In a given year, construction activity in the Bay watershed cumulatively disturbs about 132 square miles of land — an area nearly twice the size of the District of Columbia.

On average, those building sites dump more sediment per acre into streams and rivers than just about any other human activity. But construction is so ubiquitous, it’s a pollution source hiding in plain sight.

“I drive by construction sites all the time, but it’s not something I ever noticed before,” said Matthew Henjum, a staff attorney with the nonprofit Chesapeake Legal Alliance.

His perspective changed last year when he joined Richard Klein, an environmental consultant, to survey erosion controls at construction sites in the greater Baltimore region.

“I was surprised by how many construction sites there are,” Henjum recalled. “Most of the sites that we visited were not even close to being in compliance with even very basic requirements.”

Klein has been leading a sometimes lonely campaign against “mud pollution” for decades. But in the last couple of years, he’s gotten company, as he began recruiting and training volunteers to examine construction sites for problems that could send sediment into nearby waterways and, eventually, the Bay, adding to its water quality woes.

Sediment, along with nitrogen and phosphorus, is one of the three pollutants targeted by the state-federal Bay cleanup effort.

In Klein’s Greater Baltimore Survey completed last year, those volunteers found just 37 percent of the 131 construction sites they evaluated in Baltimore and five surrounding counties had adequately stabilized soil with grass, straw or mulch to reduce runoff. The good news: That was a 61 percent improvement over a survey conducted the previous year.

County and state officials contend that local programs are doing a better overall job than Klein’s data suggests. But many agree with one of his basic assertions — in general, there aren’t enough inspectors to keep tabs on all of the construction going on.

“There’s not a sediment control enforcement agency that’s not understaffed,” said Brian Clevenger, manager of the sediment, stormwater and dam safety program of the Maryland Department of Environment, which just added six inspectors to help with its erosion control oversight. “Everybody needs boots in the field.”

While environmental groups often campaign for tougher laws and regulations, the problem with construction site erosion illustrates a different issue. Adequate laws are generally in place, Klein said, but often they’re just not adequately enforced.

He pins the blame largely on enforcement staff cutbacks over the years by counties and municipalities, as well as by the MDE. As a result, he said, there are too few people to oversee too many construction sites, which are often large, complex and filled with lots of activity.

“Laws are only as good as they are enforced,” said Jennifer Herzog, the Chesapeake Bay Foundation’s Maryland grassroots manager, who was active in last year’s surveys. “It is not the sexiest issue for a lot of folks, but it is essential for water quality.”

Most inspections are carried out by local agencies. State law requires construction sites to be inspected at least once every two weeks, but in most counties, checking on erosion and sediment controls is just part of each inspector’s many responsibilities. The MDE, which also has staff limitations, is responsible for overseeing local programs, as well as directly regulating construction sites in jurisdictions that do not have their own erosion and sediment control programs.

The short staffing can also be a problem for builders. With inspection staffs stretched thin, problems are more likely to be caught late, be more serious and result in fines. Klein said an MDE inspection is 12.5 times more likely to result in a fine now than in 1997. If caught early, he said. “it’s far easier to get a contractor to fix a small problem without resorting to a fine or penalty.”

The public is generally unengaged when it comes to things like erosion control. If they think about it at all, Klein acknowledged, they believe the black sediment fences that skirt the edge of a construction site are keeping waterways safe from mud pollution.

But those fences, along with adjacent berms and sediment traps, are actually the last line of defense, and can get overwhelmed during storms. Klein’s surveys focused on something more important — the need to stabilize exposed, highly erodible soils on the construction site itself.

“Exposed soil reacts to rainfall much the way that a parking lot does,” Klein said. “It only takes a tenth of an inch of rain to produce runoff from barren soil.” In comparison, he added, “it takes an inch and a half of rain to produce runoff from your lawn.”

He’s even reduced this to a mathematical formula: Exposed Soil Equals Pollution, or ES=P.

A one-time stream biologist at the Maryland Department of Natural Resources, Klein saw firsthand the impact that sediment could have on waterways. It smothers bottom-dwelling organisms, kills fish eggs and destabilizes stream banks. In recent decades, he has tried to raise awareness about the problems posed by construction sites.

“Very few folks are aware of this,” said Klein, whose goal is to turn exposed soil at work sites “into something that becomes socially unacceptable.”

In recent years, he has sought to build awareness by training citizens and staff from other organizations who can add to his voice, saying “we saw what Klein saw” — and, ultimately, to start their own watchdog efforts. Eventually, he hopes that yields more public support for beefing up county and state inspection efforts.

He seems to be gaining traction. Some local groups are starting their own initiatives. And the CBF is looking at ways to support broader efforts.

