SPDSS_Task7-2_WellUseWellAugmentationPlans

• Title: SPDSS Task 7.2 - Well Use and Well Augmentation Plans
• Description: This memorandum and associated appendices characterizes the 20 largest well augmentation plans and develops recommendations for representing well use and augmentation in SPDSS modeling efforts.
• Decision Support - Doc Type: Task Memorandum
• Date: 12/14/2007
• DSS Category: Groundwater
• DSS: South Platte
• Basin: South Platte
• Contract/PO #: C153953
• Grant Type: Non-Reimbursable
• Bill Number: SB01-157, HB02-1152, SB03-110, HB04-1221, SB05-084, HB06-1313, SB07-122
• Prepared By: Leonard Rice Engineering

• The association of a well to the augmentation plan ID may be incorrect in HydroBase.
System Overview
Central WAS has claimed recharge projects, ditch company and reservoir company shares,
augmentation wells, and leased reusable supplies in its plan. Some of the WAS shares are
already changed for augmentation uses. Other shares owned by WAS; shares owned jointly by
WAS and GMS, and shares subsequently purchased by the subdistricts that have been included
in numerous succeeding Water Court change case applications (about 35 pending change cases
for Central, both GMS and WAS, as of early 2007. Central also has annual and multi-year leases
for the use of reusable effluent and ditch and reservoir company shares from various entities
included in numerous SWSPs filed to supplement the claimed sources in the WAS application.
Per the WAS application, lagged well depletions and recharge accretions to the South Platte
River are to be accounted via the Glover method. Wells under the WAS subdistrict were
typically not metered, although all wells covered under the Central plans will have meters
installed by April 2008. Per the WAS application, out-of-priority lagged well depletions are to be
administered with priority dates specific to the ground water rights included in the plan.
Recommendations
The Central operations are complex due to the ever-changing portfolio of water supplies used for
augmentation purposes. Recommendations for representing the Central WAS augmentation plan
in the initial development of the SPDSS StateMod Water Resources Planning Model input files
should be determined after the final decree in Case No. 03CW99 is adjudicated. In the meantime,
conditions decreed in the Central GMS plan are claimed in the WAS application and can be used
for modeling purposes.
Augmentation Plan Demands
To represent pumping for the entire SPDSS study period (1950 to present), well pumping to
supply irrigated lands should be estimated by the consumptive use algorithm in StateCU and
StateMod, to meet the irrigation water requirement less simulated surface water deliveries (if
applicable). Lagged well depletions affect river flows based on timing and location factors
defined in StateMod input files. Lagged depletions should be accounted in six Central WAS
depletions plan structures corresponding with administration of the augmentation plan in six
reaches, Reach A through Reach F, listed below based on approximate administrative locations:
• Riverside Ditch to Upper Platte & Beaver Ditch (9903394_A)
• Lower Platte & Beaver Ditch to Riverside Ditch (9903394_B)
• St. Vrain Creek-South Platte River confluence to Lower Platte & Beaver Ditch (9903394_C)
• Beebe Draw to confluence with South Platte River (9903394_D)
• Boxelder Creek to confluence with South Platte River (9903394_E)
• Burlington Ditch to St. Vrain Creek-South Platte River confluence (9903394 F)
Wells associated with the Central WAS plan should be assigned to the various administration
reaches based on spatial location.
A-13 of A-106