is required to provide proper due diligence to maintain their groundwater source by adapting to changing hydrology (installing a well pump). However, as we move forward into the future, it will be important to revisit water law as it pertains to groundwater to ensure that the best available knowledge and experience is brought to bear. When it makes sense to adjust historic water law for the benefit of better groundwater management, then we need to be prepared to make adjustments. We have come to understand the subsurface storage and movement of groundwater over the last several decades, but it remains a challenge and requires study and planning to characterize recharge boundaries, flow patterns, confined and unconfined dynamics that often coexist in alluvial aquifers. The early groundwater development approach was overly simplistic and neglected proper evaluation and study of available water quantity and quality in the subsurface. With modern analytical tools, including the development and application of numerical models, we gain more accurate perspectives on groundwater supplies, and the ability to adjust to aquifer responses that tell us more about what we cannot visually observe. Groundwater Recharge. Over the last several decades, water managers have begun to promote recharge to the subsurface through artificial recharge projects via infiltration basins or through direct injection wells. When surface water is available in abundance or supplies exceed demands as it often can be during a wet spring runoff season in the Intermountain area, groundwater recharge projects have demonstrated value in helping mother nature to restore the naturally occurring subsurface water storage. [Note: see the Water Resources IMPACT issue Managed Aquifer Recharge , Volume 19 No. 5 September 2017.) Source Protection. Other evidence of our evolution and progress in groundwater management are source protection rules and strategies to protect subsurface water supplies. The EPA required all States to implement
Groundwater cannot be assessed and evaluated directly by visual observation. Therefore, the water industry has developed methods and tools to measure and interpret groundwater through collected data of what cannot be visually observed. The U.S. Geological Survey has played an important role in helping to develop credible scientific methods for defining and quantifying aquifers. More recently, numerical groundwater models have been developed to assist in managing datasets and projecting impacts from increased groundwater withdrawals or changing recharge due to climate change. States also play an important role in studying groundwater in the various water basins and providing high level groundwater characterizations that facilitate more specific, focused study and evaluation. Groundwater management plans are another administrative tool that has proven valuable to bring water users to a greater awareness of resource limitations. Water Law . Since groundwater is essential to the economic engine of
of all public water supplies originate from groundwater. Surface water sources in the intermountain west are impacted regularly by periods of drought. For many years, the common understanding existed that groundwater was less vulnerable to drought. Effects on groundwater may appear less impactful because they are less obvious, but 75 years of groundwater data tell us that drought impacts aquifers over years. In a similar manner, it takes years for aquifers to recover after enduring successive years of drought and decline caused by often increased withdrawals with reduced natural recharge. As groundwater development occurred during the 1940s through 1970s and beyond, the management and administrative philosophies typically followed the supposition that aquifers were extensive, unknown in capacity and therefore practically unlimited for additional development. In the last thirty to forty years, impacts to sustained groundwater withdrawals have been manifest through increased drawdown, lack of source sustainability and even
Figure 2. Typical alluvial aquifer (Photo credit: Courtesy of U.S. Geological Survey)
the Intermountain West, it has become essential that more understanding of the subsurface dynamics provides input to decision making. In the State of Utah for instance, a legal court ruling has stated that a groundwater right that was initially developed as an artesian well is a manifestation of a current hydrologic condition, but not an implied right and cannot be sustained by water law when groundwater levels decline. The water right owner
subsidence of the ground surface and a consolidation or collapse of aquifers, greatly reducing the interstitial pore spaces where groundwater is stored. Thus, administrative and management practices are changing to recognize the limited capacity of groundwater sources. There is clearly not an infinite supply of groundwater. Many states are beginning to conjunctively manage surface water and groundwater supplies.
September 2019
VOLUME 21 - NUMBER 5 | 21
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