individual NOAA station records considered most representative of 

 the individual wetland sites in order to evaluate longer historical 

 records and more recent local climatic trends. 



The use of mean cell values to approximate site mean annual 

 precipitation is arbitrary and introduces error to this field. In 

 mountainous areas with steep precipitation gradients and large 

 precipitation contour intervals in the 1978 compilation, this error 

 may be fairly large. There is probably a tendency to overestimate 

 precipitation values relative to the 1978 interpolation in these 

 cases, since the wetland site locations are probably biased toward 

 lower elevations within the elevation range of any given MAPS cell. 



Wetland Area (Field Wet Area^ 



Wetland areas for the sampled wetlands are derived from 

 Arclnfo coverages of the sites. For smaller sites which do not 

 appear as hydrographic features in the 1:100,000 RF3 coverages, 

 wetland areas were digitized from 7.5 minute topographic sheets. 

 In all cases and particularly for smaller sites or those with 

 transient extent, precision is low. Areas may not reflect free 

 water extent at the time of sampling, and are not intended to 

 represent jurisdictional wetland areas. 



Drainage Basin Area (Field Basin Area) 



Drainage basin areas for the sampled wetlands (in acres) are 

 derived from Arcinfo coverages of contributing catchment areas. 

 For sites with smaller contributing basins (those covering 1 or 2 

 7.5 minute topographic quadrangles), basin boundaries were 

 digitized from manually drawn boundaries on the 7.5 minute quads. 

 For sites with larger contributing basins, boundaries were 

 estimated from the 1:100,000 RF3 hydrographic coverage of Montana. 

 For sample wetlands known to receive a large fraction of their 

 water from interbasin imports (e.g. Lake Bowdoin, Ninepipe 

 Reservoir, Homestead Lake), basin areas for the streams 

 contributing imported water are included. 



Surficial and bedrock geologic units (fields Surf qeo and Bed geo.) 



Surficial and bedrock geologic fields are occupied by the U.S. 

 Geological Survey alphanumeric codes for geologic units in Montana. 

 Geologic units were determined from the best available geologic 

 mapping of the wetland, cited in the accompanying Annotated 

 Bibliography of Wetland Site Geology. Geologic units are those 

 interpreted to be underlying the wetland itself; other geologic 

 units may underlie the contributing drainage basin. 



The coding system does not include paludal or modern 

 lacustrine sediments, which are a ubiquitous feature of the sample 

 sites. The provisional codes 110"LAC", 111"LAC" or 112"LAC" are 

 adopted for sites where (nonglacial) lacustrine sedimentation is 



