1988-09-26_ENFORCEMENT - M1977378 ‎(2)‎

• Permit No: M1977378
• IBM Index Class Name: ENFORCEMENT
• Doc Date: 9/26/1988
• Doc Name: Civil Penalty Pymts. of $12,200.00 and $500.00 with Supporting Docs.
• From: Sunnyside Gold Corp
• To: MLRD
• Media Type: D
• Archive: No

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RIPRAP SPECIFICATIONS FOR PROPOSED HIGHWAY EMBANKMENT
The proposed tailings pond No. 4 and the new alignment for State
Highway 110 will constrict the Animas River Flood plain. The existing
width of the flood plain ranges from approximately 500 to 750 feet
in the vicinity of proposed tailings pond No. 4. Construction of
a new highway alignment embankment will reduce a portion of the flood
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plain to an average width of approximately 140 feet along the extreme
southern edge of pond No. 4. j
To provide for adequate flood protection of the new highway
embankment along the southern edge of proposed pond No. 4, a 100-year
ifrequency flood discharge was determined for the Animas River to estimate ,
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a design flood stage.
The method used to determine the 100-year frequency flood for f '
the Animas River was based on that given in U.S.G.S. Water Supply
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Paper 1683. ,
A mean annual flood for the Animas River of 1380 cfs was calculated j
from the equation:
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Qa = .021A'86 3.06 H where �
Qa = Peak annual discharge in cfs
A = Drainage area in square miles
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H = Mean drainages elevation in hundreds of feet
From the interpolation of U.S.G.S. Flood Frequency curves, the ratio
of the 100-year flood to the mean annual flood is approximately 2.5.
Therefore, the estimated 100-year flood for the Animas River is:
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