TMDL

Could be To many Damn Lawyers.

But it’s intended to be a measure of Total Maximum Daily Load; the amount of sediment, bacteria, heat, and other pollutants that a river system can carry without exceeding a standard for usage by people, animals or towns and industries.

Little River TMDL Hydric soils

Also call your attention to the following abstract which references the connection between water quality and headwater wetlands and backs this up with discussion of jurisdictional concern.

THE ROLE OF HEADWATER STREAMS IN DOWNSTREAM WATER QUALITY1

Richard B. Alexander, Elizabeth W. Boyer, Richard A. Smith, Gregory E. Schwarz, and Richard B. Moore2

ABSTRACT: Knowledge of headwater influences on the water-quality and flow conditions of downstream waters

is essential to water-resource management at all governmental levels; this includes recent court decisions on the

jurisdiction of the Federal Clean Water Act (CWA) over upland areas that contribute to larger downstream

water bodies. We review current watershed research and use a water-quality model to investigate headwater

influences on downstream receiving waters. Our evaluations demonstrate the intrinsic connections of headwaters

to landscape processes and downstream waters through their influence on the supply, transport, and fate of

water and solutes in watersheds. Hydrological processes in headwater catchments control the recharge of subsurface

water stores, flow paths, and residence times of water throughout landscapes. The dynamic coupling of

hydrological and biogeochemical processes in upland streams further controls the chemical form, timing, and

longitudinal distances of solute transport to downstream waters. We apply the spatially explicit, mass-balance

watershed model SPARROW to consider transport and transformations of water and nutrients throughout

stream networks in the northeastern United States. We simulate fluxes of nitrogen, a primary nutrient that is a

water-quality concern for acidification of streams and lakes and eutrophication of coastal waters, and refine the

model structure to include literature observations of nitrogen removal in streams and lakes. We quantify nitrogen

transport from headwaters to downstream navigable waters, where headwaters are defined within the

model as first-order, perennial streams that include flow and nitrogen contributions from smaller, intermittent

and ephemeral streams. We find that first-order headwaters contribute approximately 70% of the mean-annual

water volume and 65% of the nitrogen flux in second-order streams. Their contributions to mean water volume

and nitrogen flux decline only marginally to about 55% and 40% in fourth- and higher-order rivers that include

navigable waters and their tributaries. These results underscore the profound influence that headwater areas

have on shaping downstream water quantity and water quality. The results have relevance to water-resource

management and regulatory decisions and potentially broaden understanding of the spatial extent of Federal

CWA jurisdiction in U.S. waters.

(KEY TERMS: rivers streams; nitrogen; transport and fate; streamflow; headwaters; SWANCC; Rapanos.)

Alexander, Richard B., Elizabeth W. Boyer, Richard A. Smith, Gregory E. Schwarz, and Richard B. Moore,

2007. The Role of Headwater Streams in Downstream Water Quality. Journal of the American Water Resources

Association (JAWRA) 43(1):41-59. DOI: 10.1111/j.1752-1688.2007.00005.x

1Paper No. J06018 of the Journal of the American Water Resources Association (JAWRA). Received February 3, 2006; accepted October

23, 2006. a 2007 American Water Resources Association. No claim to original U.S. government works.

2Respectively, Research Hydrologist, National Water Quality Assessment Program, U.S. Geological Survey, 413 National Center, Reston,

Virginia 20192; Assistant Professor, Department of Environmental Science, Policy, and Management, University of California, Berkeley, California;

Hydrologist, National Water Quality Assessment Program, U.S. Geological Survey, Reston, Virginia; Economist, National Water Quality

Assessment Program, U.S. Geological Survey, Reston, Virginia; Hydrologist, New Hampshire State Science Center, U.S. Geological

Survey, Pembroke, New Hampshire (E-Mail Alexander: ralex@usgs.gov).

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION 41 JAWRA

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