correlated from information provided by the Deerlodge National Forest Land System Inventory, 

 Natural Resource and Conservation Service soil surveys, and field mapping completed by a 

 DNRC soil scientist. The results of that analysis are summarized in the following table: 



Table 3-2. WATSED 

 Results for the Upper Willow Creek Drainage 



* Equivalent Clearcut Area (ECA) is calculated by the WATSED model as a function of 



area (acres) treated, % of forest crown removed and estimates on the amount of 

 hydrologic recovery due to vegetative re-growth. Recovery values were verified and 

 adjusted by observations made in the field. 



** WYI refers to estimated % water yield increase due to forest crown removal. 



The WATSED model was not used for cumulative watershed effects analysis in Beaver Creek, 

 Bear Creek, Huepeck Gulch, Slusser Gulch. Arbuckle Gulch and the two unnamed tributaries. 

 However, the area covered by these watershed analysis areas is included in the modeled results 

 for the entire Upper Willow Creek Watershed. The WATSED model was not used for these sub- 

 watershed analysis areas due to one or more of the following reasons: 1) These watersheds have 

 intermittent, ephemeral or discontinuous flow regimes; 2) A lack of well defined stream channels 

 or lack of continuous stream channels; 3) These are low ordered streams with small drainage 

 areas, and 4) The low levels of existing timber harvest and low road densities within the sub- 

 watershed analysis areas. 



Potential water yield increases were analyzed in these tributaries using the Equivalent Clearcut 

 Area (ECA) methodology as outlined in Forest Hydrology Part 11 (Region 1 - USES, 1974). 

 Sediment yields were analyzed using intensive ground surveys carried out to identify existing and 

 potential sources of erosion and sediment delivery. The results of water yield analysis using the 

 ECA methodology are summarized in the following table: 



45 



