Despite hundreds of millions of dollars spent annually in the United States on environmental monitoring, policy and decision makers seldom have ready access to monitoring data to aid in prioritizing reasearch and assessment efforts or to assess the extent to which current policies are meeting the desired objectives. EPA is currently conducting research to evaluate options for establishing an integrated, cooperative monitoring program, with participation by federal, state, and private entities, that could result in annual statistical reports and interpretive summaries on the status and trends in indicators of adverse disturbance and corresponding 'health' of the nation's ecosystem on the regional and national scale.

To assess the regional acid-base status of streams in the mid-Atlantic and southeastern United States, spring base flow chemistry was surveyed in a probability sample of 500 stream reaches representing a population of 64,300 reaches (224,000 km). Approximately half of the streams had acid-neutralizing capacity (ANC) < 200 taeq L -1 . Acidic (ANC <-0) streams were located in the highlands of the Mid-Atlantic region (southern New York to southern Virginia, 2330 km), in coastal lowlands of the Mid-Atlantic (2600 km), and in Florida (462 kin). Acidic streams were rare (less than 1%) in the highlands of the Southeast. Inorganic monomeric aluminum (Alim) concentrations were highest in acidic streams of the Mid-Atlantic Highlands where over 70% of the acidic streams had Alim greater than !00 t•g L -1, a concentration above which deleterious biological effects have frequently been re13orted. Dissolved organic carbon concentrations were much higher in lowland coastal streams, compared with inland streams. Our data support a hypothesis that atmospheric sources and watershed retention control regional patterns in streamwater sulfate concentrations. Most stream watersheds retain the vast majority of the total nitrogen loading from wet deposition. The data suggest, however, that some deposition nitrogen may be reaching streams in the Northern Appalachians. These results show that acidic surface waters are found outside the glaciated northeastern portions of the United States and that watershed sulfate retention is not sufficient to prevent acidic conditions in some Mid-Atlantic Highlands streams. undertaken in the Northeast, Upper Midwest, Southeast [Linthurst et al., 1986], and mountainous areas of the West [Landers et al., 1987]. There remain, however, large areas in the Mid-Atlantic and Southeast where lakes are uncommon and where large numbers of streams with very low ANC are found. Despite the availability of a number of data sets collected at intensively studied stream research sites in the Mid-Atlantic and Southeast [Sharpe et al., 1984; Katz et al., 1985; Morgan and Good, 1988; Swank and Waide, 1988; Webb et al., 1989] and several stream surveys over small portions of these two regions [Silsbee and Larson, 1982; Lynch and Disc, 1985; Sharpe et al., 1987], no synoptic data sets existed prior to the recent National Stream Survey efforts from which a quantitative synoptic assessment could be made of the acid-base status of an explicitly defined population of streams in the Mid-Atlantic and Southeast. In the spring of 1986, the U.S. Environmental Protection Agency (EPA) conducted the National Stream Survey tNSS) on a probability sample of 446 streams in the mid-Atlantic and southeastern United States [Kaufmann et al., 1988; Sale et al., 1988]. This full-scale field effort was preceded a year earlier by a pilot survey of 54 streams in the Southern Blue Ridge. The pilot survey demonstrated the feasibility of the design, logistics, and analytical protocols used in the fullscale survey [Messer et al., 1986, 1988]. The objecti...

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The cost-effectiveness of total maximum daily load (TMDL) programs depends heavily on program design. We develop an optimization framework to evaluate design choices for the TMDL for the Potomac River, a Chesapeake Bay sub-basin. Scenario results suggest that policies inhibiting nutrient trading or offsets between point and nonpoint sources increase compliance costs markedly and reduce ecosystem service co-benefits relative to a least-cost solution. Key decision tradeoffs highlighted by the analysis include whether agricultural production should be exchanged for low-cost pollution abatement and other environmental benefits and whether lower compliance costs and higher co-benefits provide adequate compensation for lower certainty of water-quality outcomes.