The Department of Environmental Quality regulates ground water withdrawals of 1,000 gallons a day or more in designated ground water management areas. Virginia has used a ground water flow model developed over thirty years ago to evaluate the impact of groundwater withdrawals on the aquifers in its attempts to manage groundwater withdrawals. Virginia has recently admitted that this model over predicts impacts in some locations and under predicts impacts in others. Over the past thirty years scientific understanding of hydraulics and the coastal aquifer system in particular has expanded exponentially, including the discovery of the Chesapeake Bay impact crater, the presence of land subsidence, and discover of inter aquifer impact. The groundwater model reflects none of these features.
Virginia DEQ has initiated an effort to merge the various sources of historical and new well information into one statewide database that can be used for regional analysis of groundwater aquifer systems. Though I tend to distrust all long term modeling efforts for their simplifications and straight line projections; however, water planning ten and twenty years out is a standard practice in the US west and other water critical areas of the world and should continue in Virginia. Water supply projections a decade or two out is a much simpler model than say climate projections, but still are impacted by non-correlated variables and limited knowledge of groundwater recharge and reserves that would make it difficult to accurately projects water demand and availability. Nonetheless to avoid the over use of a critical resource we need to manage it.
In 1992 the State Water Control Board established two groundwater management areas, one on the Eastern Shore and another covering the James-York Peninsula and Southside Virginia. It has been observed from monitoring data that artesian groundwater levels of the Northern Neck have been declining at a rate of 1.2 to 3.0 feet per year. It is likely that groundwater levels will continue to fall and several citizen’s groups have pressured the State Water Control Board to extend the Eastern Virginia Ground Water Management Area to the portion of the Coastal Plain aquifer system that underlies the Northern Neck and Middle Peninsula. Groundwater and surface water supply are not fully understood, but are limited by nature. Groundwater can only be withdrawn indefinitely at sustainable levels without irreparably damaging our water supply. The question is not should we manage our groundwater use, but how. A Regulatory Advisory Panel (RAP) was created to discuss the Notices of Intended Regulatory Action (NOIRA) to expand the Eastern Virginia Ground Water Management Area. The last meeting of the RAP will be on April 1, 2010. I look forward to reading their report.
Virginia’s water supply must be sustainable. Excessive groundwater pumping can result in reduced river flows, lower lake levels, reduced discharge to wetlands and springs and saltwater infiltration and subsidence. Overuse of groundwater can impact drinking water supplies, riparian areas and critical aquatic habitats. (See California for how to mismanage water resources.) Groundwater sustainability is achieved when recharge rate equals the pumping rate. The recharge rate is impacted by precipitation and ground surface coverage. Though we can have some impact on the recharge rate by protecting areas like the Fall Line and decisions about waste disposal we cannot directly control precipitation which is the major source of recharge in Virginia.
Our laws and regulations do not reflect a coherent concept of what water is about. Though laws create some tools for managing water on the state and county level the tools are being used in various ways and the result is a disorganized approach to each element of zoning and permitting that do not reflect a coherent concept of water management. We need a clearer concept of what we need to do to have sustainable water and then develop the legislative framework for a water budget that will allow for periodic droughts. There are many ways to approach this problem. A top down permit system is one method. Like most Virginians I abhor central control. Live Free or Die. However, there are other methods to achieve water sustainability. A market based system with tradable permits would allow optimal economic development, but may have undesirable social consequences. A combination of approaches needs to be worked out. The first step is to determine who owns the water rights in Virginia. Do water rights belong to the land?