A to Sec. 222.6--Division Assignments

To facilitate better coordination with the States, the Division

Engineers are responsible for the dam inspection program by States as

follows:

New England Division: Maine, Rhode Island, Connecticut, Vermont, New

Hampshire, Massachusetts

North Atlantic Division: New York, New Jersey, Pennsylvania, Delaware,

Maryland, Virginia, District of Columbia

Ohio River Division: West Virginia, Ohio, Kentucky, Tennessee, Indiana

South Atlantic Division: North Carolina, South Carolina, Georgia,

Florida, Alabama, Puerto Rico, Virgin Islands

Lower Mississippi Valley Division: Mississippi, Louisiana, Missouri

North Central Division: Michigan, Wisconsin, Illinois, Minnesota, Iowa

Southwestern Division: Arkansas, Oklahoma, Texas, New Mexico

Missouri River Division: Kansas, Nebraska, South Dakota, North Dakota,

Wyoming, Colorado

North Pacific Division: Oregon, Idaho, Montana, Washington, Alaska

South Pacific Division: Utah, California, Arizona, Nevada

Pacific Ocean Division: Hawaii, Trust Territories, American Samoa

Appendix B to Sec. 222.6--Inventory of Dams

(RCS-DAEN-CWE-17 and OMB No. 49-RO421)

1. The updating of the inventory will include the completion of all

items of data for all dams now included in the inventory, verification

of the data now included in the inventory, and inclusion of complete

data for all appropriate existing dams not previously listed. Data

completion, verification and updating will be scheduled over a three

year period.

2. The inventory data will be recorded on Engineering Form 4474 and

4474A (Exhibit 2). The general instructions for completing the forms are

printed on the back of the forms. Parts I and II of the forms are to be

fully completed. The instruction for completing Item 29, Line 5, Para.

II (Engr Form 4474A) is revised to conform identically with the hazard

potential classification contained in the recommended guidelines for

safety inspection of dams. Additional data has been added to designate

Corps districts in which the dam is located, Federal agency owned dams,

Corps owned dams, Federal agency regulated dams, dams constructed with

technical or financial assistance of the U.S. Soil Conservation Service,

and privately owned dams located on Federal property.

3. All inventory data will be verified utilizing all available

sources of information and will include site visitation if required.

[[Page 264]]

4. The Inventory Data Base is stored on the Boeing Computer Services

(BCS) EKS System in Seattle, Washington. The data is available to all

Corps offices for queries using Data Base Management System 2000 (S2K).

a. To access the National Data Base log on BCS and type the

following:

GET,DAMS/UN=CECELB

CALL,DAMS

b. For current information and changes to the National Inventory

Data Base, type:

OLD,HOTDAM/UN=CEC1AT

LIST

5. The inventory update data will be furnished and the National Data

Base will be updated on a monthly basis. The monthly submission will

cover all dams whose inventory data were completed since the last

report. The update data will be loaded directly onto the Boeing Computer

by the field office.

a. The procedure for loading the data on the Boeing Computer can be

printed by accessing the Boeing Computer and listing the information

file ``HOTDAM.'' (See paragraph 4b. above.)

b. It is the responsibility of the submitting office to edit the

data prior to furnishing it for the update. Editing will be accomplished

by processing the data using the Inventory Edit Computer program

developed by the Kansas City District. This procedure is described in

the ``HOTDAM'' file.

6. Federal agencies will be uniformly designated by major and minor

abbreviations according to the following list whenever applicable to

Items 46 through 53. Abbreviations are to be left justified within the

field with one blank separating major and minor abbreviations.

------------------------------------------------------------------------

Major Minor

------------------------------------------------------------------------

a. International Boundary and Water IBWC

Commission.

b. U.S. Department of Agriculture:

(1) Soil Conservation Service....... USDA SCS

(2) Forest Service.................. USDA FS

c. U.S. Department of Energy Federal DOE FERC

Energy Regulatory Commission.

d. Tennessee Valley Authority......... TVA

e. U.S. Department of Interior:

(1) Bureau of Sport Fisheries and DOI BSFW

Wildlife.

(2) Geological Survey............... DOI GS

(3) Bureau of Land Management....... DOI BLM

(4) Bureau of Reclamation........... DOI USBR

(5) Bureau of Indian Affairs........ DOI BIA

f. U.S. Department of Labor: (1) Mine DOL MSHA

Safety and Health Administration.

g. Corps of Engineers:

(1) Lower Mississippi Valley

Division:

(a) Memphis District.............. DAEN LMM

(b) New Orleans District.......... DAEN LMN

(d) Vicksburg District............ DAEN LMK

(2) Missouri River Division:

(a) Kansas City District.......... DAEN MRK

(b) Omaha District................ DAEN MRO

(3) New England Division............ DAEN NED

(4) North Atlantic Division:........

(a) Baltimore District............ DAEN NAB

(b) New York District............. DAEN NAN

(d) Philadelphia District......... DAEN NAP

(5) North Central Division:

(a) Buffalo District.............. DAEN NCB

(b) Chicago District.............. DAEN NCC

(d) Rock Island District.......... DAEN NCR

(e) St. Paul District............. DAEN NCS

(6) North Pacific Division:

(a) Alaska District............... DAEN NPA

(b) Portland District............. DAEN NPP

(d) Walla Walla District.......... DAEN NPW

(7) Ohio River Division:

(a) Huntington District........... DAEN ORH

(b) Louisville District........... DAEN ORL

(d) Pittsburgh District........... DAEN ORP

(8) Pacific Ocean Division.......... DAEN POD

(9) South Atlantic Division:

(a) Charleston District........... DAEN SAC

(b) Jacksonville District......... DAEN SAJ

(d) Savannah District............. DAEN SAS

(e) Wilmington District........... DAEN SAW

(10) South Pacific Division:

(a) Los Angeles District.......... DAEN SPL

(b) Sacramento District........... DAEN SPK

(11) Southwestern Division:

(a) Albuquerque District.......... DAEN SWA

(b) Fort Worth District........... DAEN SWF

(d) Little Rock District.......... DAEN SWL

(e) Tulsa District................ DAEN SWT

------------------------------------------------------------------------

7. Procedures for Revising and Updating the Inventory of Dams Master

File.

a. To Change Correct or Add an Item. Submit a change card that

contains the identification assigned to the dams (Columns 1 thru 7), the

proper card code (Column 80) and only the item or items changed,

corrected or added. Data on the master file is added or replaced on an

item for item basis.

b. To Delete an Item. Submit a change card that contains the

identification assigned to the dam, (Columns 1 thru 7), the proper card

code (Column 80), and an asterisk (*) in the left most column of the

item or items to be deleted. More than one item can be changed,

corrected, added on or deleted from the same card.

c. To Delete the Entire Data for a Dam from the Master File. Submit

a zero (0) card punched as follows:

Columns 1 thru 7--Item 1 identification assigned to the dam

Columns 8 thru 10--Item 2, Division Code

Columns 11 thru 16--The word DELETE

Columns 17 thru 79--Blank Spaces

Column 80--A zero

8. Keypunch Instructions and Punched Card Formats.

[[Page 265]]

a. Table 1 describes the character set to be used for keypunch cards

of Engr. Forms 4474 and 4474A.

b. Exhibit 1 is the EDPC keypunch instructions and punch card

formats defining the data fields (Items) and card columns to be used in

preparing punched cards in compliance with the requirements of this

regulation.

c. Exhibit 2 are prints of Engr. Forms 4474 and 4474A which are laid

out in punch card format to facilitate punching cards directly from the

completed forms.

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Appendix C to Sec. 222.6--Hydrologic and Hydraulic Assessment of Dams

1. Phase I inspections are not intended to provide detailed

hydrologic and hydraulic analyses of dam and reservoir capabilities.

However, when such analyses are available, they should be evaluated for

reliability and completeness. If a project's ability to pass the

appropriate flood (see Table 3, page D-12 of Recommended Guidelines) can

be determined from available information of a brief study, such an

assessment should be made. It should be noted that hydrologic and

hydraulic analyses connected with the Phase I inspections should be

based on approximate methods or systematized computer programs that take

minimal effort. The Hydrologic Engineering Center (HEC) has developed a

special computer program for hydrologic and hydraulic analyses to be

used with the Phase I inspection program. Other Field Operating Agencies

have developed similar computer programs or generalized procedures which

are acceptable for use. All such efforts should be completed with

minimum resources.

2. A finding that a dam will not safely pass the flood indicated in

the Recommended Guidelines does not necessarily indicate that the dam

should be classified as unsafe. The degree of inadequacy of the spillway

to pass the appropriate flood and the probable adverse impacts of dam

failure because of overtopping must be considered in making such

classification. The following criteria have

[[Page 277]]

been selected which indicate when spillway capacity is so seriously

inadequate that a project must be classified as unsafe. All of the

following conditions must prevail before designating a dam unsafe:

a. There is high hazard to loss of life from large flows downstream

of the dam.

b. Dam failure resulting from overtopping would significantly

increase the hazard to loss of life downstream from the dam from that

which would exist just before overtopping failure.

c. The spillway is not capable of passing one-half of the probable

maximum flood without overtopping the dam and causing failure.

3. The above criteria are generally adequate for evaluating most

non-Federal dams. However, in a few cases the increased hazard potential

from overtopping and failure is so great as to result in catastrophic

consequences. In such cases, the evaluation of condition 2c should

utilize a flood more closely approximating the full probable maximum

flood rather than one-half the flood. An example of such a situation

would be a large dam immediately above a highly populated flood plain,

with little likelihood of time for evacuation in the event of an

emergency.

4. Conditions 2a and 2b require an approximation of housing location

in relation to flooded areas. Resources available in Phase I inspections

do not permit detailed surveys or time-consuming studies to develop such

relationships. Therefore, rough estimates will generally be made from

data obtained during the inspection and from readily available maps and

drawings. Brief computer routings such as the HEC-1 dam break analysis,

using available data, are recommended in marginal cases. The HEC-1, dam

break version, is available on the Boeing Computer Services or may be

obtained from the Hydrologic Engineering Center, Davis, California.

Available resources do not permit detailed studies or investigations to

establish the amount of overtopping that would cause a dam to fail, as

designated in condition 2c. Professional judgment and available

information will have to be used in these determinations. When detailed

investigations and studies are required to make a reasonable judgment of

the conditions which designate an unsafe dam, the inspection report

should recommend that such studies be the responsibility of the dam

owner.

5. During the inspection of a dam, consideration should be given to

impacts on other dams located downstream from the project being

inspected. When failure of a dam would be likely to cause failure of

another dam(s) downstream, its designation as an unsafe dam could result

in multiple impacts. Therefore, the information should be explicitly

described in the inspection report. Such information may be vital to the

priorities established by State Governors for dam improvements.

Similarly, when the failure of an upstream dam (classified as unsafe)

could cause failure of the dam being inspected, this information should

be prominently displayed in the inspection report.

6. The criteria established in paragraph 2 for designating unsafe

dams because of seriously inadequate spillways are considered reasonable

and prudent. They provide a consistent bases for declaring unsafe dams

and also serve as an effective compromise between the Recommended

Guidelines and unduly low standards suggested by special interests and

individuals unfamiliar with flood hazard potential.

7. The Hydrometeorological Branch (HMB) of the National Weather

Service has reviewed some 500 experienced large storms in the United

States. The purpose of the review was to ascertain the relative

magnitude of experienced large storms to probable maximum precipitation

(PMP) and their distribution throughout the country. Their review

reveals that about 25 percent of the major storms have exceeded 50

percent of the probable maximum precipitation for one or more

combinations of area and duration. In fact some storms have very closely

approximated the PMP values. Exhibits C-1 thru C-5 indicate locations

where experienced storms have exceeded 50 percent of the PMP.

8. There are several options to consider when selecting mitigation

measures to avoid severe consequences of a dam failure from overtopping.

The following measures may be required by a Governor when sufficient

legal authority is available under State laws and a dam presents a

serious threat to loss of life.

a. Remove the dam.

b. Increase the height of dam and/or spillway size to pass the

probable maximum flood without overtopping the dam.

c. Purchase downstream land that would be adversely impacted by dam

failure and restrict human occupancy.

d. Enhance the stability of the dam to permit overtopping by the

probable maximum flood without failure.

e. Provide a highly reliable flood warning system (generally does

not prevent damage but avoids loss of life).

