With the deadline looming for its cornerstone 40 percent nutrient reduction goal, recent calculations indicate the Bay Program will fall short of the mark for both nitrogen and phosphorus.
The deadline for the goal, set in the 1987 Bay Agreement, was the end of this year.
Bay Program officials had long recognized they would miss their nitrogen goal, but a new analysis indicates the shortfall will be greater than thought. Further, officials had expected to meet the phosphorus goal; it now appears they will narrowly miss that mark as well.
The worse-than-expected results are primarily due to improvements to the computer model used to track cleanup progress. Officials say new information used in the model showed, among other things, that earlier assumptions had been overly optimistic about the effectiveness of some nutrient control practices.
Consequently, the refined estimates are more accurate, but show less progress.
“With most models, each time you refine them you get closer to reality, but you also tend to be more conservative,” said Tom Simpson, of the Maryland Department of Agriculture, who chairs the Bay Program’s Tributary Strategy Workgroup, which oversees the development of river-specific cleanup plans.
Baywide, the figures show the states will be about a third short of the nitrogen goal. Runoff controls at farms, upgrades at wastewater treatment plants and other actions will have reduced the amount of nitrogen entering the Bay by about 50 million pounds a year. The goal was 74 million pounds.
For phosphorus, the region will fall about 1.5 million pounds short of its 10 million pound reduction goal.
Although still considered preliminary, the Baywide numbers are not expected to change significantly. Estimates for individual tributaries are still being refined.
Bill Matuszeski, director of the EPA’s Bay Program Office, blamed the shortfall on too many wastewater treatment plant upgrades being completed too late, and rosy assumptions about agricultural nutrient control efforts.
“A number of the treatment plants that we are counting on have not come on line on time, and getting actual reductions from agriculture is a lot tougher than we thought and estimated at first,” he said. “So we are not seeing the results because we are not seeing the reductions. It’s that simple.”
Excess nutrients have long been seen as the Bay’s main water quality problem. The 40 percent reduction goal was the region’s first coordinated attempt to deal with the issue.
When excess amounts of nitrogen and phosphorus enter the Bay, they spur the growth of algae blooms which block sunlight needed by underwater grass beds that provide food and habitat for blue crabs, waterfowl, juvenile fish and other species. When the algae die, they decompose in a process that depletes the water of oxygen needed for the survival of fish and other Bay dwellers.
Mike Hirshfield, Chesapeake Bay Foundation vice president for resource protection, called the shortfall “very disappointing.” He noted that in the past decade, the Chesapeake has seen no significant Baywide water quality improvements, nor a resurgence of underwater grasses, except during dry years when fewer nutrients are washed off the land.
“If you want more underwater grasses, you shouldn’t have to rely on a drought to get them,” he said. “We need to have a Bay that has clear water even when it rains. And that means getting serious about reducing nutrients.”
After the 40 percent goal was set, specific nutrient goals — measured in pounds — were set for each of the Bay’s major tributaries. States then developed “tributary strategies” outlining how reductions would be achieved in each major river.
Model results indicate that the shortfall is less severe for rivers from the Potomac northward. Taken as a whole, those tributaries will meet their phosphorus goal, although some individual rivers may lag.
The Upper Bay will also come closer to making the nitrogen goal. Those tributaries will achieve about 38 million of their 50 million pound reduction goal, or about three-quarters of the target.
That’s important because the upper Bay tributaries have a disproportionate impact on the Chesapeake’s water quality.
(Of the Bay goal, 24 million pounds were assigned to lower Bay tributaries as an “interim” goal because they have less impact on Bay water quality. Final nutrient strategies for those tributaries, intended to improve habitat within each river, were completed only this year. The overall nutrient reduction goals remain close to those originally assigned. The strategies are to be implemented by 2010.)
In the Upper Bay, officials previously knew they would miss the nitrogen goal because of delays in completing wastewater treatment plant upgrades. Before, though, they had thought the goal would be met in 2002. Now, it may take until 2003 or later to cover the 12 million pound shortfall.
States will have to find additional reductions as well. The reason: Tributary strategies were written to not only achieve the nutrient reduction goals, but also to offset additional nutrients from the region’s growing population and changing land uses.
“Growth after 2000 is not built into the tributary strategies,” Matuszeski said. “So if you are not going to achieve the reductions until 2003, then you’ve got to do something about growth after 2000. How to do that is the major conceptual problem facing the Bay Program right now.”
States are developing plans to offset that increase even as they finish meeting the original goal. Those plans are expected to be in place early next year.
The Bay Program projects the Upper Bay tributaries will need an additional 3 million pounds of nitrogen reductions to offset growth in the next couple of years.
“It will be a ways longer down the road achieving our goal,” Simpson said, “but our strategies will include both overcoming our shortfall as well as accounting for growth in load.”
