Arizona Mining

Mining has been a major part of Arizona’s history since well before it was granted statehood in 1912 and continues to be a major industry. ERC has assisted in many aspects of the development of the Hermosa Project in southern Arizona. Some of ERC’s contributions have included completing a dam breach analysis of the mine’s TSF facility to ensure all people and structures will be out of the inundation area in the event of a dam failure and conducting hydraulic and geomorphologic assessments on local ephemeral streams to determine the impact any discharges from the mine’s water treatment plant may have. ERC has also aided the mine in their water management through the development of stochastic water balance models.

Barr Lake Reservoir Design Modifications for Public Use

In 2019, a change in State Dam Safety regulations allowed the reservoir at Barr Lake to be enlarged.  To protect State Park facilities from the increased water level, ERC undertook a project to identify impacted roads, trails and other infrastructure then design modifications to ensure their continued safe use by the public. Tasks included: developing design drawings and technical specifications to raise 3 gazebo structures, 1 pedestrian bridge, 3,000 linear feet of gravel trail, 800 linear feet of wooden boardwalk on concrete piers, and 3,300 linear feet of gravel road.  The facilities were designed to meet Colorado Parks & Wildlife (CPW) standards and current building codes.  Construction was completed in 2022.

Barr Lake Spillway

The State of Colorado determined that the spillway at Barr Lake was inadequate to safely pass the inflow design storm. ERC was retained to evaluate existing and future conditions and design a spillway upgrade. ERC evaluated extreme precipitation conditions and defined the Probable Maximum Precipitation of 30 inches in a 48-hour period. When routed the storm produced a peak inflow rate of approximately 40,000 cfs with a total runoff volume of 13,000 acre-feet. Hydraulic modeling showed that a 185 spillway was required to safely pass the inflows while maintaining the required freeboard without raising the dam. The design included replacing the existing earthen spillway with a composite concrete, riprap and soil cement spillway. Additionally, over three miles of perimeter dikes were designed and constructed to control water levels during the design event. ERC completed design, permitting and construction management for the project.

Bear Creek at O’Fallon Park

Kittridge, CO

O’Fallon Park in Kittridge CO is a heavily used park for summer recreational activities. The local Trout Unlimited Chapter was interested in restoring aquatic habitat for a 1,600 foot section of Bear Creek as it runs through the Park. ERC completed design, permitting and construction activities for the project including creation of nine, self-scouring deep overwintering pools that were generally absent through the area. Design used faster moving water from riffles to provide the higher energy to flush sediment from the pools throughout the year. Key placement of instream boulder habitat enhanced usable cover for trout. The project included moving the stream away from State Highway 74 and creating a riparian fringe barrier between the highway and the stream to minimize sand and other sediment loading that had previously been occurring from the road. ERC led volunteer efforts that included planting riparian vegetation for bank stabilization and terrestrial habitat creation.

Beaver Valley Ranch

Big Thompson River

City of Loveland, CO

Infrastructure associated with the City of Loveland’s water treatment plant was compromised as a result of the 2013 floods. After emergency repairs were completed, the City desired restoration work that would not only protect infrastructure but also improve the ecological function of the damaged river. ERC’s design/build work focused on reestablishing natural channel form and function to this degraded reach. In areas where excessive stream widening occurred during the 2013 flood, ERC returned the stream to its appropriate width. Riprap that had been installed immediately following the flood was filled and vegetated to promote ecological value and natural stream planform and profiles were reestablished through channel reshaping and construction of riffle/pool sequences that had been lost.

Blue River Phases I and II

Silverthorne, CO

ERC was hired by the Town of Silverthorne to improve angling on an approximately 3,000 foot stretch of the Blue River below the Dillon Dam. This section, which is gold medal water, was suffering from poor habitat and limited angling opportunities. ERC was hired to design, permit and construct improvements aimed at enhancing both the aquatic habitat and the angler experience. Improvements included full reshaping the overly wide channel so that the new stream channel geometry matched flow releases from the dam. The success of the project led the Town to hire ERC to complete restoration on two additional sections of the Blue River totaling and additional 3,500 feet as part of a Phase II project.

Blue River, Breckenridge, CO

Runoff in Summit County, Colorado was above average in 2019 producing flows that exceeded a 5-year event. Unfortunately this flow event was enough to result in widespread failure of a stream and valley restoration project completed by others for the… Read more »

Blue River, Getz Ranch

The Getz family property in Summit County includes approximately 1,300 feet of the Blue River, inclusive of a 500 foot high water side channel. They desired to enhance the aquatic habitat to create a better fishery during high and low flow conditions. ERC developed a design plan that controlled flows between the main and side channels and optimized aquatic habitat in each. Plans included buried cross channel cobble bars to split flows between the channels, riffles constructed of salvaged instream cobble and deeper pools designed to hold more larger fish throughout the year.

Blue River, Maryland Creek Ranch

Silverthorne, CO

The Maryland Creek Ranch development in Summit County includes approximately 3,500 feet of private water on the Blue River, including side channels. ERC designed and constructed improvements along this full stretch to optimize aquatic habitat and maximize holding capacity for large trout. The design included a deep thalweg throughout the full project reach to ensure quality habitat was retained even at times when flows are limited to minimum releases from Dillon Dam. ERC’s natural restoration created 11 different stream segments, each with its own unique habitat features to provide anglers with a variety of fishing experiences. The project, which included full reshaping and grading of the entire 3,500 foot section was completed within a three week window given tight schedule limitations imposed by project permits.