[[Page 278]]

Table 1--Storms With Rainfall =150% of PMP, U.S. East of the 105th Meridian (for 10 mi\2\, 6 Hours;

200 mi\2\, 24 Hours and/or 1,000 mi\2\, 48 Hours)

----------------------------------------------------------------------------------------------------------------

Corps assignment Storm center

Storm date Index No. (if ------------------------------------ Latitude Longitude

No. available) Town State

----------------------------------------------------------------------------------------------------------------

July 26, 1819................ 1 ................ Catskill........ NY.............. 42[deg]1 73[deg]53

2[min] [min]

Aug. 5, 1843................. 2 ................ Concordville.... PA.............. 39[deg]5 75[deg]32

3[min] [min]

Sept. 10-13, 1878............ 3 OR 9-19......... Jefferson....... OH.............. 41[deg]4 80[deg]46

5[min] [min]

Sept. 20-24, 1882............ 4 NA 1-3.......... Paterson........ NJ.............. 40[deg]5 74[deg]10

5[min] [min]

June 13-17, 1886............. 5 LMV 4-27........ Alexandria...... LA.............. 31[deg]1 92[deg]33

9[min] [min]

June 27-July 11, 1899........ 6 GM 3-4.......... Turnersville.... TX.............. 30[deg]5 96[deg]32

2[min] [min]

Aug. 24-28, 1903............. 7 MR 1-10......... Woodburn........ IA.............. 40[deg]5 93[deg]35

7[min] [min]

Oct. 7-11, 1903.............. 8 GL 4-9.......... Paterson........ NJ.............. 40[deg]5 74[deg]10

5[min] [min]

July 18-23, 1909............. 9 UMV 1-11B....... Ironwood........ MI.............. 46[deg]2 90[deg]11

7[min] [min]

July 18-23, 1909............. 10 UMV 1-11A....... Beaulieu........ MN.............. 47[deg]2 95[deg]48

1[min] [min]

July 22-23, 1911............. 11 ................ Swede Home...... NB.............. 40[deg]2 96[deg]54

2[min] [min]

July 19-24, 1912............. 12 GL 2-29......... Merrill......... WI.............. 45[deg]1 89[deg]41

1[min] [min]

July 13-17, 1916............. 13 SA 2-9.......... Altapass........ NC.............. 35[deg]3 82[deg]01

3[min] [min]

Sept. 8-10, 1921............. 14 GM 4-12......... Taylor.......... TX.............. 30[deg]3 97[deg]18

5[min] [min]

Oct. 4-11, 1924.............. 15 SA 4-20......... New Smyrna...... FL.............. 29[deg]0 80[deg]55

7[min] [min]

Sept. 17-19, 1926............ 16 MR 4-24......... Boyden.......... IA.............. 43[deg]1 96[deg]00

2[min] [min]

Mar. 11-16, 1929............. 17 UMV 2-20........ Elba............ AL.............. 31[deg]2 86[deg]04

5[min] [min]

June 30-July 2, 1932......... 18 GM 5-1.......... State Fish TX.............. 30[deg]0 99[deg]07

Hatchery. 1[min] [min]

Sept. 16-17, 1932............ 19 ................ Ripogenus Dam... ME.............. 45[deg]5 69[deg]09

3[min] [min]

July 22-27, 193.............. 20 LMV 2-26........ Logansport...... LA.............. 31[deg]5 94[deg]00

8[min] [min]

Apr. 3-4 1934................ 21 SW 2-11......... Cheyenne........ OK.............. 35[deg]3 99[deg]40

7[min] [min]

May 30-31, 1935.............. 22 MR 3-28A........ Cherry Creek.... CO.............. 39[deg]1 104[deg]3

3[min] 2[min]

May 31, 1935................. 23 GM 5-20......... Woodward........ TX.............. 29[deg]2 99[deg]28

0[min] [min]

July 6-10, 1935.............. 24 NA 1-27......... Hector.......... NY.............. 42[deg]3 76[deg]53

0[min] [min]

Sept. 2-6, 1935.............. 25 SA 1-26......... Easton.......... MD.............. 38[deg]4 76[deg]01

6[min] [min]

Sept. 14-18, 1936............ 26 GM 5-7.......... Broome.......... TX.............. 31[deg]4 100[deg]5

7[min] 0[min]

June 19-20, 1939............. 27 ................ Snyder.......... TX.............. 32[deg]4 100[deg]5

4[min] 5[min]

July 4-5, 1939............... 28 ................ Simpson......... KY.............. 38[deg]1 83[deg]22

3[min] [min]

Aug. 19, 1939................ 29 NA 2-3.......... Manahawkin...... NJ.............. 39[deg]4 74[deg]16

2[min] [min]

June 3-4, 1940............... 30 MR 4-5.......... Grant Township.. NB.............. 42[deg]0 96[deg]53

1[min] [min]

Aug. 6-9, 1940............... 31 LMV 4-24........ Miller Isl...... LA.............. 29[deg]4 92[deg]10

5[min] [min]

Aug. 10-17, 1940............. 32 SA 5-19A........ Keysville....... VA.............. 37[deg]0 78[deg]30

3[min] [min]

Sept. 1, 1940................ 33 NA 2-4.......... Ewan............ NJ.............. 39[deg]4 75[deg]12

2[min] [min]

Sept. 2-6, 1940.............. 34 SW 2-18......... Hallet.......... OK.............. 36[deg]1 96[deg]36

5[min] [min]

Aug. 28-31, 1941............. 35 UMV 1-22........ Haywood......... WI.............. 46[deg]0 91[deg]28

0[min] [min]

Oct. 17-22, 1941............. 36 SA 5-6.......... Trenton......... FL.............. 29[deg]4 82[deg]57

8[min] [min]

July 17-18, 1942............. 37 OR 9-23......... Smethport....... PA.............. 41[deg]5 78[deg]25

0[min] [min]

Oct. 11-17, 1942............. 38 SA 1-28A........ Big Meadows..... VA.............. 38[deg]3 78[deg]26

1[min] [min]

May 6-12, 1943............... 39 SW 2-20......... Warner.......... OK.............. 35[deg]2 95[deg]18

9[min] [min]

May 12-20, 1943.............. 40 SW 2-21......... Nr. Mounds...... OK.............. 35[deg]5 96[deg]04

2[min] [min]

July 27-29, 1943............. 41 GM 5-21......... Devers.......... TX.............. 30[deg]0 94[deg]35

2[min] [min]

Aug. 4-5, 1943............... 42 OR 3-30......... Nr. Glenville... WV.............. 38[deg]5 80[deg]50

6[min] [min]

June 10-13, 1944............. 43 MR 6-15......... Nr. Stanton..... NB.............. 41[deg]5 97[deg]03

2[min] [min]

Aug. 12-15, 1946............. 44 MR 7-2A......... Cole Camp....... MO.............. 38[deg]4 93[deg]13

0[min] [min]

Aug. 12-16, 1946............. 45 MR 7-2B......... Nr. Collinsville IL.............. 38[deg]4 89[deg]59

0[min] [min]

Sept. 26-27, 1946............ 46 GM 5-24......... Nr. San Antonio. TX.............. 29[deg]2 98[deg]29

0[min] [min]

June 23-24, 1948............. 47 ................ Nr. Del Rio..... TX.............. 29[deg]2 100[deg]3

2[min] 7[min]

Sept. 3-7, 1950.............. 48 SA 5-8.......... Yankeetown...... FL.............. 29[deg]0 82[deg]42

3[min] [min]

June 23-28, 1954............. 49 SW 3-22......... Vic Pierce...... TX.............. 30[deg]2 101[deg]2

2[min] 3[min]

Aug. 17-20, 1955............. 50 NA 2-22A........ Westfield....... MA.............. 42[deg]0 72[deg]45

7[min] [min]

May 15-16, 1957.............. 51 ................ Hennessey....... OK.............. 36[deg]0 97[deg]56

2[min] [min]

June 14-15, 1957............. 52 ................ Nr. E. St. Louis IL.............. 38[deg]3 90[deg]24

7[min] [min]

June 23-24, 1963............. 53 ................ David City...... NB.............. 41[deg]1 97[deg]05

4[min] [min]

June 13-20, 1965............. 54 ................ Holly........... CO.............. 37[deg]4 102[deg]2

3[min] 3[min]

June 24, 1966................ 55 ................ Glenullin....... ND.............. 47[deg]2 101[deg]1

1[min] 9[min]

Aug. 12-13, 1966............. 56 ................ Nr. Greely...... NB.............. 41[deg]3 98[deg]32

3[min] [min]

Sept. 19-24, 1967............ 57 SW 3-24......... Falfurrias...... TX.............. 27[deg]1 98[deg]12

6[min] [min]

July 16-17, 1968............. 58 ................ Waterloo........ IA.............. 42[deg]3 92[deg]19

0[min] [min]

July 4-5, 1969............... 59 ................ Nr. Wooster..... OH.............. 40[deg]5 82[deg]00

0[min] [min]

Aug. 19-20, 1969............. 60 NA 2-3.......... Nr. Tyro........ VA.............. 37[deg]4 79[deg]00

9[min] [min]

June 9, 1972................. 61 ................ Rapid City...... SD.............. 44[deg]1 103[deg]3

2[min] 1[min]

June 19-23, 1972............. 62 ................ Zerbe........... PA.............. 40[deg]3 76[deg]31

7[min] [min]

July 21-22, 1972............. 63 ................ Nr. Cushing..... MN.............. 46[deg]1 94[deg]30

0[min] [min]

Sept. 10-12, 1972............ 64 ................ Harlan.......... IA.............. 41[deg]4 95[deg]15

3[min] [min]

Oct. 10-11, 1973............. 65 ................ Enid............ OK.............. 36[deg]2 97[deg]52

5[min] [min]

----------------------------------------------------------------------------------------------------------------

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Table 2--Storms With Rainfall =50% of PMP, U.S. West of Continental Divide (for 10 mi \2\ 6 Hours or

1,000 mi\2\ for One Duration Between 6 and 72 Hours)

----------------------------------------------------------------------------------------------------------------

Storm center Duration

Index ----------------------------------------- for

Storm date No. Latitude Longitude 1,000

Town State mi\2\

----------------------------------------------------------------------------------------------------------------

Aug. 11, 1890................... 1 Palmetto........... NV................ 37[deg]2 117[deg]4 ........

7[min] 2[min]

Aug. 12, 1891................... 2 Campo.............. CA................ 32[deg]3 116[deg]2 ........

6[min] 8[min]

Aug. 28, 1898................... 3 Ft. Mohave......... AZ................ 35[deg]0 114[deg]3 ........

3[min] 6[min]

Oct. 4-6, 1911.................. 4 Gladstone.......... CO................ 37[deg]5 107[deg]3 ........

3[min] 9[min]

Dec. 29, 1913-Jan. 3, 1914...... 5 ................... CA................ 39[deg]5 121[deg]2 ........

5[min] 5[min]

Feb. 17-22, 1914................ 6 Colby Ranch........ CA................ 34[deg]1 118[deg]0 ........

8[min] 7[min]

Feb. 20-25, 1917................ 7 ................... CA................ 37[deg]3 119[deg]3 ........

5[min] 6[min]

Sept. 13, 1918.................. 8 Red Bluff.......... CA................ 40[deg]1 122[deg]1 ........

0[min] 4[min]

Feb. 26-Mar 4, 1938............. 9 ................... CA................ 34[deg]1 117[deg]1 ........

4[min] 1[min]

Mar. 30-Apr. 2, 1931............ 10 ................... ID................ 46[deg]3 114[deg]5 24

0[min] 0[min]

Feb. 26, 1932................... 11 Big Four........... WA................ 48[deg]0 121[deg]3 ........

5[min] 0[min]

Nov. 21, 1933................... 12 Tatoosh Is......... WA................ 48[deg]2 124[deg]4 ........

3[min] 4[min]

Jan. 20-25, 1935................ 13 ................... WA................ 47[deg]3 123[deg]3 6

0[min] 0[min]

Jan. 20-25, 1935................ 14 ................... WA................ 47[deg]0 122[deg]0 72

0[min] 0[min]

Feb. 4-8, 1937.................. 15 Cyamaca Dam........ CA................ 33[deg]0 116[deg]3 ........

0[min] 5[min]

Dec. 9-12, 1937................. 16 ................... CA................ 38[deg]5 122[deg]4 ........

1[min] 3[min]

Feb. 27-Mar. 4, 1938............ 17 ................... AZ................ 34[deg]5 111[deg]4 12

7[min] 4[min]

Jan. 19-24, 1943................ 18 ................... CA................ 37[deg]3 119[deg]2 18

5[min] 5[min]

Jan. 19-24, 1943................ 19 Hoegee's Camp...... CA................ 34[deg]1 118[deg]0 ........

3[min] 2[min]

Jan. 30-Feb. 3, 1945............ 20 ................... CA................ 37[deg]3 119[deg]3 ........

5[min] 0[min]

Dec. 27, 1945................... 21 Mt. Tamalpias...... CA................ 37[deg]5 122[deg]3 ........

4[min] 4[min]

Nov. 13-21, 1950................ 22 ................... CA................ 36[deg]3 118[deg]3 24

0[min] 0[min]

Aug. 25-30, 1951................ 23 ................... AZ................ 34[deg]0 112[deg]2 72

7[min] 1[min]

July 19, 1955................... 24 Chiatovich Flat.... CA................ 37[deg]4 118[deg]1 ........

4[min] 5[min]

Aug. 16, 1958................... 25 Morgan............. UT................ 41[deg]0 111[deg]3 ........

3[min] 8[min]

Sept. 18, 1959.................. 26 Newton............. CA................ 40[deg]2 122[deg]1 ........

2[min] 2[min]

June 7-8, 1964.................. 27 Nyack Ck........... MT................ 48[deg]3 113[deg]3 12

0[min] 8[min]

Sept. 3-7, 1970................. 28 ................... UT................ 37[deg]3 109[deg]0 6

8[min] 4[min]

Sept. 3-7, 1970................. 29 ................... AZ................ 33[deg]4 110[deg]5 6

9[min] 6[min]

June 7, 1972.................... 30 Bakersfield........ CA................ 35[deg]2 119[deg]0 ........

5[min] 3[min]

Dec. 9-12, 1937................. 31 ................... CA................ 39[deg]4 121[deg]3 48

5[min] 0[min]

----------------------------------------------------------------------------------------------------------------

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Appendix D to Sec. 222.6--Recommended Guidelines for Safety Inspection

of Dams

Department of the Army--Office of the Chief of Engineers

Preface

The recommended guidelines for the safety inspection of dams were

prepared to outline principal factors to be weighed in the determination

of existing or potential hazards and to define the scope of activities

to be undertaken in the safety inspection of dams. The establishment of

rigid criteria or standards is not intended. Safety must be evaluated in

the light of peculiarities and local conditions at a particular dam and

in recognition of the many factors involved, some of which may not be

precisely known. This can only be done by competent, experienced

engineering judgment, which the guidelines are intended to supplement

and not supplant. The guidelines are intended to be flexible, and the

proper flexibility must be achieved through the employment of

experienced engineering personnel.

