SWAT Model Recalibration - Tetratech-ffx.com

Beaver Lake SWAT Modeling Baseline Analysis February 12, 2009Table 15.Existing and Future (2055) Upland Sediment Loads Delivered to Beaver LakeNameExisting Load(US tons/yr)Future Load(US tons/yr)Difference(Future - Existing)Percent ChangeBrush Creek 3,624 4,246 622 17.2%East Fork 3,322 3,393 71 2.1%Beaver Lake 33,206 43,575 10,369 31.2%Lower White 2,715 3,793 1,078 39.7%Middle Fork 2,709 2,816 107 3.9%Richland Creek 7,834 8,744 910 11.6%War Eagle Creek 14,211 20,440 6,229 43.8%West Fork 5,892 5,876 -16 -0.3%Total Load 73,513 92,882 19,370 26.3%Note: Does not include estimates of sediment load from construction sites, roads, and instream channel erosion.Table 16.Sources of Existing and Future (2055) Upland Sediment Loads Delivered to BeaverLakeSourceExisting Load(tons/yr)Future Load(tons/yr)Difference(Future - Existing)Percent ChangeCropland 15,610 12,273 -3,337 -21.4%Pasture 21,810 13,639 -8,171 -37.5%Forest 20,510 16,138 -4,372 -21.3%Range Brush 12,690 10,177 -2,513 -19.8%Urban Low Density 2,231 38,936 36,705 1,645%Urban High Density 628 1,661 1,033 164.5%Point Sources 34 59 25 73.5%Total 73,513 92,883 19,370 26.3%Note: Does not include estimates of sediment load from construction sites, roads, and instream channel erosion.Table 17 summarizes the existing and future upland phosphorus loads delivered to Beaver Lake,including point sources, where applicable, while Table 18 summarizes the upland load sources.Phosphorus load delivered to the lake is predicted to remain nearly stable, declining by 1,004 lbs/yr.Loading from nonpoint sources is predicted to increase by 2,687 lbs/yr, but is offset by a decline in pointsource loads associated with new permit limits for West Fork and Huntsville WWTPs. As with the38