that best represents this variability. Polygons of the land use soil intersection map are attributed with individual curve numbers (Appendix C). Ci is the runoff coefficient applicable to the area Ai (Figure 13). Blue represents wetland complexes and open water, with a runoff value of 0. Impervious areas are colored red, with a value of 98. The lighter the shade of green the lower the runoff coefficient and greater infiltration.