FLOOD10319

• County: Arapahoe
• County: Jefferson
• Stream Name: South Platte River
• Basin: South Platte
• Title: Chatfield Reallocation Study Storage Use Patterns
• Date: 2/1/2003
• Prepared For: CWCB
• Prepared By: Brown and Caldwell
• Floodplain - Doc Type: Project

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5.3 GREEN'\lAY FOUNDATION'S AND CITY OF LITTLETON'S PROPOSED USE
OF CHATFIELD RESERVOIR REALLOCATED STORAGE

The Greenway Foundation and the City of Littleton propose to utilize reallocated storage in
Chatfield Reservoir to supplement minimum streamflows in the South Platte River through the
Denver Metro area. Water available under a junior water right or "free river" conditions would
be diverted to storage for this purpose. This diversion to storage was estimated using Denver
Water's CHATFREE data.

Target release schedules for the Greenway Foundation's use ofreallocated storage in Chatfield
Reservoir were developed based on maintaining a flow of 150 cfs downstream from the
Littleton/Englewood Wastewater Treatment Plan (WWTP) discharge from Memorial Day
weekend through Labor Day weekend. The City of Littleton proposes to utilize the reallocated
storage to supplement the minimum flows in the South Platte River. Their target flows are 30 cfs
in the winter (November through March) and lOO cfs for the rest of the year in the reach ofthe
South Platte River through South Platte River Park.

For purposes of this investigation, the Greenway Foundation's and the City of Littleton's
instream flow targets were combined into one minimum instream flow target immediately below
the Littleton/Englewood wastewater treatment plant (WWTP) discharge:

.

Memorial Day to Labor Day: 150 cfs
November-March: 30 cfs
April-May and September-October: 100 cfs

.

.

Estimated South Platte River flows immediately downstream from the Littleton/Englewood
WWTP for existing conditions for the study period (1946-1996) were provided by Denver
Water.

5.4 CENTRAL COLORADO WATER CONSERVANCY DISTRICT'S PROPOSED
USE OF REALLOCATED CHATFIELD RESERVOIR STORAGE

The Central Colorado Water Conservancy District proposes to utilize releases from reallocated
storage in Chatfield Reservoir to augment out of priority depletions from wells under Central's
augmentation plan. Water available under a junior water right or "free river" conditions would
be diverted to storage for this purpose. This diversion to storage was estimated using Denver
Water's CHATFREE data.

Central proposes to release available water from reallocated storage at a relatively constant rate
of 8 cfs in the summer (June - August) and 7 cfs during the remainder of the year.

P :\Data\GEN\CWCB\Chatfie Id\Report 12 .02\RevisedChatReport 1 03\Report2-03 .doc

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