Doug Myers, CBF’s Maryland scientist, said the surveys can be eye-opening. He was “shocked” to see sediment generated during construction overwhelm the green infrastructure techniques that environmentalists often promote to control stormwater runoff — small detention ponds and swales that catch and soak up runoff. “They were actually polluting more during the construction project than that feature was ever going to remove after it was built,” Myers said.

In the survey, volunteers visited each location several times, looking for exposed soil and signs of activity at construction sites. Bare soils are supposed to be stabilized, usually through seeding and straw mulch, within seven days after earth-moving activities cease. If necessary, those areas may need to be retreated to keep at least 95 percent of the site covered.

Some officials question whether citizens observing a site from the outside, and without having approved site plans in their hands, can authoritatively make such an evaluation. For instance, they say, some areas might be exposed because they are going to be excavated for a septic system or other purpose.

“You might see a hole, and say ‘that’s a hole,’ but maybe it’s supposed to be converted into a stormwater management device,” said Gail Engles, chief of the Carroll County Bureau of Resource Management. “So without having the plans, you don’t really know what the permittee was supposed to do.”

Not everyone agrees with Klein’s results. His survey last year found only 32 percent of sites surveyed in Baltimore County had adequate stabilization. In a statement, Donald Brand, Baltimore County Building Engineer, said an MDE review of the county in October found that 89 percent of sites reviewed were properly stabilized.

“With more than 200 miles of waterfront in Baltimore County, we take very seriously our duty to protect our waterways and the Chesapeake Bay,” he said.

One of the difficulties — and reasons for the difference — is the problem of determining when a site needs to be stabilized. While that’s supposed to happen seven days after the active ground disturbance ends, some earth-moving equipment may linger on a site for weeks, and it can be hard to know whether it’s being used.

“It is a tough call,” said MDE’s Clevenger. “You see a lot of denuded earth, and an inspector in the field has to make a judgment about whether it has been active.”

Anne Arundel County has sought to reduce that uncertainty. Once foundations are in, it prohibits any further construction until the exposed ground has been stabilized.

“That’s a big help to the inspectors,” said John Peacock, the county’s environmental program enforcement chief. Contractors, he said, “are always saying, ‘well, I’m working on it.’ But they may have just dragged a piece of equipment over it.”

“This way, there is no funny business.”

And, because contractors are usually anxious to begin construction, or “go vertical,” they have an incentive to complete the stabilization.

“You are not going vertical until all of this is done,” Peacock said.

That’s a rule Klein would like to see others adopt, but so far there has been little success. In March, 60 groups — many of which had participated in Klein’s inspections — asked Baltimore County to adopt the language used in Anne Arundel.

In a statement, building engineer Brand rejected the idea, saying it would require more staff. “We are simply not in a position to add one or more construction site visits into our biweekly inspection schedule to follow one county’s new policy, especially when it’s too recent to determine what impact it may or may not have on stopping sediment from polluting our waters,” he said.

But one thing is certain: There are lots of construction sites in the Bay watershed — on average 84,500 acres are disturbed annually — which creates a lot of potential for pollution.

Recent estimates produced by an expert panel convened by the state-federal Bay Program to examine the effectiveness of sediment and erosion control programs estimated that, left uncontrolled, a construction site would lose an average of 12 tons of sediment a year — a rate akin to cows trampling stream banks. But the panel said erosion and sediment controls can reduce that rate of loss by 74–90 percent, depending on how rigorous the programs are and how well the sites are maintained. Still, that means even in the best case scenario, a construction site would lose about a ton of sediment per acre per year.

Maintenance is a major challenge for active sites, both for the sediment controls around the perimeter, and for efforts to stabilize disturbed soils.

“The initial treatment happens, for the most part,” Klein said, “but it is the follow-up treatments that are essential for getting good cover that often don’t happen.”

Peacock agreed. “That is where, if we don’t have enough inspectors, we don’t get there often enough to say, ‘Hey you need to restabilize this area, or reseed it.’ ”

Klein has done some work in surrounding states, and said the problems he has found are not unique to Maryland. In fact, he said, Maryland is probably doing a somewhat better job than its neighbors.

Regardless of whether they agreed with Klein’s statistics, several — though not all — county and state officials said citizen monitoring can help ensure sites are properly maintained.

“The more eyes the better,” Clevenger said. “It does shed light on issues. Having volunteers interact with the appropriate enforcement agencies is key.”

Brad Knopf, of the Magothy River Association, participated in the survey and worked with a “fledgling squad” of other members from the Anne Arundel group to begin checking construction sites within their heavily urbanized watershed. When they see something that looks amiss, they write a letter to the developer.

“It works,” Knopf said. “For the most part, people do respond and try to step up a little bit.”

Only once, he said, has the group needed to report a developer to the county. Knopf is working to build on that success. “We have four foot soldiers,” he said, “with more to come.”

For a copy of the Greater Baltimore Survey, visit