One purpose of the Cache la Poudre River basin Special Study is to present data on existing and future flood potential for streams subject to the effects of increasing urbanization. Two streams in the Cache la Poudre River basin which meet this criteria are Fossil Creek near Fort Collins and Sheep Draw near Greeley. Local interests also assigned these streams priority for study. Volume III of the Special Study covers Sheep Draw and Volume IV covers Fossil Creek. Hydrologic modeling studies were conducted to determine the peak discharges for floods of various probabilities of occurrence. This information was developed first for existing watershed land use. To determine the effect of increasing urbanization on flood runoff, possible future urban land use was superimposed on the Sheep Draw basin. Volume II of this study presents details of the hydrologic studies. Hydraulic modeling studies were conducted to develop the flood water surface profiles and flood plain boundaries. Flood profiles are shown for existing and future conditions. Flooded area maps are shown for existing conditions. Originator-supplied keywords include: Floods, Floodplains - Colorado, Flood damage prevention.