Conditions found during the investigation which do not meet

guideline recommendations should be assessed by the investigator as to

their import from the standpoint of the involved degree of risk. Many

deviations will not compromise project safety and the investigator is

expected to identify them in this manner if that is the case. Others

will involve various degrees of risk, the proper evaluation of which

will afford a basis for priority of subsequent attention and possible

remedial action.

The guidelines present procedures for investigating and evaluating

existing conditions for the purpose of identifying deficiencies and

hazardous conditions. The two phases of investigation outlined in the

guidelines are expected to accomplish only this and do not encompass in

scope the engineering which will be required to perform the design

studies for corrective modification work.

It is recognized that some States may have established or will adopt

inspection criteria incongruous in some respects with these guidelines.

In such instances assessments of project safety should recognize the

State's requirements as well as guideline recommendations.

The guidelines were developed with the help of several Federal

agencies and many State agencies, professional engineering

organizations, and private engineers. In reviewing two drafts of the

guidelines they have contributed many helpful suggestions. Their

contributions are deeply appreciated and have made it possible to evolve

a document representing a consensus of the engineering fraternity. As

experience is gained with use of the guidelines, suggestions for future

revisions will be generated. All such suggestions should be directed to

the Chief of Engineers, U.S. Army, DAEN-CWE-D, Washington, D.C. 20314.

Recommended Guidelines for Safety Inspection of Dams

Table of Contents

Preface

Chapter 1--Introduction

Para.

1.1 Purpose.

1.2 Applicability.

1.3 Authority.

Chapter 2--General Requirements

2.1 Classification of dams.

2.1.1 Size.

2.1.2 Hazard potential.

2.2 Selection of dams to be investigated.

2.3 Technical investigations.

2.4 Qualifications of investigators.

2.5 Reports.

Chapter 3--Phase I Investigation

3.1 Purpose.

3.2 Scope.

3.3 Engineering data.

3.4 Field inspections.

3.5 Evaluation of hydraulic and hydrologic features.

3.5.1 Design data.

3.5.2 Experience data.

3.6 Evaluation of structural stability.

3.6.1 Design and construction data.

3.6.2 Operating records.

3.6.3 Post contruction changes.

3.6.4 Seismic stability.

Chapter 4--Phase II Investigation

4.1 Purpose.

4.2 Scope.

4.3 Hydraulic and hydrologic analysis.

4.3.1 Maximum water surface based on SDF peak inflow.

4.3.1.1 Peak for 100-year flood.

4.3.1.2 Peak for PMF or fraction thereof.

4.3.2 Maximum water surface based on SDF hydrograph.

4.3.3 Acceptable procedures.

4.3.4 Freeboard allowances.

4.4 Stability investigations.

4.4.1 Foundation and material investigations.

4.4.2 Stability assessment.

4.4.2.1 Seismic stability.

4.4.2.2 Clay shale foundation.

4.4.3 Embankment dams.

4.4.3.1 Liquefaction.

4.4.3.2 Shear failure.

4.4.3.3 Loading conditions.

4.4.3.4 Safety factors.

4.4.3.5 Seepage failure.

4.4.3.6 Seepage analyses.

[[Page 286]]

4.4.4 Concrete dams and appurtenant structures.

4.4.4.1 Requirements for stability.

4.4.4.2 Loads.

4.4.4.3 Stresses.

4.4.4.4 Overturning.

4.4.4.5 Sliding.

4.4.4.5.1 Sliding resistance.

4.4.4.5.2 Downstream resistance.

4.4.4.5.3 Safety factor.

Chapter 5--Reports

5.1 General.

5.2 Preparation of report.

5.2.1 Phase I reports.

5.2.2 Phase II reports.

Tables

Table

1 Size classification.

2 Hazard potential classification.

3 Hydrologic evaluation guidelines.

4 Factors of safety (embankment dams).

Figures

Fig.

1 Seismic zone map of contiguous States.

2 Seismic zone map of California, Nevada and Arizona.

3 Seismic zone map of Alaska.

4 Seismic zone map of Hawaii.

5 Design envelope for Case I (Table 4).

6 Design envelope for Cases II and III (Table 4).

Appendixes

Appendix I to App. D--Engineering data

Appendix II to App. D--Inspection items

Appendix III to App. D--Pub. L. 92-367

Chapter 1--Introduction

1.1. Purpose. This document provides recommended guidelines for the

inspection and evaluation of dams to determine if they constitute

hazards to human life or property.

1.2. Applicability. The procedures and guidelines outlined in this

document apply to the inspection and evaluation of all dams as defined

in the National Dam Inspection Act, Public Law 92-367. Included in this

program are all artificial barriers together with appurtenant works

which impound or divert water and which (1) are twenty-five feet or more

in height or (2) have an impounding capacity of fifty acre-feet or more.

Not included are barriers which are six feet or less in height,

regardless of storage capacity, or barriers which have a storage

capacity at maximum water storage elevation of fifteen acre-feet or less

regardless of height.

1.3. Authority. The Dam Inspection Act, Public Law 92-367 (Appendix

III), authorized the Secretary of the Army, through the Corps of

Engineers, to initiate a program of safety inspection of dams throughout

the United States. The Chief of Engineers issues these guidelines

pursuant to that authority.

Chapter 2--General Requirements

2.1. Classification of dams. Dams should be classified in accordance

with size and hazard potential in order to formulate a priority basis

for selecting dams to be included in the inspection program and also to

provide compatibility between guideline requirements and involved risks.

When possible the initial classifications should be based upon

information listed in the National Inventory of Dams with respect to

size, impoundment capacity and hazard potential. It may be necessary to

reclassify dams when additional information becomes available.

2.1.1. Size. The classification for size based on the height of the

dam and storage capacity should be in accordance with Table 1. The

height of the dam is established with respect to the maximum storage

potential measured from the natural bed of the stream or watercourse at

the downstream toe of the barrier, or if it is not across a stream or

watercourse, the height from the lowest elevation of the outside limit

of the barrier, to the maximum water storage elevation. For the purpose

of determining project size, the maximum storage elevation may be

considered equal to the top of dam elevation. Size classification may be

determined by either storage or height, whichever gives the larger size

category.

Table 1--Size Classification

------------------------------------------------------------------------

Impoundment

Category ---------------------------------------

Storage (ac-ft) Height (ft)

------------------------------------------------------------------------

Small........................... <1,000 and =50. eq>=25.

Intermediate.................... =1,000 =40 and

and <50,000. <100.

Large........................... =50,000 =100.

------------------------------------------------------------------------

2.1.2. Hazard Potential. The classification for potential hazards

should be in accordance with Table 2. The hazards pertain to potential

loss of human life or property damage in the area downstream of the dam

in event of failure or misoperation of the dam or appurtenant

facilities. Dams conforming to criteria for the low hazard potential

category generally will be located in rural or agricultural areas where

failure may damage farm buildings, limited agricultural land, or

township and country roads. Significant hazard potential category

structures will be those located in predominantly rural or agricultural

areas where failure may damage isolated homes, secondary highways or

minor railroads or cause interruption of use or service of relatively

important public utilities. Dams in the high hazard potential category

will be those located where failure may cause serious damage to homes,

extensive agricultural, industrial and commercial facilities, important

public utilities, main highways, or railroads.

[[Page 287]]

Table 2--Hazard Potential Classification

----------------------------------------------------------------------------------------------------------------

Loss of life (extent of Economic loss (extent of

Category development) development)

----------------------------------------------------------------------------------------------------------------

Low.................................... None expected (No permanent Minimal (Undeveloped to occasional

structures for human habitation). structures or agriculture).

Significant............................ Few (No urban developments and no Appreciable (Notable agriculture,

more than a small number of industry or structures).

inhabitable structures).

High................................... More than few...................... Excessive (Extensive community,

industry or agriculture).

----------------------------------------------------------------------------------------------------------------

2.2. Selection of dams to be investigated. The selection of dams to

be investigated should be based upon an assessment of existing

developments in flood hazard areas. Those dams possessing a hazard

potential classified high or significant as indicated in Table 2 should

be given first and second priorities, respectively, in the inspection

program. Inspection priorities within each category may be developed

from a consideration of factors such as size classification and age of

the dam, the population size in the downstream flood area, and potential

developments anticipated in flood hazard areas.

2.3. Technical Investigations. A detailed, systematic, technical

inspection and evaluation should be made of each dam selected for

investigation in which the hydraulic and hydrologic capabilities,

structural stability and operational adequacy of project features are

analyzed and evaluated to determine if the dam constitutes a danger to

human life or property. The investigation should vary in scope and

completeness depending upon the availability and suitability of

engineering data, the validity of design assumptions and analyses and

the condition of the dam. The minimum investigation will be designated

Phase I, and an in-depth investigation designated Phase II should be

made where deemed necessary. Phase I investigations should consist of a

visual inspection of the dam, abutments and critical appurtenant

structures, and a review of readily available engineering data. It is

not intended to perform costly explorations or analyses during Phase I.

Phase II investigations should consist of all additional engineering

investigations and analyses found necessary by results of the Phase I

investigation.

2.4. Qualifications of investigators. The technical investigations

should be conducted under the direction of licensed professional

engineers experienced in the investigation, design, construction and

operation of dams, applying the disciplines of hydrologic, hydraulic,

soils and structural engineering and engineering geology. All field

inspections should be conducted by qualified engineers, engineering

geologists and other specialists, including experts on mechanical and

electrical operation of gates and controls, knowledgeable in the

investigation, design, construction and operation of dams.

Chapter 3--Phase I Investigation

3.1. Purpose. The primary purpose of the Phase I investigation

program is to identify expeditiously those dams which may pose hazards

to human life or property.

3.2. Scope. The Phase I investigation will develop an assessment of

the general condition with respect to safety of the project based upon

available data and a visual inspection, determine any need for emergency

measures and conclude if additional studies, investigation and analyses

are necessary and warranted. A review will be made of pertinent existing

and available engineering data relative to the design, construction and

operation of the dam and appurtenant structures, including electrical

and mechanical operating equipment and measurements from inspection and

performance instruments and devices; and a detailed systematic visual

inspection will be performed of those features relating to the stability

and operational adequacy of the project. Based upon findings of the

review of engineering data and the visual inspection, an evaluation will

be made of the general condition of the dam, including where possible

the assessment of the hydraulic and hydrologic capabilities and the

structural stability.

3.3. Engineering data. To the extent feasible the engineering data

listed in Appendix I relating to the design, construction and operation

of the dam and appurtenant structures, should be collected from existing

records and reviewed to aid in evaluating the adequacy of hydraulic and

hydrologic capabilities and stability of the dam. Where the necessary

engineering data are unavailable, inadequate or invalid, a listing

should be made of those specific additional data deemed necessary by the

engineer in charge of the investigation and included in the Phase I

report.

3.4. Field inspections. The field inspection of the dam, appurtenant

stuctures, reservoir area, and downstream channel in the vicinity of the

dam should be conducted in a systematic manner to minimize the

possibility of any significant feature being overlooked. A detailed

checklist should be developed and followed for each dam inspected to

document

[[Page 288]]

the examination of each significant structural and hydraulic feature

including electrical and mechanical equipment for operation of the

control facilities that affect the safety of the dam.

3.4.1. Particular attention should be given to detecting evidence of

leakage, erosion, seepage, slope instability, undue settlement,

displacement, tilting, cracking, deterioration, and improper functioning

of drains and relief wells. The adequacy and quality of maintenance and

operating procedures as they pertain to the safety of the dam and

operation of the control facilities should also be assessed.

3.4.2. Photographs and drawings should be used freely to record

conditions in order to minimize descriptions.

3.4.3. The field inspection should include appropriate features and

items, including but not limited to those listed in Appendix II, which

may influence the safety of the dam or indicate potential hazards to

human life or property.

3.5. Evaluation of hydraulic and hydrologic Features.

3.5.1. Design data. Original hydraulic and hydrologic design

assumptions obtained from the project records should be assessed to

determine their acceptability in evaluating the safety of the dam. All

constraints on water control such as blocked entrances, restrictions on

operation of spillway and outlet gates, inadequate energy dissipators or

restrictive channel conditions, significant reduction in reservoir

capacity by sediment deposits and other factors should be considered in

evaluating the validity of discharge ratings, storage capacity,

hydrographs, routings and regulation plans. The discharge capacity and/

or storage capacity should be capable of safely handling the recommended

spillway design flood for the size and hazard potential classification

of the dam as indicated in Table 3. The hydraulic and hydrologic

determinations for design as obtained from project records will be

acceptable if conventional techniques similar to the procedures outlined

in paragraph 4.3. were used in obtaining the data. When the project

design flood actually used exceeds the recommended spillway design

flood, from Table 3, the project design flood will be acceptable in

evaluating the safety of the dam.

Table 3--Hydrologic Evaluation Guidelines

[Recommended spillway design floods]

------------------------------------------------------------------------

Spillway design

Hazard Size flood (SDF) \1\

------------------------------------------------------------------------

Low............................. Small............. 50 to 100-yr

frequency.

