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Keeping Pace with Science and Engineering. 1993. Pp. 8-38. Washington, DC: National Academy Press. Nutrient Loadings to Surface Waters: Chesapeake Bay Case Study Thomas C. Malone, Walter Boynton, Tom Horton, and Court Stevenson Nutrient pollution poses the greatest of all recognized threats to Chesapeake Bay. L. Eugene Cronin, Baltimore Sun, March 22, 1967 The thing that really bothers me is that when people like me grow old and die off, there leaves a generation back that has no idea of what the conditions of the river were. They don't have the memory at all about the ten barrels of crabs a day a person could catch . . . about the soft crabs crawlin' in the clear water across grassy bot toms.... There's going to be nothing in those computer memory banks . . . that can generate the enthusiasm for the Bay that those sights and sounds did. Senator Bernie Fowler, Baltimore Sun, June 14, 1992 Nutrient inputs that result from human activities often cause aquatic ecosystems to become overloaded with nutrients and deficient in oxygen, a process referred to as cultural eutrophication. This phenomenon occurs when nutrient inputs exceed the ability of the system to absorb and use them its assimilation capacity resulting in the degradation of water qual- ity.i Since the 1960s, environmental scientists and managers have struggled with the causes, consequences, and prevention of eutrophication. Our analysis 8
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CHESAPEAKE BAY CASE STUDY 9 is concerned with the relationship between environmental research by the science community and the formulation, implementation, and evaluation of nutrient control strategies by the management community.2 We will not explicitly treat such important problems as water use, the enforcement of government regulations, or the development of a new social ethic for the public stewardship of natural resources. We ask the question, "flow and why does the management community respond (or not respond) to new scientific information on the causes and consequences of nutrient loadings to surface waters?" Since the flow of information between the research and management communities is neither one way nor linear, we must also be concerned with the response of the research community to the needs of management. The interplay among the research and management communities characteristi- cally involves feedbacks between different levels of government (local, state, and federal), public and private institutions, citizens' groups, and individu- als. The complex nature of these interactions and the current compartmen- talization of ecology and economics into opposing forces create an inertia that reflects both the bureaucracy within which the research and manage- ment communities are imbedded and the multiple ecological, economic, and social interests that management agencies represent. For this case study, we have selected the Chesapeake Bay. As for most of the nation's coastal ecosystems, nutrient loading to the watersheds of the main Bay and its tributaries (Figure 1) has increased substantially in the decades since World War II, largely as a consequence of rapid population growth and increases in agricultural fertilization, the density of farm ani- mals, and atmospheric inputs. This has been a matter of increasing concern throughout the Chesapeake Bay watershed, especially in the states of Mary- land and Virginia, the economies of which are closely tied to the Bay and its resources. Perhaps as a consequence of this and its proximity to Washing- ton, D.C., the Bay has been the subject of much political and scientific attention and controversy since the early 1960s. For these reasons, and because the responsibility for nutrient management resides with individual states, our analysis of the relationship between science and management will focus on the state of Maryland. We hope to show how uncertainty, the availability of cost-effective solutions, and forces inherent to the conduct of the science and management communities have interacted to (1) limit the information exchange critical to the objectives of both communities and (2) inhibit the timely development and implementation of comprehensive nutri- ent management strategies. The environmental effects of anthropogenic nutrients enrichment (cul- tural eutrophication) began to receive national and international attention in the 1960s with major efforts to control nutrient loadings and continued during the 1970s to the present. In the Chesapeake region, the main event _
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0 1 1 - _: WV ~__ FIGURE 1 Drainage basin of Chesapeake Bay. MALONE, BOYNTON, HORTON, AND STEVENSON NJ | ~ J call_ DE Choptank Nanticoke during this period was the U.S. Environmental Protection Agency (EPA) Chesapeake Bay Study mandated by Congress in 1976, implemented in 1977, and completed in 1983 with the release of the Chesapeake Bay Pro- gram reports: A Profile of Environmental Change (EPA, 1983d), Findings and Recommendations (EPA, 1983b), and A Framework for Action (EPA, 1983c). The implementation of this study and the publicity that surrounded its completion had a major impact on the perspectives of both science and management communities and on the interplay between them, much of which was (and is) modulated by public interest and political pressure. Thus, for the purposes of our analysis, we divide our narrative of the sequence of events into the "formative" years prior to the EPA Bay Study (1965-1977), .
