[Code of Federal Regulations]

[Title 40, Volume 24]

[Revised as of July 1, 2006]

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

[CITE: 40CFR230.21]



[Page 265]

 

                   TITLE 40--PROTECTION OF ENVIRONMENT

 

         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)

 

PART 230_SECTION 404(b)(1) GUIDELINES FOR SPECIFICATION OF DISPOSAL SITES 

FOR DREDGED OR FILL MATERIAL--Table of Contents

 

Subpart C_Potential Impacts on Physical and Chemical Characteristics of 

                          the Aquatic Ecosystem

 

Sec.  230.21  Suspended particulates/turbidity.



    (a) Suspended particulates in the aquatic ecosystem consist of fine-

grained mineral particles, usually smaller than silt, and organic 

particles. Suspended particulates may enter water bodies as a result of 

land runoff, flooding, vegetative and planktonic breakdown, resuspension 

of bottom sediments, and man's activities including dredging and 

filling. Particulates may remain suspended in the water column for 

variable periods of time as a result of such factors as agitation of the 

water mass, particulate specific gravity, particle shape, and physical 

and chemical properties of particle surfaces.

    (b) Possible loss of environmental characteristics and values: The 

discharge of dredged or fill material can result in greatly elevated 

levels of suspended particulates in the water column for varying lengths 

of time. These new levels may reduce light penetration and lower the 

rate of photosynthesis and the primary productivity of an aquatic area 

if they last long enough. Sight-dependent species may suffer reduced 

feeding ability leading to limited growth and lowered resistance to 

disease if high levels of suspended particulates persist. The biological 

and the chemical content of the suspended material may react with the 

dissolved oxygen in the water, which can result in oxygen depletion. 

Toxic metals and organics, pathogens, and viruses absorbed or adsorbed 

to fine-grained particulates in the material may become biologically 

available to organisms either in the water column or on the substrate. 

Significant increases in suspended particulate levels create turbid 

plumes which are highly visible and aesthetically displeasing. The 

extent and persistence of these adverse impacts caused by discharges 

depend upon the relative increase in suspended particulates above the 

amount occurring naturally, the duration of the higher levels, the 

current patterns, water level, and fluctuations present when such 

discharges occur, the volume, rate, and duration of the discharge, 

particulate deposition, and the seasonal timing of the discharge.