FLOOD08628 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I D. NORTH BASIN OF RITO SECO 1. Hi story The north basin of the Rito Seco consists of 4.5 square miles that drains into the Rito Seco mainly via overland flow. The drainage concentrates in a broad swale on the high school property. Historically, and as shown by the SCS floodplain delineation in their Close-out Report, September, 1980, flow from major storms crosses 9th Street in the vicinity of State Highway 159 divides and flows overland until it reaches the Rito Seco Channel, a portion at 8th Street and the remainder near 6th Street and Highway 159. Portions of the developed part of Town are located in the floodplain, including the future post office site at 9th Street and Highway 159. 2. Investigation / u- On June 8, 1988 WRC conducted an on site inventory of the hydraul ic st ructu res along the Rito Seco commenci ng at the 24" CMP through the levee northeast of Town to its confluence with Cul ebra Creek south of Town. The inventory consisted of photographing and measuring all structures within this reach. A ground survey was conducted to check elevations with those shown on the topographic mapping provided by the Town. WRC also reviewed the water surface profile study (WSP-2) done by SCS and modified the input to be used for a HEC-2 run on the proposed improved conditions. Using the surveyed information, measurements from the inventory and the topographi c mapping, WRC confirmed that the crux of the problem was that the runoff from the North Drainage Basin does not have a defined channel to carry the flow to the Rito Seco. In order to reduce this overland flooding condition into the developed portions of Town, a flood control measure must be devised to carry the flow into the Rito Seco Channel. 3. Alternative Solutions -22-