Chapter 12 - § 12.11 • RECENT WATER STORAGE INNOVATIONS

• Jurisdiction: Colorado

§ 12.11 • RECENT WATER STORAGE INNOVATIONS

If "necessity is the mother of invention" as Ben Franklin and others have indicated, then the increasing water demands have led to several storage innovations, as described below.

§ 12.11.1—Gravel Pit Storage Reservoirs

The Environmental Protection Agency's veto in 1989 of a necessary permit for the construction of the one million acre-foot Two Forks Reservoir Project of the Denver Water Board seems to have signaled the end of the traditional large storage reservoir projects in Colorado. Since then, the population has increased in the metropolitan Front Range corridor by millions of new residents. As a result of this increased water demand and the growing inability to obtain traditional governmental construction approvals due in large part to various environmental statutes, a market has been created in converting mined-out gravel pits into municipal reservoirs. No additional state, local, or federal permits are yet required, although the state engineer has adopted certain criteria to permit storage.⁸⁹

The Office of the State Engineer treats gravel pits as "wells" since the 1988 ruling in Zigan Sand & Gravel v. Cache La Poudre Water Users Association.⁹⁰ The year following that decision, the General Assembly passed Senate Bill 89-120, which amended C.R.S. § 37-90-137(11) and "grandfathered" gravel pits prior to January 1, 1981, but required all others to augment surface evaporation in excess of historic conditions. The statute survived a constitutional challenge in Central Colorado Water Conservancy District v. Simpson.⁹¹ Because the cost of obtaining senior surface rights and processing augmentation plans to replace surface evaporation is very expensive, aggregate companies had to change the way they operated. In the past, mined-out gravel pits reverted to small lakes or ponds and the few gravel companies⁹² that bought the properties would tend to donate them to recreational users, such as fishing or water ski clubs. These new costs encouraged secondary uses that did not cause evaporation, such as landfills or even lining to keep out percolating ground water. Nowadays, most mining companies in the Denver metropolitan area purchase gravel reserve properties in fee and install "slurry walls" around the perimeter of the mining area to keep ground water out, thus reducing electric pumping costs and increasing the efficiency of mining. This also creates a water storage vessel that is highly coveted by municipal water suppliers in the vicinity of the mine and those that have "reusable water supplies" that need to recapture sewage effluent downstream of treatment plants. In this context, Arvada, Aurora, Denver, Thornton, Westminster, Consolidated Mutual Water Company, and South Adams Water and Sanitation District have all obtained the right within the last 20 years to store in converted and reclaimed gravel pits along the South Platte River north and east of Denver. This has been accomplished by both condemnation and by negotiation under threat of condemnation.⁹³

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