WSP09303

• File Number: 8220.106
• Description: Animas-La Plata
• State: CO
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 1/1/1979
• Author: Unknown
• Title: Questions and Answers - Animas-La Plata Project
• Water Supply Pro - Doc Type: Report/Study

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MAS-LA PLATA PROJECT

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12, How MUCH STORAGE WOULD BE NEEDED TO CARRY THE SERVICE AR~A THROUGH
PERIODS WHEN SENIOR RIGHTS WOULD PREVENT DIVERSIONS? Hy rology studies
indicate that approximately 1500 acre-feet of storage would be needed to meet
an annual demand of 13,800 acre-feet by the service area. This does not allow
for any water rights that the Southern Ute Tribe may receive from the Courts.

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13, WHAT ALTERNATE METHODS OF DEVELOPING WATER ARE OPEN TO THE SERVICE AREA?
The City of Durango has studied 8 alternative methods of developing a mun1ci-
water supply. The studies are summarized on page no. 8. All but one of these
plans would provide 1500 acre-feet of storage. The plans that would enlarge
the City's existing reservoir is limited to 710 acre-feet, the maximum capaci-
ty of the site. A plan utilizing a reservoir site in Horse Gulch shows to be
the most attractive. Although the cost per acre-foot is approximately the
same as that for the project, the project has a number of advantages over the
HorSe Gulch site. First the project would guarantee 18,530 acre-feet of water
at all times. Refer to question number 10. Horse Gulch would, hopefully,
supply 13,800 feet without shortages provided the Southern Ute Tribe does not
exercise its potential water rights. Horse Gulch site has the disadvantage
of being located over an abandoned land fill and has a drainage area that
encompasses one of the most logical sites for a future land fill. The studies
are based on current costs, including operation and maintenance costs. Local
REA power rates for pumping will undoubtedly increase at a faster rate than
will Colorado River storage Project power rates used for project pumping.

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14, How WILL THE PROJECT AFFECT DURANGO WATER BILLS? Durango's water system
is currently very inexpens1ve. Most of its water comes from the Florida
River. This is a gravity system that was paid for many years ago. AsDurango
grows and has to expand its system, the cost of water is bound to increase.
Durango has only 129.5 acre-feet (42 million gallons) of active storagecapaci-
ty and no storage water rights. The major cost of future expansion will in-
volve the construction of adequate storage facilities to carry Durango through
drouth periods in which it will not be allowed to divert from the Animas River
because of other senior water rights. There are a total of 655 second feet of
priority water right. Even though Durango's water bills are bound to increase,
the alternative studies described above show that the project can develop a
municipal water supply for a lesser cost than the cheapest alternatives, pro-
vided the alternative develops a comperab1e supply.

15. WILL DURANGO AND THE OTHER MUNICIPAL ENTITIaS BE LIMITED TO THEIR IN-
ITIAL ALLOCATION OF WATER? Because it is ifficu1t to identify where
growth may take place, it has been proposed that the new Animas-La Plata Water
Conservancy District subscribe for a small portion of the 8,200 acre-feet of
water now identified for the entities of the Durango service area. With this
proceedure water can then be allocated to the entity in which extra ordinary
growth takes place.
If there is a need to reallocate water between purposes such as from
irrigation to municipal, it will be necessary to renegotiate the entire re-
payment contract. This would probably be undesirable in that the irrigation
repayment capacity would no doubt be computed at a higher rate, thus increasing
the Conservancy District's total obligation.

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ENVIRONMENT - SALINITY, RECREATION, FISH & WILDLIFE

1, WHAT ARE THE ENVIRONME~TAL IMPACTS ON THE ANIMAS RIVER? Pumping from the
Animas R1ver would deplete 1ts flow by annual average of 24 percent. Half of
this amount would be pumped during May, June and July. Although the
pumping rate would be at its highest during this period, the flow depletion
would be only 15 percent because of the high flow in the river at the time.
The greatest rate of depletion as a result of pumping would occur during
October or November when the depletion would reach an average of 44 percent-No
depletion would occur approximately 11 percent of the time, when pumping would
be discontinued because of low flows, equipment maintenance, or no need for
more water in Ridges Basin Reservoir. At other times, the flow of the Animas
River would actually be supplemented by the release of water from Ridges Basin.

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