Kevin Harrison and Aaron Kunz
Uncertainty looms over the Wood River Valley as the important water management process plays out in central Idaho. At stake is how much water will be available for crop irrigation, ranching, and other business interests. These water call documents, for the Big Wood River Water Users Association, the Little Wood River Water Users Association, and the Idaho Department of Water Resources paint the legal framework for how they’ll move forward. They can be found here and here.
Idaho uses the “prior appropriation” model, also known as “first in time – is first in right.” The state’s oldest water users took water directly out of rivers, streams and lakes. They are known as surface water users. Decades later we learned how to use pumps to coax water out of underground sources such as aquifers like the giant Snake River Plain Aquifer that stretches from St. Anthony to Twin Falls. Those users are known as groundwater users and because they came after surface water users, a lot of them have junior water rights.
That became a big issue when the courts recognized that surface water and groundwater are linked. Take too much water out of the aquifer, and surface water is used to recharge the aquifer. Take too much surface water and groundwater isn’t recharged. None of this is a problem when water is plentiful, but a huge problem when water is scarce like it has been this year.
The biggest state water management legal case, known as the Snake River Basin Adjudication, has helped set the stage for the situation in the Wood River Valley, where water management is still being developed.
The Wood River Valley Groundwater-Flow Model, a joint project between the IDWR and the United States Geologic Survey, is scheduled for completion early next year. The model is meant to further our understanding of the relation between surface and groundwater in the Wood River Valley. It will also contribute to long-term planning, resource management, and conjunctive administration.
The IDWR has published a project summary that explains why the model is needed. The kick-off presentation from the initial meeting adds additional information. There are also project updates available from both the IDWR and the USGS, both from January 2014. The recent water calls for the Wood River Valley have highlighted the significance this model will play in future administration and litigation. A recent Capital Press story quotes Matt Weaver, Deputy Director of the IDWR, as stating that he doesn’t anticipate much progress will be made on these water calls until the flow-model is complete. You can read the story here.
The model may not be finished until 2016, but you’ll be hearing a lot more from the Wood River Valley as people try to prevent a water curtailment.