Intermediate...... 100-yr to \1/2\

PMF.

Large............. \1/2\ PMF to PMF.

Significant..................... Small............. 100-yr to \1/2\

PMF.

Intermediate...... \1/2\ PMF to PMF.

Large............. PMF.

High............................ Small............. \1/2\ PMF to PMF.

Intermediate...... PMF.

Large............. PMF.

------------------------------------------------------------------------

\1\ The recommended design floods in this column represent the magnitude

of the spillway design flood (SDF), which is intended to represent the

largest flood that need be considered in the evaluation of a given

project, regardless of whether a spillway is provided; i.e., a given

project should be capable of safely passing the appropriate SDF. Where

a range of SDF is indicated, the magnitude that most closely relates

to the involved risk should be selected.

1000-yr=100-Year Exceedence Interval. The flood magnitude expected to be

exceeded, on the average, of once in 100 years. It may also be expressed

as an exceedence frequency with a one-percent chance of being exceeded

in any given year.

PMF=Probable Maximum Flood. The flood that may be expected from the most

severe combination of critical meteorologic and hydrologic conditions

that are reasonably possible in the region. The PMF is derived from

probable maximum precipitation (PMP), which information is generally

available from the National Weather Service, NOAA. Most Federal agencies

apply reduction factors to the PMP when appropriate. Reductions may be

applied because rainfall isohyetals are unlikely to conform to the exact

shape of the drainage basin and/or the storm is not likely to center

exactly over the drainage basin. In some cases local topography will

cause changes from the generalized PMP values, therefore it may be

advisable to contact Federal construction agencies to obtain the

prevailing practice in specific areas.

3.5.2. Experience data. In some cases where design data are lacking,

an evaluation of overtopping potential may be based on watershed

characteristics and rainfall and reservoir records. An estimate of the

probable maximum flood may also be developed from a conservative,

generalized comparison of the drainage area size and the magnitude of

recently adopted probable maximum floods for damsites in comparable

hydrologic regions. Where the review of such experience data indicates

that the recommended spillway design flood would not cause overtopping

additional hydraulic and hydrologic determinations will be unnecessary.

3.6. Evaluation of structural stability. The Phase I evaluations of

structural adequacy of project features are expected to be based

principally on existing conditions as revealed by the visual inspection,

together with available design and construction information and records

of performance. The objectives are to determine the existence of

conditions which are hazardous, or which with time might develop into

safety hazards,

[[Page 289]]

and to formulate recommendations pertaining to the need for any

additional studies, investigations, or analyses. The results of this

phase of the inspection must rely very substantially upon the experience

and judgment of the inspecting engineer.

3.6.1. Design and construction data. The principal design

assumptions and analyses obtained from the project records should be

assessed. Original design and construction records should be used

judiciously, recognizing the restricted applicability of such data as

material strengths and permeabilities, geological factors and

construction descriptions. Original stability studies and analyses

should be acceptable if conventional techniques and procedures similar

to those outlined in paragraph 4.4 were employed, provided that review

of operational and performance data confirm that the original design

assumptions were adequately conservative. The need for such analyses

where either none exist or the originals are incomplete or

unsatisfactory will be determined by the inspecting engineer based upon

other factors such as condition of structures, prior maximum loadings

and the hazard degree of the project. Design assumptions and analyses

should include all applicable loads including earthquake and indicate

the structure's capability to resist overturning, sliding and

overstressing with adequate factors of safety. In general seepage and

stability analyses comparable to the requirements of paragraph 4.4

should be on record for all dams in the high hazard category and large

dams in the significant hazard category. This requirement for other dams

will be subject to the opinion of the inspecting engineer.

3.6.2. Operating records. The performance of structures under prior

maximum loading conditions should in some instances provide partial

basis for stability evaluation. Satisfactory experience under loading

conditions not expected to be exceeded in the future should generally be

indicative of satisfactory stability, provided adverse changes in

physical conditions have not occurred. Instrumentation observations of

forces, pressures, loads, stresses, strains, displacements, deflections

or other related conditions should also be utilized in the safety

evaluation. Where such data indicate abnormal behavior, unsafe movement

or deflections, or loadings which adversely affect the stability or

functioning of the structure, prompt reporting of such circumstances is

required without the delay for preparation of the official inspection

report.

3.6.3. Post construction changes. Data should be collected on

changes which have occurred since project construction that might

influence the safety of the dam such as road cuts, quarries, mining and

groundwater changes.

3.6.4. Seismic stability. An assessment should be made of the

potential vulnerability of the dam to seismic events and a

recommendation developed with regard to the need for additional seismic

investigation. In general, projects located in Seismic Zones 0, 1 and 2

may be assumed to present no hazard from earthquake provided static

stability conditions are satisfactory and conventional safety margins

exist. Dams in Zones 3 and 4 should, as a minimum, have on record

suitable analyses made by conventional equivalent static load methods.

The seismic zones together with appropriate coefficients for use in such

analyses are shown in Figures 1 through 4. Boundary lines are

approximate and in the event of doubt about the proper zone, the higher

zone should be used. All high hazard category dams in Zone 4 and high

hazard dams of the hydraulic fill type in Zone 3 should have a stability

assessment based upon knowledge of regional and local geology,

engineering seismology, in situ properties of materials and appropriate

dynamic analytical and testing procedures. The assessment should include

the possibility of physical displacement of the structures due to

movements along active faults. Departure from this general guidance

should be made whenever in the judgment of the investigating engineer

different seismic stability requirements are warranted because of local

geological conditions or other reasons.

Chapter 4--Phase II Investigation

4.1. Purpose. The Phase II investigation will be supplementary to

Phase I and should be conducted when the results of the Phase I

investigation indicate the need for additional in-depth studies,

investigations or analyses.

4.2. Scope. The Phase II investigation should include all additional

studies, investigations and analyses necessary to evaluate the safety of

the dam. Included, as required, will be additional visual inspections,

measurements, foundation exploration and testing, materials testing,

hydraulic and hydrologic analysis and structural stability analyses.

4.3. Hydraulic and hydrologic analysis. Hydraulic and hydrologic

capabilities should be determined using the following criteria and

procedures. Depending on the project characteristics, either the

spillway design flood peak inflow or the spillway design flood

hydrograph should be the basis for determining the maximum water surface

elevation and maximum outflow. If the operation or failure of upstream

water control projects would have significant impact on peak flow or

hydrograph analyses, the impact should be assessed.

4.3.1. Maximum water surface based on SDF peak inflow. When the

total project discharge capability at maximum pool exceeds the peak

inflow of the recommended SDF, and

[[Page 290]]

operational constraints would not prevent such a release at controlled

projects, a reservoir routing is not required. The maximum discharge

should be assumed equal to the peak inflow of the spillway design flood.

Flood volume is not controlling in this situation and surcharge storage

is either absent or is significant only to the extent that it provides

the head necessary to develop the release capability required.

4.3.1.1. Peak for 100-year flood. When the 100-year flood is

applicable under the provisions of Table 3 and data are available, the

spillway design flood peak inflow may be determined by use of ``A

Uniform Technique for Determining Flood Frequencies,'' Water Resources

Council (WRC), Hydrology Committee, Bulletin 15, December 1967. Flow

frequency information from regional analysis is generally preferred over

single station results when available and appropriate. Rainfall-runoff

techniques may be necessary when there are inadequate runoff data

available to make a reasonable estimate of flow frequency.

4.3.1.2. Peak for PMF or fraction thereof. When either the Probable

Maximum Flood peak or a fraction thereof is applicable under the

provisions of Table 3, the unit hydrograph--infiltration loss technique

is generally the most expeditious method of computing the spillway

design flood peak for most projects. This technique is discussed in the

following paragraph.

4.3.2. Maximum water surface based on SDF hydrograph. Both peak and

volume are required in this analysis. Where surcharge storage is

significant, or where there is insufficient discharge capability at

maximum pool to pass the peak inflow of the SDF, considering all

possible operational constraints, a flood hydrograph is required. When

there are upstream hazard areas that would be imperiled by fast rising

reservoirs levels, SDF hydrographs should be routed to ascertain

available time for warning and escape. Determination of probable maximum

precipitation or 100-year precipitation, which ever is applicable, and

unit hydrographs or runoff models will be required, followed by the

determination of the PMF or 100-year flood. Conservative loss rates

(significantly reduced by antecedent rainfall conditions where

appropriate) should be estimated for computing the rainfall excess to be

utilized with unit hydrographs. Rainfall values are usually arranged

with gradually ascending and descending rates with the maximum rate late

in the storm. When applicable, conservatively high snowmelt runoff rates

and appropriate releases from upstream projects should be assumed. The

PMP may be obtained from National Weather Service (NWS) publications

such as Hydrometeorological Report (HMR) 33. Special NWS publications

for particular areas should be used when available. Rainfall for the

100-year frequency flood can be obtained from the NWS publication

``Rainfall Frequency Atlas of the United States,'' Technical Paper No.

40; Atlas 2, ``Precipitation Frequency Atlas of Western United States;''

or other NWS publications. The maximum water surface elevation and

spillway design flood outflow are then determined by routing the inflow

hydrograph through the reservoir surcharge storage, assuming a starting

water surface at the bottom of surcharge storage, or lower when

appropriate. For projects where the bottom of surcharge space is not

distinct, or the flood control storage space (exclusive of surcharge) is

appreciable, it may be appropriate to select starting water surface

elevations below the top of the flood control storage for routings.

Conservatively high starting levels should be estimated on the basis of

hydrometeorological conditions reasonably characteristic for the region

and flood release capability of the project. Necessary adjustment of

reservoir storage capacity due to existing or future sediment or other

encroachment may be approximated when accurate determination of

deposition is not practicable.

4.3.3. Acceptable procedures. Techniques for performing hydraulic

and hydrologic analyses are generally available from publications

prepared by Federal agencies involved in water resources development or

textbooks written by the academic community. Some of these procedures

are rather sophisticated and require expensive computational equipment

and large data banks. While results of such procedures are generally

more reliable than simplified methods, their use is generally not

warranted in studies connected with this program unless they can be

performed quickly and inexpensively. There may be situations where the

more complex techniques have to be employed to obtain reliable results;

however, these cases will be exceptions rather than the rule. Whenever

the acceptability of procedures is in question, the advice of competent

experts should be sought. Such expertise is generally available in the

Corps of Engineers, Bureau of Reclamation and Soil Conservation Service.

Many other agencies, educational facilities and private consultants can

also provide expert advice. Regardless of where such expertise is based,

the qualification of those individuals offering to provide it should be

carefully examined and evaluated.

4.3.4. Freeboard allowances. Guidelines on specific minimum

freeboard allowances are not considered appropriate because of the many

factors involved in such determinations. The investigator will have to

assess the critical parameters for each project and develop its minimum

requirement. Many projects are reasonably safe without freeboard

allowance because they are designed for overtopping, or other factors

minimize possible overtopping. Conversely,

[[Page 291]]

freeboard allowances of several feet may be necessary to provide a safe

condition. Parameters that should be considered include the duration of

high water levels in the reservoir during the design flood; the

effective wind fetch and reservoir depth available to support wave

generation; the probability of high wind speed occurring from a critical

direction; the potential wave runup on the dam based on roughness and

slope; and the ability of the dam to resist erosion from overtopping

waves.

4.4 Stability investigations. The Phase II stability investigations

should be compatible with the guidelines of this paragraph.

4.4.1 Foundation and material investigations. The scope of the

foundation and materials investigation should be limited to obtaining

the information required to analyze the structural stability and to

investigate any suspected condition which would adversely affect the

safety of the dam. Such investigations may include borings to obtain

concrete, embankment, soil foundation, and bedrock samples; testing

specimens from these samples to determine the strength and elastic

parameters of the materials, including the soft seams, joints, fault

gouge and expansive clays or other critical materials in the foundation;

determining the character of the bedrock including joints, bedding

planes, fractures, faults, voids and caverns, and other geological

irregularities; and installing instruments for determining movements,

strains, suspected excessive internal seepage pressures, seepage

gradients and uplift forces. Special investigations may be necessary

where suspect rock types such as limestone, gypsum, salt, basalt,

claystone, shales or others are involved in foundations or abutments in

order to determine the extent of cavities, piping or other deficiencies

in the rock foundation. A concrete core drilling program should be

undertaken only when the existence of significant structural cracks is

suspected or the general qualitative condition of the concrete is in

doubt. The tests of materials will be necessary only where such data are

lacking or are outdated.

4.4.2. Stability assessment. Stability assessments should utilize in

situ properties of the structure and its foundation and pertinent

geologic information. Geologic information that should be considered

includes groundwater and seepage conditions; lithology, stratigraphy,

and geologic details disclosed by borings, ``as-built'' records, and

geologic interpretation; maximum past overburden at site as deduced from

geologic evidence; bedding, folding and faulting; joints and joint

systems; weathering; slickensides, and field evidence relating to

slides, faults, movements and earthquake activity. Foundations may

present problems where they contain adversely oriented joints,

slickensides or fissured material, faults, seams of soft materials, or

weak layers. Such defects and excess pore water pressures may contribute

to instability. Special tests may be necessary to determine physical

properties of particular materials. The results of stability analyses

afford a means of evaluating the structure's existing resistance to

failure and also the effects of any proposed modifications. Results of

stability analyses should be reviewed for compatibility with performance

experience when possible.