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CHESAPEAKE BAY CASE STUDY 11 the period of the EPA Bay Study (1977-1983), and the "action" years fol- lowing the Bay Study (1983-1992) (see Figure 2). THE FORMATIVE YEARS Nationally, the perception of eutrophication as a water quality problem was largely based on studies of the effects of nutrient loading to freshwater systems in which phosphorus (P) is usually the controlling nutrient (Ameri- can Society of Limnology and Oceanography, 1972; National Research Council, 1969). Vollenweider (1968, 1976) published his widely accepted model of phosphorus limitation in lakes, an empirical analysis that also appeared to be applicable in concept to estuaries where marine and freshwaters mix (Ketchum, 1969). The generality of Vollenweider's model for lake systems was vividly demonstrated through the experimental manipulation of lakes in Canada (Schindler, 1974). Schindler (1977) went on to show that lake communities are able to compensate for deficiencies of nitrogen (N) and carbon through gaseous exchange with the atmosphere, and that attempts to control nitrogen loading may actually degrade water quality because they may result in the growth of noxious blue-green algae (which are capable of fixing nitrogen). In contrast, research in marine systems was beginning to produce evidence that N. not P. is the principal nutrient limiting primary production (Ryther and Dunstan, 1971). However, despite new scientific evidence that N-control would also be necessary (see Boynton et al., 1982; Nixon and Pilson, 1983), nutrient management in the Chesapeake region through the 1970s and into the 1980s was dominated by the growing body of evidence for phosphorus limitation in freshwater systems. Federal Studies and Legislation The Water Pollution Control Acts (also known as the Clean Water Acts, CWAs) of 1965 and 1972 reflected a growing concern over the pollution of lakes and rivers and the threat this posed to the nation's water supply, living resources, recreational use, and aesthetics (see Figure 2~. The 1965 CWA required the adoption of enforceable ambient water quality standards for all interstate waters. As in the past, the primary responsibility for nutrient management was vested in the states. In the 1972 amendments to the CWA, Congress drastically altered the nation's management approach. It changed the focus from ambient water quality to effluent standards by calling for the nationwide implementation of secondary treatment. Technology-based per- formance standards became the basis of regulating nutrient (and other con- taminant) inputs, and federal funding to the states for the construction and upgrading of sewage treatment plants (STPs) was increased from 55 percent .
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12 Science and Engineering - NAS International Symposium on Eutrophication ~ - Point source pollution: the upper Potomac _ . - ASLO symposium on nutrients and eutrophication ~ ~ To ! ^~ _ ~ A ~ _ L _ 1 _ - ~HeCIS CT I ropical worm signed puolibneu - Nonpoint source watershed workshop - EPA Chesapeake Bay study begins - EPA symposium on effects of nutrient enrichment in estuaries - Chesapeake Bay Technical Studies: A Synthesis - Chesapeake Bay: A Profile of Environmental Change - Chesapeake Bay monitoring program; seasonal anoxia in the Chesapeake Bay - CatastroDic 1984 anoxia in the Chesapeake Bay ~ 1985 - STAC: Nutrient Control in Chesapeake Bay ~ - Nitrogen in groundwater - ~ - Sea Grant anoxia workshop MALONE, BOYNTON, HORTON, AND STEVENSON Policy and Regulation 1965 ~- Federal Water Pollution Control Act - Federal Rivers and Harbors Act - Clean Water Restoration Act _~ - Estuary Protection Act - First Govenor's Conference on Chesapeake Bay - Potomac-Washington Metro Area Enforcement Conference 1 970 ~ _~ - AL - - Advanced wastewater treatment of phosphorous: upper Potomac _ ~ - Federal Water Pollution Control Act _ - · I ' _ - Coastal Zone Management Act 19 75 ~ ~ - Chesapeake Bay Status Report , ~- Wasteload Allocation Study · National Estuary Study - Workshop: Tri-County Council of Southern Maryland - Bi-state Conference on the Chesapeake Bay - Chesapeake Bay future conditions report ~ ~ - ~- Chesapeake Bay Commission established 1980 , - Patuxent "Charrette" , - - Chesapeake Bay Commission: Need to control ,_ both nitrogen and phosphorous | ~ - BMP cost-sharing program initiated - ~' `-~-Maryland enacts stormwaterlaw · - Water Quality Management Plan for the Patuxent River Basin approved by EPA - Chesapeake Bay Commission endorses nonpoint nutrient control plan - Chesapeake Bay Program Findings and Recommendations: A Framework for action; Conference on Maryland's Future: Chesapeake Bay Agreement _-- - MOUs: EPA, NOM, USGS, SCS, and FWS it- - Maryland legislation - - Chesapeake Bay Restoration Plan , - Maryland: Phosphate detergent plan - Reduction in federal matching funds for STPs `-. - Maryland: Chesapeake Bay Trust established ~ _ 1990 - _ L a- - r , - - Clean Water Act reathorized and amended - Chesapeake Bay Commission report on nutrints I-- - 2nd Chesapeake Bay Agreement signed -- - Chesapeake Bay Program Implementation Committee: Restoration Progress and the Course Ahead - Maryland: Deadlines for implementation of nitrogen removal t- on the Patuxent River - Coastal Zone Act: Nonpoint-Source Nutrient Control - Baywide nutrient reduction reevaluation; Chesapeake Bay Agreement amended FIGURE 2 Timeline of significant events in the Chesapeake Bay management program. -
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CHESAPEAKE BAY CASE STUDY 13 to 75 percent of capital costs. The act also outlawed all point-source dis- charges of contaminants and established a permit process for dischargers who could not meet this requirement. This was the National Pollutant Discharge Elimination System (NPDES), which set legal limits on the quan- tities of contaminants that could be discharged. The 1972 CWA effectively gave the federal government the enforcement power to regulate nutrient inputs to the nation's surface waters. The responsibility for implementation remained with the states, which were mandated to report on water quality within their borders beginning in 1975. Stimulated by the availability of federal funds and guided by the prevailing "wisdom" calling for the control of point-source P inputs, a nationwide effort was set in motion to upgrade all STPs to secondary treatment, with advanced wastewater treatment for removing phosphorus as necessary. In addition to the CWAs, several studies were initiated by federal legis- lation during this period. The 1965 Rivers and Harbors Act directed the U.S. Army Corps of Engineers to conduct a comprehensive "study of water utilization and control of the Chesapeake Bay Basin," including water qual- ity control. The 1966 Clean Water Restoration Act directed the Department of the Interior to conduct a study of estuarine pollution nationwide, and the 1968 Estuary Protection Act directed Interior to "study and develop the means to protect, conserve, and restore" the nation's estuaries. This legislation resulted in four important reports, which laid the foun- dations for and ultimately led to the EPA Bay Study: 1. In 1969 the Water Pollution Control Administration reported on the adverse effects of nutrient enrichment in the tidal freshwater reaches of the Potomac and Patuxent rivers. 2. In 1970 the Interior Department's national estuarine study, conducted by the Fish and Wildlife Service, recommended that "An all-out cleanup program for the Chesapeake Bay area might serve as a national and even an international demonstration area, showing what can be accomplished by an enlightened public and a responsible Congress." 3. In 1973 the Corps of Engineers released its Chesapeake Bay Status Report in which water quality in the Bay was assessed as good, with local problems limited to the tidal freshwater reaches of some of the Bay's tribu- tar~es. 4. In 1977 the Corps presented its Chesapeake Bay: Future Conditions report (published in 1978) to the bi-state conference on the Bay. The report acknowledged the potential significance of excess nitrogen and phosphorus loading, listed (but did not quantify) major nutrient sources, and suggested that land use and nonpoint sources of nutrients are related. It is noteworthy that, although the Corps and Interior reports acknowl- edged the link between land use and nonpoint-source nutrient loadings, the ,,,
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4 MALONE, BOYNTON, HORTON, AND STEVENSON management community would not give control of nonpoint sources serious attention until the late 1980s and early l990s. This preoccupation with point sources is evident in EPA's 1975 report to Congress, which proclaimed overenrichment from sewage to be a major problem in the nation's estuar- ies. The Chesapeake Bay was identified as being particularly vulnerable. Under the leadership of Maryland's Senator Charles McC. Mathias, this would cause the Congress in 1976 to direct the EPA to "undertake a com- prehensive study of the Bay's resources and water quality, and to identify appropriate management strategies to protect this national resource." The Chesapeake Region In the midst of these studies and federal legislation, symptoms of overenrichment were appearing in Chesapeake Bay and its tributaries during the late 1960s and early 1970s. Massive algal blooms, oxygen depletion, and fish kills in the upper Potomac River were gaining the attention of the public and federal government officials in Washington, D.C. Scientists raised the issue of excess nutrient enrichment in general and N loading in particular during the first Governor's Conference on the Chesapeake Bay in 1968 (Jaworski, 19901. Nutrient distributions and historical records dating back to the 1930s indicated a trend toward increasing eutrophication in the upper reaches of the Bay and its tributaries (Carpenter et al., 1969; Heinle et al., 1970~. Declines in the abundance of submerged aquatic vegetation (SAY) were documented in the Rhode River estuary (Southwick and Pine, 1975), the upper Patuxent River estuary, and the main Bay (Bayley et al., 1968, 19781.