Monday, August 15, 2011

Coastal Scientists and Managers in a Three-legged Race to Set Nutrient Criteria

William Nuttle, Organizer for CERF 2011 Synthesis Sessions

In the ideal partnership between coastal science and management, the job of scientists is to discover underlying causes and describe possible solutions to a problem, and the managers’ job is to implement the solution. This requires scientists and managers coordinate their actions, much like teammates in a three-legged race. So, if one partner makes a change in direction, then it’s bound affect the other’s game.

The US EPA is the lead management agency in the effort to combat the growing “dead zone” the northern Gulf of Mexico. Nutrients from farm fields in Midwestern states, carried into the Gulf by the Mississippi River, feed an annual algal bloom in near shore shelf waters. The death and decay of bloom organisms depletes oxygen in the stratified bottom waters over a very large area of the coast.

The solution to this all too familiar problem of coastal eutrophication is to reduce the amount of nutrients carried to the Gulf by the Mississippi. Managers rely on scientists to provide data and analyses needed to establish defensible nutrient concentration thresholds and loading rates that protect against the negative effects of eutrophication. The key to success is to be able to link the problems caused by excess nutrients in coastal waters directly to the various processes that introduce nutrients into the river up in the watershed.

Scientists and managers have already run this three-legged race in the Chesapeake Bay and its watershed. At the end of last year, December 29, 2010, EPA established a “pollution diet” for the District of Columbia, and large sections of Delaware, Maryland, New York and Pennsylvania. These limits were established across the entire watershed of the bay, all at once, based on state-of-the-art modeling tools, extensive monitoring data, and peer-reviewed science.

However, EPA is taking a different direction in addressing the problem of coastal eutrophication in the northern Gulf of Mexico. Last month, July 2011, EPA reiterated its intent to follow a proposed Framework for State Nutrient Reductions in setting numeric nutrient criteria for the Mississippi River watershed. The proposed framework lays out a states-based approach, instead of the watershed-based approach used for the Chesapeake Bay. The first step is to establish, separately for each of the 31 states in Mississippi-Atchafalaya River Basin, priorities for nutrient reductions among hydrologic basins within the state.

What does the decision by EPA mean for the scientists who will be called on to provide the essential information needed to establish these criteria? How can water managers in Missouri factor in the impacts of eutrophication in coastal Louisiana when setting water quality criteria for rivers and streams in their state? What data will be required and what approach can be taken to perform such an analysis. Will water managers in Kansas use the same approach or a different one that they might prefer? Who can say?

These questions relate to Topic 3: Management applications and Topic 6: Management problems to be discussed during the Synthesis Sessions at CERF 2011.

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