Amid Historic Summer Storms, Clean Water Advocates Express Concerns With Major Maryland Stormwater Permit

New MDOT State Highway Administration stormwater permit does not adequately address climate change, experts say

Maryland has missed a critical opportunity to reduce stormwater pollution running off the state’s highways, roads, and bridges and into local waterways, according to experts from the Chesapeake Bay Foundation (CBF), Chesapeake Legal Alliance (CLA), and Maryland League of Conservation Voters (LCV). A new precedent-setting permit misses the mark on addressing climate change at the same time that Marylanders are enduring exceptionally heavy rainfall and flash flooding this summer.

This week, the Maryland Department of the Environment (MDE) issued an updated Municipal Separate Storm Sewer System (MS4) permit to the Maryland Department of Transportation (MDOT) State Highway Administration (SHA). This five-year permit is designed to mitigate the harmful effects of oil, gas, toxins, and other pollutants that run off of roadways and into the Chesapeake Bay when it rains—otherwise known as stormwater pollution. Research has long shown that stormwater runoff from roads contain higher concentrations of pollutants than almost any other sources.

The renewal of SHA’s MS4 permit—which only occurs every five years—was a critical opportunity. SHA’s permit covers an immense scale of surface area, including nearly 15,000 lane miles and roughly 2,600 bridges. Maryland’s section of the Capital Beltway (I-495) and Baltimore Beltway (I-695) alone see volumes of over 220,000 vehicles per day, according to MDOT data.  

On average, Maryland is seeing more intense storms and flooding. Maryland received 7.81 inches of rainfall in May—the highest in the past 131 years—according to the National Oceanic and Atmospheric Administration. A study commissioned by Pew Charitable Trusts estimated that inadequate stormwater management contributed to roadway flooding that cost Maryland more than $230 million between 2006 and 2020. An estimated 480,000 drivers are impacted by roadway flooding annually.

Yet in many cases, Maryland’s MS4 permits have not kept pace with climate change and have fallen short for water quality improvements. The permit fails to address significant deficiencies that were identified by experts in the draft permit last year, including continued use of out-of-date data, emphasis on stormwater practices that do not address the root cause of pollution, and lack of information on emerging contaminants like per- and polyfluoroalkyl substances (PFAS).

Stormwater pollution is the fastest growing source of pollution in the Chesapeake Bay watershed, according to the U.S. Environmental Protection Agency’s latest two-year progress report. While other pollution sources like agriculture have trended down in recent years, stormwater pollution has only increased. This is likely due to rapid development in the region, as well as more extreme weather and heavier rainfall from climate change. 

Polluted runoff doesn’t only harm waterways, but people too. Urban and suburban communities are enduring repeated flooding, property damage, and exposure to harmful chemicals. It is often underserved and overburdened communities that bear the brunt of stormwater damage due to a long history of discriminatory disinvestments in infrastructure. Research has consistently shown that Baltimoreans feel more vulnerable to climate impacts than most other communities in the U.S. 

MDE’s latest MS4 permit for MDOT SHA makes some minor improvements but fails to incorporate key provisions that advocates and citizens had called for during the permit’s public comment period. Suggested improvements that will not be implemented include: 

• Ensuring the permit accounts for increased storm intensity and other impacts of climate change;
• Requiring a range of effective practices to mitigate stormwater pollution, such as riparian plantings, “green infrastructure” infiltration structures, and removal of unused impervious surfaces (such as roads, parking lots, etc.), to reduce reliance on in-stream projects;
• Expanding monitoring requirements to include temperature changes and impacts to wildlife and their habitats from polluted runoff; and, 
• Tracking and addressing pollutants like polychlorinated biphenyls (PCBs) and ‘forever chemicals’ such as PFAS.

CBF, CLA, and LCV are disappointed with MDOT SHA’s final permit, but will continue urging MDE to reduce stormwater pollution whenever and wherever possible.

CBF Maryland Executive Director Allison Colden issued the following statement:

“Maryland’s current stormwater regulations are no match for nightly thunderstorms and daily floods. We are disappointed the State did not capitalize on this opportunity to lead by example and demand effective stormwater improvements with tangible benefits. Because of this, one of Maryland’s largest pollution-reducing permits will not adequately reflect current climate impacts for at least another five years. 

“The health and safety of Marylanders and the vitality of our economy cannot wait. We urge MDE and Governor Moore’s Administration to take additional actions to meet Maryland’s stormwater challenges and set an example for other jurisdictions in the Bay region.” 

Maryland LCV Executive Director Kim Coble issued the following statement:

“Maryland should be leading the efforts to restore and protect the health of the Chesapeake Bay, starting with an effective and equitable stormwater management permit. Unfortunately, this permit takes a minimalistic approach that fails to prioritize projects addressing climate resilience and water quality in communities most burdened by pollution. We cannot afford to continue doing the bare minimum while frontline communities bear the brunt of environmental degradation. Stronger, more inclusive action is urgently needed.”  

CLA Senior Attorney Evan Isaacson issued the following statement:

“On its face, this permit is not strong enough to help protect communities and streams from highly polluted roadway runoff and will not do enough to meet our Bay goals. However, we know from several decades of experience that what matters more than the contents of a permit is how it is implemented. Maryland has an opportunity to change how it spends its scarce resources and invest in the most effective and efficient stormwater and flood risk projects. The good news is that some of the very cheapest means of protecting our water and safeguarding Marylanders from storm-induced flooding are also some of the most effective, notably planting trees near roadways and along streams, and restoring wetlands in flood prone areas.”