- Stevenson and Confer suggested (1978) that these declines might be related to decreased light because of excessive algal growth. Evi- dence was also accumulating that wastewater inputs to the upper Patuxent River were beginning to cause eutrophication in the lower Patuxent (Flemer et al., 1969~. The 1975 Wasteload Allocation Study, conducted by Hydroscience, Inc. under contract to the state of Maryland, concluded that P is the primary nutrient limiting phytoplankton production in the Bay and that the removal of P from sewage wastes is the highest priority for improving water quality. At the same time, research on estuarine circulation highlighted the need for a more systemwide approach to material transport and retention (e.g. Heinle et al., 1970; Pritchard, 1969~. The concerns of federal officials, scientists, and some local officials are clearly documented by the Baltimore Sun. For example, U.S. Congressman Carlton Sickles from Maryland claimed that the Bay is polluted "to the point of public danger," and an official of the U.S. Fish and Wildlife Service reported that the Bay "could be dead in five years" (April 23, 1966~. The Assistant Secretary of Interior for fish and wildlife concluded that "you can't clean the Bay up, you've got to clean up the watershed" (August 17, .
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CHESAPEAKE BAY CASE STUDY 15 1966~. Congressman Rodgers Morton expressed concern that the Bay is getting worse (February 17, 1967), and the founders of the Chesapeake Bay Foundation charged that "ecologically, the whole Bay is in danger" (June 19, 1967~. Leading Chesapeake Bay scientists announced that "Nutrient pollution poses the greatest of all recognized threats to Chesapeake Bay" (L. Eugene Cronin, March 22, 1967) and that concerns over thermal pollu- tion from power plants are distracting the science and management commu- nities from the real problem, sewage pollution (Donald Pritchard, July 1, 1970~. During this period, a study released by the Baltimore Regional Planning Council concluded that excess N and P inputs from sewage, agri- culture, and natural sources were among the Bay's most important pollution problems (November 5, 1968~. In contrast to the perspective of federal officials and reports by local scientists and citizens' groups, state officials in Maryland insisted that the Bay was doing just fine. A representative of the State Board of Natural Resources referred to claims that the Bay is polluted and a public hazard as "irresponsible" (April 23, 1966~. The Maryland Department of Chesapeake Bay Affairs issued a statement that "Bay water quality is good and getting better" (June 20, 1969), and Governor Marvin Mandel announced that "wa- ter quality rivals that of 25 years ago" (June 25, 1969~. As late as 1977, state management officials continued to claim that the Bay was healthy and that, with the exception of a few hot spots, changes in water quality were due to natural climatic cycles (February, 1977, Baltimore Sun series, "Chesapeake Still at Bayer. Thus, the governing body responsible for implementing nutrient control plans, the state, was the least receptive to scientific evi- dence indicating the early stages of baywide eutrophication. Control of Point Source Nutrient Loading In the late 1960s, Jaworski et al. (1969, 1972) documented long-term nutrient trends and related changes in the ecology of the upper, fresh reach of the Potomac. For the first time in the Chesapeake region, Jaworski et al. clearly demonstrated a relationship between nitrogen and phosphorus load- ing from municipal wastewater discharges and deteriorating water quality, and prescribed a program of advanced wastewater treatment to remove N and P. and lower biological oxygen demand (BOD), a measure of nutrient loading. In 1969 the Potomac River-Washington Metropolitan Area En- forcement Conference agreed to set limits on the amounts of P and N that could be discharged into the upper estuary from STPs as well as on BOD levels (Jaworski, 1990~. The agreement was achieved in part because the Washington metropolitan area was faced with a ban on new construction if no action was taken and in part because President Johnson, upon signing the 1965 CWA, made restoration of the Potomac a national priority. Jaworski's i_ ._
