APPCOR10821

• Permit No: C1980004
• IBM Index Class Name: Application Correspondence
• Doc Date: 8/4/1981
• Doc Name: SHERIDAN ENTERPRISES FILE C-004-80
• From: MLR
• To: BRIAN MUNSON
• Media Type: D
• Archive: No

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STATE OF COLORADO RIC N4Rn D. ~. Gnv r,n n.
DEPARTMENT OF NATURAL RESOURCES
D. Monte Pascoe, Executive Director
MINED LAND RECLAMATION
423 Centennial Building, 1313 Sherman Street
Denver, Colorado 80203 Tel. [phone]
iii iiiiiiiiiiiii iii
999
David C. Shelton
August 4, 1981 Director
TO:
Brian Munson
FROM: R.A. Domin gue ~ f-f,~Q/•
RE: Sheridan Enterprises, In c.'s McCl one Canyon tAine Sediment Control
Our File No. C-004-80
Brian ,
I have completed my review of McClane Canyon sediment control and have found it
to be mostly in compliance. Several concerns have been identified and are Zisted
below.
Sediment Pond: The size and location of the proposed sediment pond is acceptable
to the Division. However, the pond as designed has no mode for dewatering. Due
to the expressed concern of the State Engineer's Office, this Division requires
dewatering of all sediment ponds at the I00~ sediment storage volume. It is also
the policy of this Division to require an estimate of the theoretical detention
time for the 10-year, 24-hour storm. A value of detention time between 24 and 36
hours is preferred. The Division realizes that, due to the permeable nature of
the alluvium, the pond wi1Z generally dewater to the groundwater system. However,
this process cannot be assured and the dewatering device is, therefore, required.
The pond drawing must bear the seal as well as the signature of a Registered
Professional Engineer.
All other design criteria of the proposed pond are acceptable.
Ditch Designs: Sheridan Enterprises has not provided any estimate of the velocity
of flow under conditions of the 10-year, 24-hour storm. Estimates of these
velocities have been done in this office and have been found to be erosive in
sorry channel materials.
Using a Manning's n of 0.04 and the estimated flow as given by S.E.I., estimates
of flow velocities are as follows:
Area Dl v = 5.15 fps depth of flow = 0.48'
Area DI & D2 v = 5.5 fps depth of flow = 0.64'
Area Dl,D2&D3 V = 4.7 fps depth of flow = 0.79'
Sheridan Enterprises should provide a description of ditch material for each of these
reaches and show that they are not erodible under the estimated flow velocities,
or provide appropriate lining.