4.4.2.1. Seismic stability. The inertial forces for use in the

conventional equivalent static force method of analysis should be

obtained by multiplying the weight by the seismic coefficient and should

be applied as a horizontal force at the center of gravity of the section

or element. The seismic coefficients suggested for use with such

analyses are listed in Figures 1 through 4. Seismic stability

investigations for all high hazard category dams located in Seismic Zone

4 and high hazard dams of the hydraulic fill type in Zone 3 should

include suitable dynamic procedures and analyses. Dynamic analyses for

other dams and higher seismic coefficients are appropriate if in the

judgment of the investigating engineer they are warranted because of

proximity to active faults or other reasons. Seismic stability

investigations should utilize ``state-of-the-art'' procedures involving

seismological and geological studies to establish earthquake parameters

for use in dynamic stability analyses and, where appropriate, the

dynamic testing of materials. Stability analyses may be based upon

either time-history or response spectra techniques. The results of

dynamic analyses should be assessed on the basis of whether or not the

dam would have sufficient residual integrity to retain the reservoir

during and after the greatest or most adverse earthquake which might

occur near the project location.

4.4.2.2. Clay shale foundation. Clay shale is a highly

overconsolidated sedimentary rock comprised predominantly of clay

minerals, with little or no cementation. Foundations of clay shales

require special measures in stability investigations. Clay shales,

particularly those containing montmorillonite, may be highly susceptible

to expansion and consequent loss of strength upon unloading. The shear

strength and the resistance to deformation of clay shales may be quite

low and high pore water pressures may develop under increase in load.

The presence of slickensides in clay shales is usually an indication of

low shear strength. Prediction of field behavior of clay shales should

not be based solely on results of conventional laboratory tests since

they may be misleading. The use of peak shear strengths for clay shales

in stability analyses may be unconservative because of nonuniform stress

distribution and possible progressive failures. Thus the available shear

resistance may be less than if the peak shear strength

[[Page 292]]

were mobilized simultaneously along the entire failure surface. In such

cases, either greater safety factors or residual shear strength should

be used.

4.4.3. Embankment dams.

4.4.3.1. Liquefaction. The phenomenon of liquefaction of loose,

saturated sands and silts may occur when such materials are subjected to

shear deformation or earthquake shocks. The possibility of liquefaction

must presently be evaluated on the basis of empirical knowledge

supplemented by special laboratory tests and engineering judgment. The

possiblitity of liquefaction in sands diminishes as the relative density

increases above approximately 70 percent. Hydraulic fill dams in Seismic

Zones 3 and 4 should receive particular attention since such dams are

susceptible to liquefaction under earthquake shocks.

4.4.3.2. Shear failure. Shear failure is one in which a portion of

an embankment or of an embankment and foundation moves by sliding or

rotating relative to the remainder of the mass. It is conventionally

represented as occurring along a surface and is so assumed in stability

analyses, although shearing may occur in a zone of substantial

thickness. The circular arc or the sliding wedge method of analyzing

stability, as pertinent, should be used. The circular arc method is

generally applicable to essentially homogeneous embankments and to soil

foundations consisting of thick deposits of fine-grained soil containing

no layers significantly weaker than other strata in the foundation. The

wedge method is generally applicable to rockfill dams and to earth dams

on foundations containing weak layers. Other methods of analysis such as

those employing complex shear surfaces may be appropriate depending on

the soil and rock in the dam and foundation. Such methods should be in

reputable usage in the engineering profession.

4.4.3.3. Loading conditions. The loading conditions for which the

embankment structures should be investigated are (I) Sudden drawdown

from spillway crest elevation or top of gates, (II) Partial pool, (III)

Steady state seepage from spillway crest elevation or top of gate

elevation, and (IV) Earthquake. Cases I and II apply to upstream slopes

only; slopes; and Case IV applies to both upstream and downstream Case

III applies to downstream slopes. A summary of suggested strengths and

safety factors are shown in Table 4.

Table 4--Factors of Safety\1\

----------------------------------------------------------------------------------------------------------------

Factor

Case and loading condition of Shear \2\ strength Remarks

safety

----------------------------------------------------------------------------------------------------------------

I Sudden drawdown from spillway crest or \3\ 1.2 Minimum composite of R and Within the drawdown zone

top of gates to minimum drawdown S shear strengths. See submerged unit weights of

elevation. Figure 5. materials are used for

computing forces resisting

sliding and saturated unit

weights are used for computing

forces contributing to sliding.

II Partial pool with assumed horizontal 1.5 R+S/2 for RS........ of R and

S shear strengths. See Figure

III Steady seepage from spillway crest 1.5 Same as Case II............

or top of gates with Kh/Kv=9 assumed\4\.

IV Earthquake (Cases II and III with 1.0 (\5\ )..................... See Figures 1 through 4 for

seismic loading). Seismic Coefficients.

----------------------------------------------------------------------------------------------------------------

\1\ Not applicable to embankments on clay shale foundation. Experience has indicated special problems in

determination of design shear strengths for clay shale foundations and acceptable safety factors should be

compatible with the confidence level in shear strength assumptions.

\2\ Other strength assumptions may be used if in common usage in the engineering profession.

\3\ The safety factor should not be less than 1.5 when drawdown rate and pore water pressure developed from flow

nets are used in stability analyses.

\4\ Kh/Kv is the ratio of horizontal to vertical permeability. A minimum of 9 is suggested for use in compacted

embankments and alluvial sediments.

\5\ Use shear strength for case analyzed without earthquake. It is not necessary to analyze sudden drawdown for

earthquake loading. Shear strength tests are classified according to the controlled drainage conditions

maintained during the test. R tests are those in which specimen drainage is allowed during consolidation (or

swelling) under initial stress conditions, but specimen drainage is not allowed during application of shearing

stresses. S tests allow full drainage during initial stress application and shearing is at a slow rate so that

complete specimen drainage is permitted during the complete test.

4.4.3.4. Safety factors. Safety factors for embankment dam stability

studies should be based on the ratio of available shear strength to

developed shear strength, SD :

[GRAPHIC] [TIFF OMITTED] TC15NO91.000

Where:

C=Cohesion

[phis]=Angle of internal friction

[sigma]=Normal stress

The factors of safety listed in Table 4 are recommended as minimum

acceptable. Final accepted factors of safety should depend upon the

degree of confidence the investigating engineer has in the engineering

data

[[Page 293]]

available to him. The consequences of a failure with respect to human

life and property damage are important considerations in establishing

factors of safety for specific investigations.

4.4.3.5. Seepage failure. A critical uncontrolled underseepage or

through seepage condition that develops during a rising pool can quickly

reduce a structure which was stable under previous conditions, to a

total structural failure. The visually confirmed seepage conditions to

be avoided are (1) the exit of the phreatic surface on the downstream

slope of the dam and (2) development of hydrostatic heads sufficient to

create in the area downstream of the dam sand boils that erode materials

by the phenomenon known as ``piping'' and (3) localized concentrations

of seepage along conduits or through pervious zones. The dams most

susceptible to seepage problems are those built of or on pervious

materials of uniform fine particle size, with no provisions for an

internal drainage zone and/or no underseepage controls.

4.4.3.6. Seepage analyses. Review and modifications to original

seepage design analyses should consider conditions observed in the field

inspection and piezometer instrumentation. A seepage analysis should

consider the permeability ratios resulting from natural deposition and

from compaction placement of materials with appropriate variation

between horizontal and vertical permeability. An underseepage analysis

of the embankment should provide a critical gradient factor of safety

for the maximum head condition of not less than 1.5 in the area

downstream of the embankment.

[GRAPHIC] [TIFF OMITTED] TC15NO91.001

Where:

ic=Critical gradient

i=Design gradient

H=Uplift head at downstream toe of dam measured above tailwater

Hc=The critical uplift

Db=The thickness of the top impervious blanket at the

downstream toe of the dam

[gamma]m=The estimated saturated unit weight of the material

in the top impervious blanket

[gamma]w=The unit weight of water

Where a factor of safety less than 1.5 is obtained the provision of

an underseepage control system is indicated. The factor of safety of 1.5

is a recommended minimum and may be adjusted by the responsible engineer

based on the competence of the engineering data.

4.4.4. Concrete dams and appurtenant structures.

4.4.4.1. Requirements for stability. Concrete dams and structures

appurtenant to embankment dams should be capable of resisting

overturning, sliding and overstressing with adequate factors of safety

for normal and maximum loading conditions.

4.4.4.2. Loads. Loadings to be considered in stability analyses

include the water load on the upstream face of the dam; the weight of

the structure; internal hydrostatic pressures (uplift) within the body

of the dam, at the base of the dam and within the foundation; earth and

silt loads; ice pressure, seismic and thermal loads, and other loads as

applicable. Where tailwater or backwater exists on the downstream side

of the structure it should be considered, and assumed uplift pressures

should be compatible with drainage provisions and uplift measurements if

available. Where applicable, ice pressure should be applied to the

contact surface of the structure of normal pool elevation. A unit

pressure of not more than 5,000 pounds per square foot should be used.

Normally, ice thickness should not be assumed greater than two feet.

Earthquake forces should consist of the inertial forces due to the

horizontal acceleration of the dam itself and hydrodynamic forces

resulting from the reaction of the reservoir water against the

structure. Dynamic water pressures for use in a conventional methods of

analysis may be computed by means of the ``Westergaard Formula'' using

the parabolic approximation (H.M. Westergaard, ``Water Pressures on Dams

During Earthquakes,'' Trans., ASCE, Vol 98, 1933, pages 418-433), or

similar method.

4.4.4.3. Stresses. The analysis of concrete stresses should be based

on in situ properties of the concrete and foundation. Computed maximum

compressive stresses for normal operating conditions in the order of \1/

3\ or less of in situ strengths should be satisfactory. Tensile stresses

in unreinforced concrete should be acceptable only in locations where

cracks will not adversely affect the overall performance and stability

of the structure. Foundation stresses should be such as to provide

adequate safety against failure of the foundation material under all

loading conditions.

4.4.4.4. Overturning. A gravity structure should be capable of

resisting all overturning forces. It can be considered safe against

overturning if the resultant of all combinations of horizontal and

vertical forces, excluding earthquake forces, acting above any

horizontal plane through the structure or at its base is located within

the middle third of the section. When earthquake is included the

resultant should fall within the limits of the plane or base, and

foundation pressures must be acceptable. When these requirements for

location of the resultant are not satisfied the investigating engineer

should assess the importance to stability of the deviations.

4.4.4.5. Sliding. Sliding of concrete gravity structures and of

abutment and foundation rock masses for all types of concrete dams

[[Page 294]]

should be evaluated by the shear-friction resistance concept. The

available sliding resistance is compared with the driving force which

tends to induce sliding to arrive at a sliding stability safety factor.

The investigation should be made along all potential sliding paths. The

critical path is that plane or combination of planes which offers the

least resistance.

4.4.4.5.1. Sliding resistance. Sliding resistance is a function of

the unit shearing strength at no normal load (cohesion) and the angle of

friction on a potential failure surface. It is determined by computing

the maximum horizontal driving force which could be resisted along the

sliding path under investigation. The following general formula is

obtained from the principles of statics and may be derived by resolving

forces parallel and perpendicular to the sliding plane:

[GRAPHIC] [TIFF OMITTED] TC15NO91.002

Where:

RR=Sliding Resistance (maximum horizontal driving force which

can be resisted by the critical path)

[phis]=Angle of internal friction of foundation material or, where

applicable, angle of sliding friction

V=Summation of vertical forces (including uplift)

c=Unit shearing strength at zero normal loading along potential failure

plane

A=Area of potential failure plane developing unit shear strength ``c''

[alpha]=Angle between inclined plane and horizontal (positive for uphill

sliding)

For sliding downhill the angle [alpha] is negative and Equation (1)

becomes:

[GRAPHIC] [TIFF OMITTED] TC15NO91.003

When the plane of investigation is horizontal, and the angle [alpha]

is zero and Equation (1) reduced to the following:

[GRAPHIC] [TIFF OMITTED] TC15NO91.004

4.4.4.5.2. Downstream esistance. When the base of a concrete

structure is embedded in rock or the potential failure plane lies below

the base, the passive resistance of the downstream layer of rock may

sometimes be utilized for sliding resistance. Rock that may be subjected

to high velocity water scouring should not be used. The magnitude of the

downstream resistance is the lesser of (a) the shearing resistance along

the continuation of the potential sliding plane until it daylights or

(b) the resistance available from the downstream rock wedge along an

inclined plane. The theoretical resistance offered by the passive wedge

can be computed by a formula equivalent to formula (3):

[GRAPHIC] [TIFF OMITTED] TC15NO91.005

Where:

Pp=Passive resistance of rock wedge

W=Weight (buoyant weight if applicable) of downstream rock wedge above

inclined plane of resistance, plus any superimposed loads

[phis]=Angle of internal friction or, if applicable, angle of sliding

friction

[alpha]=Angle between inclined failure plane and horizontal

c=Unit shearing strength at zero normal load along failure plane

A=Area of inclined plane of resistance

When considering cross-bed shear through a relatively shallow,

competent rock strut, without adverse jointing or faulting, W and

[alpha] may be taken at zero and 45[deg], respectively, and an estimate

of passive wedge resistance

[[Page 295]]

per unit width obtained by the following equation:

[GRAPHIC] [TIFF OMITTED] TC15NO91.006

Where:

D=Thickness of the rock strut

4.4.4.5.3. Safety factor. The shear-friction safety factor is

obtained by dividing the resistance RR by H, the summation of

horizontal service loads to be applied to the structure:

[GRAPHIC] [TIFF OMITTED] TC15NO91.007

When the downstream passive wedge contributes to the sliding

resistance, the shear friction safety factor formula becomes:

[GRAPHIC] [TIFF OMITTED] TC15NO91.008

The above direct superimposition of passive wedge resistance is

valid only if shearing rigidities of the foundation components are

similar. Also, the compressive strength and buckling resistance of the

downstream rock layer must be sufficient to develop the wedge

resistance. For example, a foundation with closely spaced, near

horizontal, relatively weak seams might not contain sufficient buckling

strength to develop the magnitude of wedge resistance computed from the

cross-bed shear strength. In this case wedge resistance should not be

assumed without resorting to special treatment (such as installing

foundation anchors). Computed sliding safety factors approximating 3 or

more for all loading conditions without earthquake, and 1.5 including

earthquake, should indicate satisfactory stability, depending upon the

reliability of the strength parameters used in the analyses. In some

cases when the results of comprehensive foundation studies are

available, smaller safety factors may be acceptable. The selection of

shear strength parameters should be fully substantiated. The bases for

any assumptions; the results of applicable testing, studies and

investigations; and all pre-existing, pertinent data should be reported

and evaluated.

