Water Pollution: An Explainer

Contaminants in our waterways and drinking water supplies come from obvious places and places that aren’t so obvious. Managing the pollution is a constant challenge.

When the Environmental Integrity Project issued a report on America’s water quality on the 50th anniversary of the federal Clean Water Act in September 2023, it placed the First State dead last.

Of our 775 square miles of bays, harbors, and estuaries with assessments filed with the Environmental Protection Agency, 100 percent were impaired. Of 1,104 miles of rivers and streams assessed, 97.3 percent were impaired. Of 2,982 acres of ponds and reservoirs assessed, 70.5 percent were impaired.

“Impaired” for rivers and streams refers to aquatic life. “Impaired” for the other categories means they cannot be used safely for swimming, fishing, or as sources of drinking water.

There are two culprits to low water quality: point-source pollution and, to a much greater degree, nonpoint source pollution.

Point sources, by definition, are obvious. “Point sources are what come from pipes, like sewers,” says Jerry Kauffman, director of the University of Delaware Water Resources Center. Other point sources include ditches, channels, tunnels, conduits, wells, concentrated animal feeding operations, and vessels or other floating craft that discharge pollutants.

Nonpoint sources, in contrast, aren’t obvious: the rainbow sheen of oil-based pollutants floating atop water sheeting across a roadway or parking lot, for example, or all the chemical particulates from tailpipes that settle on roadways, only to be washed by rain into a local waterway, or the excess nutrients from fertilizers and the waste of farm animals. “Nonpoint is a fancy way of saying it comes from far away,” Kauffman says.

At times it’s hard to tell the difference. Wastewater discharged through spray irrigation after treatment in a plant might appear to be a point source in Delaware, but “regionally they are referred to as contributors to nonpoint source pollution,” according to the Delaware Department of Natural Resources and Environmental Control.

The Environmental Integrity Project report covers 92 percent of the state’s bays, harbors, and estuaries, but only 25 percent of the rivers and streams and 26 percent of the ponds and reservoirs. Even so, the conclusions are still shocking. Part of the disconnect might come from Delaware’s small size. It has more water quality and weather stations per square mile than any other state, Kauffman says, so there’s more data. 

All of this brings good news and bad.

Steps Forward, Steps Back

Beginning in 1951, the state and federal governments started to seriously address the environment. The state created the Delaware Water Pollution Commission in 1951. The federal Water Resources Research Act of 1964 created water research centers in every state. The administration of then-Governor Russell W. Peterson, a champion of the environment, established DNREC in 1969, the EPA was created in 1970, and the Clean Water Act followed in1973.

Over time, the Clean Water Act corrected many issues with point-source pollution by creating the National Pollutant Discharge Elimination System under the EPA. The NPDES monitors water quality and issues permits that limit the pollution an individual permittee can discharge through treated wastewater. NPDES is intended to ensure the discharge does not hurt water quality or human health.

Since inception of the NPDES, “Many of the heavy industry facilities in Delaware that were point source dischargers have either closed or changed their practices to reduce or eliminate discharges to waters of the state,” according to DNREC. 

There are always lingering effects, challenges, and setbacks, however. Legacy pollution still contaminates the sediments of rivers that once saw heavy industry.  Evolving wastewater treatment technologies require that states continually re-evaluate disposal practices, and emerging contaminants such as PFAs may require new options for safe disposal. 

An important emerging issue is the quality of groundwater supplies. As the NPDES has pushed to eliminate pollution discharges to streams, some dischargers have begun to discharge to groundwater. The practice can have impacts on drinking water aquifers that supply our wells and the watershed as a whole. The issue is complicated by sea level rise and emerging contaminants. 

So Delaware, like states everywhere, needs to continue to evaluate and modernize statewide wastewater disposal to meet future challenges.

In Other News…

Delaware still struggles with some categories of nonpoint source pollution. NPS includes excess fertilizers, herbicides, and insecticides from agricultural lands and residential areas; oil, grease, and toxic chemicals from urban runoff and energy production; sediment from improperly managed construction sites, croplands, forests, and eroding streambanks; bacteria and nutrients from livestock, pet waste, and faulty septic systems; and more.

Day after day, poultry farms in Delaware produce manure full of nitrogen and phosphorous that runs into waterways. Those nutrients promote algal blooms and reduce oxygenation below levels fish need to survive. These and other aberrations–such as the overflow of plants that treat bacteria-heavy human waste–can lead to fish kills, set back the local shellfish industry, and ultimately endanger the tourism industry, Delaware’s Delaware’s fourth-largest private employer.

Perhaps nowhere is the problem more acute than in the watershed of Delaware’s three Inland Bays, tidal waterbodies that are barely separated from the Atlantic Ocean by a narrow spit of land. Though the bays are bordered by increasingly heavy development, their tributaries pass through miles of cropland and chicken farms, picking up contaminated runoff as they flow into the bays.

“Despite decades of work to improve the health of the Bays, the estuary continues to face serious challenges,” the Delaware Center for the Inland Bays reports in the “State of the Delaware Inland Bays 2021.” It gave the bays’ water quality a grade of D grade–the same as it did five years earlier in 2016.