Boulder Creek Master Plan

Boulder Creek, like many of Colorado’s front range streams, was significantly altered by the 2013 floods. ERC was part of a team of consultants tasked with evaluating the environmental and geomorphologic conditions of the stream and developing a master plan for future resilient improvements. ERC evaluated historic aerial photographs of Boulder Creek to understand evolution of the stream’s alignment during recent and pre-development periods. From this assessment, a range of natural sinuosity and meander wavelengths were defined and alignments for future restoration were identified. Typical cross-sectional geometries that replicate natural stream conditions were determined for low flow, bankfull flow and flood flow events. Critical habitat features along the riverine corridor were defined and recommended riparian buffer zones to protect the corridor from further development were determined.

Boxwood Gulch Fly Fishing Ranch Phases I – III

North Fork of the South Platte River, Shawnee, CO

Boxwood Gulch is one of the premier private fishing waters in the Denver metro area. With its reputation for holding large numbers of large trout, quality habitat needed to support these fish was a vital concern. ERC was hired by Boxwood Gulch to improve the habitat and holding water for an initial 2,200 foot section of the North Fork of the South Platte River. Variable flows are one of the main challenges facing this fishery. Located below Roberts Tunnel, this reach of water is subject to extreme low flows in winter months when no tunnel releases are made as well as extended periods of high flows throughout the summer and fall months. ERC’s design addressed these flow challenges and the need for significant habitat. Improvements included a wide array of techniques aimed to optimize habitat throughout the varying characteristics of the site. Larger cascade features were utilized in the narrow, steeper canyon sections. Longer riffle and bend pools were created where they fit well into the stream alignment and a deep, meandering thalweg with extensive instream cover was provided throughout. The success of ERC’s initial improvements has led to two additional phases of work being undertaken. Completed improvements provide a great variety of angling opportunities for all types of fly fishing over the full spectrum of flow conditions.

Brush Creek

Snowmass Village, CO

The Town of Snowmass Village is one of Colorado’s premiere ski and outdoor destinations. In the early 2000s when the Town undertook a major development project to modernize infrastructure and amenities, ERC was hired to restore Brush Creek, one of the first things visitors to the Town notice upon arrival. Past development had encroached upon the river, and it didn’t provide significant ecological benefits or recreational opportunities. ERC’s design recreated a stream segment that optimized habitat while providing a more enjoyable and user friendly resource. The stream was re-meandered and a total of 27 step/pool and riffle/pool features were created to provide pool habitat over a 1,300 foot segment. The corridor along the stream was regraded and native riparian was planted to create a healthy riverine system to support aquatic and terrestrial habitat. These improvements served to beautify the Town entrance.

Buffalo Peaks Ranch, Middle Fork of the South Platte River

Park County, CO

Colorado Parks and Wildlife holds an easement that allows fishing significant portions of the Middle Fork of the South Platte River in Park County. One of the factors that limit the aquatic habitat through much of this water is pool habitat. ERC was selected to develop plans to optimize habitat along a 21,700 foot stretch of the Middle Fork known as Buffalo Peaks Ranch. The design included 79 habitat segments, each with a created pool to address the habitat limitations of the area. Pools were designed to work in combination with cascade features, riffles and bends, depending on site specific conditions. Funding was raised allowing for a priority reach of 9,800 feet to be completed. Using a natural restoration approach, ERC created 33 unique habitat units, each with a deepened pool along the priority reach.

Burlington Canal Headworks

ERC designed and oversaw construction to modernize the main Burlington Canal headworks off of the South Platte River. The diversion structure included four main crest gates (two 6 foot gates and two 12 foot gates) a 4’ x 13’ crest gate for bypass flow operations and a 4’x4’ sandout gate all with flow measuring capabilities. ERC’s work included hydraulic modeling, gate design, 404 and floodplain permitting and construction observation. The completed facility has the ability to pass and measure flows up to approximately 1,000 cfs. Gates were designed to fit within the original Burlington diversion structure while improving operational flexibility and safety.

CDWA Culvert Improvement

In 2019, The Church Ditch Water Authority decided to improve a deteriorating culvert crossing under Arapahoe Street in Golden, CO.  ERC was tasked with designing a new culvert and overseeing the construction process.  Tasks included: initial site survey and hydraulic design, structural design, preparation of bid documents, helping select a construction contractor, and managing construction.  The final design piped the ditch under the road and across adjacent property that was difficult to access and maintain.  ERC obtained permits from the City of Golden and the Colorado Department of Transportation (CDOT), and worked closely with adjacent property owners.  Construction was completed before the 2022 water-delivery season.  The final product eliminated stormwater runoff into the ditch, improved hydraulic efficiency and reduced maintenance headaches.

Church Ditch Headgate 53 Retaining Wall

The Church Ditch hired ERC to repair a concrete-block retaining wall holding back high banks along the ditch in Arvada. The wall showed signs of heaving and overturning in several spots due to a poor design and the expansive soils in the area. ERC designed a concrete footer for the existing blocks and a system of steel angles to tie the blocks together. Approximately 800 linear feet of wall was repaired. The sections were between 6 and 10 feet tall. Design work included hydraulics, stability analysis, and permitting. ERC also managed the project by providing construction oversight.

Church Ditch Headworks

In 2016-2017, ERC managed the project to modernize the headworks structure of the Church Ditch on Clear Creek in Golden, Colorado. During the design phase, ERC conducted hydraulic modeling to size new gates. These included two 4-ft by 4-ft Fresno slide gates, a 4-ft Rubicon overshot gate for controlling upstream head, and a 4-ft slide gate for flushing debris. We also worked with the City of Golden and Jefferson County Open Space to permit the project. In the construction phase, ERC provided bid support to select a contractor then provided oversight and observation to ensure a smooth process. The structure includes security fencing, solar power and the ability to operate the gate and measure flows remotely.

Church Ditch Leyden Flush Structure