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16 MALONE, BOYNTON, HORTON, AND STEVENSON research provided the scientific basis for action, but the politics of the day provided the leverage. By 1972 the Blue Plains STP, which discharges into the tidal (freshwater) Potomac, had begun construction of an advanced waste- water treatment facility to remove P and lower BOD. Implementation of N removal was delayed, in part because the management community was skepti- cal of the need and in part because there was no cost-effective technology. As this chapter in the Potomac episode was drawing to an end, a grass roots confrontation was developing in the Patuxent River watershed. It involved local politicians and scientists on one hand and regulatory agen- cies of the state and federal governments on the other (Bunker and Hodge, 1982~. In 1971 a workshop involving university scientists and the Tri- County Council of Southern Maryland concluded that the water quality of the lower (salty) Patuxent River estuary had declined to unacceptable levels as a consequence of increases in municipal wastewater nutrient loadings to the upper (fresh) Patuxent. Critical to this conclusion was the existence of "baseline" water quality data collected in the 1930s by university scientists. Armed with this information and a commitment to restoring the Patuxent, the Tri-County Council under the leadership of Senator Bernie Fowler ap- pealed to the state for action over the next five years (1972-1976) to no avail. Finally, in 1977, the council filed suit against the EPA to halt the expansion of an upstream STP until an environmental impact statement could be prepared. In 1978 the council again filed suit, this time against both the state and EPA, claiming that the Patuxent River Basin Water Qual- ity Management Plan, which had been approved by EPA, violated 13 of 15 requirements of the 1972 Clean Water Act. The plan advocated P control as the preferred advanced wastewater treatment method for controlling eutrophi- cation of the Patuxent. The council felt that N control was also needed, a position advocated by the Patuxent River Technical Advisory Group (TAG), an ad hoc committee of prominent university scientists. The U.S. District Court ruled in favor of the Tri-County Council and directed EPA to prepare an environmental impact statement and the state and EPA to prepare a new water quality plan for the basin. As part of this process, the state contracted with HydroQual, Inc. to assess the impact of a set of nutrient control scenarios using a computer model. The model pre- dicted that P removal would be sufficient, a conclusion that the TAG did not agree with. Following an evaluation of the HydroQual model, the TAG concluded in a letter to William Eichbaum (assistant secretary for the newly created Office of Environmental Programs, Maryland Department of Health and Mental Hygiene, February 6, 1981) that, although the model "is at or near the state-of-the-art for water quality modeling," uncertainties associ- ated with the entire modeling process "preclude the use of model projec- tions as the sole foundation for a management decision of this nature." At this point the state was in a bind. In the absence of an approved
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CHESAPEAKE BAY CASE STUDY ~7 1 nutrient control plan, the federal government was threatening to withdraw funding to build and upgrade STPs on the river. Faced with the loss of millions of dollars, the state sponsored the Patuxent "Charrette" in 1981, a historic conference organized by Mr. Eichbaum. Using a time-constrained, conflict-resolution process to reach a consensus, the stalemate was broken, laying the foundations for the Patuxent River Nutrient Control Plan for controlling both point and nonpoint inputs of N and P. Like the Potomac plan, the Patuxent plan set limits on total N and P loadings to the river as a whole, and, again, economics was an important factor. Unlike the Potomac plan, which was restricted to the tidal freshwater reach of the system and was formulated quickly in response to new scientific information, the Patuxent plan was truly basinwide and took a decade of struggle and confrontation to develop. Control of Nonpoint Source Nutrient Loading A major event occurred in June 1972 that would have a delayed but dramatic impact on the subsequent course of nutrient research and manage- ment throughout the Chesapeake region. Hurricane Agnes arrived, inundat- ing the watershed with up to 18 inches of rainfall.4 The watershed as a whole (64,000 square miles) received over 5 