EPA Science Inventory

Sources and Loading of Nitrogen to U.S. Estuaries

Citation:

Detenbeck, N., D. Sobota, J. Compton, AND T. Plessel. Sources and Loading of Nitrogen to U.S. Estuaries. Presented at Coastal and Estuarine Research Federation (CERF) 22nd Biennial Conference, San Diego, CA, November 03 - 07, 2013.

Description:

Previous assessments of land-based nitrogen loading and sources to U.S. estuaries have been limited to estimates for larger systems with watersheds at the scale of 8-digit HUCs and larger, in part due to the coarse resolution of available data, including estuarine watershed boundaries. We present a comprehensive assessment of nitrogen loading to estuaries and source partitioning linked to watersheds of 344 estuarine systems in the conterminous United States. Based on NHDPlus version 1 catchment data (http://www.horizon-systems.com/nhdplus/), watershed boundaries have been derived for 344 estuarine systems and are now publically available through the US EPA Estuary Data Mapper (EDM; http://ofmpub.epa.gov/rsig/rsigserver?edm/index.html). Loading and source estimates were derived from regional SPARROW models, supplemented by estimates of direct atmospheric deposition from the Community Multi-Scale Air Quality Model (CMAQ, http://www.cmaq-model.org/). The EDM application provides a user-friendly interface to CMAQ time series of loading data by estuary and estuarine watershed. USGS SPARROW model outputs are compared with more recent national data on the inputs of nitrogen by sources compiled by Sobota et al. (2013) at the HUC8 scale and updated to the HUC12 scale in 2013. This work will allow us to compare information on estuarine conditions with the magnitudes and sources of nitrogen inputs from upstream watersheds.

Purpose/Objective:

Previous assessments of land-based nitrogen loading and sources to U.S. estuaries have been limited to estimates for larger systems with watersheds at the scale of 8-digit HUCs and larger, in part due to the coarse resolution of available data, including estuarine watershed boundaries. We present a comprehensive assessment of nitrogen loading to estuaries and source partitioning linked to watersheds of 344 estuarine systems in the conterminous United States. Based on NHDPlus version 1 catchment data (http://www.horizon-systems.com/nhdplus/), watershed boundaries have been derived for 344 estuarine systems and are now publically available through the US EPA Estuary Data Mapper (EDM; http://ofmpub.epa.gov/rsig/rsigserver?edm/index.html). Loading and source estimates were derived from regional SPARROW models, supplemented by estimates of direct atmospheric deposition from the Community Multi-Scale Air Quality Model (CMAQ, http://www.cmaq-model.org/). The EDM application provides a user-friendly interface to CMAQ time series of loading data by estuary and estuarine watershed. USGS SPARROW model outputs are compared with more recent national data on the inputs of nitrogen by sources compiled by Sobota et al. (2013) at the HUC8 scale and updated to the HUC12 scale in 2013. This work will allow us to compare information on estuarine conditions with the magnitudes and sources of nitrogen inputs from upstream watersheds.

URLs/Downloads:

CERF 2013_ABSTRACT_ND060413[1].PDF   (PDF,NA pp, 34.047 KB,  about PDF)

Record Details:

Record Type: DOCUMENT (PRESENTATION/ABSTRACT)
Completion Date: 01/09/2014
Record Last Revised: 01/09/2014
Record Created: 01/09/2014
Record Released: 01/09/2014
OMB Category: Other
Record ID: 266301

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB

ATLANTIC ECOLOGY DIVISION

WATERSHED DIAGNOSTICS BRANCH