Looking at Freshwater Use in Delaware

The water we use in our daily activities comes from many sources. We may use water from a public supply system or from our own wells or from surface water sources.  Homes and small communities relying on individual wells are typically classified as domestic “self supplied” users.   Public water is provided to users by a public or private supplier.  Besides daily personal use, water is used by thermoelectric power plants to generate electricity for our homes, by commercial businesses such as restaurants, motels, carwashes, and by institutions such as schools, churches, hospitals, and military installations.

Major Types of Freshwater Use in 2000

In 2000, the most recent year for which complete statistics are available, a total of approximately 584 million gallons (mg/d) of freshwater was used every day in Delaware.  Approximately 80% (467 mg/d) of that was taken from our surface water sources, the rest came from ground water sources.  Delaware's seven major water uses include:

• Thermoelectric Power Supply — Thermoelectric power plants use freshwater, mostly from surface water sources, to cool condensers.  The cooling water is eventually returned to the source.  In 2000, power plants used approximately 366 mg/d.

• Public Supply — There are more than 300 public water supply systems in Delaware which provided water to 617,000 people in 2000, or about 79% of the Delaware’s population.  Total withdrawals for public water supply in 2000 were 95 mg/d.  50 mg/d came from surface water sources, and 45 mg/d from ground water sources.   The largest withdrawals from public water supplies came from New Castle County (72 mg/d), Sussex County (13 mg/d), and Kent County (10 mg/d).

• Industrial — Our industries, such as producers of chemicals, plastics, and food products used about 73 mg/d of freshwater in 2000.  Sussex County had the most withdrawals for industrial use (39 mg/d), New Castle County required 18 mg/d and Kent County industries used 2 mg/d.  The majority (59 mg/d) was self supplied, mainly from surface water sources (42 mg/d).  The rest (14 mg/d) was supplied by public suppliers.

• Irrigation — Differences in rainfall distribution and other weather conditions, crops grown, and soil type are important factors in determining the amount and timing for irrigation water application.  The amount of freshwater used for irrigation purposes on each farm changes yearly, depending on local conditions.  During 2000, approximately 43 mg/d of freshwater was used to irrigate crops, golf courses, and nursery stock. The majority (35 mg/d) came from ground water sources.

• Domestic — Domestic water users in Delaware get their water from public suppliers or are self supplied from their own wells.  Total average water use in 2000, statewide, was 63 mg/d.  Fifty million gallons per day were delivered by public suppliers, and the remainder, about 21% of the state’s population, withdrew from individual household wells.

• Commercial — Commercial users include businesses such as restaurants, motels, and carwashes, as well as institutions such as schools, hospitals, and military installations.  Commercial users fulfilled their water needs through public suppliers and individual self supplied wells.  Total commercial use during 2000 was 23 mg/d, 21 mg/d of which was supplied through public suppliers.

• Livestock — Livestock production is another major source of freshwater demand.   In 2000, livestock activities, specifically watering, feedlot, dairy operations, and aquaculture, utilized 3.99 mg/d, 3.77 of which came from ground water sources.  Sussex County is the largest user of water for livestock in the state, withdrawing 3.04 mg/d in 2000.

Ground water sources provided only 20% (117 mg/d) of the freshwater required on a daily basis in 2000 from the following sources:

New Castle County is the most densely populated and industrialized portion of the state and has the highest demand for freshwater, approximately 462 mg/d in 2000.  Kent and Sussex County are significantly more rural and agricultural and had lower demands, 31 mg/d and 91 mg/d, respectively, in 2000.  New Castle County is mainly supplied by surface water sources (almost 93%).  Water for Kent (90%) and Sussex Counties (60%) is supplied mainly by ground water sources. 

Water supplies are generally adequate in all areas of the state.  However, available quantities are affected during low flow periods, such as extended periods of drought, or by seasonal high demand, especially in New Castle County, which depends on surface water or stream flows.  As Delaware's population increases so does the demand for water, which places stress on surface and ground water resources in the state.  The Delaware Department of Natural Resources and Environmental Control and the U.S. Geological Survey work together to collect, compile, estimate, and store site specific and cumulative water use data that is useful for managing Delaware’s water resources.

Source: USGS Fact Sheet FS 111-03: Freshwater Use In Delaware,2000. Judith Wheeler, 2003