inches in less than three days. Agnes served as a "lightning rod," focusing research activities on a number of important questions, including the response of the Bay and its tributaries to nutrient enrichment (Cheaspeake Research Consortium, 1976~. (The im- mense amount of water runoff carried with it large amounts of nutrients from nonpoint sources such as fertilizers and animal wastes.) The storm demonstrated the systemwide susceptibility of the Bay to nutrient enrich- ment. Major findings included large increases in nutrient levels caused by high runoff and erosion, and the realization that most of the large quantities of nutrients delivered to the Bay are retained within the Bay (rather than being exported to the ocean). Much of the nutrient input entered the sedi- ments and was released during subsequent years, resulting in unusually high phytoplankton production (Boynton et al., 19821. In effect, Agnes brought important environmental issues before the public and primed the science and management communities for what was to become the EPA's Chesa- peake Bay Study. Clark et al. (1973) made an early assessment of nonpoint nutrient inputs in the Chesapeake watershed. They reported that N runoff from agriculture was more than an order of magnitude higher than that from forested areas. These results were reflected in Maryland's 1975 report to EPA (as required by the 1972 CWA), which emphasized point source inputs but also acknowl- edged that, "The heavy use of fertilizers and manure on the land results in some runoff to the streams." In 1977 the National Science Foundation ,
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18 MALONE, BOYNTON, HORTON, AND STEVENSON (NSF) sponsored a major workshop on watershed research in North America at the Smithsonian Center for Chesapeake Bay Research in Edgewater, Maryland. Results presented at the workshop confirmed that nonpoint N inputs were a major, if not the dominant, term in the N budget of the Bay. Although managers from both state and federal agencies attended the watershed workshop, more than a decade would pass before this reality would begin to be incorporated into a management scheme specifically directed at nu- trient control. There was strong resistance by the management community in general, and by agricultural interests (both scientists and managers) in particular, to the idea that farming practices are related to nutrient loading and water quality in the Bay. This resistance was expressed by the Secre- tary of the Maryland Department of Natural Resources (DNR), James B. Coulte.r, who in referring to nonpoint nutrient sources, was quoted as stat- ing that, "There is more alarm than is necessary; it can be controlled with just good housekeeping and old fashioned general sanitation" (Baltimore Sun, February 7, 19771. Unfortunately, this "common sense" approach relied heavily on best management practices (BMP), which were intended primarily to minimize the loss of soil and thereby increase or sustain agricultural productivity. Because most P enters the estuary attached to particles, one by-product of this strategy has been to reduce nonpoint inputs of P. Despite earlier warn- ings (Walter et al., 1979) and information on loading rates (Jaworski, 1981) that indicated that BMPs derived from soil conservation would have little impact on dissolved nutrients such as N. management planning continued to stress problems of erosion, with little consideration for nutrient control per se. The significance of this was highlighted by studies in the Choptank River basin (on the eastern shore of the Bay), which indicated that nonpoint sources account for about 80 percent of N and 60 percent of P inputs (Lomax and Stevenson, 1981~. The emphasis on point-source nutrient control would not begin to change until after the release of the results and conclusions from the Bay Study in 1982 and 1983. The fact that the Bay is imbedded in a large watershed (about 28 units of land area for each unit of Bay surface area), which was being rapidly modified by human activities, was not generally a part of management or scientific thinking at the time. Management was focused on point-source discharges, and funding for research tended to focus the science community on the effects of sewage and thermal discharges. The problems of overenrich- ment were thought to be restricted to a few local tributaries such as the upper Potomac and Patuxent River estuaries, where point-source inputs were clearly related to the degradation of water quality. Despite the effects of Tropical Storm Agnes and subsequent research findings, the baywide im- pacts of nonpoint nutrient loading were not broadly appreciated at this time. Agnes planted the seeds, but serious attempts to understand and control .
