Stormwater pollution is proving to be one tough nut to crack in restoring the Chesapeake Bay. To understand how tough, just look at how Maryland’s largest city and the state’s biggest suburbs have struggled with it.Construction crews restore Chinquapin Run in Baltimore city, moving a sewer line out of a channel and stabilizing banks. Trees planted along the stream by volunteers were taken out, but officials say the reductions in erosion and sewage leaks outweigh the loss. (Dave Harp)

A year ago, despite having spent more than $100 million on a slew of projects, Montgomery County failed to meet state requirements for reducing polluted runoff from its streets, parking lots and rooftops. In a consent agreement with state regulators, it pledged to catch up and pay a $300,000 fine — or spend a like amount on an extra stormwater management project.

Officials in the city of Baltimore and Anne Arundel and Baltimore counties said they’ve managed to avoid a similar fate. But they only did so with help from the Maryland Department of the Environment, which approved ways of complying with its mandates that critics find questionable.

Baltimore city, for instance, did it mainly by sweeping its streets — an approach that experts say is, at best, only modestly effective at curbing the nutrient pollution that plagues the Bay.

Anne Arundel County, meanwhile, took advantage of a new state program that permits pollution “trading.” This let the county offset its big shortfall in reducing stormwater runoff by taking credit for the better-than-required performance of its sewage treatment plants.

And Baltimore County benefited from another helpful state decision. The MDE announced late last year that localities could claim greatly increased pollution reduction credits for stream restoration projects — far beyond what a number of experts think is warranted.

State officials say they did those things to provide flexibility in meeting the ambitious stormwater reduction target they set because the effort was costly and difficult and each locality seemed to have different challenges meeting it.

“Each county is finding practices that work best in their landscape and environment,” said Lee Currey, director of the MDE Water and Science Administration.

But environmentalists and even some stream restoration professionals contend that the state has let localities off easy. Under pressure from local officials, they say, regulators permitted and expanded credit for measures of debatable value in reducing polluted runoff — or, in the case of trading, that simply put off dealing with it until sometime in the future.

“This agency is trying to turn every environmental restoration initiative into an accounting exercise, ripe for accounting gimmicks to make the status quo look like progress,” said Evan Isaacson, a policy analyst with the Center for Progressive Reform. “Whether it’s a juiced stormwater accounting guidance document, nutrient trading market or rigging stream restoration assumptions, there is just far too much talk of ‘credit.’ ”

The MDE’s Currey rejected the criticism, insisting that the agency’s actions were based on research and expert advice.

Baltimore city relies heavily on vacuum-powered street sweepers, like the one shown here with its operator Alonzo Ames, to pick up dirt, litter, sediment and other pollutants. Experts’ reviews found the practice only modestly effective at reducing nutrient pollution from stormwater runoff, even if done frequently. (Dave Harp)“I don’t agree that this is being done just to meet the [permit requirement],” he said. “I believe that the science is evolving, and we’re doing our best to adapt to that in a thoughtful and meaningful way.”

The dispute matters because stormwater is a significant source of the nutrients and sediment fouling the Bay and, according to the federal-state Bay Program Office, the only source of those pollutants that’s still growing.

When rain falls on streets, highways, parking lots, sidewalks and rooftops, it runs off, flushing fertilizer, sediment, pet waste, oil, chemical contaminants and litter into nearby waterways. In most urban areas, it is the number one cause of stream impairment, according to the Center for Watershed Protection, a nationally recognized research nonprofit based in Maryland.

The best way to curb stormwater pollution is to let rainfall simply soak into the ground. States are now required to ensure that new development is built in a way that directs runoff to holding ponds, wetlands or open vegetated areas that can soak up the precipitation. But older cities and suburbs built before those controls were required must find ways to retrofit storm sewer systems that were designed mainly to siphon rainfall off streets and into streams as quickly as possible.

The Bay watershed’s older communities are all struggling to get stormwater under control, especially in Maryland, the nation’s fifth most densely populated state. Controls on new development runoff are far from complete, and progress retrofitting older areas has been slow.

Since the 1990s, the U.S. Environmental Protection Agency has required large and medium cities everywhere, as well as counties with at least 100,000 residents, to regulate their stormwater. Under EPA oversight, states have issued those localities discharge permits for their storm drain outfalls. The permits typically require plans for controlling polluted runoff and must be renewed every five years.

The initial stormwater permits didn’t require much. Pressure to do more grew in later years, especially for the Bay states after 2010, when the EPA imposed nutrient and sediment reduction requirements through its Baywide “pollution diet.”

About that time, Maryland ordered its localities with more than 250,000 residents to essentially double their efforts to either reduce or treat their stormwater discharges. The state’s stormwater permits required those localities to restore the runoff-absorbing capability of 20 percent of their “impervious” surfaces, meaning their lands covered by pavement and buildings. That was a tall order — unrealistic, some say — requiring them to treat thousands of acres.

The most direct way to do that is through “green infrastructure” that collects and absorbs stormwater — ripping up pavement, for example, so rainfall could soak into soil again, or covering roofs with moisture hungry-plants. Other approaches involved building or enlarging stormwater detention ponds, creating a multitude of “rain gardens” or planting more trees.

But in heavily developed areas, it’s not easy to find enough open space to collect rainfall. Forty-five percent of Baltimore city is covered with pavement and buildings, for instance, but in some rowhouse neighborhoods, it’s up to 85 percent impervious. Costs also were a challenge, with early estimates for various retrofit projects ranging from $20,000 to more than $300,000 per acre.

With local officials worried about logistical and financial challenges, the MDE issued guidance in 2014 approving a menu of practices and projects for treating impervious surfaces, including some, like street sweeping and stream restoration, that only dealt with runoff indirectly.

According to state officials, those alternative measures provide equivalent benefits by reducing nutrient or sediment pollution, or both. Others, though, are skeptical.

The five-year stormwater permits for five localities have now expired. Here is a summary of what each says it has achieved:

Baltimore City

With 52,000 storm drains across its 81 square miles, Baltimore had been ordered by the state to deal with runoff from 4,300 acres of pavement and buildings. City officials announced earlier this year they’d succeeded in treating the equivalent of 4,530 acres. Four-fifths of that came from sweeping streets.

Kimberly Grove, chief of compliance and laboratories for the city’s Department of Public Works, said officials originally planned to install a greater amount of green infrastructure. But Grove said planners had to scratch many projects because of difficulties getting access to private property. And some sites were so small the projected expenses were exorbitant. In one case, she said, it would have cost up to $250,000 per acre.

Amanda Oxendine and Matt Cherigo, pollution control analysts with the Baltimore City Department of Public Works, check water quality in Gwynns Run. City crews make regular checks for nutrients, bacteria and other pollutants at dozens of storm outfalls and stream sites. (Dave Harp)The city did go after stormwater in other ways, cleaning more than 500 tons of dirt and debris out of storm drain inlets last year. The work the city is doing separately under regulators’ orders to fix and replace leaky sewer lines also likely reduced stormwater pollution, Grove said.

But the city needed to find less expensive ways to make stormwater progress, as its mandated sewer overhaul is expected to cost more than $2 billion by 2030. The MDE had blessed street sweeping as an alternative to retrofitting storm drains and other capital projects, even though it has to be repeated constantly to have any effect.

The MDE’s Currey said regulators based their decision on the findings of a panel of experts for the Bay Program.

But the panel revisited the issue a couple of years later and concluded that they had overestimated the pollution reduction benefits of street sweeping.

“No monitoring studies have shown a detectable water quality change within storm drains that can be attributed to upland street sweeping, and it is doubtful whether future monitoring efforts will be any more successful,” the panel’s 2016 report said.

Currey acknowledged the new findings but said state officials decided not to change the rules because it would be unfair to localities like Baltimore that had acted on the earlier guidance. Baltimore city bought a fleet of nearly 40 street-sweeping trucks equipped with vacuum equipment to whisk dust and dirt from streets and gutters.

“It’s only a five-year permit,” Grove pointed out, “and to find the funding and execute things, it’s difficult to do that when the rules suddenly change midway through.”

Frequent sweeping using vacuum trucks does keep some sediment and contaminants out of the streams, experts say. It also picks up some litter, which helps the city with another regulatory mandate it faces — to halt the torrent of trash getting into the harbor from streets and parking lots.

The trucks vacuum some streets in the city’s core four times a week, Grove said, with others getting weekly or monthly sweeping. Larger debris clogs the vacuums, though, so the drivers have to stop and deal with that manually. And the sweepers can’t get at dirty gutters when residents don’t move their cars on scheduled street cleaning days — a chronic issue in some neighborhoods.

A recent study in Madison. WI. found that the rigorous removal of fallen leaves from streets — including before every rainfall — did reduce phosphorus in streams, but its authors acknowledge that this is not realistic. Stream sampling in Baltimore has detected phosphorus and bacteria reductions in places, but those could also be the result of fixing leaky sewers.

MDE officials say they may very well reduce the stormwater credit for street sweeping in the next permit, which is to be issued later this year. If that happens, the city will have to find other ways to meet most of its treatment requirements.

The city is also at work on other projects to be completed in the next two years. One involves restoring more than two miles of Chinquapin Run, a channelized stream that flows through northern Baltimore neighborhoods. Stream restorations rework and sometimes armor stream channels to reduce bank erosion. In some cases, they also recreate flood plains or wetlands to enhance wildlife habitat. This project also involves moving a failing sewer line out of the channel.Stream sampling in Baltimore city has detected drops in phosphorus and bacteria levels in some places. City officials attribute the declines to their stormwater reduction efforts, but acknowledge they could also be from fixing sewage leaks and overflows. (Dave Harp)

Stream restorations in the city have proven controversial, as the projects require felling trees in an urban landscape that lacks adequate canopy. Along Chinquapin Run, hundreds of trees were removed that had been planted by volunteers over the last several years. Grove called the tree removal unfortunate, but said the environmental benefits of the stream restoration, including the sewer upgrade, outweigh the temporary loss of foliage. She said the trees would be replaced elsewhere.

Jenn Aiosa, executive director of the nonprofit watershed group Blue Water Baltimore, said she’s glad the city has met its stormwater permit requirements and avoided having to pay a fine. But she hopes to see more done to reduce runoff with projects that also enhance neighborhoods’ quality of life.

“We are seeing highly urbanized cities like Philadelphia, like the District of Columbia, like Atlanta, like Cleveland that are committed to doing more green infrastructure,” Aiosa said, “not only for the ... pollution reduction benefits but because there’s a whole slew of other benefits associated with planting trees and perennials and letting rain seep into the ground.”

Anne Arundel County

Just south of Baltimore, Anne Arundel County faced a different dilemma. Needing to treat runoff from nearly 5,000 acres of pavement and buildings, the county relied more on reducing shoreline erosion, retrofitting stormwater detention ponds, stream restoration and pumping out septic tanks. But by year’s end, with its permit about to expire, the county had treated the equivalent of just 2,300 acres, less than half of what was required.

The county just couldn’t get enough runoff treatment projects built by the permit’s five-year deadline, explained Erik Michelsen, administrator of watershed protection and restoration for Anne Arundel’s Department of Public Works.

Anne Arundel managed to close the gap through nutrient trading, using state regulations finalized last July. Trading is designed to let parties needing to reduce nutrient pollution acquire credits from another party that has already reduced its pollution more than the law requires. For example, municipalities facing costly stormwater requirements might be able to save taxpayers money by paying industries or farmers who’ve been able to reduce their runoff for less.

In this case, though, the trade will be cost-free and in-house — taking advantage of state-subsidized upgrades made to Anne Arundel’s wastewater treatment plants, which are now removing much more nutrients than their discharge permits require. The trade essentially buys the county time to comply with its stormwater mandate, Michelsen said. But the county fully expects to do the needed projects, he added, and already has them in the pipeline.

“We will be using the credits generated by the overperformance of the county’s wastewater treatment plants to close that 2,700-acre gap,” he said, “with the expectation that we will ‘burn off’ that nutrient trade with stormwater projects in the ground — all of which are in design or under construction at this point — during the next permit cycle.”

Baltimore County

Suburban Baltimore County had also hoped to use nutrient trading to help it meet its requirement to treat 6,036 acres of impervious surfaces. But the county found itself in a bind because Baltimore city owns and operates the treatment plants that process the county’s wastewater, and it wasn’t clear what, if any, credits the county might be able to take.

So, county officials began searching for whatever might count to close the gap.

“We’ve got a pretty accomplished restoration program, and when we noticed we were looking like we were behind, that gave us some pause and reason to go back and make sure we were accounting for what we were doing,” said Robert Hirsch, manager of watershed management and monitoring for the county’s Department of Environmental Protection and Sustainability.

Officials found some related projects that were done before the stormwater permit had been issued, which MDE credited. But what put the county over the top was the MDE’s decision late last year to increase the stormwater reduction credit for stream restoration projects. Baltimore County has been a leader regionally in such projects.

Using the new MDE guidelines, Hirsch said, the credits the county could claim for stream restoration increased up to eightfold. Hirsch welcomed the change, saying it was overdue.

“It’s like some of the pollution removal work that we’ve known stream restoration has done simply wasn’t accounted for in the [original] 2014 guidance,” Hirsch said.

There’s been debate for years among scientists and stream restoration practitioners about the effectiveness of such projects, with some agreeing that it depends on how and where they’re done.

Several consultants engaged in stream restoration say that the state initially gave such projects too little credit for reducing sediment and nutrient pollution. But the policy change last fall, prompted by one consultant’s request for credit on a single project, went too far, they contend, and boosted the credit beyond what the science supports. The change effectively lets localities off the hook, they say, even though more is needed to curb stormwater pollution.

“It’s going to reduce the amount of restoration we have to do to comply with the law, but it won’t get us the restoration we need,” warned Jim Gracie, president of the environmental consulting firm Brightwater, Inc., who has been doing stream projects for three decades. “There’s a huge disconnect,” he added, between doing what it takes to meet the state’s stormwater permit and actually improving water quality.

Hirsch rejected such criticism and suggested that stream consultants are complaining because they fear they might not be hired by counties and municipalities to do as many projects.

Gracie acknowledged that he’s concerned about the impact on the industry. But he and other stream professionals say they’re more concerned about the impact on the pace of the cleanup.

“Does it affect what work we might get?” asked Rich Starr, a senior water resources scientist with Ecosystem Planning and Restoration, a Columbia consulting firm. “Yeah, potentially, but I do this because I’m passionate about streams and want to see the Bay get better. I want to see it done right.”

MDE’s Currey said the stormwater treatment credits given to stream restorations are “the best estimate we have today” of the benefits, based on estimates from the Bay Program’s expert panel.

But Tom Schueler, co-chairman of the panel, said he can’t vouch for the way the MDE converted the group’s estimates of pounds of pollutants reduced into acres of impervious surface treated. And Schueler, executive director of the nonprofit Chesapeake Stormwater Network, said the panel is taking yet another look at available research and may revise its estimates.

Bill Stack, deputy director of the Center for Watershed Protection, said he thinks the MDE significantly overestimated the sediment removal benefits of stream restorations in deciding how much credit to give them.

“They’re pretty sharp people,” said Stack, who’s the other co-chair of the Bay Program panel. “But I do question their making such a dramatic change.”

Currey said regulators had tried to account for uncertainties about stream restoration benefits, imposing a cap on how much credit could be taken for any one project. But he said the MDE would revisit its decision if the experts decide that stream restoration is less effective.

“Stormwater management is an evolving science,” Currey said. “In some ways it’s still in its infancy.”

