Environmental Engineering Reference
In-Depth Information
Shredders
Grazers
Predators
Microbes
1
Trout
Collectors
Coarse
particulate
matter
Fine
particulate
matter
Collectors
Periphyton
2
Smallmouth
bass
Shredders
Microbes
3
Predators
Va scular
hydrophytes
Grazers
4
5
Perch
Coarse
particulate
matter
Periphyton
6
Fine
particulate
matter
Fine
particulate
matter
7
8
Microbes
Phytoplankton
Collectors
Predators
9
Catfish
10
11
12
zooplankton
Relative channel width
FIGURE 7.2
The river continuum concept. (From Vannote, R.L., Minshall, G.W., Cummins, K.W., Sedell, J.R.,
and Cushing, C.E.,
Canadian Journal of Fisheries and Aquatic Sciences
, 37, 130-137, 1980. With permission.)
The standards may be narrative or speciic (numeric) to a certain chemical. An example of a
narrative criterion could be
The waters of the State may not be polluted by … substances … that are unsightly, … odorous, … create
a nuisance, or interfere directly or indirectly with water uses,
while an example of a numeric criterion could be
the water quality standard for dissolved oxygen may be 5.0 milligrams per liter oxygen for some desig-
nated uses and 6.0 for others.
To ensure that the standards are met, a permitting system was established, the National Pollutant
Discharge Elimination System (NPDES), which is a program that requires that every point source
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