PERMFILE62457

• Permit No: M1998013
• IBM Index Class Name: Permit File
• Doc Date: 6/22/1998
• Doc Name: EARTH DAM AND SLURRY WALL
• Media Type: M
• Archive: No

Westminster, Colorado Jim Baker Reservoir
EARTH DAM AND SLURRY WALL
The site for Westminster Gravel Lake is located in
the Clear Creek Valley in Adams County,
Colorado.
RMC was retained to evaluate the site for the
feasibility of construction of a 1,200 acre -foot
reservoir. The reservoir would store exchange
water for augmentation of upstream Clear Creek
diversions. Groundwater modeling was required
to evaluate the effects of construction and
operation of the reservoir on adjacent properties.
In 1993, RMC was retained to design the reservoir
and prepare plans and specifications for the
project. Construction was performed in 1994 and
1995. RMC provided all construction related
engineering services.
The design includes a 4,035 -foot long earth
embankment with a maximum height of 50 feet.
The embankment has upstream slopes of 3:1
(horizontal to vertical) and downstream slopes of
3:1 with a crest width of 12 feet. A 3,430 -foot
long perimeter slurry wall was constructed to
complete isolating the reservoir from the shallow
alluvial aquifer.
The reservoir has a 36 -inch diameter ductile iron
pipe outlet works near the southeast corner of the
site. The outlet works is designed to drain the top
14 feet of the reservoir by gravity. A pump station
was designed and constructed to convey below
grade storage water. The over - the - embankment
spillway is designed to pass the Probable
Maximum Flood (PMF) and incorporates an ogee
section, concrete lined chute, and stilling basin.
permit Number 22 �W- 04
Class. enml /
Sectio/Exhibit: Q "
_ (_ . _:;��- S8
__._.___._._._._._._._Class ❑Revision ._
Type /Seq:
_- --Class: ------
- .___. -__ 0-Re-port O Hydro ❑General
Doc Type:
-___—___—________— _______________________..___ _
OApplication (Coal only) ❑ Bond O Enforcement � Inspection ���
ROCKY MOUNTAIN CONSULTANTS, INC.
11111 Jig IIIII Jill 1111
l