Sun, Feb. 23

New NAU program focuses on Verde watershed<br>Ongoing studies reveal more layers of Verde groundwater system

Northern Arizona University is establishing a Verde Watershed Research and Education Program with a $250,000 grant from the Salt River Project.

The program will pay for student research projects relating to the Verde basin’s water quantity, an annual Verde Watershed Symposium, and public education, program co-chair Abe Springer of NAU’s geology department said.

The program also can provide a central repository in Flagstaff for the massive amount of studies experts have conducted on the Verde watershed over the past several decades, program co-chair Charlie Schlinger of NAU’s civil and environmental engineering department added.

The college and Salt River Project (SRP) chose to focus on the Verde watershed instead of other Arizona watersheds because of the exceptional cooperation and study coordination going on here, Springer said.

Only a small part of Coconino County, where NAU is located, is within the Verde watershed. Most is within Yavapai County.

"Yavapai County is pretty progressive," Springer said.

The Yavapai County Board of Supervisors created a Water Advisory Committee last year to encourage cooperation between watershed users and coordinate water supply studies.

At times during the past several years, western Yavapai County and the Verde Valley have been at odds because Verde officials worry that groundwater use in the Prescott tri-city area will deplete the flow of the river through their valley below.

The committee has led successful regional efforts to bring in federal, state and local money for water studies seek to quantify how much groundwater is available in the upper river basin, and where it comes from.

But a central location to make all the studies available to the public has been lacking, SRP’s Greg Kornrumph said. NAU is a perfect site because it will remain in perpetuity, he said.

Kornrumph, Schlinger and Springer were among more than 50 people who participated in a trip on the Verde Canyon Railroad Wednesday.

Yavapai County and the Verde Natural Resource Conservation District sponsored the trip to bring water experts together with local government officials to talk – and to give them a first-hand look at the river they regularly discuss and study. The U.S. Bureau of Reclamation helped pay for the trip.

U.S. Geological Survey officials in the midst of a Verde watershed study also joined the trip. So did Prescott Active Management Area (AMA) Director Phil Foster, and other Arizona Department of Water Resources officials.

Money from the state, county, local cities and towns is paying for the Geological Survey and Department of Water Resources studies. The Yavapai County Water Advisory Committee and its technical advisory group decided how to allocate the money.

The Department of Water Resources just added advanced monitoring equipment to 17 wells in the watershed, to better understand the groundwater system. And it has installed four new surface water gauges.

The Department of Water Resources also is loading new and refined data from its monitoring systems into its 1996 Prescott AMA groundwater model, Foster said. The model will then tell a more accurate story about how the upper Verde groundwater system works.

Laurie Wirt is one of the U.S. Geological Survey (USGS) officials working on a three-year study of the Big Chino Basin.

A previous study she helped conduct already strongly suggests that most of the water in the upper Verde River comes from the Martin limestone in the Big Chino. State law gives tri-city officials the right to pump water from the Big Chino into the Prescott AMA below, but Verde Valley officials want assurances that action wouldn’t reduce the river’s flow.

The USGS has not yet released that study to the public. Because of the sensitive political issues involving the watershed and the use of its groundwater, the USGS is conducting extensive peer reviews of the study first.

"The USGS prides itself on being unbiased, so it’s our reputation at stake," Wirt said.

Wirt and others are now six months into their latest study, which involves two major components.

Also because of the highly charged political climate in the Verde basin, a local oversight committee gets to approve the new study plan and review the study when it’s completed. So does the Arizona Department of Water Resources.

One component of the USGS study is using salt tracers in the upper Verde River. It will help quantify how much water the upper Verde Basin spring systems discharge into the river, and where the springs flow into the river.

Officials continuously dripped salted water into the river for three hours last month, at a site about two miles downstream from Sullivan Lake just below the mouth of Granite Creek. Then they sampled 25 spots downstream to see how much the salt had diluted.

The study located several outflows from the Big Chino into the Verde, Wirt said.

The scientists know the lower Granite spring likely comes from the Little Chino aquifer, and Big Chino Springs come from Martin limestone in the Big Chino aquifer, for example. But they need more groundwater flow information in the future to determine the exact location of the springs’ source, which would allow local officials to protect those sources.

The second component of the USGS study is collecting magnetic and radiometrics data on the Big Chino and Little Chino aquifers by flying over them.

The USGS will end up with a three-dimensional map that shows the sub-surface geology of the aquifers. For example, it will reveal the location of faults and volcanic layers that can be conduits and obstructions to the flow of groundwater.

The USGS plans to publish the raw data from the fly-over this fall, Wirt said, then spend more time interpreting it.

Eventually, all these studies will help local and state officials create a water budget that better estimates the available groundwater in the river’s upper basins, Wirt noted.

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