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WETLAND MAPPING CONVENTIONS 

 FOR 1985 FOOD SECURITY ACT (FSA) 



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This document outlines the procedures and methods the SCS will use to conduct an 

 FSA wetland inventory. These procedures and methods (conventions) are not 

 intended to state or document service policy. They are designed to ensure 

 mapping consistency between field offices. These conventions are a result of 

 the Wetlands Inventory and Mapping Workshop held in Portland, and derive from 

 the Midwest NTC Technical Note No. 190-LI-8 as modified by the participants. 

 Conventions will conform to the FSA definitions and meet the basic wetland 

 criteria. (See FSA Manual - July 1988). The criteria for mapping conventions 

 of wetlands considers landscape, soils, flooding frequency, vegetation, etc. 



GENERAL INFORMATIOH 



J^ Size of an area is not part of the wetland criteria. However, areas large 

 enough to be detected when interpreting aerial photography will be mapped. 



2,- At any step in the process that the reviewing person or mapping team is 

 satisfied that the area in question either is or is not a wetland, further 

 evaluation is unnecessary. Decisions and the supporting material used will be 

 documented in each step of these guidelines. Frequent field checking should be 

 done until the reviewing person or mapping team has become proficient at photo 

 interpretation in each mapping location. 



^ %^ Maps developed from these conventions will be used as the primary basis for /^ 



completing wetland determinations in accordance with established FSA definitions 

 and policy. Final determination decisions are the responsibility of the 

 district conservationist. Field determination of hydric soils and hydrophytic 

 vegetation may still be needed. 



Wetlands will be inventoried using the following procedure. The process takes 

 •.'•'no. -^^^^ consideration both above normal and below normal precipitation years. The 

 "^-' C- principle tools used to make the wetland determination are: soil survey, USGS 

 5uads, weather data, NWI maps, ASCS color slides, and black and white aerial 

 photos. Generalized maps developed in consultation with Corps of Engineers, 

 USFS, state agencies, etc., showing flooded or flood prone areas may be used. 

 Source documentation is required in the case file. 



TERMINOLOGT 



Wetland areas that are seasonally flooded or ponded that have been manipulated 

 prior to December 23, 1985, to produce an agricultural commodity but otherwise 

 continue to meet wetland criteria shall be mapped as a farmed wetland "FW" as 

 defined below. 



—CROPLAND. — Surface water must be present on cultivated fields for extended 

 periods in the growing season to qualify as seasonally flooded or ponded for 

 farmed wetland "FW", or wetland "W" . Extended periods occur if surface water is 

 continually present for 15 consecutive days or more of the growing season under 

 / average conditions (50 percent chance of occurrence). Growing season for 



wetland plants in the West is defined in Hydric Soils of the Onited States. ^ 



