Unintended Consequences due to Salinity Management – Example from the Lower

Colorado River

Multi-State Salinity Coalition2012 Annual Conference

January 25, 2012

Chuck CullomColorado River Programs Manager

Colorado River Basin

• Study Structure and Schedule

• Summary of Key Activities

• Upcoming Meetings• Further Discussion,

Follow-up

Complex River System 10 major reservoirs

14.7 maf Av. Supply 34 million people 4 million irrigated acres Salt load long-term

concern to users

Distribution of Flow and Salt Load

Salinity increases downstream

Natural sources Springs Tributaries Evaporation

Ag runoff M&I discharges

Lower Colorado River System

Lower Colorado River Key Facilities

• Study Structure and Schedule

• Summary of Key Activities

• Upcoming Meetings• Further Discussion,

Follow-up

Imperial Dam Point of diversion for 5 maf/yr

Morelos Dam Point of delivery for Mexico - 1.5

maf/af Yuma Desalting Plant Cienega de Santa Clara

Significant wetland in Mexico relying on US drainage water

Salinity History in the Lower Colorado River

Lower Colorado River Salinity Requirements

• Study Structure and Schedule

• Summary of Key Activities

• Upcoming Meetings• Further Discussion,

Follow-up

Numeric Criteria Hoover – 723 ppm Parker – 747 ppm Imperial – 879 ppm

International Water Treaty Delivery point = Morelos Dam Salinity Differential Imperial Dam + 115 ppm +/- 30

ppm

Sources of Water for Delivery to Mexico

Colorado River Water Natural drainage Ag drainage

Pumped Drains

MAXIMIZE Efficient Water Management + MEET Treaty Requirements

Yuma Area Return Flows ~80% CR Water ~20% Drainage Linkage between

Surface flows Drainage Pumping

Yuma Area Salinity Management +

Accounting

Alternatives

What do we already know?• YDP operated at 30% capacity from May 3, 2010 to March 26,

2011• YDP operations diverted flow away from Bypass Drain/Ciénega• YDP operations added brine to Bypass Drain• 30,000 acre-feet of “arranged water” added to Bypass

Drain/Ciénegain 18 month period from Oct 29, 2009 until April 28, 2011

• Magnitude 7.0 earthquake, April 4, 2010• Extensive fire, March 23-25, 2011 There are no

simple experiments in

nature