“Inputs of nitrogen from nonpoint sources continue to far exceed healthy limits in all three Bays, with no improving trend,” the report continues. It notes that residential and commercial development “brings with it more roadways and other impervious surfaces, as well as increased demands on wastewater treatment systems.”

The University of Delaware Water Resources Center is also concerned about dairy and horse farms out of state because three-quarters of northern Delaware’s drinking water comes from Brandywine Creek, which flows out of Pennsylvania.

Nudges and Advice

Government agencies, nonprofits, and individuals are trying to change the behavior of individuals and businesses in all sorts of ways.

Some efforts focus on plain ol’ dirt. Water made murky by too much sediment blocks out the sunlight that bottom-dwelling plants need to thrive. Sediment fences around construction sites prevents soil from washing into the water.

Signs on storm drains remind Delawareans to care for the watershed. They include “No dumping–drains to creek” in Newark and “Only rain down the drain” from New Castle County’s Clean Streams campaign and the University of Delaware Water Resources Center.

Farmers are encouraged to adopt more environmentally friendly practices, such as planting winter cover crops, not tilling the soil, building berms around retention ponds to reduce the risk of spills, composting dead birds, and managing poultry manure.

In 1999, Delaware established a nutrient management program to regulate manure disposal and fertilization. Statutory regulation of construction minimizes sedimentation and ensures that stormwater management systems continue to function properly when projects are complete. Roofs covered with plants, porous pavements and rain barrels all reduce the amount of water hitting–and potentially overwhelming–the stormwater system.

The National Ocean Service also brings attention to nonpoint pollution from marinas and boating activities, including chemicals used to maintain and repair boats, spilled or discharged fuel, and poorly maintained sanitary waste systems and pump-out stations.

Success Stories

DNREC runs a program to provide funding to reduce nonpoint sources, and it has posted 12 success stories regarding nonpoint sources. Success can be complicated–the stories include seven to 11 partners–and expensive: the cheapest ran $84,000; most topped $1 million, and the most expensive cost $6.2 million).

Two successes involve Pike Creek, part of the National Wild and Scenic Rivers System, and Little Assawoman Bay, the smallest of Delaware’s iconic Inland Bays.

In 2005, DNREC completed a restoration of a mile of Pike Creek with “significant bank erosion, which contributed to heavy sediment loads and degraded aquatic habitat.” Workers stabilized the banks, built riffles and pools and planted 3,500 native trees and shrubs. The project involved eight partners and almost $634,000 in funding. “The site now serves as an outdoor classroom.”

In 1996, Delaware added Little Assawoman Bay , the smallest of the Inland Bays, to its list of impaired and threatened waters due to bacteria from agriculture and leaking septic systems. The 2001 project–developed as a model watershed area–involved 11 partners and $100,000 in funding to rework how nearby poultry farms operate and plant cover crops and trees. The bay was removed from that list in 2006.

About the Author: Ken Mammarella is a Delaware native and longtime journalist who in his spare time likes to explore the terrain by bike.

Learn more

Environmental Integrity Project Clean Water at 50 report CWA-report-UPDATED-8.9.23.pdf (environmentalintegrity.org)

State of the Delaware Inland Bays 2021  2021 State of the Bays Report – DE Center for the Inland Bays

Delaware Department of Agriculture Nutrient Management Program  Nutrient Management – Delaware Department of Agriculture – State of Delaware

If you want to help

Plant stuff in bare areas. More plants reduce runoff and erosion. The best choices are native plants, which can more easily handle Delaware’s climate and better support native wildlife.

Properly dispose of motor oil and household chemicals. The Delaware Solid Waste Authority has a disposal guide. And don’t change your oil on the street. Have the work done at a facility that recycles the oil. 

Wash your car on your lawn, where the water can soak in instead of washing down a storm drain that leads directly to a waterway. Better yet, get your vehicle washed at a facility that recycles its water.

Use fertilizers and pesticides sparingly on lawns and gardens. Excess chemicals can lead to a deadly reduction of oxygen in downstream bodies of water. A single springtime application following manufacturer’s directions is OK, Kauffman says.

Even better, replace part of your landscape with a rain garden, which allows the water to filter into the watershed through the soil, and with native plants, which are adapted to our climate. Learn more about gardening for water and wildlife hereGardening for Water and Wildlife – Delaware Nature Society

Use a rain barrel to reduce runoff from your roof and use the rainwater on your garden. Rainwater has more of the nitrogen plants like and less of the stuff plants don’t like, like the chlorine, fluoride and sodium added to tap water.

Clean up your neighborhood, its green spaces, and its roadways. Such cleanups can be casual or formalized through the Adopt-a-Highway Program. Trash can clog storm drains or foul water downstream bodies.

Clean up after pets. Issues for pet waste resemble the issues for cow, horse, and chicken manure.

Report pollution violations to the Delaware Department of Natural Resources and Environmental Control.

Recycle. “Reducing the waste stream is the goal of all measures to control nonpoint source pollution,” the Ocean Service says.

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