Chapter 5--Reports

5.1. General. This chapter outlines the procedures for reporting the

results of the technical investigations. Hazardous conditions should be

reported immediately upon detection to the owner of the dam, the

Governor of the State in which the dam is located and the appropriate

regulatory agency without delay for preparation of the formal report.

5.2. Preparation of report. A formal report should be prepared for

each dam investigated for submission to the regulatory agency and the

owner of the dam. Each report should contain the information indicated

in the following paragraphs. The signature and registration

identification of the professional engineer who directed the

investigation and who was responsible for evaluation of the dam should

be included in the report.

5.2.1. Phase I reports. Phase I reports should contain the following

information:

5.2.1.1. Description of dam including regional vicinity map showing

location and plans, elevations and sections showing the essential

project features and the size and hazard potential classifications.

5.2.1.2. Summary of existing engineering data, including geologic

maps and information.

5.2.1.3. Results of the visual inspection of each project feature

including photographs and drawings to minimize descriptions.

5.2.1.4. Evaluation of operational adequacy of the reservoir

regulation plan and maintenance of the dam and operating facilities and

features that pertain to the safety of the dam.

5.2.1.5. Description of any warning system in effect.

5.2.1.6. Evaluation of the hydraulic and hydrologic assumptions and

structural stability.

5.2.1.7. An assessment of the general condition of the dam with

respect to safety based upon the findings of the visual inspection and

review of engineering data. Where data on the original design indicate

significant departure from or non-conformance with guidelines contained

herein, the engineer-in-charge of the investigation will give his

opinion of the significance, with regard to safety, of such factors. Any

additional studies, investigations and analyses considered essential to

assessment of the safety of the dam should be listed, together with an

opinion about the urgency of such additional work.

5.2.1.8. Indicate alternative possible remedial measures or

revisions in operating and maintenance procedures which may (subject to

further evaluation) correct deficiencies and hazardous conditions found

during the investigation.

5.2.2. Phase II reports. Phase II reports should describe the

detailed investigations and should supplement Phase I reports. They

should contain the following information:

5.2.2.1. Summary of additional engineering data obtained to

determine the hydraulic and hydrologic capabilities and/or structural

stability.

5.2.2.2. Results of all additional studies, investigations, and

analyses performed.

5.2.2.3. Technical assessment of dam safety including deficiences

and hazardous conditions found to exist.

5.2.2.4. Indicate alternative possible remedial measures or revision

in maintenance and operating procedures which may (subject

[[Page 296]]

to further evaluation) correct deficiencies and hazardous conditions

found during the investigation.

[GRAPHIC] [TIFF OMITTED] TC31OC91.017

[[Page 297]]

[GRAPHIC] [TIFF OMITTED] TC31OC91.018

[[Page 298]]

[GRAPHIC] [TIFF OMITTED] TC31OC91.019

[[Page 299]]

[GRAPHIC] [TIFF OMITTED] TC31OC91.020

[[Page 300]]

[GRAPHIC] [TIFF OMITTED] TC31OC91.021

Appendix I to App. D to Sec. 222.6--Engineering Data

This appendix lists engineering data which should be collected from

project records and, to the extent available, included in the

[[Page 301]]

Phase I investigation report. The list is intended to serve as a

checklist and not to establish rigid data requirements. Such a

compilation should also facilitate future inspections and

investigations. Only data readily available will be included in Phase I

reports, but data lacking and deemed necessary for an adequate safety

evaluation should be identified.

1. General Project Data.

a. Regional Vicinity Map showing the location of the dam, the

upstream drainage area and the downstream area subject to potential

damage due to failure of the dam and misoperation or failure of the

operating equipment.

b. As-Built Drawings indicating plans, elevations and sections of

the dam and appurtenant structures including the details of the

discharge facilities such as outlet works, limited service and emergency

spillways, flashboards, fuse plugs and operating equipment.

2. Hydrologic and Hydraulic Data including the following:

a. Drainage area and basin runoff characteristics (indicating

pending changes).

b. Elevation of top of conservation pool or normal upper retention

water surface elevation, as applicable (base level of any flood

impoundment).

c. Storage capacity including dead or inactive storage,

corresponding to top of conservation or normal upper retention level

(cumulative, excluding flood control and surcharge storage).

d. Elevation of the top of flood control pool.

e. Storage capacity of flood control zone (incremental).

f. Elevation of maximum design pool (corresponding to top of

surcharge storage or spillway design flood).

g. Storage capacity of surcharge zone (incremental, above top of

flood control pool or, above normal upper retention level if flood

control space not provided).

h. Height of freeboard (distance between maximum design flood water

surface and top of dam).

i. Elevation of top of dam (lowest point of embankment or non-

overflow structure).

j. Elevation of crest, type, width, crest length and location of

spillways (number, size and type of gates if controlled).

k. Type, location, entrance and exit inverts of outlet works and

emergency drawdown facilities (number, size and shape of conduits and

gates, including penstocks and sluices).

l. Location, crest elevation, description of invert and abutments

(concrete, rock, grass, earth) and length of limited service and

emergency spillways.

m. Location and dscription of flashboards and fuse plugs, including

hydraulic head (pool elevation) and other conditions required for

breaching, along with the assumed results of breaching.

n. Location and top elevation of dikes and floodwalls (overflow and

non-overflow) affected by reservoir. Include information on low reaches

of reservoir rim.

o. Type, location, observations and records of hydrometeorological

gages appurtenant to the project.

p. Maximum non-damaging discharge, or negligible damage rate, at

potential damage locations downstream.

3. Foundation Data and Geological Features including logs of

borings, geological maps, profiles and cross sections, and reports of

foundation treatment.

4. Properties of Embankments and Foundation Materials including

results of laboratory tests, field permeability tests, construction

control tests, and assumed design properties for materials.

5. Concrete Properties including the source and type of aggregate,

cement used, mix design data and the results of testing during

construction.

6. Electrical and Mechanical Equipment type and rating of normal and

emergency power supplies, hoists, cranes, valves and valve operator,

control and alarm systems and other electrical and mechanical equipment

and systems that could affect the safe operation of the dam.

7. Construction History including diversion scheme, construction

sequence, pertinent construction problems, alterations, modifications

and maintenance repairs.

8. Water Control Plan including regulation plan under normal

conditions and during flood events or other emergency conditions. The

availability of dam tenders, means of communication between dam tenders

and authority supervising water control, and method of gate operation

(manual, automatic, or remote control) should be included. Flood warning

systems should be described in sufficient detail to enable assessment of

their reduction in the flood hazard potential.

9. Operation Record.

a. Summary of past major flood events including any experiences that

presented a serious threat to the safety of the project or to human life

or property. The critical project feature, date and duration of event,

causative factor, peak inflow and outflow, maximum elevation of water

surface, wind and wave factors if significant, issuance of alert or

evacuation warnings and adequacy of project feature involved should be

included in the summary of past experience of serious threat to the

safety of the project.

b. Records of performance observations including instrumentation

records.

c. List of any known deficiencies that pose a threat to the safety

of the dam or to human life or property.

[[Page 302]]

d. History of previous failures or deficiencies and pending remedial

measures for correcting known deficiencies and the schedule for

accomplishing remedial measures should be indicated.

10. Earthquake History including a summary of the seismic data of

significant recorded earthquakes in the vicinity of the dam and

information on major damage in the vicinity of the dam from both

recorded and unrecorded earthquakes. Regional geologic maps and other

documents showing fault locations should be collected.

11. Inspection History including the results of the last safety

inspection, the organization that performed the inspection, the date

inspection performed and the authority for conducting the inspection.

12. Principal Design Assumptions and Analyses.

a. Hydrologic and Hydraulic Determinations.

(1) Quantity, time and area distribution, and reference source of

depth-area-duration data of spillway design storm precipitation (point

precipitation if applicable).

(2) Maximum design flood inflow hydrograph including loss rates

(initial and average for design flood conditions) and time of runoff

concentration of reservior watershed (peak inflow only when applicable).

(3) Maximum design flood outflow hydrograph (maximum outflow only

when applicable).

(4) Discharge-frequency relationship, preferably at damsite,

including estimated frequency of spillway design flood for small dams,

when appropriate.

(5) Reservior area and storage capacity versus water surface

elevation (table or curves).

(6) Rating curves (free flow and partial gate openings) for all

discharge facilities contributing to the maximum design flood outflow

hydrograph. Also a composite-rating of all contributing facilities, if

appropriate.

(7) Tailwater rating curve immediately below damsite including

elevation corresponding to maximum design flood discharge and

approximate nondamaging channel capacity.

(8) Hydrologic map of watershed above damsite including reservior

area, watercourse, elevation contours, and principal stream-flow and

precipitation gaging stations.

b. Stability and Stress Analysis of the dam, spillway and

appurtenant structures and features including the assumed properties of

materials and all pertinent applied loads.

c. Seepage and Settlement Analyses. The determination of

distribution, direction and magnitude of seepage forces and the design

and construction measures for their control. Settlement estimates and

steps adopted to compensate for total settlement and to minimize

differential settlements.

Appendix II to App. D to Sec. 222.6--Inspection Items

This appendix provides guidance for performing field inspections and

may serve as the basis for developing a detailed checklist for each dam.

1. Concrete Structures in General.

a. Concrete Surfaces. The condition of the concrete surfaces should

be examined to evaluate the deterioration and continuing serviceability

of the concrete. Descriptions of concrete conditions should conform with

the appendix to ``Guide for Making a Condition Survey of Concrete in

Service,'' American Concrete Institute (ACI) Journal, Proceedings Vol.

65, No. 11, November 1968, page 905-918.

b. Structural Cracking. Concrete structures should be examined for

structural cracking resulting from overstress due to applied loads,

shrinkage and temperature effects or differential movements.

c. Movement--Horizontal and Vertical Alignment. Concrete structures

should be examined for evidence of any abnormal settlements, heaving,

deflections, or lateral movements.

d. Junctions. The conditions at the junctions of the structure with

abutments or embankments should be determined.

e. Drains--Foundation, Joint, Face. All drains should be examined to

determine that they are capable of performing their design function.

f. Water Passages. All water passages and other concrete surfaces

subject to running water should be examined for erosion, cavitation,

obstructions, leakage or significant structural cracks.

g. Seepage or Leakage. The faces, abutments and toes of the concrete

structures should be examined for evidence of seepage or abnormal

leakage, and records of flow of downstream springs reviewed for

variation with reservoir pool level. The sources of seepage should be

determined if possible.

h. Monolith Joints--Construction Joints. All monolith and

construction joints should be examined to determine the condition of the

joint and filler material, any movement of joints, or any indication of

distress or leakage.

i. Foundation. Foundation should be examined for damage or possible

undermining of the downstream toe.

j. Abutments. The abutments should be examined for sign of

instability or excessive weathering.

2. Embankment Structures.

a. Settlement. The embankments and downstream toe areas should be

examined for any evidence of localized or overall settlement,

depressions or sink holes.

b. Slope Stability. Embankment slopes should be examined for

irregularities in

[[Page 303]]

alignment and variances from smooth uniform slopes, unusual changes from

original crest alignment and elevation, evidence of movement at or

beyond the toe, and surface cracks which indicate movement.

c. Seepage. The downstream face of abutments, embankment slopes and

toes, embankment--structure contacts, and the downstream valley areas

should be examined for evidence of existing or past seepage. The sources

of seepage should be investigated to determine cause and potential

severity to dam safety under all operating conditions. The presence of

animal burrows and tree growth on slopes which might cause detrimental

seepage should be examined.

d. Drainage Systems. All drainage systems should be examined to

determine whether the systems can freely pass discharge and that the

discharge water is not carrying embankment or foundation material.

Systems used to monitor drainage should be examined to assure they are

operational and functioning properly.

e. Slope Protection. The slope protection should be examined for

erosion-formed gullies and wave-formed notches and benches that have

reduced the embankment cross-section or exposed less wave resistant

materials. The adequacy of slope protection against waves, currents, and

surface runoff that may occur at the site should be evaluated. The

condition of vegetative cover should be evaluated where pertinent.

