1988-04-18_PERMIT FILE - C1981008A ‎(3)‎

• Permit No: C1981008A
• IBM Index Class Name: PERMIT FILE
• Doc Date: 4/18/1988
• Doc Name: Sedimentation Pond 006
• Section_Exhibit Name: Tab 13 Attachment F
• Media Type: D
• Archive: Yes

DESIGN ANALYSIS
GENERAL
Sediment Pond 006 was evaluated and redesigned to meet or exceed the
design and performance requirements of the Colorado Mined Land
Reclamation Division while utilizing as much of the existing structure
and topography as was possible.
HYDROLOGY
The hydrology of the watershed was analyzed by utilizing the SEDIMOT II
computer program. In performing this analysis, the characteristics of
the minesite and reclamation procedures along with onsite sediment
control procedures were considered. Addendum A and B contain complete
listings of the SEDIMOT II inputs and outputs for the 10-year, and
25-year design storms, respectively. Table 1 is a summary of these
results.
TABLE 1
Design Hydrology and Sedimentology Summary
Structure 006
DESCRIPTION 10yr-24hr 25yr-24hr
Precipitation Depth 1.60-in. 1.80-in.
Inflow Runoff Volume 4.78-ac-ft 6.63-ac-ft
Pond Volume at Peak Stage 6.93-ac-ft 8.66-ac-ft
Peak Stage 8.72 -ft 9.92-ft
Peak Inflow Rate 28.41-cfs 40.93-cfs
Peak Discharge Rate 0.76-cfs 0.87-cfs
Basin Trap Efficiency 100.00% ---
Detention of Flow (Sediment) 49.70-hrs ---
Detention of Hydrograph Centers 15.52-hrs ---
In determining the hydrology parameters to be used as input to the
SEDIMOT II- computer program, each major watershed was subdivided into
logical junctions, branches, structures, and subwatersheds. The basis
of the subwatershed were drainage boundary, similar soil and vegetation
type, and similar land use. The drainage area for this sediment pond
was measured on 1-inch equals 400-feet and 1-inch equals 2000-feet
topographic maps (see Exhibit 13-4 and Exhibit 13-6, respectively).
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