Results

    The results of the analysis of the Upper White Watershed show that there will be 12.44 inches of runoff per year and have 5.32 tons of erosion per acre. The streamflow results are summarized in Table 1. Yearly evaporation was found to be 43.4 inches and yearly precipitation was determined to be 16 inches.

     

    Watershed Precipitation

    The Nebraska Department of Natural Resourcescollected precipitation data Nebreska. The figure shown was used to obtain an annual precipitation value of 16 inches for the Upper White Watershed.

    Figure ##: Average Annual Precipitation in Nebraska

    Avg Annual Precip During Growing Season.JPG

     

    Mean Annual Lake Evaporation for Upper White Watershed

    Pan Evaporation = 62 inches (Refer to Figure 4.14 in Trimble and Ward Textbook)

    Pan to Lake coefficient = 0.7 (Refer to Figure 4.15 in Trimble and Ward Textbook)

    Equation4.JPG

     

    Runoff Considerations

    The Curve Number, CN, for the Upper White Watershed is assumed to be 74. This was based off of the assumptions that this watershed has a Hydrologic Soil Group of C. Soil reports indicate high content of silt and loam. The land use is primarily pasture or range in good condition (Refer to Table 5.1 in Trimble and Ward Textbook).

    Equation5.JPG

     

    Stream Flow

     

     Table ##: Discharge and Gage Height for Big Bordeaux Creek

    PeakStreamflow.png

     

    Erosion

     

    From Table 9.1 of Trimble and Ward, the Upper White Watershed is of mostly a canopy of forest, shrub, and grassland. The watershed is assumed to have 75% of total surface area hidden and a total of 50% of total surface area covered by trees. Grassland has little to no canopy but covers 35% of the total surface area. Shrub will cover 50% or total surface area hidden with 15% total surface area coverage. From these assumptions, the C value was found to be 0.095.

    Figure ##: Ground Cover

    GroundCover.png

     

     The R factor and K factor were found from Trimble and Ward (Figure 9.6 and Figure 9.8 respectively). R = 60 and K = 0.33

     

    For the Upper White Watershed the P factor and LS factor were assumed to be 1.0 and 10 respectively. (Trimble and Ward Table 9.3 and Figure 9.10)

    Equation6.JPG

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