BOARD02441

• Board Meeting Date: 3/26/2001
• Description: ISF Section - Donation Water Division 7 - Carbon Lake Ditch
• Board Meetings - Doc Type: Memo

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STATE OF COLOMD

Colorado Water Conservation Board
Department of Natural Resources
1313 Sherman Street, Room 721
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
www.cwcb.stale.co.uS

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Bl/tOwens
Governor
Creg E. Walcher
Executive Director
Rod Kuharich
ewes Director
. Dan McAuliffe
Deputy Director

MEMORANDUM

TO:

Members, CWCB

Dan Merrim~
Anne Janicki

FROM:

DATE:

March 14,2001

SUBJECT:

Agenda Item 21, March 26 - 27,2001 Board Meeting-
Stream and Lake Protection - Donation
Water Division 7 - Carbon Lake Ditch

Attached for the Board's consideration is a draft Donation Agreement for the Carbon Lake Ditch
which is located northwest of Silverton in San Juan County (see attached map),

Backl!round

The Carbon Lake Ditch diverts from the Big Hom Gulch drainage, which is tributary to Mineral
Creek (North Fork) in the upper Animas River basin. The Carbon Lake Ditch was decreed in 1966, for 15
c.f.s., with an appropriation date of July 13, 1954. The ditch diverts water out of the Animas River basin
(Water Division 7) to irrigate 675 acres in Montrose and Ouray Counties (Water Division 4).

The upper Animas River basin includes the Silverton and Red Mountain Mining Districts. Metal
contamination and acid mine drainage in these Districts is a serious concern to state and local entities.
The Animas River Stakeholders' Group (ARSG), whose mission is to "improve water quality and aquatic
habitat in the Animas watershed", has detennined that drainage from the Kohler Tunnel contributes the
largest amounts of zinc, cadmium, aluminum and copper to the Animas watershed. Accordingly, the
ARSG has designated the tunnel drainage as the highest priority for remediation.

Researchers believe that the Kohler Tunnel drains water seeping into the San Antonio Mine. The
Carbon Lake Ditch traverses the mine complex near the headwaters of the basin. Recent studies have
indicated a high probability that the ditch is leaking water into the mine workings. Additionally, ice
build-up and heavy monsoon rains occasionally breach the ditch and cause erosion and seepage into the
mine. ARSG has detennined that the most practical solution to the drainage problem is to eliminate the
source ofthe water that infiltrates the mine.