MD-DE-DC WSC Water Use & Water Supply Capabilities

Comprehensive Assessment of Water Supply in Maryland

Comprehensive Assessment of Water Supply in Maryland

Referencing the Wolman Report. A joint effort of USGS, MDE, MGS, and Maryland DNR addressing water regulators, planners, and policy makers need to know how much water can be withdrawn from wells and streams without causing adverse impacts.


Drought forecasting in northeastern United States

Drought forecasting in northeastern United States

USGS Water Science Centers in the northeast have combined resources and methodologies to produce this fact sheet, describing the drought forecasting techniques used in a study to predict droughts for streamflow and groundwater.


Estimated use of water in the United States

Estimated use of water in the United States

Water use in the United States in 2015 was estimated to be about 322 billion gallons per day (Bgal/d), which was 9 percent less than in 2010.  Thermoelectric power, irrigation, and public-supply withdrawals accounted for 90 percent of total in 2015.


Science Center Objects

In Maryland, public supply water is delivered to users for domestic, commercial, and industrial purposes. Most is used for public services, such as public pools, parks, firefighting, water and wastewater treatment, and municipal buildings, and some is unaccounted for because of leaks, flushing, tower maintenance, and other system losses. 5.7 million Marylanders get their water from the public supply.

While Maryland, Delware and the DIstrict of Columbia all fall within the green zone, as far as water use goes, our placement on that list comes from years of hard-fought regulation, convincing policy makers that water, although seemingly an enless resource, is anything but. In fact, in some parts of the world it can be as valuable as gold. Especially when it's clean, potable water.

Water supply in the area that the MD-DE-DC WSC serves comes surface water (streams and rivers), groundwater (fractured rock aquifers and Coastal Plain aquifers), and reservoirs. Water is a vital component of human existence, as well as critical to all forms of life. In order to protect and preserve this resource for future generations, we must have a baseline of information to make decisions. Decision and policy makers must know the answers to three fundamental questions: where is the water used, how is it used, and how much is used.

Surface Water                                                    -------------------------------------------------  

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Lake Montibello Water Treatment Plant

Lake Montibello Water Treatment Plant in Baltimore, MD

The MD-DE-DC USGS Water Science Center operates a network of 224 streamgages in MD, 58 in Delaware, and 13 in the DIstrict of Columbia. Within that count are In Maryland, about 10% of the community water systems (around 50 systems) rely on surface water. In Delaware, about 80% of the population relies on surface water while 20% rely upon wells drilled on their property. Practically all of the drinking water in the District of Columbia comes from the Potomac River. The USGS National Water Information System (NWIS) makes the actual streamgage data available to the public, most of it in "near–real" time. 

To provide data from the existing streamgage network to decision-makers in a useful format, the USGS has conducted statistical analyses of streamgage records and developed hydrologic models for specific basins. For example, the StreamStats web application has been implemented for many States to provide estimates of these statistics. These estimates are derived using regression techniques that have been developed to perform well for streamflow statistics. The WaterWatch application provides nationwide estimates of runoff (flow per unit area) for HUC-8 watersheds in the continental U.S.

Groundwater                                                 -------------------------------------------------  

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Groundwater, which is found in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Groundwater is the source of about 38% of the water that county and city water departments supply to households and businesses (public supply) in the United States. It provides drinking water for more than 97 percent of the rural population who do not get their water delivered to them from a county/city water department or private water company.

Flowing or seeping downward and saturating soil or rock, supplying springs and wells, groundwater often begins as precipitation and soaks into the ground where it is stored underground in rock crevices and in the pores of geologic materials (these are aquifers), the same way as water fills a sponge. The upper surface of the saturated zone is called the water table.

Confined aquifer are below the land surface that is saturated with water. Layers of impermeable material are both above and below the aquifer, causing it to be under pressure so that when the aquifer is penetrated by a well, the water will rise above the top of the aquifer. A water-table, or unconfined, aquifer is an aquifer whose upper water surface (water table) is at atmospheric pressure, and thus is able to rise and fall. Water-table aquifers are usually closer to the Earth's surface than confined aquifers are, and as such are impacted by drought conditions sooner than confined aquifers.

Artesian wells tap into confined aquifers. This aquifer is a water-bearing geologic material below ground that is surrounded by other rock or material that does not allow water to pass through easily. The surrounding material may add pressure on the aquifer, and water in this aquifer can be pushed up the well, sometimes all the way to the surface, creating a flowing well.