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<br />Flood Protection Measures
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<br />Since the devastating 1958 flood, a number of flood
<br />protection improvements have been made on Indian Wash.
<br />The primary flood protection measure is the U.S.
<br />Department of Agriculture Soil Conservation Service 111'-1
<br />retention structure. The structure, shown below, is
<br />located northeast of the airport, and was completed in
<br />the early 1960 I s. The structure drains an area of 6.2
<br />square miles and was designed for a total storage
<br />capaci ty of 2140 acre-feet including 570 acre-feet of
<br />sediment storage. Recent measurements indicate that
<br />sediment accumulation has accounted for approximately 20
<br />acre-feet since completion of the structure. This value,
<br />which is much less than anticipated, results from the
<br />fact that a number of small upstream reservoirs, which do
<br />not provide flood protcction, do trap sedimcnt. It is
<br />estimated that the structure will provide protection for
<br />the 6.2 square miles of watershed for floods greater than
<br />100-year frequency event (Reference 1).
<br />
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<br />Figure 4
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<br />Soil Conservation Service IW-l Structure
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