Wetlands Characteristics and Boundaries (1995) / Chapter Skim
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6 ESPECIALLY CONTROVERSIAL WETLANDS
6 ESPECIALLY CONTROVERSIAL WETLANDS
Pages 149-167
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From page 149... ...
These areas are the source of many problems related to wetland regulation and delineation; their classification is particularly sensitive to changes in delineation procedures. PERMAFROST WETLANDS Permafrost is soil that has a temperature continuously below 32°F (0°C)
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From page 150... ...
The continuous permafrost areas of Alaska are mainly treeless tundra; discontinuous permafrost supports many plant communities, including forests. At the southern limits of permafrost and in low regions, thickening of the active layer can occur readily if the thermal regime changes.
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From page 151... ...
With increasing soil moisture, forested sites of interior Alaska tend toward hydrophytic communities characterized by black spruce, ericaceous shrubs, and Sphagnum mosses. Such sites remain wetlands until floodplain processes, fire, or anthropogenic disturbances reinitiate succession.
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From page 152... ...
Because permafrost wetlands do not differ in their essential characteristics from other wetlands, separate regulatory treatment of them is not justifiable scientifically. Recommendations on permafrost wetlands can be found at the end of this chapter, numbers 1 to 3.
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From page 153... ...
Alteration has accompanied regulated activities such as gravel mining, bridge crossings, and the creation of new dams and diversions, and such unregulated activities as reduction of surface discharge or lowering of water tables due to ground water pumping or surface water withdrawal. Other activities that can alter riparian zones include clearing of land for agricultural development, logging, or recreation (Stromberg, 1993~.
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From page 154... ...
Complementary programs that acknowledge the importance of riparian zones in hydrologic buffering and in the maintenance of water quality and biodiversity are warranted but have not yet been developed. Riparian zones may contain wetlands that meet the present regulatory definitions of wetland as well as the reference definition that is given in Chapter 3.
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From page 155... ...
This conclusion does not imply that riparian zones are unimportant to the goals of the Clean Water Act, or that riparian zones are not critically threatened in much the same way that wetlands are threatened, but rather that extension of the definition of wetland to cover all riparian zones would unreasonably broaden the definition of wetland and undermine the specificity of criteria and indicators that have developed around wetland delineation. A recommendation from this section can be found at the end of this chapter, recommendation number 4.
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From page 156... ...
Even water quality functions might not be fully separate for isolated and other wetlands because of the ground water connections between isolated wetlands and surface waters. Special treatment of headwaters is also questionable, given that headwaters affect water quality downstream and perform many of the other functions of wetlands (Johnson and McCormick, 1979; Lowrance et al., 1984a, b; Peterjohn and Correll, 1984; Cooper and Gilliam, 1987; Cooper et al., 1987J.
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From page 157... ...
During the rising floodwater period, fish take advantage of food and shelter in riparian wetlands. Shallow wetlands could be especially valuable in maintenance of water quality because of their high ratio of sediment surface relative to water volume.
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From page 158... ...
The cost to NRCS for carrying out these new responsibilities will be $15.6 million annually if intensively managed agricultural lands alone are delineated. If native grazing lands are included, the cost will be an additional $10.4 million per year (personal communication, 1994, Billy Teels, Wetlands Staff Leader, NRCS)
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From page 159... ...
considered for exemption under the swampbuster provisions. Table 6.2 lists some varieties of agricultural wetlands that are recognized by the National Food Security Act Manual, third edition.
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From page 160... ...
. Agricultural wetlands are generally found in an extensively altered landscape where they can be particularly important for controlling water quality, preventing floods, and maintaining biodiversity.
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From page 161... ...
Because many former wetlands were drained for crop production, the hydroperiods of wetlands that remain on or near agricultural lands might have been altered and floodwater retention functions diminished. Thus, although the wetlands in agricultural settings are potentially valuable for maintenance of water quality, they can be significantly disturbed and can show reduced functional capacity.
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From page 162... ...
Altered sites are those at which disturbance has been recent enough and extensive enough that normal conditions are not readily apparent by the indicators of hydrology, substrate, and biota. Special methods could be required for the assessment of such sites for wetland determination and delineation.
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From page 163... ...
These actions also can influence the hydrology of a site. Soil disturbances and associated ramifications include the following: · Soil removal, which can change the results of soil analysis or alter the relative water retention capacity of the substrate, thus either increasing or decreasing the degree of saturation and vegetation of a site.
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From page 164... ...
When the determination of normal conditions must be made at altered sites, special methods must sometimes be used in assessing normal vegetation, soils, and hydrology. Assessment of Altered Lands Evidence of normal vegetation can be derived from · Review of aerial photographs.
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From page 165... ...
Aerial photographs can provide evidence of standing water, but they do not indicate saturation. Aerial photographs only rarely provide indications of duration of inundation, but the use of gauging or meteorologic data can increase the utility of these photographs.
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From page 166... ...
Although they typically contain wetlands, riparian zones cannot be defined wholly as wetlands by any broad definition. If national policy extends to protection of riparian zones pursuant to the goals of the Clean Water Act, regulation must be achieved through legislation that recognizes the special attributes of these landscape features, and not by attempting to define them as wetlands.
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From page 167... ...
Restoration on agricultural lands should be encouraged whenever these practices can reduce impairment of the remaining natural wetlands on or near agricultural lands.
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