by Paul Ruffins

In 2021, the Maryland Department of the Environment (MDE) published a study documenting the growing issue of flooding in the state. The report’s warnings and calls for mitigation measures come as relatively old news to many College Park residents, however. 

Brook Biddulph, who lives in the city’s Cherry Hill neighborhood, recounted a soggy experience some years back. “In May of 2018, we came home after a long rain, and our yard was flooded so deeply we couldn’t see our driveway. Later, we found that our garbage cans had floated off into the woods,” she said. 

Resident Bob Baer recently told the Here & Now, “My property on Calvert Road has had sewage back up into our basement three or four times. WSSC is blaming the problem on a stormwater drain and is still only offering temporary fixes.” 

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A crew installing a new drainage pipe along Rhode Island Avenue in Calvert Hills.
Credit: Paul Ruffins

While the MDE report primarily addresses increased flooding due to global climate change, water-related problems here in the city run even deeper than that. In this edition of “The Science of the City,” we’ll dive into some of the city’s flooding issues and explore some of the reasons why some neighborhoods — Calvert Hills, in particular — suffer more than others. 

The following brief timeline highlights the roles of local, state and federal agencies involved in water and sewer management in our region. 

1820s: Soil erosion. During the War of 1812, the Anacostia River was deep enough for large British warships to sail up to Bladensburg, which was a bustling port at that time. As upstream forests were cleared for farms and homes, though, runoff quickly filled in the harbor there, ruining it for commercial shipping. Today, one can paddle only a small boat like a kayak or canoe upstream beyond Mount Rainier, and the area along Bladensburg Waterfront Park now has to be dredged every year.

1870s: Federal initiatives transform the District. The Army Corps of Engineers begins filling in local wetlands, which we now know are crucial to floodwater absorption. The corps creates the National Mall with material dredged from Potomac.

 1880 to 1918: Plumbing. Baltimore mandates indoor plumbing. Local towns begin to develop water and sanitary systems that discharge raw sewage downstream into Rock Creek, and the Potomac and Anacostia rivers.

1918: Washington Suburban Sanitary Commission (WSSC). Pollution from Prince George’s and Montgomery counties becomes so bad that the District threatens to sue. Officials in the two counties established WSSC to address the pollution generated by the counties. The commission soon consolidates several local water companies in an effort to improve drinking water and sewage services in both counties; the new utility direct much of its sewage to the Blue Plains water treatment plant in the District.   


1940s to ‘50s: Rapid growth. As suburban roads and populations explode, WSSC begins constructing a separate sewer system to manage stormwater runoff.

1972: Federal Clean Water Act (CWA). The Environmental Protection Agency (EPA), established in 1971, is authorized to regulate point sources of pollution into waterways, such as outfalls from factories and sewer systems. 

1987: Amendments to CWA. New regulations are mandated to govern pollution from stormwater runoff.

Over the next few years, primary responsibility for stormwater management shifts from WSSC to Prince George’s and Montgomery Counties.

2005: WSSC agrees to reduce sewage overflows. By 2020, the utility had completed 256 construction projects addressing issues in numerous waterways, including Rock Creek, Sligo Creek, and the Northeast and Northwest Branches of the Anacostia River, at a cost of over $1.1 billion.  

2007: WSSC launches initiative to counter sewer backups. The utility’s FOG (Fats, Oils and Grease) Program issues food industry regulations aimed at reducing sewer backups. 

2010: The EPA issues new regulations. Agency orders states in Chesapeake Bay watershed to reduce pollution due to stormwater runoff.   

2012: Maryland levies fees. The state votes to use stormwater fees in 10 jurisdictions to cover $14.8 billion cost for the programs and infrastructure needed to clean up the Bay. Critics denounce it as a rain tax. 

2015: University Of Maryland focuses on stormwater management. The university’s environmental finance center prepares a detailed report on the best opportunities for high impact solutions to stormwater management issues in College Park, focusing particularly on issues in the Cherry Hill and Calvert Hills neighborhoods 

2019: Prince Georges’s County stormwater initiative begins. The county undertakes the design phase of Calvert Hills Drainage Improvement Project. As of March 2022, this phase has not yet been completed.

February 2022: City Council takes action. The College Park City Council appropriates $600,000 in federal stimulus funds for engineering studies to identify strategies for stormwater management, with a specific focus on the Calvert Hills neighborhood.


Understanding College Park’s water-management infrastructure

College Park’s sanitary sewer system is managed by WSSC, which operates six sewage treatment plants, all located in Maryland — though most of College Park’s sewage flows into the massive Blue Plains Advanced Wastewater Treatment Plant in Southeast D.C. Blue Plains is operated by DC Water and has been treating waste water from the District and surrounding jurisdictions in Maryland and Northern Virginia for nearly a century. College Park also has a separate system of culverts and pipes for directing runoff stormwater into local waterways; this system largely dates to the 1940s and ‘50s and is maintained by Prince George’s County.   

