| Idaho Snake-
What is the Project About?
The Idaho Snake-Payette Water Quality Hydrologic Unit Project is one of 74 projects funded nationally by USDA. The purpose of these 5-year, federally funded projects is to accelerate the transfer of technology necessary to protect ground and surface water quality while maintaining farm profitability. This project has three phases: (1) determination of groundwater problems in the study area, (2) development of best management practices (BMPs) to deal with observed problems, and (3) implementation of developed BMPs on farms in the study area.
Water quality is an environmental issue that will dominate federal and state legislation in the 1990s. In fact, water quality is a presidential initiative! Because of this there is much at stake with these projects. These projects may be the last chance agriculture has to demonstrate that voluntary best management practices (BMPs) developed to protect water quality can and will work. If these projects are deemed a success, increased regulatory activity may not follow.
Description of Project Area
The Idaho Snake-Payette Rivers Hydrologic Unit Water Quality Project comprises over 840,000 acres in Canyon, Gem, Payette and Washington counties. Within this project are over 3,400 farms covering more than 500,000 acres. Virtually all of the highly productive farmland is irrigated. Agriculture within the study area is very diverse as over 40 different crops are grown. Major crops include: alfalfa (76,800 acres) barley (25,100 acres), beans (12,100 acres), corn (20,800 acres), hops (2,600 acres), oats (9,800 acres), onions (7,700 acres), orchards (12,090 acres), peppermint (11,000 acres), potatoes (5,000 acres), seed crops (8,800 acres), spearmint (2,000 acres), sugarbeets (39,100 acres) and wheat (52,400 acres).
Groundwater monitoring surveys have shown that agrichemicals are contaminating many aquifers in Idaho. The Idaho Division of Environmental Quality has identified the Payette and Boise River aquifers in southwestern Idaho as particularly vulnerable aquifers. These aquifers are found in this hydrologic unit study area. This is a major concern since groundwater is the source of drinking water for over 90 percent of Idahoans.
An extensive amount of baseline groundwater data collected in the study area has shown groundwater contamination by nitrates and Dacthal (a herbicide). Intensive and extensive agrichemical use occurs in the study area. Average nitrogen application is 145 lb/acre. Nitrogen use efficiency by crops in the study area averages 50 percent; however, nitrogen use efficiency is less than 20 percent under poor management conditions. In addition to nitrogen, over 100 agrichemicals are used in the study area.
Shallow sensitive water tables exist within the study area. For marketing and storage reasons, surface irrigation is the preferred method for irrigating most crops in the study area; however, furrow irrigation efficiency average 35 percent and has been measured as low as 20 percent on some farms. Irrigation sets are often long runs and extended duration, which results in deep percolation of soluble materials. This results in a serious loss of water and movement of chemicals under cropping systems where large amounts of water and agrichemicals are applied.
This project site was selected because agricultural cropping systems and hydrological characteristics make groundwater in southwestern Idaho particularly vulnerable. If voluntary BMPs developed and implemented here work, they can be applied in other irrigated parts of the Northwest.
The objectives of this project include:
Three lead agencies are principally responsible for this project: Soil Conservation Service (SCS), University of Idaho Cooperative Extension System (CES) and Agricultural Stabilization and Conservation Service (ASCS).
Other Major Participants:
Payette Soil Conservation District
Canyon Soil Conservation District
Gem Soil Conservation District
Weiser River Soil Conservation District
Idaho Department of Agriculture
Idaho Department of Water Resources
Idaho Division of Environmental Quality
Idaho Soil Conservation Commission
Local Irrigation Districts
University of Idaho Agricultural Experiment Station
West Cassia Soil and Water Conservation District
This brochure, WQ-4, was prepared by R. L. Mahler. Mahler is
Water Quality Coordinator, Soil Science Division, University of Idaho, Moscow,
Idaho 83844-2339. Project office located at: 1630 Third Ave. S., Payette,
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All contents copyright © 1997-2003. College of Agricultural and Life Sciences, University of Idaho. All rights reserved. Revised: January 3, 2003