WSP12534

• File Number: 8282.400
• Description: Colorado River Operations and Accounting - Deliveries to Mexico
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 3/1/2000
• Author: Unknown
• Title: New Report Compiles Data on Dam Removals - Excerpted from Nonpoint Source News-Notes - Number 60 - 03-01-00
• Water Supply Pro - Doc Type: Publication

California Farmers
Adopt Tradable
Loads Program to
Reduce Selenium in
Agriculture Irrigation
Runoff
(continued)

001059

The Grassland Basin Drainage Steering Committee

For several reasons, the rule did not have a significant impact during water year 1998 (October 1,
1997-September 31, 1998). To begin with, water year 1998 was nearly over by the time the rule
was adopted. More importantly, however, water year 1998 was an El Nifio year that yielded the
heaviest rainfall in the Grassland Drainage Area during the 50-year period of record. Because
increasing irrigation efficiency plays a major part in lowering selenium discharge, the heavy rains
caused the Grassland Area Farmers to exceed their regional selenium load targets even when they
were not irrigating. The GBDSC's oversight committee, charged with ensuring that the cap is met
each year, determined that "uncontrollable and unforeseeable events" caused the exceedances
during those months in water year 1998, resulting in only one trade.

The second year of the program was much more successful. The GBDSC adopted a rule
establishing a tradable loads program for water year 1999 on January 18, 1999. The 1999 rule
differs slightly from the 1998 rule. In 1998, the fee for anyexceedance over the regional selenium
load target was divided among the districts that exceeded their selenium load allocation (SLA). In
the 1999 water year, the rule also included a fee and rebate system that imposed fees on districts
that exceeded their SLA (regardless of whether the region exceeded its target) and awarded rebates
to districts whose discharge was lower then their SLA. In 1999 there were eight trades. The rule for
water year 2000 remains the same except that the SLAs are set even lower and the fee for not
meeting them is even higher. Two trades have taken place already, and a third is nearing
completion; several more are under consideration.

Progress in the Grassland Drainage Area

The tradable loads program works together with other district-specific policies to reduce selenium
influx. Because increasing irrigation efficiency reduces selenium discharge, many of the programs
designed to encourage water conservation through irrigation efficiency also decrease selenium
discharge. For example, Broadview Water District, one of the member districts of the Grassland
Area Farmers, pioneered a tiered water pricing policy in which increasing block-rate pricing
motivates the use of water conservation practices. Other districts in the Grassland Drainage Area
have followed suit by implementing their own tiered water pricing policies. Additional
incentive-based water conservation programs in the Grassland Drainage Area include low-interest
state revolving fund loans and land management incentives. This work is supported by Clean
Water Act section 319 funding from EPA for controlling nonpoint sources.

Irrigation system improvements in the Grassland Drainage Area include quarter-mile furrows (in
place of half-mile furrows, which cause excess percolation at the top of the furrow), gated pipe
(allowing more accurate control of irrigation water), sprinklers, and drip irrigation systems.
Districts also pursue methods aimed directly at selenium reduction, including recirculation of
drainage water, displacement of selenium by using selenium-laden water to wet roads for dust
control, and even some selenium removal projects. Currently, the districts are still in the
experimental phases of such selenium removal projects. The most promising treatment will likely
be a combination of reducing the volume of drainage through irrigation on salt-tolerant crops and
membrane treatment such as low-pressure reverse osmosis followed by a solidification process and
disposal of solids.

With the exception of the very wet water year 1998, selenium discharge data show continual
reduction in selenium discharge since water year 1995. In fact, in 1999 selenium load targets were
met every month and the loads are predicted to be the lowest since 1986. Project Director Susan A.
Austin believes that the tradable loads program will soon catch on in other areas. "It is a working
demonstration of how market forces can be used to create the right incentives for meeting
environmental goals in a fair and efficient manner," she said. "It is one important policy tool among
the many that the Grassland Area Farmers use to control subsurface drainage."

[For more information, contact Joe McGahan, Drainage Coordinator for the Grassland Area Farmers,
Summers Engineering, Inc., P.O. Box 1122, Hanford, CA 93232. Phone: [phone]; e-mail:
[e-mail]; or Susan A. Austin, Project Director, P.D. Box 31934, San Francisco, CA
94131-0934. Phone: [phone]; e-mail: [e-mail].]

MARCH 2000, ISSUE #60

NONPOINT SOURCE NEWS-NOTES

17