3. Spillway Structures. Examination should be made of the structures

and features including bulkheads, flashboards, and fuse plugs of all

service and auxiliary spillways which serve as principal or emergency

spillways for any condition which may impose operational constraints on

the functioning of the spillway.

a. Control Gates and Operating Machinery. The structural members,

connections, hoists, cables and operating machinery and the adequacy of

normal and emergency power supplies should be examined and tested to

determine the structural integrity and verify the operational adequacy

of the equipment. Where cranes are intended to be used for handling

gates and bulkheads, the availability, capacity and condition of the

cranes and lifting beams should be investigated. Operation of control

systems and protective and alarm devices such as limit switches, sump

high water alarms and drainage pumps should be investigated.

b. Unlined Saddle Spillways. Unlined saddle spillways should be

examined for evidence of erosion and any conditions which may impose

constraints on the functioning of the spillway. The ability of the

spillway to resist erosion due to operation and the potential hazard to

the safety of the dam from such operation should be determined.

c. Approach and Outlet Channels. The approach and outlet channels

should be examined for any conditions which may impose constraints on

the functioning of the spillway and present a potential hazard to the

safety of the dam.

d. Stilling Basin (Energy Dissipators). Stilling basins including

baffles, flip buckets or other energy dissipators should be examined for

any conditions which may pose constraints on the ability of the stilling

basin to prevent downstream scour or erosion which may create or present

a potential hazard to the safety of the dam. The existing condition of

the channel downstream of the stilling basin should be determined.

4. Outlet Works. The outlet works examination should include all

structures and features designed to release reservoir water below the

spillway crest through or around the dam.

a. Intake Structure. The structure and all features should be

examined for any conditions which may impose operational constraints on

the outlet works. Entrances to intake structure should be examined for

conditions such as silt or debris accumulation which may reduce the

discharge capabilities of the outlet works.

b. Operating and Emergency Control Gates. The structural members,

connections, guides, hoists, cables and operating machinery including

the adequacy of normal and emergency power supplies should be examined

and tested to determine the structural integrity and verify the

operational adequacy of the operating and emergency gates, valves,

bulkheads, and other equipment.

c. Conduits, Sluices, Water Passages, Etc. The interior surfaces of

conduits should be examined for erosion, corrosion, cavitation, cracks,

joint separation and leakage at cracks or joints.

d. Stilling Basin (Energy Dissipator). The stilling basin or other

energy dissipator should be examined for conditions which may impose any

constraints on the ability of the stilling basin to prevent downstream

scour or erosion which may create or present a potential hazard to the

safety of the dam. The existing condition of the channel downstream of

the stilling basin should be determined by soundings.

e. Approach and Outlet Channels. The approach and outlet channels

should be examined for any conditions which may impose constraints on

the functioning of the discharge facilities of the outlet works, or

present a hazard to the safety of the dam.

f. Drawdown Facilities. Facilities provided for drawdown of the

reservoir to avert impending failure of the dam or to facilitate repairs

in the event of stability or foundation problems should be examined for

any conditions which may impose constraints on their functioning as

planned.

5. Safety and Performance Instrumentation. Instruments which have

been installed to measure behavior of the structures should be

[[Page 304]]

examined for proper functioning. The available records and readings of

installed instruments should be reviewed to detect any unusual

performance of the instruments or evidence of unusual performance or

distress of the structure. The adequacy of the installed instrumentation

to measure the performance and safety of the dam should be determined.

a. Headwater and Tailwater Gages. The existing records of the

headwater and tailwater gages should be examined to determine the

relationship between other instrumentation measurements such as stream

flow, uplift pressures, alignment, and drainage system discharge with

the upper and lower water surface elevations.

b. Horizontal and Vertical Alignment Instrumentation (Concrete

Structures). The existing records of alignment and elevation surveys and

measurements from inclinometers, inverted plumb bobs, gage points across

cracks and joints, or other devices should be examined to determine any

change from the original position of the structures.

c. Horizontal and Vertical Movement, Consolidation, and Pore-Water

Pressure Instrumentation (Embankment Structures). The existing records

of measurements from settlement plates or gages, surface reference

marks, slope indicators and other devices should be examined to

determine the movement history of the embankment. Existing piezometer

measurements should be examined to determine if the pore-water pressures

in the embankment and foundation would under given conditions impair the

safety of the dam.

d. Uplift Instrumentation. The existing records of uplift

measurements should be examined to determine if the uplift pressures for

the maximum pool would impair the safety of the dam.

e. Drainage System Instrumentation. The existing records of

measurements of the drainage system flow should be examined to establish

the normal relationship between pool elevations and discharge quantities

and any changes that have occurred in this relationship during the

history of the project.

f. Seismic Instrumentation. The existing records of seismic

instrumentation should be examined to determine the seismic activity in

the area and the response of the structures of past earthquakes.

6. Reservoir. The following features of the reservoir should be

examined to determine to what extent the water impounded by the dam

would constitute a danger to the safety of the dam or a hazard to human

life or property.

a. Shore line. The land forms around the reservoir should be

examined for indications of major active or inactive landslide areas and

to determine susceptibility of bedrock stratigraphy to massive

landslides of sufficient magnitude to significantly reduce reservoir

capacity or create waves that might overtop the dam.

b. Sedimentation. The reservoir and drainage area should be examined

for excessive sedimentation or recent developments in the drainage basin

which could cause a sudden increase in sediment load thereby reducing

the reservoir capacity with attendant increase in maximum outflow and

maximum pool elevation.

c. Potential Upstream Hazard Areas. The reservoir area should be

examined for features subject to potential backwater flooding resulting

in loss of human life or property at reservoir levels up to the maximum

water storage capacity including any surcharge storage.

d. Watershed Runoff Potential. The drainage basin should be examined

for any extensive alterations to the surface of the drainage basin such

as changed agriculture practices, timber clearing, railroad or highway

construction or real estate developments that might extensively affect

the runoff characteristics. Upstream projects that could have impact on

the safety of the dam should be identified.

7. Downstream Channel. The channel immediately downstream of the dam

should be examined for conditions which might impose any constraints on

the operation of the dam or present any hazards to the safety of the

dam. Development of the potential flooded area downstream of the dam

should be assessed for compatibility with the hazard classification.

8. Operation and Maintenance Features.

a. Reservoir Regulation Plan. The actual practices in regulating the

reservoir and discharges under normal and emergency conditions should be

examined to determine if they comply with the designed reservoir

regulation plan and to assure that they do not constitute a danger to

the safety of the dam or to human life or property.

b. Maintenance. The maintenance of the operating facilities and

features that pertain to the safety of the dam should be examined to

determine the adequacy and quality of the maintenance procedures

followed in maintaining the dam and facilities in safe operating

condition.

[[Page 305]]

[GRAPHIC] [TIFF OMITTED] TC31OC91.022

[[Page 306]]

[GRAPHIC] [TIFF OMITTED] TC31OC91.023

Appendix E to Sec. 222.6--Suggested Outline

Inspection Report--National Dam Inspection Program (RCS-DAEN-CWE-17 and

OMB No. 49-R0421)

Title Sheet

Name of Dam

ID Number from Inventory

State, County and River or Stream where dam is located

Owner

Size and Hazard Classification

Names of Inspectors

Names of Review Board

Approval Signature of District Engineer

Table of Contents

General Assessment

Give brief assessment of general condition of dam with respect to

safety, including a listing of deficiencies, and recommendations

indicating degree of urgency.

1. Introduction

a. Authority

b. Purpose and Scope of Inspection

2. Project Information

a. Site Information

b. Description of Structures--Dam, Outlet, Spillway and other

principal features.

c. Purpose of Dam

d. Design, Construction and Operating History

3. Field Inspection

Briefly describe physical condition of the dam and appurtenant

structures as they were observed during the field inspection. (If field

inspection form is appended, only present summary.) Describe operational

procedures, including any warning system, condition of operating

equipment, and provision for emergency procedures. Describe any

pertinent observations of the reservoir area and downstream channel

adjacent to dam.

[[Page 307]]

4. Evaluation

a. Structural and Geotechnical

(1) General

(2) Embankment and/or Foundation Condition

(3) Stability--Briefly discuss pertinent information such as design,

construction and operating records. Assess stability under maximum

loading on basis of the record data, together with observations of field

inspection and results of any additional, brief calculations performed

by inspectors. If additional, detailed stability analyses are considered

necessary, recommend that the owner engage a qualified engineer or firm

to provide the analysis.

b. Hydrologic and Hydraulic

(1) Spillway Adequacy--Briefly describe pertinent record information

such as hydrologic and hydraulic design data, flood of record, and

previous analyses. Describe any hydraulic and hydrologic analyses made

for this inspection. Present conclusion with respect to adequacy of

spillway to pass the recommended spillway design flood without

overtopping dam. If overtopping would occur, and if available from the

type of analysis used, give maximum depth over top of dam and duration

of overtopping, assuming the dam does not fail. Also indicate the

largest flood, as a percentage of the probable maximum flood which can

be passed without overtopping.

(2) Effects of overtopping--If dam is overtopped by the recommended

spillway design flood, provide assessment as to whether or not dam would

likely fail, and if, in case of failure, the hazard to loss of life

downstream of the dam would be substantially increased over that which

would exist without failure. If information upon which to base a

reasonable assessment is insufficient, so state and describe the needed

data, and recommend that the necessary studies be performed by engineers

engaged by the owner.

c. Operation and Maintenance

Assess operating equipment and procedures, emergency power for gate

operation, and Emergency Action Plan. Assess quality of maintenance as

it pertains to dam safety.

5. Conclusions

Provide conclusions on condition of dam and list all deficiencies.

If dam is considered unsafe, so state and give reason.

6. Recommendations

List all recommended actions, including additional studies,

installation of new surveillance procedures and devices, development of

Emergency Action Plans, and remedial work. Recommend that a qualified

engineering firm be retained to accomplish any recommended additional

investigations and studies and also to design and supervise remedial

works.

Appendixes

a. Inspection Checklist (if available)

b. Other Illustrations as follows:

(1) Include a map showing location of the dam. Usually a portion of

a USGS quadrangle sheet can be used which will show the topography of

the area, location of the dam, exent of the lake and drainage basin, and

perhaps indicate the downstream development.

(2) If available, include a plan and section of the dam.

(3) General photographs of the dam and downstream channel should be

included.

(4) Color photographs of deficiencies should be included. These

should be held to the minimum required to illustrate the deficiencies.

(5) Available engineering data including Hydrologic/Hydraulic

calculation and physical test results that might be available.

Appendix F to Sec. 222.6

Instructions for Unsafe Dam Data Sheet (RCS-DAEN-CWE-17 and OMB No. 49-

R0421)

The indicated information shall be provided in the format shown on

Pg F-3 for each dam assessed to be unsafe during the reporting period. A

separate data sheet should be provided for each unsafe dam. The

information supplied should conform to the following.

a. Name--Name of dam.

b. Id. No.--Dam inventory identity number.

c. Location--List state county, river or stream and nearest D/S city

or town where the dam is located.

d. Height--Maximum hydraulic height of dam.

e. Maximum Impoundment Capacity--List the capacity of the reservior

at maximum attainable water surface elevation including any surcharge

f. Type--Type of dam, i.e., earth, rockfill, gravity, combination

earth-gravity, etc.

g. Owner--Owner of dam.

h. Date Governor Notified of Unsafe Condition--The date and method

of notification, such as, by telegram, letter, report, etc.

i. Condition of Dam Resulting in Unsafe Assessment--Brief

description of the deficiencies discovered which resulted in the unsafe

assessment.

j. Description of Danger Involved--Downstream (D/S) hazard potential

category and a brief description of the danger involved.

k. Recommendations Given to Governor--Brief description of the

actions recommended to Governor at time of notification of unsafe

condition to eliminate or reduce the danger.

l. Urgency Category--State whether the unsafe condition of the dam

is an emergency or non-emergency situation. An emergency situation

should be considered to exist if the failure of the dam is judged to be

imminent

[[Page 308]]

and requires immediate action to eliminate or reduce the danger.

m. Emergency Actions Taken--In case of an emergency situation, list

the actions taken. For non-emergency situation, put NA for ``not

applicable.''

n. Remedial Action Taken--For non-emergency situations list remedial

actions taken.

o. Remarks--For other pertinent information.

Format for Unsafe Dam Data Sheet (RCS-DAEN-CWE-17 and OMB No. 49-R0421

National Program of Inspection of Non-Federal Dams--Unsafe Dam Data

Sheet

a. Name:

b. Type:

c. Height:

d. Id. No.

e. Location:

State: County:

Nearest D/S City, Town or Village:

River or Stream:

f. Owner:

g. Date Governor Notified of Unsafe Condition:

h. Condition of Dam Resulting in Unsafe Assessment:

i. Description of Danger Involved:

j. Recommendations Given to Governor:

k. Urgency Category:

l. Emergency Actions Taken:

m. Remarks:

Appendix G to Sec. 222.6

National Program for Inspection of Non-Federal Dams--Monthly Progress

Report (RCS-DAEN-CWE-19)

I. Instructions for Monthly Progress Report. The indicated information

shall be provided in the format shown on page G-2.

1. Division Reporting:

2. Date:

3. Information Required for Each State Regarding Total Number of

Inspections Performed (AE Inspections included) (Cumulative):

3.1. Number of Inspections Initiated by on-site inspection or the

review of engineering data from project records. \1\

---------------------------------------------------------------------------

\1\ Each of the initiated inspections reported should be planned for

completion within a reasonable period of time (30 days.)

---------------------------------------------------------------------------

3.2. Number of Inspections Competed (The number of inspection

reports which have been submitted to the District Engineer for review

and approval).

3.3 Number of Dams Reported to the Governor as Unsafe. \2\

---------------------------------------------------------------------------

\2\ An unsafe dam is defined as a dam with deficiencies of such a

nature that if not corrected could result in the failure of the dam with

subsequent loss of lives or substantial property damage.

