The drought which the Upper Gunnison River Basin experienced in 2002 and 2003 focused attention on the vulnerability of domestic and other water users in the basin to calls from senior irrigation water rights within the basin as well as senior water rights downstream from the Wayne N. Aspinall Unit. Even though neither the senior irrigation rights diverting from the Slate River nor the Colorado water Conservation Board (CWCB) instream flow rights in the Slate River had ever placed a call when water was in short supply, it became apparent that a significant number of domestic wells diverting from the Slate River had been issued permits based on plans for augmentation which were inadequate. In some cases, the replacement water supply was based upon rights that are curtailed during dry years. In other cases, augmentation ponds were never constructed or were not functional due to sediment, inoperable outlet works or other defects. In 2003, the Division Engineer advised well owners that the Division of Water Resources would begin administering domestic wells with non-functioning plans for augmentation. This announcement placed a significant number of domestic wells in the Slate and East River drainages at serious risk of curtailment as a result of calls by senior irrigation ditches diverting from those streams and the CWCB instream flow water rights. The District’s Meridian Lake Reservoir project was initiated to respond to this need for replacement water.
Following two years of negotiation and due diligence, and obtaining a decree approving a plan for augmentation (Case Nos. 03CW107 and 2018CW3002), the District purchased Meridian Lake Reservoir in August, 2005. The District then made improvements to the dam and outlet structure to improve its efficiency and to comply with requirements of the State Engineer. The total cost of the purchase and improvements was approximately $1,400,000.00.
Under the plan for augmentation, the District sells Augmentation Certificates in increments of 0.05 acre-feet of water per year (Base Units) which entitle the holder to have water released from Meridian Lake Reservoir to replace out-of-priority depletions. The owner of an Augmentation Certificate is entitled to the benefits of the District’s plan for augmentation and is not required to implement or amend an individual plan. As of April 30, 2019, the District has sold 561 Base Units.
The Meridian Lake Reservoir plan for augmentation has two unusual features. First, owners of existing wells whose wastewater is piped to the East River Treatment Plant would have had to purchase nine Base Units if required to replace their depletions from domestic indoor use for 365 days per year. At the initial price for Base Units, the cost to augment domestic indoor use only for a well serving a single dwelling unit connected to the treatment plant would have been $13,500.00. For virtually all of these existing well owners, local residents who work in the area, such a requirement would have made the such augmentation unaffordable. To solve this problem, the District negotiated a settlement with the Colorado Water Conservation Board – holder of senior instream flow water rights in the Affected Reach – that permitted these well owners to satisfy their augmentation requirements by purchasing two Base Units.
Secondly, depletions to senior instream flow water rights occurring during the Winter months cannot be replaced by releases from Meridian Lake Reservoir at the time they occur because of icing at and below the outlet works of Meridian Lake Reservoir and because any water released must be passed through Meridian Lake Park Reservoir No. 1. The latter reservoir is normally frozen over in Winter, making it difficult or impossible to pass releases of replacement water through the reservoir. Consequently, injury could result to the CWCB instream flow rights during the rare periods of shortage occurring in the Winter months. The District negotiated a settlement with the CWCB that provides a “Winter mitigation pool” created by assessing each Base Unit an amount of water approximately equivalent to ten days’ depletions (in addition to actual depletions and transit loss). Pursuant to the settlement, the CWCB is be entitled to request that the Division Engineer order releases from Meridian Lake Reservoir at any time during late Fall or Winter when conditions (or future improvements in technology) would permit the discharge from the reservoir to flow to a reach of the stream protected by an instream flow right. The CWCB may request the release in any amount up to the total Winter mitigation pool, whether or not the instream flow rights could be calling.