West Fork Clear Creek Projects Corridor:

Berthoud Falls to Empire

Projects Overview

The West Fork Clear Creek is a high priority pre-wildfire preparedness corridor, with water quality and flood risk reduction measures identified starting from the community of Berthoud Falls to the Town of Empire. This area requires measures to ensure upstream reach does not further degrade. There are opportunities for bank reinforcements with room for a water quality basin upstream from the Guanella Reservoir for sediment control. There are opportunities throughout the corridor for detention ponds. The Town of Empire is holding public meetings to plan the development of a reservoir on the Ball Placer parcel, a site that is identified in the Clear Creek County Water Bank of potential reservoirs and included in the South Platte Basin Implementation plan.

Mitigation Measures Proposed

Three main mitigation measures are proposed for this project corridor. Each is explained with additional detail further down this page.

1. A potential reservoir at Ball Placer, identified in the Clear Creek County Water Bank and included in the South Platte Basin Implementation Plan, is located in this corridor. This decreed water right is held to address the anticipated future water supply and demand gap. The reservoir would additionally serve as flood and sediment controls to protect water facilities infrastructure downstream. Recommend research and outreach to potential reservoir development partners.

2. From the community of Berthoud Falls to the Town of Empire, recommend corridor enhancements and expansion of wetland footprint. Low-tech process-based restoration is known to safeguard against flooding by spreading water across the floodplain, which has proven benefits for water temperature and quality.

3. On North Empire Creek is the Old Empire landfill, upstream of projects FM-3 and FM-4 north of Empire (see map). Recommend constructed wetlands as a natural and economical alternative in the treatment of metal containing water and possible other contaminants seeping into North Empire Creek from below the landfill. A wildfire event and post-fire flooding would impact the water quality of this stream that feeds into Clear Creek West Fork.

Estimated Costs & Permitting

Estimated costs for these mitigation activities should be developed in separate task orders for the different mitigation measures proposed. Permitting requires further project development and analysis.

  1. Ball Placer Reservoir

The proposed Ball Placer Reservoir site is in the town of Empire, Colorado (location flagged ‘2’ in the map image below). This site has an extensive feasibility study that was completed by WRC Engineering in February 2003. This study was developed using site topography and proposed grading plans were prepared to include cut and fill quantities. The Ball Placer Reservoir site is in the immediate area of three identified mitigation projects addressing floodplain and streamchannel resilience: SR-12, FR-17, and SP-23. Technical assistance is needed to update the 2003 study to include current development costs, evaluation of funding mechanisms and firm yield, hydrology, permitting requirements, and beneficiaries.

Ball Placer Site Notes

• The site has been previously disturbed and existing site conditions include mine tailings from an old gold mining operation.

• No significant wetland impacts are anticipated for this site.

• The potentially hazardous materials in the mine tailing could be cause for environmental concerns that would require additional water quality safeguards such as a flexible membrane liner.

• The preliminary reservoir statistics in the Ball Placer study show a capacity of 110 acre-ft with a surface area of 7.3 acres and a 900 ft long dam with a maximum height of 30 ft.

Proposed Ball Placer Reservoir (2003 study)

  • Dam Crest Elevation: 8573 Ft

  • Reservoir Surface Area: 6.6 Acres

  • Max Dam Height: 32 Ft - Includes 5 feet of free board

  • Max Storage: 110 Ac-Ft

Ball Placer Reservoir schematic plan from the 2003 feasibility study.

2. Flood & Sediment Controls: Corridor Preservation & Wetland Expansion

The drainage of West Fork Clear Creek stream corridor above and through Empire was flagged for several channel and floodplain preservation opportunities by the Pre-Wildfire Planning Study. This heavily wooded basin is at high risk of burning and post-fire flooding and sediment or debris flows. Of note, a sediment control basin was recommended for the upper reaches of this basin in the final report of a 2014 CSM Senior Design project. This project corridor targets the reach of West Fork Clear Creek upstream of Empire, including medium and high-priority projects SR-8, SP-7, SP-8, SP-13.

3. Old Empire Landfill Mitigation

A retired landfill sits just upstream of Empire off Lion Creek, where North Empire Creek appears to run under and through the capped landfill site. Observed conditions downstream of the landfill suggest that acid mine drainage is impacting the water (pictured below). Post-fire flooding or debris flows on North Empire and Lion Creeks could further degrade water quality at this location; a project at this site will help address the identified flood risks at project FR-16 in the identified projects list.

Further development of mitigation proposals is underway with partners in abandoned minelands reclamation.

Observed acid mine drainage conditions downstream of the Old Empire/County Landfill.