If the Bay states pulled out all of the stops and did everything possible to clean up the Chesapeake, they couldn’t return it to the condition found by John Smith almost 400 years ago.

But, a recent Bay Program computer estimate suggests they might get more than halfway there, at least in terms of nutrient reductions.

The estimate, which suggests far greater nutrient reductions are possible than what was thought only a few years ago, is not just an academic exercise. By the end of 2001, the Bay states are to adopt new nutrient and sediment reduction goals that will achieve a “clean” Chesapeake Bay by 2010.

That could mean significant additional nutrient reductions aimed at reducing algae blooms, clearing the water and increasing the amount of oxygen in the Bay for fish, clams and other creatures.

For years, the Bay Program has had a term for defining the maximum possible cleanup: the “limit of technology.” It is considered to be the outer edge of what’s possible, and some may consider it beyond the realm of fiscal and practical reality.

“It’s an important marker in terms of achievability,” said Lewis Linker, modeling coordinator for the EPA’s Bay Program Office. “Although we want to remove impairments by 2010, we do want achievability.”

The Bay Program’s definition of limit of technology is a list of currently used nutrient and sediment control practices which are implemented to the maximum extent possible.

It assumes that all farmers in the watershed use nutrient management plans to guide fertilizer use, that forest buffers line all streams, and that all waterways in pastures have fences to keep out cows and other livestock.

It assumes better management of all septic systems; that homeowners, golf courses and others use no more fertilizer than is needed; and that wastewater treatment plants make significant further reductions in nutrient discharges.

Just because such things are theoretically possible doesn’t mean they would happen.

In our current system, getting the political, corporate and individual will to actually go all the way and implement limit of technology is still a challenge,” said Tom Simpson, of the Maryland Department of Agriculture, who is the chair of a Bay Program workgroup that helps set the definition.

But as the Bay Program faces potentially stiff new nutrient reductions, he and others caution that “limit of technology” is not the firm limit some believe it is. “Frankly, I don’t even like the term,” Simpson said.

That’s because, he and others say, the limit of technology has proved in the past to be not a ceiling, but a moving target.

In 1992, the Bay Program calculated that the limit of technology would achieve only a 27 percent nitrogen reduction and a 47 percent phosphorus reduction for the Bay.

Today, the Bay Program estimates the limit of technology would achieve a 51 percent nitrogen reduction, and a 56 percent reduction for phosphorus.

“The mistake we made in 1992,” Linker said, “was we didn’t call it the current limit of technology.”

The realm of what’s considered possible has changed dramatically. Increased focus on nutrient control has opened the door to new practices. In 1992, streamside forest buffers were not recognized for their nutrient control potential. Yet research shows they can, in some cases, keep up to 90 percent of the nitrogen from reaching a stream.

Other research has shown that winter cover crops can take up excess nitrogen on fields, greatly reducing the potential for runoff. “No one even considered forest buffers in 1992,” Linker said. “Ditto for cover crops.”

Likewise, just eight years ago, air pollution was considered totally uncontrollable. Today, new pollution regulations on everything from cars to power plants to chain saws are expected to slash airborne nitrogen in the region.

The fact that the limit of technology changes is an important concept because, in the next year, the Bay states will have to set nutrient and sediment reduction goals that could approach — if not go beyond — what’s currently considered possible.

The Bay Program has always been concerned about whether its goals are attainable. When it set a 40 percent nutrient reduction goal in 1987, officials worried it was not doable. The goal was changed to a 40 percent reduction of “controllable” nutrients. Ultimately, the “40 percent” goal became a 20 percent reduction for nitrogen and a 31 percent reduction for phosphorus for the watershed.

Officials were reluctant to push further because they were close to what was then considered to be the limit of technology. And indeed, the goal has been difficult to achieve: The Bay Program expects it won’t be met until 2003, rather than this year as was hoped.

But those reductions won’t be enough to “clean up” the Bay. Last year, the EPA placed the Chesapeake on its list of “impaired waters.” Unless it meets water quality standards by 2011, an enforceable cleanup plan, known as a Total Maximum Daily Load, will have to be developed for the watershed.

To head that off, the Chesapeake 2000 Agreement called for eliminating water quality problems by 2010.

Exactly what level of nutrient and sediment reductions will be needed remains to be determined. But preliminary computer model estimates indicate that if the Bay states were to achieve nutrient reductions equivalent to limit of technology, it would significantly improve water quality.

Because the original nutrient reduction goals are nearly met — and people now recognize more action is feasible — such a bold goal may be more thinkable than in the past. “There’s more confidence in the system now that we can set goals and achieve them,” Linker said.

And, some argue, the limit of technology is not actually the maximum potential nutrient reduction. By definition, it takes known practices, such as planting forest buffers, and extends them throughout the watershed.

What it doesn’t do is anticipate new technologies, changes in behavior, or adopting any nutrient control practices not now in use.

For example, Simpson said, the government today pays farmers to take wetlands, highly erodible land and other sensitive areas out of production. Limit of technology assumes that happens on all eligible lands in the watershed.

In the future, he said, similar programs might be established to pay farmers to use less fertilizer while guaranteeing certain levels of production. If those levels of production are not achieved, the farmers would be reimbursed the difference.

Likewise, new programs and technologies could result in animal waste being handled differently, or in wastes getting some sort of treatment to prevent pollution.

“All of those things are beyond limit of technology,” Simpson said.

Limit of technology also assumes that people will keep consuming the same amount of land for each new house — even though the Chesapeake 2000 Agreement calls for policies that reduce the rate of land consumption. It assumes all behavior trends, such as the consumption of meat — which requires more nutrients to produce — remain unchanged.

Eventually, action could even be taken to address the amount of nutrients being shipped in and out of the watershed in the form of animal feed and manure — a concept that was floated by a recent National Academies of Science report.