---------------------------------------------------------------------------

3.4. Number of Approved Inspection Reports Submitted to the

Governor.

4. Information Required for Each State Regarding Inspections

Performed Under AE Contracts (Cumulative):

4.1. Number of Dams Contracted for Inspection by AE's with State or

Corps.

4.2. Number of Inspections Initiated by AE's by on-site inspection

or the review of engineering data from project records. \1\

---------------------------------------------------------------------------

\1\ See footnote on previous page.

---------------------------------------------------------------------------

4.3. Number of Inspections Completed by AE's (The number of

inspection reports which have been submitted to the District Engineer

for review and approval).

4.4. Number of Approved Inspection Reports Prepared by AE's

Submitted to the Governor.

II. Formation for Monthly Progress Report.

National Program for Inspection of Non-Federal Dams--Monthly Progress

Report

1. Division Reporting:

2. Date:

3. Information Required for Each State Regarding Total Number of

Inspections Performed (Cumulative):

------------------------------------------------------------------------

Unsafe

Inspection Inspection Dams Approved

State Initiated Completed Reported Reports

(3.1) (3.2) (3.3) (3.4)

------------------------------------------------------------------------

===========================================

Total.......................

------------------------------------------------------------------------

4. Information Required for Each State Regarding Inspections

Performed Under A/E Contracts (Cumulative):

----------------------------------------------------------------------------------------------------------------

Dams

Under A/ A/E A/E A/E

State E Inspections Inspections Reports

Contract Initiated Completed Approved

(4.1) (4.2) (4.3) (4.4)

----------------------------------------------------------------------------------------------------------------

=============================================

Totals............................................................

----------------------------------------------------------------------------------------------------------------

Appendix H to Sec. 222.6

Suggested Scope of Work Contract for Architect-Engineer Services for

Safety Inspection of Dams Within the State of --------

1. General Description of Scope of Work. The services to be rendered

by the Architect-Engineer (AE) under the proposed contract

[[Page 309]]

shall include all engineering functions, hereinafter described, as

needed to inspect the dams listed in Appendix A of this contract for the

purpose of evaluating their risk of failure. A report which (a)

describes the assessed condition of the dam, (b) provides conclusions as

to which particular conditions could cause failure, (c) makes

recommendations on remedial measures believed necessary, and (d) makes

recommendations on whether and what type of future investigation should

be conducted shall be provided for each inspected dam. The work shall

proceed in accordance with Phase I of the Recommended Guidelines for

Safety Inspection of Dams established by the Office of the Chief of

Engineers (OCE) and the supplemented requirements listed in paragraph 3

below. The OCE guidelines are listed in Appendix B of this contract.

2. Information and Services To Be Furnished by the Government. The

Contracting Officer will furnish the following information and services

to the AE:

a. All information pertaining to each dam to be inspected as

contained in the National Inventory of Dams.

b. Copies of recommended format for preparation of inspection

report, engineering data check list and visual inspection check list.

c. All available pertinent information pertaining to the Dam

Inspection Program and previous investigations having a bearing on

inspections to be performed under this contract.

d. Right-of-entry for access to each dam site.

3. Services To Be Rendered by the Architect-Engineer. The principal

services, subject to the optional provisions of the contract, to be

rendered by the AE are itemized below:

a. Technical Investigations.

(1) Engineering Data Collection. To the extent feasible, the

engineering data listed in Appendix I of the OCE guidelines relating to

the design, construction and operation of the dam and appurtenant

structures, should be collected from existing records and reviewed to

aid in evaluating the general condition of each dam, including an

assessment of the hydraulic and hydrologic features and structural

stability of the dam. Where the necessary engineering data are

unavailable, inadequate or invalid, a listing shall be made of those

specific additional data deemed necessary by the engineer in charge of

the investigation and included in the inspection report. The engineering

data checklist provided by the Contracting Officer shall be used as a

guide to compile this data.

(2) Field Inspections. The field inspection of each dam shall

include examination of the items listed in Appendix II of the OCE

guidelines, electrical and mechanical equipment for operation of the

control facilities, reservoir area, downstream channel in the vicinity

of the dam and any other significant feature to determine how these

features affect the risk of failure of the dam. The inspection shall be

conducted in a systematic manner to minimize the possibility of any

significant feature being overlooked. The visual inspection checklist

provided by the Contracting Officer shall be used as a guide to document

the examination of each significant feature.

Particular attention shall be given to detecting evidence of

leakage, erosion, seepage, slope instability, undue settlement,

displacement, tilting, cracking, deterioration, and improper functioning

of drains and relief wells. The degree and quality of maintenance and

regulating procedures for operation of the control facilities shall be

assessed. The design and existing condition of such control facilities

(i.e., spillway, outlet works, etc.) shall be evaluated. An assessment

of the degree of siltation that is evident and its effect on the dam's

reservoir shall be performed. Photographs and drawings should be used to

record conditions in order to minimize written descriptions.

(3) Engineering Analyses.

(a) Evaluation of Hydraulic and Hydrologic (H&H) Features.

Evaluation of the hydraulic and hydrological features of each dam shall

be based on criteria set forth in the OCE guidelines. If it is

determined that the available H&H data are insufficient, the Contracting

Officer must be so informed and may exercise an option of requiring the

AE to perform an overtopping analysis at additional agreed-upon

compensation. The methodology to be used by the AE for this analysis

will be based on the OCE guidelines and subject to the approval of the

Contracting Officer.

(b) Evaluation of Structural Stability. The evaluation of structural

stability of each dam is to be based principally on existing conditions

as revealed by the visual inspection, available design and construction

information, and records of performance. The objectives are to determine

the existence of conditions, identifiable by visual inspection or from

records, which may pose a high risk of failure and to formulate

recommendations pertaining to the need for any remedial improvements,

additional studies, investigations, or analysis. The results of this

phase of the inspection must rely substantially upon the experience and

judgment of the inspecting engineer. Should it be determined that

sufficient data are not available for a reasonable evaluation of the

structural stability of a dam and appurtenances, the Contracting Officer

should be informed which information is required prior to attempting to

evaluate the risk of failure of the dam.

electrical operating equipment is used in controlling the

[[Page 310]]

reservoir of a dam, an evaluation of the operational characteristics of

this equipment from the standpoint of risk of failure must be performed.

(d) Evaluation of Reservoir Regulation Plan and Warning System. The

operational characteristics of each dam's existing reservoir regulation

plan and warning system in event of a threatened failure shall be

investigated.

b. Emergency Situations. The Contracting Officer must be immediately

notified of any observed condition which is deemed to require immediate

remedial action. After being notified, the Contracting Officer will

contact the appropriate State personnel and will meet the AE at the site

to determine the appropriate course of action. This will not relieve the

AE of his responsibility to prepare a comprehensive inspection report at

the earliest practicable date.

c. Qualifications of Investigators. The technical investigations

shall be conducted by licensed professional engineers with a minimum of

five years experience after licensing in the investigation, design and

contruction of earthfill, rockfill and concrete dams and/or in making

risk of failure evaluations of completed dams. These engineers must be

knowledgeable in the disciplines of hydrology, hydraulics, geotechnical,

electrical, mechanical and structural engineering, as necessary. All

field inspections should be conducted by engineers, engineering

geologists and other specialists who are knowledgeable in the

investigation, design, construction and operation of dams, including

experts on mechanical and electrical operation of gates and controls,

where needed.

d. Preparation of Report. A formal report shall be prepared for each

dam inspected for submission to the Contracting Officer. Each report

should contain the information specified in OCE guidelines and any other

pertinent information. The recommended format provided by the

Contracting Officer shall be used to document each report. The signature

and registration identification of the professional engineer who

directed the investigation and who was responsible for evaluation of the

dam should be included in the report.

4. Supervision and Approval of Work. All work performed under this

contract shall be subject to the review and approval of the Contracting

Officer or his designee. Meetings will be held on a regular basis in the

District office, during which the progress of inspections will be

discussed and questions relating to inspection reports previously

received by the Contracting Officer will be addressed. Reports will be

revised as necessary when required by the Contracting Officer.

5. Coordination. During the progress of work, the AE shall maintain

liaison with the *-------- and other local authorities through the

Contracting Officer as required to assure the orderly progression of the

inspection. Copies of all correspondence with such authorities shall be

provided to the Contracting Officer.

---------------------------------------------------------------------------

* Note: Write in the designated State Authority.

---------------------------------------------------------------------------

6. Submission of Report.

a. Each inspection report will be submitted for review to the

Contracting Officer. Reports will be revised as required by the

Contracting Officer. After all revisions have been made, the original

and ---- copies of each inspection report shall be submitted to the

Contracting Officer.

b. Text of all reports shall be typewritten and printed on both

sides of 8x10\1/2\ paper. All notes, inspection

forms, sketches or similar matter shall be legible, distinct and

suitable for reproduction.

7. Period of Services.

a. All inspections and reports included under this contract shall be

completed within ---- days from date of Notice to Proceed.

b. If the option for performing an H&H analysis for any particular

site is exercised, the AE shall complete such analysis within ---- days

from date of Notice to Proceed. However, the overall completion time

stated in paragraph 7a above shall not change.

Appendix I to Sec. 222.6

Procedure for Using NASA Land Satellite Multispectral Scanner Data for

Verification and Updating the National Inventory of Dams

1. Purpose. This appendix states the objective, defines the scope,

prescribes procedures, and assigns responsibilities for using NASA Land

Satellite (LANDSAT) Multispectral Scanner data along with NASA's Surface

Water Detection And Mapping (DAM) Computer program to assist in

verification and updating the National Inventory of Dams.

2. Applicability. This appendix is applicable to all divisions and

districts having Civil Works responsibilities except POD.

3. Reference. NASA, DETECTION AND MAPPING PACKAGE, Users Manuals,

Volumes 1, 2a, 2b, and 3 dated June 1976, published by the Johnson Space

Center, Houston, Texas.

4. Objectives. Provide a uniform method, nation-wide, to help insure

that all dams subject to Public Law 92-367, 8 August 1972 are properly

identified and located in the National Inventory of Dams.

5. Scope. The computer printer overlay maps produced by the

procedure described in reference 3b will be used by district and/or

state or contractor personnel as a tool to assist in verification and

updating of the National Inventory of Dams.

[[Page 311]]

6. Exceptions. a. If a Division/District attempts the use of the

procedure for a given region within their area of responsibility and

finds the overlay maps cannot be used to assist in verification and

updating the National Inventory of Dams, they may request an exception

for a selected region. A selected region may include areas where

conditions can reasonably be assumed to be the same as the region where

the procedure was tried.

b. Request for exceptions should be documented to include firm

boundary definitions and appropriate justification to demonstrate why

the procedure cannot be used. This request should be submitted to WRSC

WASH DC 20314, through the normal engineering chain of command.

c. Map overlays will be produced for all areas of the Continental

United States even if they are not used in a few selected regions. This

processing is required for a future Computer Water Body Change Detection

system.

7. Procedures. Acquisition of LANDSAT data, registration of

satellite coordinates to earth latitude and longitude and computer

processing to produce overlay maps will be accomplished by two Regional

Centers. Nashville District and Seattle District have been designated as

the Regional Centers, with each responsible for processing maps by state

based on Divisional assignments in Appendix A. Regional Centers will

support divisions as follows:

------------------------------------------------------------------------

Regional Center Division

------------------------------------------------------------------------

Nashville District New England

North Atlantic

South Atlantic

Ohio River

Lower Mississippi Valley

North Central

Seattle District Southwestern

Missouri River

North Pacific

South Pacific

------------------------------------------------------------------------

8. Responsibilities. a. The Water Resources Support Center at Fort

Belvoir has overall responsibility for coordination and monitoring of

this activity between NASA, Division Offices, and Regional Centers, and

for providing Regional Center funding.

b. Regional Centers are responsible for:

(1) Acquiring proper LANDSAT data tape from EROS Data Center (Sioux

Falls, South Dakota). Actual data scene selection will be coordinated

with Division and/or District to insure proper consideration is given to

local priorities and seasonal coverage.

(2) Arranging computer processing support using NASA's DAM package.

(3) Establishing proper control between satellite scanner-oriented

coordinates and earth latitude/longitude.

(4) Producing total coverage of map overlays at a scale of 1:24,000

and/or smaller scales as required by Divisions and/or Districts.

(5) Instructing District, State, or contractor personnel in the

assembly and use of map overlays.

c. Divisions/Districts are responsible for:

(1) Designating one person from each Division and District as the

point of contact with the Regional Center and provide this person's name

and phone number to the Regional Center.

(2) Providing the Regional Center with map coverage of their area of

responsibility. This will include state indexes and 7\1/2\ minute

quadrangle sheets (scale 1:24,000) where available.

(3) Coordinating with the Regional Center in selecting LANDSAT data

tapes.

(4) Providing information to Regional Center on scale and priorities

of desired computer produced map overlays.

(5) Assembling computer print-outs into overlay maps, and using as

appropriate to assist in verification and updating the National

Inventory of Dams.

9. Points of Contact. The points of contact in the Regional Centers

for this program are as follows:

Name, Office Symbol, and Telephone

Jim Cook--DAEN-ORNED, (615) 251-7366; FTS 852-7366.

Jack Erlandson--DAEN-NPSEN, (206) 764-3535; FTS 399-3535.

[44 FR 55336, Sept. 26, 1979, as amended at 45 FR 18925, Mar. 24, 1980.

Redesignated at 60 FR 19851, Apr. 21, 1995]