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28 MALONE, BOYNTON, HORTON, AND STEVENSON by public and political pressures precipitated by local water quality prob- lems that did not require sophisticated tools of science to uncover. The relationship between point source inputs and water quality (as indicated by such phenomena as red tides, noxious odors, and fish kills) was usually obvious, and it was generally assumed that nutrient loading could be man- aged through secondary treatment to control point source loadings. Man- agement moved out in front of the science and formulated their own "best guess" scenarios as to the degree and kinds of nutrient reductions needed to improve water quality. The Potomac case may be considered an exception in this regard. Sci- entific research preceded management action, which appeared to be closely coupled to new scientific information establishing quantitative relationships between nutrient loading and water quality. Low rainfall during the 1960s undoubtedly exacerbated conditions in the Potomac River where noxious algal blooms, fish kills, and generally unsanitary conditions were occurring at the doorstep of the White House. Here, secondary treatment and ad- vanced wastewater treatment for P reversed the trend of declining water quality, at least in the tidal freshwater reach of the estuary (Jaworski, 1990~.5 However, the Potomac case was unique, not only in terms of the apparent close coupling between new scientific information and management action (which probably reflected the river's proximity to Washington, D.C., and its role as a political showcase as much as anything else), but also in terms of the massive expenditure of federal funds (about $1 billion) and its limited impact on research and management in the greater Chesapeake Bay region. A fundamental change in the relationship between science and manage- ment began to emerge with the controversy over N control in the Patuxent River basin. The spatial displacement between the upstream location of point source nutrient inputs and downstream effects not only set the stage for a decade-long debate over the control of N and nonpoint source inputs, it marked the beginning of a systemwide approach to the problem of eutrophica- tion in the Bay and its tributaries. With this seed, the connection between nutrient loading and water quality in the Bay as a whole began to crystalize when research sponsored by the EPA Bay Program related widespread de- cline of SAV to overenrichment. At this point, science began to move out in front of management, in part because of the complex nature of the prob- lem and in part because of the lack of funding (including financial incen- tives from the federal government) to develop and implement new approaches and technologies required to address the problems of N and controlling nonpolnt source inputs. The management community as a whole did not acknowledge the need to control N and nonpoint source inputs until the late 1980s when the cumu- lative impact of evidence from environmental research became overwhelm- ing. With each iteration of nutrient inventories and budgets, the predomi ., ..,
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CHESAPEAKE BAY CASE STUDY 29 nance of nonpoint sources became unequivocal. The shift from P to N limitation along the transition from fresh to salt water areas was clearly demonstrated. Studies of benthic nutrient fluxes revealed that models of water quality in the Bay would have to incorporate benthic-water column interactions into their calculations; large-scale baywide studies revealed the mechanisms by which nutrient inputs cause oxygen depletion in the main Bay, and showed that nonpoint sources were the principal cause; and cur- rent soil conservation practices were shown to have little effect on N input to the Bay. These advances could not have been made without a major research and monitoring effort by the science and management communities in the Chesapeake Bay region. Rather than depending on science informa- tion generated by research in Canadian and European lakes, the manage- ment process was increasingly guided by new scientific information on the Bay itself, information that currently influences nutrient management in estuarine systems worldwide. Explicit actions to control N loading have been limited to point source discharges to the upper Potomac and Patuxent rivers, and strategies that target nonpoint sources of N are only now being seriously considered. On the receiving end, the 1992 Bay Agreement identifies the return of SAV as an initial measure of the effectiveness of nutrient management in the resto- ration of living resources and water quality. Long lags (on the order of 10 years or more) between scientific discovery and management action are a common feature of each of these cases. To some extent, this reflects a considered and informed decision-making process related to social and eco- nomic considerations