3/26/2013 1:07:00 PM My Turn: Is our water budget broken?
By Tom O’Halleran
On April 11, 4-6 p.m., the Verde River Basin Partnership will sponsor a presentation by the United States Geological Survey (USGS) on the findings of their report: Human Impacts on the Verde River’s Streamflow, 1910-2109: Applying the USGS Northern Arizona Regional Groundwater Model.
The public is encouraged to attend this landmark presentation at the Camp Verde Multi-Use Complex Auditorium, 37 Camp Lincoln Road, Camp Verde. For more information go to the Partnership’s website at www.vrbp.org or Facebook at Facebook.com/verderiverbasinpartnership.
Over the past year and a half, the USGS has been conducting a study of the Verde Valley to determine our water budget and water availability. A water budget estimates how much water exists in a watershed or in the case of the Verde Valley sub-watershed over a period of time.
Water budgets account for water that is being added to a watershed, such as precipitation and removed such as discharge of groundwater to rivers and creeks and groundwater pumping. The budget also accounts for changes in groundwater storage.
The USGS has also been using the Northern Arizona Groundwater-Flow Model released in 2011 for the first time to predict our past, current and future affects from groundwater pumping on our groundwater storage and surface waters of the rivers and creeks within the Verde Valley.
This analysis will help us determine how we may be impacted but importantly help us in realizing that through cooperative management of our water resources there are options to minimize potential future impacts.
The USGS used three forward looking computerized numerical simulations to estimate the impacts on the Verde River hydrologic system. All these simulations were based on very conservative estimates of additional stress levels on our water resources.
The first simulation held the distribution and magnitude of human stresses at their 2005 level across the entire model area until 2109.
This means that there would be no additional groundwater used over approximately the next 100 years. Based on growth patterns in Arizona this is very unlikely but will indicate how we are currently impacting our water resources.
The second simulation increased stress levels to the system 3 percent each decade, 50 percent less than projected growth, until 2060 for a net gain in stress of 15 percent. After 2060 the stress level was held constant through 2009.
Again, based on current growth projections this is a very conservative estimate of additional stress to the hydrologic system. The USGS based these additional stress levels on half the additional future water demands identified in the Bureau of Reclamation (BOR) study: Central Yavapai Highlands Water Resources Management Study. It should be noted that the additional water demands identified in this study were the result of consultation with Yavapai County, the cities and towns in the Prescott and Verde Valley areas and the Yavapai County Water Advisory Committee.
As indicated in the BOR study this additional water demand has already taking into account additional water conservation measurers.
The third simulation decreased the distribution and magnitude of human stresses by three percent per decade through 2060 for a total decrease of 15 percent by the year 2060, and then held that level constant through 2109.
This simulation would take into account introducing conservation and other water management measures in order to reduce stresses to the system.
Why is all this so important? Up to now we have been managing our water resources on the hope that water will be available in the future. We have been making decisions based on Arizona water law that does not acknowledge the scientific fact that groundwater and surface water are connected.
By using the model and understanding what the results mean we will be able to protect our economy, quality of life and the investments we have made in our businesses and homes.
When the USGS released the groundwater-flow model they indicated that it was a management tool that could be used, in its present form, to predict future impacts to our water resources.
The other use for these types of models is to identify how different management options could help us protect our resources through regional water resource management.
We have a choice. We can look at this presentation as having the potential of telling us that we are impacting our water resources to a level that they will be unsustainable or we can make the decision that this is an opportunity to make the changes necessary to sustain our precious water resources.
Water management decisions are much more then just moving water from one location to another. There is a cost associated with each and every decision make. The cost may be monetary, environmental, impact to wildlife or residents quality of life but there is a cost.
The meeting on April 11th will be your first opportunity to look into our water future. It will help you identify what solutions may be available. It is one of the only opportunities where you will be able to have scientific experts available to present the facts and answer your questions.
For additional information visit the Verde River Basin Partnership at www.vrbp.org or on Facebook at Facebook.com/verderiverbasinpartnership.
Tom O’Halleran is the Chairman of the Verde River Basin Partnership.