The cost of implementing Maryland’s tributary strategies has gone down, but the costs for other jurisdictions may be on the rise, as the Bay states work to bring some consistency among their cost estimates for the Bay cleanup.

Early estimates of the costs of meeting the region’s nutrient and sediment reduction goals came in with widely varying costs attached to them—Maryland’s $13.6 billion costs were more than four times than the initial $3.2 billion estimate from Virginia. Pennsylvania’s estimate was still under development but was expected to top $3 billion as well.

But state officials are re-examining their cost estimates, and the EPA’s Bay Program Office is working to smooth out differences to produce a more cohesive estimate by midsummer.

That’s important because the Bay Program’s Blue Ribbon Finance Committee, which is working to make suggestions about how to fund the cleanup effort, needs the figures as it nears an October deadline for making its final report. The panel, chaired by former Virginia Gov. Gerald Baliles, is a group of business and government leaders trying to identify innovative funding opportunities.

The tributary strategies are river-specific plans for achieving the nutrient and sediment reduction goals set by the Bay Program last year to clean up the Chesapeake.

Maryland initially estimated its strategy would cost $13.6 billion, but that figure was revised to $10 billion after officials concluded the costs of installing nitrogen controlling septic systems—which had accounted for half of the cost of the state’s strategies—was overestimated, said Jamie Baxter, tributary strategy coordinator for the Maryland Department of Natural Resources.

Apart from that change, states made very different assumptions about the costs of different actions. Maryland assumes cover crops cost $40 per acre to implement, while Virginia puts the cost at $19. The Bay Program in an earlier report estimated the costs at $27 an acre.

Maryland used a higher cost in part because because it assumes higher payments will be needed to increase farmer participation to levels anticipated in the strategy.

Some costs in Maryland are greater because the state included operation and maintenance expenses for many urban and agricultural nutrient control practices. That’s something that Virginia officials said they may take another look at.

For some actions, operation and maintenance can be a “major cost,” agreed Moria Croghan, tributary strategy coordinator for the Virginia Department of Conservation and Recreation, and the state may update its figures with new information. In some cases, she said, “we really didn’t have good information on costs and operation and maintenance.”

Maryland wasn’t always more expensive. Its cost for nutrient management plans was only $4 per acre, compared to $7 per acre in Virginia. And it put the cost of grass buffers on agricultural lands at $140 per acre, versus $175 in Virginia.

“Some of the assumptions may differ from state to state,” Baxter said. “That’s normal. Each state funds their programs somewhat differently.”

But the main reason Maryland’s costs are higher, Baxter said, hinges on a single issue—its tributary strategies assume that nutrient loads from wastewater treatment plants have an absolute cap.

All major wastewater treatment plants in the state have been—or will be—upgraded with state-of-the-art nutrient control technology that, initially, will sharply reduce nutrients. But some of that benefit will eventually be lost as the population grows and more homes and businesses are hooked to sewer systems.

Nonetheless, each wastewater treatment plant was given an absolute nutrient limit, based on the design capacity of the plant, and the level of nutrient treatment it is expected to achieve. Once they hit that cap, they have to remain there, either through new technology or trading programs.

Because the strategies assume the treatment plants are already at their cap, the full nutrient reduction of the initial upgrades is not reflected in the strategies.

That means more nutrient reductions have to come from other sources. Many of those sources include more expensive things such as retrofitting urban stormwater systems, and upgrading old septic systems to remove nitrogen.

In effect, Baxter said, the strategy outlines—and the costs reflect—not just how to achieve the nutrient reductions statewide, but how to maintain that level of reduction into the future.

“It’s a cap management approach,” Baxter said. “Wastewater treatment plants have to fit into their load cap. They don’t get an additional allocation. That drove implementation for practices on nonpoint sources to much higher rates, many of which are expensive.”