ENFORCE29200

• Permit No: M1977210
• IBM Index Class Name: Enforcement
• Doc Date: 4/4/1990
• Doc Name: MEMO-FINAL DESIGN ANALYSIS FOR CULVERT HR-6 CORRECTIVE ACTION PLAN SNYDER QUARRY FN M-77-210
• From: MLRD
• To: DAN HERNANDEZ
• Violation No.: MV1989015
• Media Type: D
• Archive: No

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999
MINED LAND RECLAMATION DIVISION
Department of Natural Resources
1313 Sherman 57., Room 215
Denver, CO 80203
303 866-3567
FA x: 303 832-8106
STAT~OF COLORADO
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Roy Romer,
Governor
Fretl R. Banta.
Division Director
DATE: April 4, 1990
T0: Dan Hernandez
FROM: John T. Doerfer
RE: Final Design Analysis for Culvert HR-6, Corrective Action Plan,
Snyder Quarry, File No. M-77-210
I have reviewed the hydrologic aspects of the above-referenced report received
March 23, 1990 from Castle Concrete Company.. The report was prepared by
Oberring, Worth & Associates in response to Item 1(e) of the Board Order of
December 13, 1989. The report offers four (4) possible solutions to the issue
of drainage design in the area of the Snyder Quarry access/haul road, My
comments on each of the alternatives is provided below.
~0~~ppt--i--o--n~--1~ This option is for Castle Concrete Company (Castle) to install a
pert at HR-6 as originally proposed on October 6, 1989 and for
Cedar Heights Lenders (Cedar Heights) to install a new 27" culvert. at the
location designated in the Black Canyon Master Drainage Report.
This plan is acceptable with the condition that an evaluation and design be
completed for the section of roadside ditch downstream of HR-6 to the
54" culvert at HR-7. The capacity and erosional stability of this roadside
ditch in Carrying 28.9 cfs needs to be determined. The Division identified
this concern in its original review dated November 7, 1989.
As a point for clarification, the original plan for HR-6 identified the HW/D
as 1,25 and the slope as 2% producing a Q of 17 cfs. Although th6 same size
of culvert is consistent with that originally proposed (24"), the HW/D has
been modified to 2.3 and slope to 5% to produce a larger flow of i:7.5 cfs, As
the available headwater is 2.5, the revised design under Option i is
acceptable.
Option 2 This option is for Castle to install the 24" culvert at; HR-6 as
orig na y proposed and for Cedar Heights to upgrade the existing culvert to
30" at its present location, If Cedar Heights agrees to hold Casl;le harmless
for any damage to the 400 feet section of roadside ditch along Ceriar Heights
Drive, this plan is acceptable if the same consideration of stable channel
design for the access road ditch noted above is completed by Castle.