“We don’t have to keep doing everything the way that we’ve always done it,” Simpson said, “and yet limit of technology assumes that we will.”

Achieving nutrient reductions equivalent to the limit of technology would be difficult to achieve if it had to be achieved only through today’s technology, Simpson added. “But we are going to improve some of these things, I hope.”

Mike Hirshfield, vice-president for resource protection with the Chesapeake Bay Foundation, agreed that limit of technology assumptions are a “straight line extrapolation of conventional thinking.”

Technological advances already on the horizon may result in unanticipated nutrient reductions. For example, Hirshfield said, the advent of fuel cells may mean the widespread use of vehicles that don’t pollute at all.

“My concern is that we not lock ourselves into the limits of today’s technology,” he said.

As people are pressed for further nutrient reductions, he said, they will come up with better, more efficient ways of getting the job done. Estimated costs for new regulations, he said, have often been overstated because they fail to account for improved technology.

“Historically, every time there has been new regulations proposed and cost estimates associated with them, the cost estimates are always huge because they are based on a very narrow view of what technology is capable of,” Hirshfield said. “New regulations tend to be technology-forcing.”

Similar things have happened here. In 1992, some Bay Program estimates placed the cost of using biological nutrient removal — a highly effective technique of removing nitrogen in wastewater treatment plant effluent — at $20 to $30 for each pound of nitrogen removed.

Today, plants using that technology often remove nitrogen at a cost of $4 or less per pound. And in some cases, plants have adopted the technology because it can save more money than conventional treatment systems.

Right now, plants operating with BNR are generally expected to achieve a nitrogen level of 8 milligrams per liter in their effluent. But many plants exceed that mark, including the District of Columbia’s Blue Plains facility, the largest treatment plant in the watershed, said Allison Wiedeman, point source coordinator with the EPA’s Bay Program Office. “There is evidence of that all over the watershed,” she said.

Still, limit of technology for wastewater treatment plants is defined now — as it was in 1992 — as 3 mg/l, something not being achieved.

But it is not out of the question, Wiedeman said. In Connecticut, nitrogen levels of 4 mg/l are being placed in permits, while Florida includes 3 mg/l in some of its permits.

“It appears through experience in operating BNR for the past 10 years in the Bay watershed and other places on the East Coast that it is possible to get to levels considerably below 8, and that might lead us to believe that the limit of technology is something below 3, and we are in the process of looking at that,” Wiedeman said.

One way to improve performance is to add sources of carbon, such as methane, which improve the efficiency of the microbes that transform nitrate in the wastes to inert nitrogen gas.

“As we gain experience in working with the engineers, we are going to be able to tweak it to get better performance,” Wiedeman said. “And we see that happening all over the watershed with different technologies being explored.”

But, she cautioned, each plant is different, and what is possible at one may not be possible at another. Some plants have had difficulty reaching and maintaining 8 mg/l. And, doing things like adding carbon sources could in some cases substantially increase costs.

“There are a lot of factors here to think about when it comes to whether we want to change our expectations of the levels that we can get beyond the current limit of technology,” she said.

In the next year, people from all around the watershed will increasingly have to weigh exactly what “limit of technology” actually means for them — and the Bay.

“What is possible, and what is not possible, is always in the eyes of the beholder,” said Rich Batiuk, associate director for science with the EPA’s Bay Program Office.

The challenge, he said, is to make sure goals are challenging enough to drive restoration forward, but not so unattainable that they appear doomed to failure before efforts even start.

“We’re going to get into some pretty lively discussions,” he said. “We’re still years away from maxing out what we can do out there. There is no doubt in my mind. But a lot of it comes down to political will and policy.”

Not All Limits Created Equal

Under the Chesapeake Bay Program’s definition for “limit of technology,” different types of activities have more potential to make greater nutrient reductions than others.

Here are some examples of theoretical reductions using available practices and technologies measured from a 1985 baseline:

All Agriculture

Nitrogen: 70 percent

Phosphorus: 60 percent

Urban Runoff

Nitrogen: 10 percent

Phosphorus: No change

Point Sources

Nitrogen: 80 percent

Phosphorus: 95 percent

Thus, for individual watersheds, the amount of reductions possible depends on the types of land use within the basin. The more agriculture or point sources found in the watershed, the greater the potential for reductions.

Pushing Technology to the Limits in the Chesapeake Watershed

The Bay Program’s “Limit of Technology” assumes the following practices are in place:

  • Conservation tillage practiced on 75 percent of crop land.
  • The Conservation Reserve Program and Conservation Reserve Enhancement Program are fully implemented.
  • All highly erodible crop land becomes permanent unharvested grass cover.
  • Nutrient management practiced on all crop land.
  • Nutrient management applied on all urban land.
  • Animal waste controls and pasture stabilization systems implemented where needed.
  • Streambank protection with fencing on all pasture land.
  • Forest or grass buffers on all pervious urban land.
  • Erosion and sediment controls on all urban disturbed land.
  • 50 percent of all urban impervious land serviced by stormwater retrofits.*
  • Soil and water conservation plans on all crop and pasture lands.
  • Cover crops implemented wherever practical.
  • 100 percent grazing land protection.
  • Forest buffers on all crop land.
  • Septic loads are managed by septic connections, septic denitrification or septic system pumping.
  • Municipal and industrial wastewater treatment plant effluent is controlled to a level of 0.075 milligrams per liter for phosphorus, and 3.0 mg/l for nitrogen.
  • All urban combined sewer overflows are collected and treated at treatment plants with biological nutrient control technology.
  • Maximum implementation of air pollution control programs.

* Retrofitting stormwater controls on all existing urban land is considered too expensive to be practical.