Delaware considering underground storage and wastewater re-use

By JEFF MONTGOMERY

Staff reporter
10/18/2002

Northern Delaware water planners reported Thursday that the area needs to be able to store or find an additional 450 million gallons of water to meet public demand in future serious droughts.

Options for meeting that goal range from enlarging above-ground and underground reservoirs to re-using treated wastewater from Wilmington's regional sewage plant.

Members of the state's Water Supply Coordinating Council agreed to the new water-supply goal based on an analysis of the record-dry summer of 2002.

The group called last month for a water-supply plan capable of meeting public needs during a repeat of this year's unprecedented rainfall and streamflow shortages. Then-Gov. Tom Carper formed the council after a drought emergency in 1999 to recommend ways to meet the state's water-supply needs during droughts.

Costs to state taxpayers or utility customers could increase as an eventual result of the group's recommendation. The Public Service Commission could consider the future cost of some projects recommended the group when setting rates for United Water Delaware or Artesian Water Co.

In a worst-case, 75-day drought, public water supplies could fall short by 6 million gallons a day by 2020, officials said Thursday. Six million gallons represents 6.8 percent of normal use in northern Delaware.

"It's sound planning to assume that this may happen sometime in the next 17 years," said state Water Supply Coordinator Gerald Kauffman.

Gov. Ruth Ann Minner declared a drought warning in Delaware on March 5. She put northern Delaware under mandatory water restrictions on Aug. 2. Those were lifted Oct. 11.

Supplies to residents never were jeopardized, although washing cars by hand and watering lawns were banned. Some garden and landscaping companies reported severe financial losses.

"I think we did a very good job of managing the drought this year," said John H. Talley, associate director of the Delaware Geological Survey.

But state officials acknowledged that the region avoided trouble largely because interstate water allocation rules give Wilmington a right to pump the Brandywine nearly dry if necessary to meet customer needs. To protect downstream aquatic life, past studies have found that the city should stop pumping from the waterway when flows drop below 49 million gallons a day.

Estimates released Thursday assumed that Wilmington eventually will be required to quit pumping water from the Brandywine when flows drop below 49 million gallons a day. Newark and United Water Delaware already operate under dry-weather pumping restrictions.

Under the latest analysis, areas north of the Chesapeake & Delaware Canal would need an extra 262 million to 450 million gallons of water by 2020 to meet routine demands during a 75-day drought while still leaving minimal flows in local creeks.

Worst-case shortfalls roughly equal the daily needs of the Newark and New Castle city water systems combined.

Utilities could meet the need by completing several projects already under review or in the works, including:

• Storing more water in underground aquifers.

• Increasing the storage capacity of Wilmington's 1.8 billion-gallon Hoopes Reservoir by blocking a portion of its spillway.

• Diverting treated wastewater into the Brandywine to make up for public water withdrawals or to supply industrial needs.

• Relaxing current dry-weather water-use limits along White Clay Creek.

• Building a saltwater purification plant or a pipeline to deliver water from Philadelphia.

The group will meet again next month to set priorities.

Reach Jeff Montgomery at 678-4277 or jmontgomery@delawareonline.com.