One way of calculating river stages from flowrates is through a rating curve like the Manning equation. An assumption of the Manning equation, stemming from its uniform flow assumption, is that the riverbed slope, S o , is equal to the energy gradient slope, S f . The width of the river was assumed to be constant throughout the river length. The calculation of the two main variables, the flowrate and riverbed slope, will be explained in the next section. Methodology Figure 3.
C R is the riverbed conductance and is constant.
Initially, Milam, Lee and Bastrop counties were intersected in Arc View with the HUC subwatershed shapefile to determine which subwatersheds were underlying the three counties. They were then clipped out in the shape of the subwatershed basins of interest. They were then converted from their original floating point format to integer format to save disk space and decrease computing time in the subsequent analysis stage. This is mentioned because the loss of accuracy in the DEM caused problems in the subsequent analysis of river bed slope. Flow direction grid of domain.