A guest post from Mark Solomon:
Over-appropriation is hitting the fan in south Idaho with IDWR ordering the first curtailment of use order in its history.
So far, the courts are upholding the agency order. The facts are complicated, but basically, junior groundwater pumpers are being curtailed to meet the call of senior surface water users. Simple on its face, but the surface water users are actually supplied by springs from the aquifer where they exit the cliff face of the Snake River canyon at Thousand Springs. Only problem is the spring user rights are hydrologically unsustainable as they were awarded at a time when the aquifer was being artificially recharged by leaky canals and flood irrigation practices and before cheap hydropower spurred development of groundwater pumping. To compound the issue, the spring users apply the water to aquaculture, producing most of the farmed trout in the country, a high return on water investment compared to field crops. It is also a largely non-consumptive use (there were and still are to some extent issues with return water quality, but that is being addressed through CWA enforcement), which is critical for Idaho's ESA balancing act for salmon.
The situation cries for a market response, but the groundwater users know they will come out on the wrong side of the cost/benefit equation so it is being fought as a game of political and legal chicken.
The state convened a stakeholder group to write a Comprehensive Aquifer Management Plan that obliquely looks to markets to replace prior appropriations as the dominant management tool, but the current legal wrangling may cause it to be stillborn.
DZ's Bottom Line: It's hard to move to a new system if some people hold onto the old (broken) one.