Droughts, Floods and Sprawl –They’re All Connected

By
Carol R. Collier
Executive Director, Delaware River Basin Commission
and
Jan Bowers
Executive Director, Chester County Water Resources Authority

September 1999

It seems quite ironic to be sitting at a battery-powered laptop computer during a hurricane, writing about solutions to a drought. But the fact is floods happen even during droughts. Unfortunately most of this much-needed water is quickly diverted to the nearest creek or river via stormwater drains and pipes. Flow from rooftops, parking lots and streets is not retained but ushered downstream. Of course engineered solutions are necessary to control unusual high flows that are a threat to public safety, but we have traditionally ignored the value of stormwater as a resource, and as a partial solution to droughts.

A drought is a natural phenomenon caused by changes in weather patterns resulting in less than normal rainfall. We cannot manufacture more rain, but we can better manage the water that falls in our region. The recent drought has been especially devastating because the region’s ground water had substantially declined over the past two years. Ground water is the underground water that feeds our streams and water supply wells. This underground reservoir is recharged ONLY by sufficient infiltration of rainfall through the soil. Without either rainfall or infiltration, ground water becomes scarce and streams become dry.

This year, the simultaneous occurrence of the severe drought and flooding from Hurricane Floyd hit hard in Pennsylvania. The impacts of both have been documented through ongoing USGS stream and ground water monitoring programs in Chester County. Small perennial tributaries were observed dry in the late stages of the drought in suburban areas such as near Exton, PA, in the West Valley Creek watershed. Stream flows dropped to record low levels (over 70 years of record) for most of July and August in Brandywine Creek – the source of water supply for nearly a half million people in Pennsylvania and Delaware – and flowed at levels below Q7-10 for 19 consecutive days. During July and August much of the Brandywine Creek flow was dependent upon discharges from two large wastewater treatment plants. When Floyd struck, small streams such as Valley Creek at Valley Forge National Park – a small watershed with two major highways and expanding development – rose rapidly within hours from low drought flows to damaging flood flows.

What causes such sudden and extreme flows? Slope, soils, geology and climate contribute to the rate of watershed runoff. But the rapid expansion of impervious cover, especially in our urban and suburban areas, has made it especially difficult for rainwater to recharge the ground water. It has been shown that if impervious cover exceeds 10 to 15 % of the total surface area of any watershed, the rate and volume of this runoff dramatically increases.

What can we do differently so more water recharges this critical ground water supply? How can we better plan and design new developments so adequate water supply is assured and storm damage is lessened?

The underlying problem is that current law treats water management in a disconnected and piecemeal fashion; ground water and surface water are treated as independent and separate resources. In addition, primarily because of the way the federal water laws have been written, most states’ environmental protection departments have separate bureaus or sections for each water issue - water supply, wastewater, stormwater, wetlands, floodplains, erosion and sediment control, and flood prevention design. Land use management is performed through the separate roles of county and local governments under the Municipalities Planning Code, which limits our ability to address water resource issues. Each development site is often evaluated as if standing alone, and not in the context of adjacent land uses.

Land and water management is like a jigsaw puzzle. Staring at an individual piece can be frustrating and unfruitful, but when the pieces are successfully connected together, a clear picture emerges.

At all levels, we must manage land and water as inter-dependent resources. The Report of the Governor’s 21^st Century Environment Commission recommended that we "develop comprehensive watershed management strategies that incorporate water quality and quantity, surface and ground water, aquatic ecosystem and natural diversity considerations".

Some new programs in Pennsylvania are moving toward a watershed approach. The Delaware River Basin Commission (DRBC) has designated the majority of southeastern Pennsylvania as a "Ground Water Protected Area" within which there are lower water withdrawal permit triggers (10,000 gpd) and withdrawals are viewed on a cumulative basis by subwatershed. PADEP has created watershed manager positions in all six regional offices to facilitate solving environmental problems in a watershed context. But more has to be done by all, including government, citizens and land owners.

Critical needs include:

A state-wide water resources plan with goals and directions by major water basins

A water resources law requiring integrated water resource management

Funding and guidance for local integrated watershed planning and implementation

Elimination of "road blocks" and creation of incentives and/or regulation to:

• increase rainwater infiltration as high in the watershed as possible;
• increase rainwater infiltration on a "lot-by-lot" basis;
• design new detention/retention basins to retain and infiltrate flows from small storms (less than or equal to the 2 year storm flows) in order to increase ground water levels and improve surface water quality;
• retrofit existing detention basins to infiltrate flows from small storms;
• increase water reuse and gray water systems;
• increase land application of treated wastewater, and
• protect ground water from over-withdrawal

Programs to encourage water conservation

Programs to discourage development in floodplains and encourage the restoration/naturalization of these riparian corridors

Project and subdivision reviews that include analysis of potential watershed impacts.

If we treat the flows from small storms and treated wastewater as RESOURCES instead of WASTES, we can reduce damage from stormwater runoff and drought impacts, and most importantly, store this critical water for stream baseflow and water supply.

Some people question whether the Commonwealth can realize strong economic progress if stricter environmental standards are in place. The simultaneous improvement of the economy, community and environment is the only definition of progress. By improving the integrity of our water resources while reducing the potential damages from storms and droughts, Pennsylvania’s economic diversity will be strengthened. Agriculture, tourism and industry will continue to thrive, and the Commonwealth will be in a stronger position to attract the high tech, clean industries we desire. If we respect the natural value of our ground water, streams, and riparian corridors and realize the development potential of working with the natural system, our communities will be more livable and desirable.

P.O. BOX 7360, West Trenton, NJ 08628-0360
Voice (609) 883-9500 FAX (609) 883-9522
clarke.rupert@drbc.state.nj.us