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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />Design Criteria <br /> <br />USACE design criteria will be used and includes the following <br />references: <br /> <br />EM 1110-2-1415 <br />EM 1110-2-1419 <br />Studies <br />EM 1110-2-1601 <br />EM 1110-2-1619 <br /> <br />Hvdroloaic Freauencv Analvsis <br />Hvdroloaic Enaineerina Reauirements for Flood Damaae Reduction <br /> <br />Hydraulic Desian of Flood Control Channels <br />Risk-Based Analvsis for Flood Damaae Reduction Studies <br /> <br />Task 1 - Data Collection and Evaluation <br /> <br />Review and evaluate existing Corps files, past studies, and other available data for <br />the Cache la Poudre in and around Greeley, CO that pertain to hydrology. Some of the <br />major studies include: <br /> <br />1988 Update. Hydroloaic Analysis ofthe Cache La Poudre River Basin. by USACE <br />USGS stream aaae records <br />Flood Plain Information - Cache La Poudre River. Greeley. Weld County by <br />USACE <br />Various hYdroloaic models - e.a. SWMM <br />905(b) (WRDA 86) Preliminarv Analvsis - Cache La Poudre River - Greelev. <br />Colorado. Flood Damaae Reduction and Environmental Restoration StudY <br /> <br />Task 2 - Site Reconnaissance <br /> <br />Conduct a site reconnaissance of the features in the Greeley area. Specific <br />areas to be observed include the Cache La Poudre River Watershed, the existing gravel <br />pits, proposed, tributaries of the Cache La Poudre River in and around Greeley, <br />waterfowl preserves or production areas, and USFWS properties or easements. A field <br />reconnaissance report will be prepared summarizing the findings. <br /> <br />Task 3 - Statistical Analysis <br /> <br /> <br />3.1 Review and Update Frequency Curves. Discharge-frequency curves will <br />be derived for use in the HEC-RAS steady flow model that will be developed by the <br />Hydraulics Section. Flows for the 10-, 50-, 100-, and 500-year events will be derived for <br />the Cache La Poudre River at the near Greeley gage based on the methodology that <br />was used for the 1988 Corps study. Additional annual peak discharges from 1986 <br />through 2004 will be included in the update of the 1988 study. Streamflow data will be <br />obtained through the USGS or the Colorado Department of Natural Resources where <br />necessary. Results will be reviewed and compared to the original study and final curves <br />adopted. Peak Discharge Frequency relationships are required for use in the steady <br />flow hydraulic model and also are used in development of the balanced flood <br />hyd rog ra phs. <br /> <br />35 <br />