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... particularly infiltration practices and environmental site design measures. In Carroll County, MD, the drywells required to drain roof water from most new homes will facilitate the infiltration of an average of up to 130 gallons per day (gpd) in rain water back into the groundwater supply. This infiltrated rainfall goes a long way toward supplying the 300 gpd of water used by the average American family.
In many areas in Carroll County, MD and parts of York and Adams
 | House Seepage Pit Under Construction
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County, PA residents rely on groundwater from wells for their water supply. Groundwater is also a source of clean water to maintain the health of many aquatic systems such as streams, lakes and rivers. In another area of the United States, a study recently completed by NASA and University of California, Irvine used a satellite to discover that over 75% of the water loss in the Colorado River Basin since late 2004 came from groundwater.
The Colorado River is the only major river in the southwestern United States. The study determined that groundwater loss poses a greater threat to the water supply of the western United Sates than previously suspected. This area, which includes Southern California, has been suffering from a severe drought since 2000. The last 14-year period has been the driest in this area for the last 100 years.
Researchers used data gathered by a NASA satellite mission to track changes in the mass of the Colorado River Basin. Measurements of the change in water mass from December 2004 to November 2013 showed that the basin lost almost 53 million acre feet of freshwater. This volume is almost double the volume of water held in the nation's largest reservoir, Lake Mead in Nevada. More than 75% of this water loss was from groundwater. A water resources specialist at the University of California, Irvine said they thought the picture might be bad but that this is shocking. She went on to say that because they are unsure about how much groundwater is left in the area, they don't know when they are going to run out.
Although surface water in the Colorado River basin's lakes and rivers is managed by the U.S. Bureau of Reclamation and it's losses recorded, pumping from ground water sources is regulated by individual states and often not well documented. This river basin supplies water to about 40 million people in seven states and irrigates around four million acres of farmland. Jay Famiglietti, a senior water cycle scientist said "With Lake Meade at its lowest level ever, we wanted to explore whether the basin, like most other regions around the world, was relying on groundwater to make up for the limited surface-water supply. We found a surprisingly high and long-term reliance on groundwater to bridge the gap between supply and demand."
 | Lake Meade at today's low water level
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It is, thus, critical that we do what we can to maintain both the quality and quantity of our ground and surface water supplies. Infiltration practices and other Environmental Site Design practices help maintain the quality and quantity of our local groundwater supply.
Another interesting related story from Southern California also validates the necessity of local stormwater management programs. The many lawns seen in the affluent areas of southern California were created on a dessert, so each residence and most grass medians and roadway shoulders have sprinkler systems that are active for a significant amount of time each day. In fact, some local homeowner's associations specify that a member's yard must include a certain percentage grass (in the dessert!). The cost of this is not only a dwindling water supply, but water bills of over $800 per month for a family of four.
These stories from the western United States should help us to appreciate the stormwater management regulations and water conservation efforts in Maryland and Pennsylvania.
For more information: Contact Kristin Barmoy at kbarmoy@hanoverlandservices.com
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Hanover Land Services, Inc. is happy to introduce Nick Alexander who joined our team as a survey rodman in Spring 2014. 
