Gulf of Mexico Hypoxia and Mississippi River Basin Nutrient Losses Herb Buxton, USGSRob Magnien, NOAA Co-Chairs, Monitoring, Modeling, and Research Workgroup, Mississippi River/Gulf of Mexico Watershed Nutrient Task Force

What Causes Gulf Hypoxia? “Hypoxia in the Northern Gulf of Mexico is caused primarily by excess N delivered by the MARB in combination with stratification of Gulf Waters.” – Integrated Assessment, 2000

Hypoxic Zone Measured since 1985 Largest extent, 2002 Gulf Hypoxia NOAA, Rabalais et al. Area of Hypoxic Zone (km 2 x1000) Hypoxic Zone Extent, July 21-25, Rabalais, LUMCON o o o o o ooo

NITRATE LOAD, ANNUAL STREAMFLOW AND N CONCENTRATION Avg. = 350,000 t/yr Avg. = 950,000 t/y Conc. (mg/l)

Artificially Drained Land, MRB Millions of Acres Nitrogen Cycling N Inputs and Outputs (Million metric Tons). Landscape changes. Urban Runoff?? INPUTS OUTPUTS

MR/GM Watershed Nutrients Task Force Federal Agencies (USEPA*, NOAA, USDA, USACE, DOI) States (Agriculture and Environment Departments) Tribal representatives

Task Force Organization Coordinating Committee (Implementation) –Finance/Budget Workgroup –Monitoring, Modeling and Research Workgroup –Management Response Workgroup Point Sources Non Point Sources Restoration

CENR Science Assessment Integrated Assessment, May 2000

A Science-based Action Plan Adaptive management. Consider all causal and mitigating factors. Voluntary Basis. Task Force Action Plan, January 2001

Action Plan Goals Coastal Goal: By 2015, reduce the 5-yr average zone to < 5,000 Km 2. Within Basin Goal: To restore and protect the waters of the 31 States and 77 Tribes in the Basin. Quality of Life Goal: Improve the communities and economic conditions across the Mississippi Basin. 5,000 km 2 Area of Hypoxic Zone (km 2 x1000)

Reducing Nutrient Loads Decreasing N losses Reducing Point Sources and Urban Runoff Filter Strips Farm N Management Riparian Forest Buffers

Reducing Nutrient Loads Diversions to Coastal Wetlands Davis Pond Diversion Structure Increasing Denitification Lock & Dam Management Restoring Wetlands

Ohio 32% Missouri 15% Upper Mississippi 10% Middle Mississippi 28% Arkansas/Red 7% Lower Mississippi 7% USGS Gaging Station Nitrogen Loads, Water-Quality Measurements on 9 large sub-basins. 1.6M metric tons per year

Yield on 42 small Sub-basins calculated from >4000 additional water-quality measurements. Nitrogen Yield,

N Input From Wet Deposition N Input From Fertilizer N Input From Point Sources Component Nitrogen Inputs

Statistical extrapolation from representative basins (from 42 measured Sub-basins to 133 Sub-basins of entire Mississippi Basin). Inference Nitrogen Yield, YIELD

Model Estimation of Total Nitrogen Delivered to the Gulf of Mexico (SPARROW) A - Municipal and Industrial Discharges B - Atmospheric Deposition, and C - Fertilizer and Livestock Wastes. A C B 6% +/- 3 64% +/-21 18% +/- 10 Increasing yield

Fraction of In-Stream Nitrogen Delivered to Gulf Alexander et al. Nature, 2000

MMR Strategy A Science Strategy to Support Management Decisions Related to Hypoxia in the Northern Gulf of Mexico and Excess Nutrients in the Mississippi River Basin Available on the Internet: toxics.usgs.gov/hypoxia/task_force_workgroup.html

Chapters/Topical Groups (leads) Gulf Monitoring and Reporting (Rex Herron, NOAA) Modeling and Research (Kenric Osgood, NOAA) Social and Economic Issues (Rita Curtis, NOAA) Watershed Monitoring and Reporting (Joe Engeln, MO DNR) Modeling and Research (Rich Alexander, USGS) Social and Economic Issues (Marc Ribaudo, USDA) Coordination and Information Needs Resource Needs

Management Questions THE WATERSHED What are the major sources and causes of excess nutrients within the Mississippi River Basin?

BASIN MONITORING FRAMEWORK Nested scales to address and integrate processes from landscape to Basin-Gulf interrelationships.  MRB MOUTH  Large Sub basins  Small Sub basins  Smaller watersheds

BASIN MONITORING: Level 1 MRB MOUTH High Frequency data. Nutrients, carbon and other related data. Explain cause-effect linkages to Hypoxic zone.

BASIN MONITORING: Level 2 Large Sub basins Estimate annual loads. Monitor Sub-basin management strategies. Explain variations in loads at the mouth. USGS Gaging Station

Small Sub basins Annual loads. Explain load variations due to climate, sources. Representative sites useful for model extrapolations. Response of cumulative management actions. Explain time lags. BASIN MONITORING: Level 3

Smaller watersheds Quantify specific source contributions and evaluate specific management actions. Useful for model extrapolations. Explain time lags in response to management actions. Explain processes affecting larger basins. BASIN MONITORING: Level 4

Priorities for Basin Monitoring and Reporting Adopt a four-level watershed monitoring system… Supplement existing monitoring efforts …on smaller rivers and streams… Coordinate monitoring and reporting through leadership at the federal level… Link watershed monitoring to management actions…

Next Step: Action Plan: short-term action 11 By December 2005, and every 5 years thereafter, the Task Force will assess the nutrient load reductions achieved and the response of the hypoxic zone, water quality throughout the Basin, and economic and social effects. Based on this assessment, the TF will determine appropriate actions to continue to implement this strategy or, if necessary, revise the strategy.

Info On the Internet USGS Hypoxia in the Gulf of Mexico: USEPA Hypoxia Task Force: NOAA Science Assessment: