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ENGINEERING METHODS Hvdrolol!ic Analvsis Basin delineation for drainages in the vicinity of Saguache are shown on Figure 2, Catchment Areas. Design points important to the Town of Saguache include Saguache Creek at Saguache (Design Point I), Findley Gulch at Highway 114 (Design Point 2), and Unnamed Tributary at Saguache (Design Point 3). USGS Gage No. 08227000 on Saguache Creek is located about 8 miles above the Town of Saguache. Flood peaks for the 10-, 50-, 100-, and 500- year event for Saguache Creek were statistically analyzed using probability analysis and approximately 93 years of record at the Gaging Station by CWCB (CWCB, 1999), These data were updated to include the 1999 event along Saguache Creek and were calculated to be approximately 690 cfs, 1100 cfs, 1290 cfs, and 1780 cfs for the 10-, 50-, 100-, and 500- year event, respectively. The drainage area of Saguache Creek at the Gaging Station is approximately 595 sq. mi., and the drainage area between the Town and the Gage is approximately 117 sq, miles, as shown on Figure 2. Flood peak estimates downstream of the USGS Gage at Saguache are calculated using the area ratio equation suggested by Vaill for the Rio Grande Region, QI = Q2 {AI / A2 }088 , 0,5 < {AI / A2 } < 1.5 (Vaill, 2000) where; QI = projected flood peak, cfs, Q2 = known flood peak, cfs, AI = drainage area at projected site, mi2, and, A2 = drainage area at known site, me. The drainage areas of Findley Gulch and Unnamed Tributary are 18.6 and 10.5 square miles, respectively, Flood peaks for these two streams can be estimated using the USGS Regression equations (Vaill, 2000). These regression equations have a large standard error (around 50 per cent) and, as a result, the flood peaks should be considered accurate only to an order of magnitude, Flood peak estimates are presented in the Table below. 7