GENERAL44458

• Permit No: C1981041
• IBM Index Class Name: General Documents
• Doc Date: 2/18/1983
• Doc Name: POWDERHORN COAL CO PLAN FOR SURFACE WATER MONITORING OF RAPID AND COTTONWOOD CREEKS AND CONTINGENCY
• From: MLRD
• To: JERRY ZIMPFER
• Permit Index Doc Type: STIPULATIONS
• Media Type: D
• Archive: No

~ III IIIIIIIIIIIIIIII ~
DEPARTMENT OF NAIUr+HL It tJVUHCtS
D Monle Pascoe. EzecWive Director
MINED LAND RECLAMATION DIVISION
DAVID C. SHELTON Director
R is hartl D. Lamm
Governor
February 18, 1983
T0: Jim Herron
FROM: Jerry Zimpfer~~y,.~rt
RE: Powderhorn Coal Company, Plan for Surface Water Monitoring of Rapid
and Cottonwood Creeks and Contingency Plan for Rapid Creek
I have reviewed Powderhorn Coal Company's response to Stipulations No. 4 and 5
of the Division's mine permit approval. The operator has attempted to
directly respond to the requirements of the stipulations, and I am pleased
with the response. However, two concerns were identified which must be
resolved.
The existing surface water monitoring station SWGS-Ol is equipped with a
four-foot Parshall flume. The operator has indicated that a smaller nine-inch
flume"~a~ be added to this location. The four-foot flume is rated to
measure flow down to 1.3 cfs, but low flows at the site are below 1 cfs during
late summer. Since mining activities are more_ likely to affect low flows, the
smaller flume must b in alTd- "-
The operator's contingency plan would install a corrugated metal culvert to
convey flow past the affected reach of stream. This is an acceptable
temporary solution. However, because culverts require frequent maintenance,
it may not provide a permanent solution following the cessation of
operations. Possible permanent solutions include requiring a plan of
augmentation or constructing a lined channel. Other solutions may also be
possible. It is difficult to design an acceptable permanent solution without
having identified the specific problem to be solved. The operator should
rewrite the contingency plan to indicate that a corrugated metal culvet would
be installed in a timely manner as a temporary solution, and that the operator
would then consult with the Division and would provide ar~ppropriate
permanent solution for the problem. The revised contingency plan should
identify alternative water supplies that could be used, if necessary.
If you or the operator have any questions concerning this review, feel free to
ask.
/mt
cc: Jim Pendleton
Brian Munson
Doc. No. 989
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203 Tel. [phone]