WSP03817

• File Number: 8102
• Description: Arkansas River Basin Basic Hydrology
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 5/7/1999
• Author: Inter Fluve Inc
• Title: Fluvial Geomorphic Assessment of Upper Arkansas River Final Report
• Water Supply Pro - Doc Type: Report/Study

3.2. F/ow Diversions and Augmentations

3.2.1. The Diversion/Augmentation System

The Upper Arkansas River basin has a long and complex history of trans basin diversions
and augmentation of natural channel flows with diverted water (Figure 3.1). Transbasin
diversions were first constructed on tributaries of the upper Arkansas River as early as the
early 1900's when water was conveyed from the Colorado River basin through ditches to
placer mines in the Arkansas River Valley (Jewell, 1999). Additional diversions began in
1925 when the Busk-lvanhoe system (the Carlton Tunnel) began importing water to Lake
Fork Creek, a tributary that enters the Arkansas River 1.5 miles downstream ofCalifomia
Gulch (Abbot, 1985). In August 1962, the Fryingpan-Arkansas River Project was
authorized by the U.S. Congress, establishing the onset of a major construction effort to
divert Colorado west slope water to the east slope for supplemental irrigation and
municipalities.

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Flow augmentations occur on the Arkansas River upstream of California Gulch via the
Ewing and WUrtz Ditch, and Wurtz Ditch Extension. These ditches discharge into
Tennessee Creek. The East Fork Arkansas River also receives additional flows from the
Columbine Ditch.

Augmentations into the Lake Fork basin are derived from the Busk-lvanhoe, Boustead,
and Homestake Tunnels that flow into and store west slope water in Turquoise Lake
Reservoir, which is impounded by Sugarloaf Dam (Figure 3.1). The Homestake tunnel
began operation in May, [967, followed by the Bousted tunnel in May, 1972. Prior to
June, 1981, both imported and native flows were delivered down Lake Fork Creek to the
Arkansas River.

3.2.2. Hydrologic Effects

Two major subwatersheds that are utilized to convey diverted flows contribute water to
the project reach. First, in the portion of the project reach located upstream of the Lake
Fork confluence, native flows are augmented by water diverted from the Colorado Basin
and conveyed down Tennessee Creek and the East Fork Arkansas River. At the Lake
Fork confluence, additional flows that enter the project reach reflect native inputs from
Halfmoon Creek, as well as and releases from SugarloafDam, which stores both native
and augmented flows.

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The patterns and hydrologic effects of the augmentation and reservoir release practices
have been evaluated in limited detail (Studzinski 1996; O'Neill and others, J 997;
Dominick and O'Neill, 1998; Jewell, 1999). Upstream of the Lake Fork confluence, the
Ewing, Wurtz, and Columbine ditches have contributed up to 10-15% of the total annual
flow recorded just downstream at the USGS Leadville Junction gage, and during peak
flows, have contributed as much as 22% of the total streamflow (Studzinski, 1996).

May 7. 1999

Fluvial Geomorphological Assessment
Upper Arkansas River

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