Chambers Reservoir

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Chambers Reservoir, located on the Eastern edge of Grandview Estates along Chambers Rd., is a 1,400 acre-foot storage facility owned by the Arapahoe County Water and Wastewater Authority (ACWWA), built by ACWWA in association with their ACWWA Flow Project started in 2009 to expand ACWWA’s non-potable irrigation system. When in-use it will tend to be filled to capacity before Spring when water will start to be pulled out for irrigation purposes. 

Where’s the Water?

Chamber's reservoir was originally built with a clay liner that almost immediately failed, allowing water to seep out while potentially allowing leakage into the reservoir from underground sources (possibly the Upper Dawson). ACCWA was never able to fill the reservoir to capacity nor use it for irrigation.

What’s Chambers’ Status?

ACCWA has obtained permission from Douglas County and other authorities to remediate and re-grade Chambers, targeted for completion and use by ACCWA by Summer 2020. The work includes these improvements:

  1. Raising reservoir bottom above groundwater levels (which includes transporting and stockpiling 1,000s of yards of dirt),
  2. Regrading side slopes (to recapture volume lost to raising bottom),
  3. Addition of finger drains to maintain regional groundwater flow at reservoir bottom,
  4. Minor drainage improvements at permiter access road, and
  5. Installation of new geosynthetic liner to minimize seepage, replacing the original clay barrier. This liner will be visible as it must extend above the water line.

ACCWA has provided a truck access plan designed to keep dust and vibrations to a minimum: Download a PDF of the plan.

ACCWA has also created a project flyer providing a nice summary of the project: https://drive.google.com/open?id=1uSqAAUNogKH7y1xBny547SJdQriDRh06

Currently, GERWCD is working with ACCWA on a new water testing scheme to ensure no cross-contamination with resident's wells. GERWCD sent a letter to ACCWA  with the following requests/recommendations:

GERWCD is grateful for the monitoring program that the Douglas County Planning Commission mandated at the initial L&E for the Chambers Reservoir which has allowed for evaluation of the health risk,  We are also grateful for the installation of the synthetic liner by ACWWA.  We recommend the following conditions for approval:

  • ACWWA shall complete the baseline analysis round for all sample points by sampling and analysis of the water for conductivity, TDS, iron, manganese, radon-222, uranium, radon 226, and radium 228.

  • Results above the MCL shall be resampled for analysis of those analytes for confirmation.

  • Results will be reviewed to determine if any additional analysis needs to be continued on the monthly sampling.

  • Monthly sampling shall be conducted from house spigots and monitoring wells for conductivity and TDS.

  • Results shall be provided to GERWCD within 30 days

  • Monthly samplings shall be terminated upon successful installation and testing of the synthetic liner.

Documents & ACWWA Reports

July 13 Experts Meeting - Joint Statement

ACWWA monitors and the reservoir at the surface and via wells, testing for manganese and other compounds. These reports have been produced by ACWWA and their contracted agents:

Chambers Reservoir Quality Monitoring - July 2018
Chambers Sampling Report - July 2018
Chambers Reservoir Quality Monitoring - June 2018
Chambers Sampling Report - June 2018