WSP08256

• File Number: 8272.100.60
• Description: Colorado River Basin Salinity Control Forum
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 10/1/2002
• Author: CRBSCF
• Title: 2002 Review - Water Quality Standards for Salinity - Colorado River System
• Water Supply Pro - Doc Type: Report/Study

Colorado River water users in the Lower Basin have suffered significant economic losses due
to long-term continued use of water with elevated salinity levels. Figure 2-3 shows known salinity
damages in Arizona, California, and Nevada resulting from long-term continued use at various levels
of salinity based on the Metropolitan-Reclamation Salinity Management Study conducted by
Reclamation and The Metropolitan Water District of Southern California. At the 1999 salinity level
of 669 m:g/L at Imperial Dam, Figure 2-3 shows direct economic damages currently nearing $200
million per year. This would increase to $500 million per year if salinity were allowed to return to
the numeric criteria levels of the standard (879 mg/L at hnperial Dam). Salinity impacts from the
use of 1.5 maf per year of water delivered to Mexico have not been quantified but Mexico has
indicated that they are significant.

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Agricultural water users suffer
economic damage as a result of using highly
saline waters through reduced crop yields,
added labor costs for irrigation management,
'it
and added drainage requirements. Urban ~
users incur additional costs due to more E 400
frequent replacement of plumbing and water i
using appliances, use of water softeners and tll 300
the purchase of bottled water. Industrial ~
users and water' treatment and waste water
utilities incur reductions in the useful life of
system facilities and equipment from higher
levels of salinity .

Salinity Damage Curve

700

600

500

200

100

o
50g

600 700 800 900 1000
Salinity at Imparlal Dam (mg/L)

Another significant economic loss in
the Lower Basin results from the regulatory
restrictions imposed by local and regional water quality standards and management programs which
protect ground water supplies. Regulatory agencies have placed restrictions on reuse or recharge of
waters that exceed specified salinity levels. If the salinity . levels of the Colorado River increase,
these regulatory actions result in additional expensive treatment of water prior to reuse or disposal
instead of reuse of the waters. If disposal options are selected, additional costly water must be
developed or imported to meet the demands previously met or that could be met by water reuse.
These costs are not currently captured in the above damage curve.

Figure 2-3. Salinity Damages in Lower Basin.

Future Water Depletions

Qne of the significant factors affecting salinity concentrations is water use. Estimates of
projected water use through the year 2020 were developed by the Basin states for the 2002 Review.
Table 2-2 presents a sununary of these estimated water depletions in the Upper Colorado River
Basin, and from the mainstem of the Lower Colorado River.

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