1999-11-24_PERMIT FILE - M1999051

• Permit No: M1999051
• IBM Index Class Name: PERMIT FILE
• Doc Date: 11/24/1999
• Doc Name: Adequacy comments on reclamation permit application
• From: AmerAlia, Inc.
• To: DRMS
• Media Type: D
• Archive: No

The runoff potential for each soil group was calculated based on the existing conditions at
the Project site using information in the SCS "Procedures for Determining Peak Flows in
Colorado," Release No. 55, March 1984. Runoff curve numbers were generated for each
soil group; and culverts, ditches, and other facilities were designed accordingly. The
following runoff curve numbers, weighted as necessary to account for runoff from
various facilities with little or no infiltration, were developed for the various facilities:
Facility Soil Group
Access Road B
C
D
Plant Site C
D
Well Pads C
D
1.8 Receiving Waters
2.0 Control Measures
2.1 Timing of Controls
•
Pre - Development
Curve Number
61 -79
74 -86
80 -89
77
83
77
83
4
Post - Development
Curve Number
85
89
91
(not used)
87
87
89
In all cases, water management facilities have been designed using the larger runoff curve
number to size stormwater management structures with more than adequate capacities.
In addition, culverts were specified larger than required for the calculated peak runoff
volumes to avoid plugging by any silt or brush which could be in the runoff.
Runoff from the project would travel down dry washes to Yellow Creek some '/2 to 1
mile away. The water of Yellow Creek has a protected use for agriculture only. No anti -
degradation rules exist for Yellow Creek.
Maps and Drawings showing the locations of proposed facilities, areas of soil
disturbance, and approximate slopes after major grading activities are provided in Figures
501— 506, 509, 513, 514, 520, and 525 from the engineering/design package and Revised
Figure C -1 from the Division of Minerals and Geology (DMG) 112 Permit Application.
Minor changes in actual alignments and configurations may result from efforts to reduce
impacts to surface resources under the jurisdiction of the Bureau of Land Management;
however, the facilities will be constructed as presented.
Structural controls, including straw bale barriers or gravel - filled sand bag barriers, check
dams, and sediment traps, will be installed prior to commencing any construction
activities. Silt fences will be installed where there is potential for pollutants to enter