An advantage of having separate systems, one for managing residential and commercial sewage, and a second for stormwater runoff, is that by directing only sewage to treatment plants, millions of gallons of stormwater, which is comparatively clean, is not processed — a significant cost-saving move. Having parallel systems is also supposed to also prevent stormwater from overfilling sanitary sewer lines that could then discharge raw sewage. During large rain events, however, both WSSC’s and  D.C.’s systems sometimes overflow and discharge untreated sewage onto customers’ properties or into local waterways, in violation of the Clean Water Act (1972). 

Among the many stormwater management challenges that College Park faces, three are of primary concern: reducing the sheer amount of water and managing flow speed, controlling water pollution and upgrading the city’s infrastructure.

As climate change leads to more frequent and severe storms, some natural characteristics of our area further amplify the impact of these weather events. Soil in our region typically contains a lot of clay, which impedes drainage; the effects of poor drainage are generally more severe in neighborhoods located within the Anacostia River’s flood plain. Explosive development, much of which incorporates impermeable surfaces — roofs, roads and parking lots — further exacerbates the problem, as impermeable surfaces limit absorption. When soil isn’t sufficiently absorptive, excess water pools in flatter areas, and it travels downhill faster and potentially farther in hilly ones. 

  As runoff moves through an area, it picks up oil, gasoline and antifreeze, road salt, pesticides, fertilizers and herbicides, and contaminants from animal waste. It also carries sand and dirt from construction sites, plastic bottles and bags, and other debris, all of which can clog culverts and storm drains. And even with measures introduced by WSSC in 2007 to regulate the food industry’s disposal of grease and fats, sewers may be clogged with discarded food and food  byproducts. Individuals add to the problem when they flush products like baby and hand wipes.

  The city is also struggling with the limitations of its aging stormwater infrastructure — the system of culverts and pipes that is 70 or 80 years old at this point. Pipes expand and contract with temperature changes, they are vibrated by nearby traffic, and they are ground down by the constant flow of grit and debris. They can be accidently broken by construction crews and compromised by tree roots. Sometimes they simply collapse into themselves — all pipes eventually wear out. Stormwater can easily infiltrate cracked sanitary sewer pipes, and excess stormwater in a sewer pipe can lead to sewer backups. You likely have heard about the sewer backups plaguing homes and businesses in the city — perhaps you’ve been unfortunate enough to experience one.

            College Park is responsible for reducing the city’s contributions to pollution — an example of this would be covering piles of salt used to treat icy roads. Cities and towns frequently have education programs to encourage citizens to pick up after their dogs, put used cooking oil in containers and discard them in the trash, and recycle household waste, including some hazardous materials such as pesticides and car batteries. And municipalities are responsible for enforcing new building codes, some of which regulate materials and methods; all construction sites in Prince George’s County (and in many other jurisdictions), for example, are now required to use protective fabric skirts to retain soil when it rains. 

Prince George’s County also operates a program through which residents may earn rebates by installing rain barrels, cisterns and rain gardens; by planting trees and replacing old pavement with more permeable surfacing; and by installing a green roof to reduce runoff.

Some mitigation actions can be fairly straightforward. Biddulph noted that in her Cherry Hill neighborhood, the stormwater inlets were only about three inches high, and were easily clogged with sticks and leaves. Simply making the opening larger made a big difference.”

The water problem in Calvert Hills is a lot more complex, though, in part due to the presence of Gilford Run, a stream that starts in Guilford Woods, about a mile northwest of the university’s campus. City Councilmember Stuart Adams (District 3), who is a flood plain engineer, strongly opposed developing Guilford Woods; his primary concern was that the tree canopy, which plays a crucial role in reducing runoff, should be preserved. Guilford Run flows in an open channel parallel to Guilford Drive, then crosses east under Route 1 through a series of pipes and culverts; it then flows for several blocks under the sidewalk along Calvert Drive and under the Metro and CSX tracks, finally emerging into an open channel leading to the Northeast Branch. Calvert Hills also receives water flowing in irrigation ditches along Rhode Island Avenue and the trolley trail. 

The county’s Calvert Hills Drainage Improvement Project is a significant engineering initiative that will upgrade road culverts and open channels, and add new storm pipes and a massive underground vault to contain stormwater. “The vault is basically an empty concrete box [that is] 100 long, 100 feet wide and ten feet tall installed under a playing field to hold excess stormwater,” said David Dorsch, a Calvert Hills resident with more than 30 years of commercial construction experience. “I believe it’s a good solution. The problem is that it was supposed to be completed in April 2021 and it hasn’t even started yet.”

Plans for these projects are posted on the city’s website,