WSP05903

• File Number: 8583
• Description: Rio Grande Decision Support System
• State: CO
• Basin: Rio Grande
• Water Division: 3
• Date: 2/1/1998
• Author: Dr. John W. Hernande
• Title: Evaluation Of Salvage Well Production Problems In The Closed Basin Of The San Luis Valley Colorado
• Water Supply Pro - Doc Type: Report/Study

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CC16Jl

reported to be in the eastern half of the Closed Basin and along the borders of tributary streams

entering the Basin (NRC, page 121), The NRC places the maximum recovery at about 75 percent

of the "pooled water" ,and consumptive use by native grasses and brush, but none of that being

used by trees, The report concludes that some of the existing depletions by crops and native

vegetation will continue after the sump drains are installed (NRC, pages 123-125), Noting that

the 75 percent recovery is an upper limit, the NRC provides a rounded estimate of the total net

annual recovery by drains of 40,000 acre-feet per year (Table 105 and page 125), With respect to

the use of sump-drains as the salvage technique, the NRC report offers an additional caution: a

reduction in yield will occur after the accumulated water in soil storage has been withdrawn, The

NRC report (page 16) concluded that a sump-drain and trunk~drain system will be able to

salvage about 40,000 acre-feet per year with an initial salt content on the order of 1.5 tons per

acre-foot of water,

THE NATURE OF THE CURRENT PROBLEM AS REPORTED BY OTHERS

As noted in the first section of this report, the major problem associated with the

Bureau's San Luis Project is the reduction in the production of some of the salvage wells, and the

resulting failure of the Project to produce the volume of water that was anticipated in the design,

There is little, or no disagreement as to the source of the problem: bacterial growths have

reduced yields in some of the salvage wells, There are a variety of opinions on the nature of the

bacterial masses that have caused the reduced production, Reports have been made available

from eight consulting groups that have performed services for Reclamation related to the

bacterial growth issue, Some of the reports are from firms that have taken samples from affected

wells, and lor performed multiple laboratory analyses on samples, Some of the reports are from

contractors who have undertaken well treatment and cleaning operations and who have done

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