That task will barely be done when the job gets tougher.
The Bay has been placed on the EPA’s “dirty waters” list and, under a court order, could need an enforceable cleanup plan, known as a Total Maximum Daily Load, in 2011 unless it is cleaned up before then.
The recently signed Chesapeake 2000 Agreement calls for completing the Bay cleanup by 2010, heading off the need for a TMDL, which officials believe would be more costly to implement.
To achieve a clean Chesapeake, the Bay Program next year will set new — potentially steep — nutrient reduction goals. In 2002, the states will have to develop new tributary strategies to achieve the reductions.
The CBF’s Hirshfield said the failure to meet the last goal “calls into question whether the states have the will to reach the goals that we’re going to have to get to by 2010.
“We took the Bay Program seriously when they signed Chesapeake 2000. These results show that we need to start today to do all of the additional nutrient retrofits on sewage treatment plants, not wait to start three years from now,” he said. “We also need to make sure that we don’t allow any new or increased loadings in the interim.”
Simpson agreed that — especially with the shortfall — the time frame will be tight for achieving the 2010 goal. To get a head start, he said people should begin identifying potential new sources of reductions now. “That will, I hope, hasten the process of deciding what our strategy will be to reach the new goal,” he said. “But it’s a very tight time line for that new goal.”
Tracking Nutrient Reductions
Estimates of progress toward meeting the nutrient reduction goals are made by the Bay Program’s watershed model.
The model calculates how rainfall drives nutrients from different land uses throughout the Bay’s 64,000-square-mile watershed into rivers, streams and groundwater, and ultimately delivers those nutrients to the Chesapeake.
It also accounts for natural processes that remove nutrients in the environment — fewer nutrients from upstream areas reach the Bay than from areas close by.
Information about the number of nutrient reduction actions taken by farmers, cities, wastewater treatment plants and others are entered into the model, which uses all of the figures to estimate the amount of nitrogen and phosphorus that reaches the Chesapeake. At places, the model loads are compared to monitoring data to check for accuracy.
The model, of course, is not reality, but only a simulation of the real world. It has a number of limitations. For example, it assumes nutrient runoff controls immediately benefit the Bay when, in fact, many nutrients are transported through groundwater and take years to reach the Chesapeake.
Efforts are constantly under way to improve the way the model simulates the real world. Those changes make the model more accurate. But — as in the case with the recent refinement — they also change estimates of progress being made to clean the Bay.
A number of changes incorporated in the last few years resulted in the model showing fewer nutrient reductions had been achieved than earlier thought.
For example, officials say the effectiveness of several agricultural runoff control practices were previously overestimated. One example: It was assumed that nutrient management plans — which guide nutrient applications on crop lands — recommended the exact amount of nitrogen needed by the plants. In fact, plants aren’t that efficient. Nutrient management plans actually recommend 130 percent of the nitrogen needed by the plant, leaving more to potentially run off.
In addition, the model uses a longer, more realistic, 12-year simulation of river flow. Longer river flow estimates allow more and better river monitoring data to be used. This improves model estimates of sediment and phosphorus loads, which are very sensitive to flow conditions. The model averages the wet, dry and normal rainfall years over that period to calculate “average” annual nutrient loads to the Bay.
The revised model also includes more current land use information, and better information about nutrient discharges from point sources such as wastewater treatment plants.
In another change, the model for the first time reflects the increasing population of agricultural animals in the watershed.
“Before, we were careful to think about increased people in the watershed, but we didn’t think about the animal populations at all,” said Lewis Linker, modeling coordinator for the EPA’s Bay Program Office. “It simply wasn’t considered anywhere in the program.”
40% Is Less Than One Might Think
The Bay Program set its 40 percent nutrient reduction goal in 1987, but the goal it has actually been striving for is much less.
Shortly after it was set, the 40 percent nitrogen and phosphorus goal was redefined to mean a reduction is “controllable” sources. Nutrients from states not in the Bay Program — New York, West Virginia and Delaware — as well as those from air pollution and from natural “background” conditions were considered “uncontrollable.”
As a result of that change, almost half the 340 million pounds of nitrogen that flow into the Bay each year were considered “uncontrollable.”
With those taken off the books, the 40 percent reduction amounted to 74 million pounds of nitrogen — or only about 22 percent of the total amount of nitrogen entering the Bay.
So far, the Bay states have reduced about 50 million pounds. That’s about 15 percent, or a bit better than 1 percent a year since the goal was set. Most of the reductions, though, were achieved in recent years.
For phosphorus, the 40 percent reduction of the “controllable” amount was about a 35 percent reduction. So far, the Bay states have reduced about 31 percent of the total amount entering the Chesapeake Bay.