Synthesis of Literature on the Use of Water-Stained Leaves in the Delineation of Wetlands
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
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The 1987 Corps of Engineers Wetlands Delineation Manual and the 1989 Federal Manual for Identifying and Delineating Jurisdictional Wetlands described three criteria for delineating wetlands hydrophytic vegetation, hydric soils, and wetland hydrology. Evidence of all three parameters should be present before an area is considered to be a wetland subject to Federal jurisdiction. To meet the wetland hydrology criterion, an area must be saturated at the surface or inundated for at least 5 of the growing season 1987 or one week or more during the growing season 1989 in most years. It is difficult to meet this criterion directly because quantitative data on surface water or groundwater levels are rarely available for specific sites. In lieu of direct measurements of hydrology, the 1989 Manual suggested 11 field indicators that may be readily observed during a field inspection and can be used as evidence that the wetland hydrology criterion has been met. One of the field indicators that was emphasized in the 1989 Manual was the presence of water-stained leaves on the floor of a forested wetland. Although water-stained leaves continue to be used as hydrologic indicators for wetland delineation, little is known about the technical validity of this indicator. Accordingly, a literature review was conducted, which has resulted in a bibliography and this Technical Note. This Technical Note synthesizes the literature reviewed in a bibliography, WRP Technical Note HY-DE-6.1. In particular, it examines factors that could potentially influence the occurrence of water-stained leaves in wetland conditions. These factors are temperature, redox, water, pH, nutrients, sediments, light, microorganisms and animals, plant species, and leaf condition. The note suggests that, until more research on the subject yields other pertinent results, water-stained leaves should continue to be considered as a secondary hydrologic indicator of wetlands.
- Geology, Geochemistry and Mineralogy
- Hydrology, Limnology and Potamology