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I I I I I I I I I I I I I I I I I I I second. Given these floodwater flow rates a number of phenomena will occur. Water flowing at a rate of 7-8 feet per second or greater will cause severe erosion of streambanks and lands and is capable of transporting rocks and large trees. Water flowing at about 2 feet per second or less will deposit sand, silt and other floodborne debris. The floodplain has a number of natural and man-made obstructions to streamflow including trees, brush, gravels, rocks, and various structures. Without stabilization structures or natural streambank armament, the river will migrate across the floodplain during periods of flood, as was experienced in many locations during the 1983 flood. THE 1983 FLOOD The 1983 flood was equivalent in magnitude to the past floods of 1927, 1938, 1957, and 1975. The flood was of a lesser magnitude than the flood-of-record which was recorded on June 13-14, 1921. The resultant damage to floodplain lands and structures are presented by on site pictures and field inspections on pages through The pictures will illustrate many of the concerns of the land owners and local government officials. It should be understood that not all of the critical flood damaged areas have been identified. The entire 44 mile study reach experienced flond-related losses and damages. FLOOD DAMAGED AREA Plates 1-5 form an index detailing the 45 sites where flood damages have been identified or illustrating where improve- ments should be/have been implemented. The pictorial illustrations will demonstrate the concerns and needs of local officials for mitigating flood-related losses and damages throughout the Uncompahgre River Valley. -3-