PERMFILE46457

• Permit No: M1992038
• IBM Index Class Name: Permit File
• Doc Date: 9/2/1992
• Doc Name: Permit Application
• From: Sand Creek Farms
• To: MLRD
• Media Type: D
• Archive: No

MATRIX ENGINEERS, INCORPORATED
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Civil Engineering 1066 West 102nd Avenue Member
Structural Engineering Northglenn, Colorado 80221 American Consulting
Land Surveying phone [phone] Engineers Council
June 8, 1992
~ Mr. Robert Fleming
ADCO Consulting
2090 E. 104th Avenue, #305
Thornton, Colorado 80233
Re: Sand Creek Farms, Adams County Case # 49-92 C
~ Staff Comments Dated 6/5/92
Dear Bob:
As per your request, I have reviewed your submittal in the above
referenced case and the Planning Staff concerns relating to
~ drainage and floodplain issues, and would have the Following
response to their concerns:
1. Stockpiles of material can occur in the floodplain area of a
watercourse. Witness the County's own sand and gravel mining
operation at the Adams County Fairgrounds, where stockpiles
• are obviously in the floodplain area. What is important, is
that stockpiles be located outside oP the floodway area and in
the flood storage area be oriented in such a manner as to not
cause diversion of storm water onto .other properties during
flooding events.
~ The floodplain area of West Bijou Creek is delineated on FIRM
Map panel 235 Por Adams County. This FIRM map does not
delineate between the floodway and flood storage area, but the
100'± area you show on your reclamation plan should be more
than sufficient to cover the probable floodway area of West
Bijou Creek. In this 100' area no stockpiles should be
~~' allowed. Outside of this area, stockpiles should be oriented
in a north-south alignment, since most of the mining area is
located within the delineated floodplain area.
2. In regard to the probability of upstream headcut, there is no
~ logical comparison between the conditions oP this application
and West Bijou Creek, and those which occur on the South
Platte River. West Bijou Creek is an intermittent stream that
may only flow once or twice a year, and some years not at all
in some locations. Even when it does flow, the maximum water
conveyed is probably in the hundreds or low thousands cubic
~ Peet per second for a very limited period oP time, usually
less than a day. The South Platte Plows continually and can
flow at over twenty to thirty thousand cubic Peet per second
in the spring time Por weeks at a time. Even for the South
Platte River, a request Por identification of structures, etc.
Por Pour miles upstream and downstream would be excessive.
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