Draft Excuetive Summary: Tamarack Modeling Team December 13 2002

• Description: related to the Platte River Endangered Species Partnership ‎(aka Platte River Cooperative Agreement [CA]; aka Platte River Recovery Implementation Program [PRRIP])‎
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 12/13/2002
• Author: Halstead, Mary, CDOW and Val Flory, NCWCD
• Title: Draft Excuetive Summary: Tamarack Modeling Team December 13 2002
• Water Supply Pro - Doc Type: Correspondence

DRAFT EXCUETIVE SUMMARY
TO: Tamarack Modeling Team
FROM: Mary Halstead, CDOW1
Val Flory, NCWCD2
SUBJECT: Tamarack Recharge Project Model
DATE: December 13, 2002
CDOW, NCWCD, Colorado State University, and Colorado Division of Water Resources
are working together to monitor site hydrology and develop a groundwater model for the
Tamarack Recharge Project (Project). Located on CDOW's Tamarack State Wildlife
Area (SWA), the Project redistributes excess South Platte River flows through managed
groundwater recharge. The Project is designed to pump wells in the winter /spring
season, when there is no call on the South Platte River, and then to discharge this water to
recharge ponds. This recharge water becomes part of the alluvial groundwater system,
and travels back to the South Platte River providing "recharged" water to the South Platte
River when additional flows are needed.
The facilities currently include 10 pumping wells located along the South Platte River
and three recharge ponds located within the Sand Hills several thousand feet south of the
river. At buildout, this project will pump an average of 30,000 acre -feet of water into
recharge ponds, where a portion of that water will return back to the South Platte River
during times of shortage to provide flows to benefit native fish species in Colorado, and
incidentally provide flow for threatened and endangered species in central Nebraska.
Groundwater and surface water monitoring are providing critical data needed to assess
changes in wetland and waterfowl habitat, and to track groundwater returns to the South
Platte River. A numerical groundwater model has been developed to optimize Project
operations and better define the complex interactions of the site - specific hydrogeology,
groundwater pumping, and surface recharge pond.
TAMARACK MODELING EFFORT
The Tamarack modeling effort is a process. The model is used as a project operation and
management tool and is continually updated and improved as operations change. The
primary objectives of the modeling effort are to: 1) determine the timing, amount and
location of return flows to the South Platte River, 2) optimize the design and operation of
1 Colorado Division of Wildlife
z Northern Colorado Water Conservancy District
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