With recent estimates placing the Bay cleanup cost in the billions of dollars, some are asking a fundamental question: Just how clean of a Chesapeake can the region actually attain — and afford?

To answer that, the Bay Program has started an economic analysis to determine what the overall price tag would be for different cleanup scenarios — and who would foot the bill. Ultimately, officials want to know how much it will cost to achieve different levels of nutrient and sediment reductions, both by state and by river basin. They also want to know whether different levels of expenditures would result in dramatic changes in Bay water quality.

If the analysis shows the costs are “significant” or “widespread,” it’s possible that new water quality standards for the Bay may be scaled back to fit the budget.

Or, it may be possible that political leaders — who have stated that cleaning the Bay is a top priority — will choose to increase their financial support to ease the burden on sectors that may be significantly impacted, such as farmers or wastewater treatment plant operators.

Nonetheless, economics is expected to play some role as policy makers move toward setting new water quality standards for the Bay, and — by the end of September — establishing river-specific nutrient and sediment goals to meet those standards.

But officials stress decisions will not be based on economics alone. They characterize the cost exercise as a “reality check.”

“It’s not that we are picking what is the most affordable, but we will be trying to make a balanced decision, and not pick something that will cause economic disaster,” said Allison Wiedeman, of the EPA’s Bay Program Office. “We would also weigh other factors such as technical feasibility, growth and other environmental factors,” she said.

The need for the economic analysis is rooted in both the Chesapeake 2000 agreement, and the Clean Water Act. The Chesapeake 2000 agreement called for removing the Bay from the EPA’s impaired water list by 2010. Parts of the Bay are on the list because they fail to meet state water quality standards.

This is partly because the states have a one-size-fits-all water quality standard that relates to nutrients: they call for having 5 milligrams of oxygen per liter of water throughout the Bay. That standard would never be attained in deep parts of the Bay largely because of natural factors that limit oxygen concentrations in the summer. At the same time, dissolved oxygen standards alone would not protect many sensitive species such as young fish and underwater grasses.

As a result, the Bay Program is working to develop a comprehensive set of new water quality criteria and designated uses [See box on page.] tailored to the needs of the Chesapeake’s aquatic life. Those criteria and designated uses will ultimately be adopted as new state water quality standards. That’s where the Clean Water Act comes in. While some standards will be more stringent than what exists today, others will be lowered — particularly for dissolved oxygen in deep waters.

The Clean Water Act requires a study, known as a “use attainability analysis,” whenever a standard is made less restrictive. As part of that analysis, states must show scientific, technical, economic or other reasons why the standards cannot be met.

Although a use attainability analysis is required only for lowered standards, state and federal Bay officials have decided to expand the economic analysis to cover the new, more stringent standards as well.

“It would be foolish of us to adopt all of these new uses and then have to come back and say the Bay is still impaired because we can’t attain the new uses,” said Rich Eskin, of the Maryland Department of Environment, who chairs a Bay Program group working on UAA issues. “We would be right back to where we started.”

The economic information will not be used to set criteria — criteria must be scientifically based to reflect the needs of the resource being protected, such as fish, crabs or underwater grasses. But the economic analysis could affect the placement of designated uses where criteria apply.

For example, the water clarity criteria is the amount of sunlight that must reach underwater grasses for them to grow. But if the costs of attaining that criteria at a depth of 2 meters would be socially disruptive in some areas, the designated use where the water clarity criteria would apply might instead be set at a maximum depth of 1.5 meters or less.

Officials say they will not draw lines based only on cost, but that economics will be among the mix of factors considered in setting new standards.

“People are reading too much into this if they think the use attainability analysis is going to magically tell us what the nutrient and sediment load allocations for rivers will be, or where the designated use boundaries will be,” said Rich Batiuk, associate director for science with the EPA’s Bay Program Office.

“The use attainability analysis does not mean economics are going to drive the process.” he said, “but it is a recognition that economics has a role in how you define the designated uses out there.”

Nonetheless, the emphasis being given the economic analysis has caused some concern. William Gerlach, a staff attorney with the Chesapeake Bay Foundation, said the Bay Program’s use of economic factors appeared “arbitrary” and was making the already complex task of setting new water quality standards even more difficult for the public to understand. “I don’t know that all the complexity in the whole thing really serves the public interest,” he said.

Also, he said, the Bay Program approach raises the possibility that the Chesapeake 2000 goal would be met by setting easier-to-achieve standards to remove the Bay from the impaired waters list. “It’s like redefining the unemployment rate and saying you’re no longer unemployed,” he said. “We want to see actual water quality improvements. We have some issues with the way it is playing out.”

Figuring out just how to use economic factors in the Bay cleanup has been a problem.

The EPA has guidance which sets a series of tests to determine if a water quality standard will adversely affect a community. For example, if the standard would have “significant” impacts, such as closing factories and increasing poverty and unemployment in an area, it is justification for a lowered standard.

If the impacts are “widespread,” such as lowering a household income by certain amounts over a wide area, it could also justify lowering a standard.

But those use attainability analysis tests were designed primarily for small stream segments where a single industry might be affected. No one has ever contemplated an analysis for a 64,000-square-mile watershed, such as the Chesapeake’s.

As a result, Bay officials are not sure their analysis will get to that level of detail set out in EPA guidance. But they want to know what types of costs will be incurred by different river basins, and particular sectors, such as agriculture.

Even if the cleanup costs were to exceed the economic markers laid out by EPA, it doesn’t mean officials cannot set higher water quality standards if they choose to do so. For example, if officials or political leaders believe higher costs to the agriculture community may be mitigated by increased federal spending in the Farm Bill, they may opt for more strict standards, despite costs. Similarly, legislation pending in Congress would provide more aid to wastewater treatment plants, which could help offset their additional costs.

In coming weeks, the Bay Program plans to use computer models to estimate the costs and impacts for various “tiers” of nutrient and sediment control actions.

Tier I represents implementation of all current and planned nutrient activities, such as wastewater treatment plant upgrades that are on the drawing boards, and continuing the present level of implementation for agricultural nutrient control programs.

Tier 4 represents an extreme level of implementation. Dubbed “everything by everyone everywhere,” it assumes such things as maximum nutrient control technologies at all wastewater treatment plants, 100-foot buffers along streams, and new nitrogen-controlling septic systems replacing existing systems throughout the watershed.

Those two tiers are assumed to frame maximum and minimum nutrient and sediment control efforts, and officials will estimate the costs for each. Officials also plan two tiers between those extremes, each with different assumptions about the extent of implementation. Those, too, will generate estimated costs and impacts.

Eventually, the nutrient and sediment reductions achieved from each “tier” will be used by the Bay Program’s water quality computer model to determine how they would affect proposed new water quality criteria and designated uses.

The stakes are huge, not just for the Bay, but for the pocketbook.

Last December, Maryland officials estimated that it would cost the state, local governments and others about $4 billion to achieve nutrient and sediment reductions. But the Maryland figures assumed stringent controls, not unlike those in the “tier 4” scenario.

By contrast, a Virginia estimate put its tab somewhere between $1.7 billion and $2.7 billion. That was based on the assumption that the final cleanup goal would be somewhere between the current level of action, and the maximum “tier 4” type level of implementation.

While saying costs will be part of decision making, officials also say economics presents a reason to revisit — and potentially strengthen — Bay water quality standards in the future.

“The economics and technologies can change over time,” Wiedeman said. “The cost effectiveness of technologies can change very fast, and what is not affordable or technically feasible today may be doable and affordable tomorrow.”

The Clean Water Act requires states to revisit water quality standards every three years.