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In the absence of any existing stream or climatological data for the study area, we had to use the "synthetic hydrograph" procedure to estimate the runoff, The frequency used in this analysis was that which would occur once every 100 years or which has a probability of occurrence of 1% in any one year and this is known as the "100 year flood". For comparison purposes we constrocted synthetic hydrographs by two separate methods: (I) the Colorado Urban Hydrograph Procedure (CUHP) as outlined in the Drainage Criteria Manual of the Denver Regional Council of Governments and (2) by the same basic,Procedure as outlined in the USDA Soil Conservation S..rvice National Engineering Handbook, Section 4 _ Hydrology, Hydrographs by the two methods were constructed for the 3 locations considered most representative and most critical with respect to flood hazard potential for the Town of Elizabeth. This report includes only the hydrographs constructed by the SCS method but it is interesting to note thZl.t a comparison of those constructed by the DRCOG method yield compatible results. The reason we did not feel we should inclnde the latter in the re port is that the data in the DRCOG Manual v must be extrapolated in order to apply to Elbert County. A general Soil Map of Elbert County, Colorado was obtained from the SCS, The watershed :Heas were plotted onto the soils map and the different soils were planimetE'ryd. 1% Nunn-Fort Collins association B-C Soil Group 1% T ruckton-B resser- Blakeland assoc. B " II 51% Fondis-Kutch association C II II ,;.., 45% Brussett-Jarre ass ociation B II " 20/0 Kettle-Pring- Peyton association B II " Soils Assoc. for watershed basin of Point (I) 1% Nunn-F~t Collins association B-C Soil Group 2% Truckton -Bresser-Blakeland assoc. B " " 50% Fondis - Kutch II C " II L 45% Brussett-Ja;rre II B " II 2% Kettle -Pring- Peyton " B II " Soils Assoc. for watershed basin of Point (2) -3-