Upper Beaver Brook Dam Spillway Improvements Project

March 10, 2016 by  
Filed under Storage Increase @ UBB - 2016

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Project to Increase Storage Capacity at Upper Beaver Brook Reservoir

As of May 1st, 2017, the project has reached the substantial completion milestone.  The new spillway is being monitored under the First Fill Plan, which will last for a minimum of one year.  The project is now in close-out phase.

The John Roscoe Dedication event took place July 8, 2017.

See April Upper Beaver Brook Newsletter 

And July 2017 – Dedication

The reservoir and dam site including District land around the lake is CLOSED to the public and will be monitored during construction for safety and securityForest Service Alert:  http://www.fs.usda.gov/alerts/arp/alerts-notices/?aid=34904


Project Owner     Lookout Mountain Water District

Engineer                GEI Consultants, Inc.      www.geiconsultants.com       Login to GEI Sharefile

Design Permit     Dam Safety Branch and Office of the State Engineer (Permit Issued April 25, 2016)

Colorado Division of Water Resources, Department of Natural Resources  Dam Safety Branch Construction Coordination Memo

Other Permits        Arapaho and Roosevelt National Forests

Forest Service, United States Department of Agriculture  Staging Permit CLC752

Funding      Colorado Water Conservation Board  http://cwcb.state.co.us/

Colorado Department of Natural Resources

Department of Local Affairs, State of Colorado

Water Activity Enterprise of the Lookout Mountain Water District

General Contractor     SEMA Construction, Inc.  www.semaconstruction.com

Beneficiaries               Customers and tap owners in Lookout Mountain Water District

Division 1 (South Platte River Basin) Colorado Division of Water Resources


The project consists of construction of a 3-cycle concrete labyrinth weir spillway constructed at the existing spillway location, modification of the existing access roadway, and modifications to the outlet works.  A temporary cofferdam will be required to protect the construction work from water.   Spillway construction will include rock excavation (which may include controlled blasting) and removal and reuse of excess excavated material, construction of a shallow grout curtain and rock anchors.


Design started in August 2013 and completion expected in April 2016

Construction funding secured in November 2015

Construction planned for April 2016 to June 2017


John Roscoe Reservoir at Upper Beaver Brook located on Lookout Mountain Water District lands, accessible through easement on USFS lands. Approximately 7.5 miles northwest of Evergreen, Colorado, in Clear Creek County within the Beaver Brook Watershed. The only adjacent property is under the jurisdiction of the United States Department of Agriculture.


The John Roscoe Reservoir at Upper Beaver Brook is the primary source of water supply for the Lookout Mountain Water District, which serves approximately 485 homes, several private businesses, a high school, and a number of government-owned facilities.  The reservoir was built by the City of Golden in 1924 and currently holds 257 acre feet of water when full (each acre foot of water contains 325,851 gallons). The District supplies its customers with a total of 140 to 180 acre feet of water in most years, so there is little carry-over storage capacity in the current reservoir to provide for a multi-year drought.  Water supply is entirely dependent on the annual stream flows from the Beaver Brook Watershed and related water rights.


The current design safety margins are such that the existing upper dam and reservoir are physically capable of storing an additional 138 acre feet of water if the reservoir’s water level is increased by 10 feet. Engineering studies indicate that a 10-foot concrete labyrinth weir can be installed to safely raise the dam’s spillway. With this planned expansion of the reservoir, its new capacity will be nearly 400 acre feet. Water rights are not expected to be able to fill the reservoir to 100% capacity in every water year.

Total costs for the project are estimated at about $3,325,000 including engineering, legal, water rights, permitting, financial planning, and construction, excluding financing. State and Federal permitting requirements have been a significant part of the initial costs (LMWD received a matching grant for the engineering and permitting phase).

Security / Impact

The reservoir and dam site is CLOSED to the public and will be monitored during construction for safety and security. Noise and visual impact is expected for the duration of the project, due to rock excavation and blasting, operation of heavy machinery, and hauling of material and equipment.  Primary impact is to residents living within 10 miles of the site, visitors within the Beaver Brook Watershed and neighboring land, and travelers along Highway 103 corridor.  Excavation and blasting will occur most frequently from July 2016 through September 2016.  Construction traffic from Squaw Pass to Old Squaw Pass through the Forest Service gate and dirt access road will be noticeable for the duration of the project.  Staging areas between the primary access gate at Old Squaw Pass Road and District property have been approved by USFS permit for the duration of the project.

Impact to Water Supply

Work within and near the spillway must be completed while dry, requiring that the reservoir’s water level be kept between one to five feet (1′ to 5’) lower than the ordinary high water level.   The excess capacity cannot be re-filled until several conditions are met:  1) construction within the spillway is complete 2) water rights are sufficient to allow capture during run-off 3) run-off from the watershed is occurring.  In a best-case scenario, construction will be complete in time to acquire run-off during the spring of 2017.  In a worst-case scenario, the full refill does not occur until 2019 or beyond.  Normally, capture of seasonal run-off primarily occurs from April through July.  The District will attempt to refill as quickly as possible after construction.  Water conservation measures will be implemented if needed.


Site Operator and Water Manager:  Jeremy Wheeler  and Mark Cleaveland –  Treatment Technology     mailto:jeremy@treatmenttech.net or mark@treatmenttech.net

District Office/Administrator:  Christina Shea                     cshea@blacklockintegrated.services                303-526-2025

District Board Representative:  Dean Snyder                        dsnyder6@comcast.net

Project Manager, GEI:  Chad Masching, P.E.          cmasching@geiconsultants.com

RPR/Lead Inspector, GEI:   Thomas Daigle, P.G.       tdaigle@geiconsultants.com

Project Manager, CWCB:  Derek Johnson, P.E.        derek.r.johnson@state.co.us

Project Manager, SEMA:  Thomas Saele, P.E.        tsaele@semaconstruction.com

Project Supervisor, SEMA:  Ken Grossman              kgrossman@semaconstruction.com

Quality Assurance Testing:  Terracon

Blasting:  Rock Solid Solutions

Site Security:  Evergreen Security and Patrol          303-674-2288

District Counsel:  Richard Toussaint                rtoussaint@tnclaw.com

Arapaho and Roosevelt National Forests/Clear Creek/Idaho Springs Ranger Station     303-567-3000

Clear Creek County Sheriff:    303-569-3232 to request assistance or file a report      Main office:  303-679-2300



Bidding Phase Results: 

At the April 11th Regular Board Meeting of the Lookout Mountain Water District, the Board selected SEMA Construction, Inc. as the general contractor for the Upper Beaver Brook Spillway Improvements Project.  Nine contractors submitted bids, which were opened at the public bid opening and special meeting on April 8th.  The Board completed its review and analysis on April 11th, and by unanimous vote, the Board accepted the bid provided by SEMA Construction, Inc. including all alternatives and unit pricing (if needed).  The Contract was issued in May and the Notice to Proceed was issued for June 1, 2016.

UBB Spillway Project Pre-bid slide show