Stack said that, while he’s a believer in stream restoration, he worries that the MDE crediting decisions put too much emphasis on such projects now, discouraging efforts to reduce or treat runoff in upland areas. And too many of the projects he sees are focused almost exclusively on reducing nutrient and sediment pollution, he said, without also trying to restore aquatic life to the waterway — which he said should be the ultimate goal.

“Hopefully, the next permit will be written differently,” Stack said.

Prince George’s County

Though lauded by some as a trailblazer for forging a public-private partnership to tackle stormwater pollution, Prince George’s County appears likely to fall short of the state’s treatment requirement. County officials are still finalizing their report on the permit, which expired Jan. 1, according to Jerry Maldonado, head of water quality and compliance in the stormwater management division of the county’s Department of Environment.

Under the county’s permit, it was required to reduce or treat runoff from 6,100 acres of pavement and buildings. Last year, county officials reported they had completed work on 2,215 acres, with another 2,860 acres in planning, design or construction.

The county had hoped to cover the gap with credits from overperforming wastewater treatment plants, as Anne Arundel did. But the county’s waste is treated by a regional authority, the Washington Suburban Sanitary Commission, and a credit-sharing agreement has not been reached, according to Maldonado.

Three years ago, Prince George’s drew widespread attention when it signed an agreement with a private company to take over much of the job of dealing with its stormwater issues. Corvias Solutions had partnered before with the Pentagon and universities to build and manage military housing complexes, college dormitories and other government facilities. County officials said the deal promised to save costs and speed pollution reductions.

“Their contracting targets are being met,” Maldonado said of Corvias. But the company was only responsible, he pointed out, for doing about a third of the required impervious surface treatment.

Maldonado, though, questioned the logic behind the state’s stormwater credit system.

“Baltimore [city] spent $20 million in four years on street sweeping and achieved it,” he said, “and Prince George’s spent $200 million, and we haven’t achieved it. Houston, we have a problem here.”

Montgomery County

Long recognized as a leader among state localities in tackling stormwater pollution, Montgomery County discovered that it was still difficult to meet the state’s permit requirement. But after admitting failure last year, county officials say Montgomery has now caught up and achieved compliance, albeit more than three years after the original deadline. The county reported to the MDE that it had reached the permit goal of treating runoff from 3,778 acres of impervious areas and also completed its extra stormwater project.

“We used every single possible tool we could to meet this,” said Amy Stevens, section chief for watershed planning and monitoring in the Montgomery Department of Environmental Protection. “Everything in the guidance that MDE put out, we worked to try to access that credit.” The county did street sweeping, outfall repairs, stream restorations and even planted more than 11,000 trees, she noted.

“It was a tremendous lift, even in an eight-year period to get this work done,” said Frank Dawson, the department’s chief of watershed capital projects.

The county did not take advantage of the MDE’s decision to increase credits for stream restoration. Dawson said the decision came too late for county officials to factor it into their reporting. But he said if the MDE guidance remains unchanged, he hopes the county can take additional credits from already completed stream projects to apply to the next stormwater permit the county must work on.

The next permit?

With permits issued in 2013 and early 2014 now expired, state officials are preparing to issue new ones this year, setting goals for localities’ stormwater pollution reduction efforts from 2019 to 2023.

Some want the state to keep the pressure on localities to treat another 20 percent of their built landscape. Others want to apply a different yardstick, requiring measurable reductions in pollution rather than awarding credits for various surrogate practices and projects deemed equivalent.

“We would like to see actual water quality improvements rather than participation awards,” said Elaine Lutz, a lawyer with the Chesapeake Bay Foundation.

The MDE’s Currey said that state officials haven’t decided yet what to require next, but he indicated it’s likely to be different.

“It’s going to be tailored to each jurisdiction,” he said, “because we’ve learned the last five years, trying to achieve that 20 percent … each jurisdiction faces different challenges.”

(As originally posted, a wayward decimal point instead of a comma caused this story to misstate the number of acres of impervious surface Baltimore County needed to restore. The Bay Journal regrets the error.)