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EXECUTIVE SUMMARY PROJECT OVERVIEW The Upper Willow Creek Watershed Flood Control and Stream Stability Study was conducted by Agro Engineering, Inc. for the Willow Creek Reclamation Committee (WCRC) in Creede, Colorado. Funding was provided by the Colorado Water Conservation Board (CWCB) and the Federal Emergency Management Agency's (FEMA's) Project Impact. Project review was provided by Montgomery Watson Harza Americas, Inc. The primary purpose of the study was to analyze Upper Willow Creek for flood control and debris/sediment problems, and develop a plan to address these problems. The study reach was limited to the portion of Upper Willow Creek and its associated watershed above the masonry flume in downtown Creede. The goals of the study were to: 1) Quantify the risk of flood damage from Upper Willow Creek 2) Examine problems related to debris and sediment transport in Upper Willow Creek 3) Develop strategies to reduce the risk of property damage and destabilization of potential pollution sources during flood events and improve the aesthetic qualities, habitat conditions, and physical functioning of Upper Willow Creek The Willow Creek watershed is located in the eastern San Juan Mountains in southwestern Colorado. Willow Creek enters the Rio Grande just below the City of Creede. The Willow Creek watershed extends to the Continental Divide with a high point of 13895 feet and drains to the Rio Grande just downstream of Creede. The watershed is characterized by steep slopes in its drop to Creede which is at an elevation of 8870 feet. DA T A ANALYSIS Topography For general watershed analysis, lower resolution, 40-foot topographic contours were developed for the Willow Creek watershed using Digital Elevation Models (DEMs) from the U.S. Geological Survey. Higher resolution topography was developed in the channel floodplain area of Upper Willow for hydraulic modeling. To create topography in the wider floodplain areas, a grid of 661 survey points was measured using traditional surveying to establish elevation and a Global Positioning System unit to record horizontal position. Cross-sections were measured at regular representative and critical locations in the main channel using a survey tape to establish higher horizontal accuracy. A total of 55 cross-sections, with 1077 individual points, were measured in the field. Aerial color photographs were taken of the floodplain area of Upper Willow Creek to facilitate the contouring of topographic features. Individual photos were geo-referenced and mosaiced using Geographic Information System (GIS) software. Two-foot topographic contours were drawn on the aerial photos using the survey points.