FLOOD04722

• County: Las Animas
• Basin: Arkansas
• Title: Storm and Flood of July2-3, 1981 Frijole Creek Basin
• Date: 9/1/1982
• Prepared For: Colorado and Southern Railway
• Prepared By: Bishop Associates, Inc.
• Floodplain - Doc Type: Flood Documentation Report

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several reasons. First, the headwaters of these downstream tributaries

generally received much less rainfall than those contributing to flow

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above the railway bridge and, consequently, these lower tributaries

contributed much less to total flood volume than their drainage areas

alone would indicate. Second, it is unlikely the peak runoffs from all

or most of the lower tributaries coincided with the passage of the

mainstream flood peak considering the abruptness of the mainstream flood

peak, In such instances where the main and tributary flood peaks did

not closely coincide, the tributary flow adds to overall flood volume

but does not add significantly to the peak rate of flow. Third and most

important, as a result of channel storage of flood waters and of signi-

ficant overland flow (at low velocity) outside of the main stream

channel in the reach of relatively low and uniform stream gradient below

the railway bridge and above the USGS measuring point, the flood peak

was attenuated through this stream reach. Thus, the rate of flow at the

flood peak was less and the total flood volume was greater at the USGS

measuring point than at the railway bridge,

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