Flow, Sediment, and Nutrients (This section is under construction)

We used the Soil and Water Assessment Tool (SWAT) to model flow, sediment, and nutrients across the watershed and stream channels. This model uses information on soils, topography, land cover, rainfall, and temperature to simulate hydrologic processes on the land surface that create surface flow, infiltration and subsurface flow, and routes these flows, sediment and nutrients through stream channels. We used daily data from 2000 to 2009 to run the model and to compare the simulated outputs to observations. We averaged daily flows and nutrient loadings simulated in each subwatershed from 2000-2009 and selected results, presented below. Please refer to the Cypress Creek Project Watershed Characterization Report, for more information on watershed modeling.


Simulated sediment yields tend to be largest in the northern and eastern portions of the watershed where slopes are high and vegetation cover is sparser (Figure 4.11). Sediment yield tends to be highest during the summer months, when large and intense storms are more common. Average sediment yield for the watershed was 275 lb/acre/year.

Simulated organic nitrogen yields range from 0 to 2.5 lb/acre/year and are highest in upland areas and the more developed areas along the perennial creek (Figure 4.12). Simulated organic phosphorus yields range from 0 to 0.4 lb/acre/year, and follow a similar spatial pattern to nitrogen (Figure 4.13).