If a Ground Water Accounting System is adopted, how might it be used?

SCENARIO 1: USING MANAGED RECHARGE TO AID IN FLOW AUGMENTATION

Under this scenario, the Bureau of Reclamation would participate in managed recharge and accrue ground water credits. An additional mechanism to accrue ground water credits would be to supply surface water to the owners of supplemental wells at times when otherwise they would have pumped ground water. The Bureau would receive credit for the foregone pumping. It could also purchase "left over" mitigation credits that are generated when a transfer mitigation plan generates benefits to other reaches of the river besides the reach targeted.

These ground water credits would be withdrawn at critical times to provide flow augmentation. One withdrawal mechanism would be to use existing exchange wells (wells that pump directly into rivers) in the upper Snake River area to extract Bureau-owned water from the aquifer and directly add it to river flows at critical times. Another mechanism would be for the Bureau to enter into agreements with farmers who have both surface-water rights and supplemental wells. The farmers would use their wells to withdraw Bureau-owned water stored in the aquifer, and the surface water that otherwise would have gone to the farmers would be left in the river for flow augmentation. A final withdrawal mechanism would be to direct that river gains and spring discharges that result from the recharge be left in the river for instream purposes.

Accounting would allow quantification of potential effects on hydropower production to aid in conflict resolution of recharge decisions.

SCENARIO 2.FACILITATING ECONOMIC GROWTH

Suppose a highly desirable industry proposes locating a plant on the Eastern Snake River Plain. The only obstacle is obtaining water. The cost of a water right is insignificant, but the time it takes to get a water right could be a deal breaker.

With a functioning ground-water accounting system, the new industry could immediately secure a temporary water supply by leasing from the bank or other water users. Development would proceed, while a transfer or water - right permit and mitigation plan were being processed.

SCENARIO 3. COPING WITH CLIMATE CHANGE

If climate change predictions come true, the snow pack that has historically supplied summertime Snake River flows will instead come off as wintertime runoff from rainfall. This has environmental implications based on the changing of the seasonal hydrograph. Reduced springtime flows could affect spawning, and reduced summertime flows could affect nutrient loads and water temperatures. The loss of traditional snowmelt flows would also obviously affect irrigated agriculture.

Aggressive managed aquifer recharge could capture much of this water which otherwise would leave the basin in the winter. Increased spring discharge and river gains would offset some environmental concerns, and well pumping could augment river flows at environmentally critical times. Stored water in the aquifer could also be available for other uses.

Managed recharge on this scale would require investment in infrastructure and cooperation among owners of facilities and owners of water rights. An accounting system would allow parties to join together in a combined effort to recharge the aquifer. Individual blocks of ground water could be assigned to participants, based on contributions to the recharge activities. By providing ownership of the benefits created, ground-water banking could provide economic incentive to attract resources to the costs of developing the required infrastructure.

Owners with environmental and fisheries preferences could direct their aquifer storage be allowed to stay in aquifer to maintain Snake River base flows and water temperatures. The Bureau of Reclamation could extract its stored water via the exchange wells to enhance river flows at critical times. Other owners might elect to extract their storage for more traditional economic uses.

SCENARIO 4: MANAGING GROUND-WATER AND SURFACE-WATER IRRIGATION TO STABILIZE SPRING FLOWS

An irrigation district and a ground-water district in the same geographic area could join forces and use creative management to minimize the impacts to springs. In years when surface water is plentiful, the irrigation district could supply surface water to ground-water users within the district. The foregone extraction would accrue as additional storage in the aquifer. An accounting system would allow this to be credited as an in-lieu recharge. In years when surface water was short, the ground water owned by the consortium could be withdrawn for the use of all users in both districts. The volume of water already stored and already generating increased spring flows would protect spring users.

In a year when aquifer water levels were especially low due to drought, the consortium could provide short-term relief to the springs by curtailing ground water pumping near the springs. This supply would be replaced by surface water, supplemented by ground water pumped at a distant location. Water would be carried in the irrigation district canals to farms near the springs. This would have the double benefit to the springs of reducing local withdrawal and providing additional local recharge. An accounting system would allow quantification of when and where the benefits of this exchange would appear and ensure that the distant pumping did not overshadow the benefit of the nearby curtailment.

SCENARIO 5: ASSESSING THE IMPACT OF RECHARGE ON POWER GENERATION

Water that goes past Milner Dam generates power at Milner, Shoshone Falls, Twin Falls, and on down the Snake River; it bypasses the Thousand Springs and Malad power plants.

Water diverted above Milner for recharge bypasses Milner, Shoshone Falls, and Twin Falls, but a large portion of it eventually emerges at the Thousand Springs and Malad power plants; from there it also generates power all the way down the Snake River System.

Recharge delays the timing of power production by months or years. If recharge occurs when demand is low and the benefit to sping flows occur when demand is high, this can benefit power producers. If, in general, power prices are increasing faster than the cost of funds, recharge can "bank" electricity for future higher market prices.

An accounting system will allow assessment of future power generation, benefits or recharge, which may partially offset current power generation costs of recharge.