and to the uncertainty of environmental science. However, the record also suggests that this is often not the case, in part because sufficient information is simply not available (increasing the uncertainty), but also because of ineffective information exchange between the science and management communities. Consequently, delays in the use of new scientific information are often related more to politics and economics (compare the histories of point source nutrient control in the Potomac and Patuxent cases) than to the quantity and quality of available information. As clearly stated by Ian Morris, the director of the Center for Environmental and Es- tuarine Studies of the University of Maryland (Baltimore Sun, July 17, 1983), "There is nothing wrong with forging ahead before knowledge of a problem is complete fbecauseJ it never is but you need to keep close touch with good scientific study, and that close touch is being lost." A compara- tive study of coastal seas management in different regions from the Baltic Sea to the Inland Sea of Japan clearly shows the importance of "indepen- dent but relevant science" to the decision-making process (Morris and Bell, 1988~. This study suggests that, although new scientific information rarely initiates management action, the availability of good information and scien- tific advice not only enhances the responsiveness and quality of manage . ..~ . ._
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30 MALONE, BOYNTON, HORTON, AND STEVENSON ment actions but also often reinforces management decisions and helps keep the management process one-track. Sources of Inertia Inertia in the management process occurs for a variety of reasons that range from the sheer magnitude of the problem and the cost of solving it to poor problem definition, uncertainties inherent in the prediction of ecosys- tem behavior, and polarization between the science and management com- munities. Two features of the Chesapeake Bay experience that exemplify magnitude and cost stand out: the need for more STPs with advanced waste- water treatment and the need to control nonpoint sources. Clearly, reliance on a particular technology (secondary treatment) as the basis for regulating nutrient inputs has inhibited the development of alternative (less costly, more effective?) approaches and technologies (see Officer and Ryther, 19779. Furthermore, as the fiscal realities of advanced wastewater treatment for P removal became apparent in the 1970s, the Congress and the General Ac- counting Office became alarmed and instituted a federal "Advanced Waste- water Treatment Policy," which essentially subjected STPs contemplating advanced P or N removal to extreme scrutiny. The effect was to create a powerful disincentive for advanced wastewater treatment, especially for N. Consequently, STPs on the Patuxent did not begin to remove nitrogen until 1991, several years after cost-effective technology became available, a de- cade after the Patuxent Charrette, and more than two decades after scientists first began to worry about N loading to the Bay. In the case of nonpoint sources, their diffuse nature and relationship to patterns of landuse catapulted the problem of nutrient regulation to a new level involving not only water quality and living resources but also socio- economic forces related to population growth in the watershed. Implemen- tation of point source controls has little direct impact on the social fabric of the population, and the costs of reducing point source inputs can be pre- dicted with a relatively high degree of certainty based on knowledge of loading rates and the required technology. This is not the case for nonpoint inputs. Management of nonpoint sources inevitably leads to conflicts be- tween prevailing patterns of land use (by farmers, homeowners, industry, government, etc.) and the implementation of nutrient control schemes. The cost of reducing nonpoint sources is more unpredictable because of uncer- tainties in loading rates and in the effectiveness of different methods of nutrient control. Thus, for justifying the social and economic costs of nutrient management, it becomes much more important to demonstrate cause- effect relationships between nonpoint sources, water quality, and the capac- ity of the ecosystem to support living resources. Decision makers insist on more information before implementing control measures.
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CHESAPEAKE BAY CASE STUDY 31 Scientists and managers typically function on different time scales, re- sulting in tension and distrust between the two groups, which in turn inhib- its effective exchange of information and consensus on problems and their solution. For the most part, environmental scientists are cast in the role of conducting research intended to further our understanding of nature. Ad- vances occur on time scales that are dictated by factors ranging from the peer review process to the variability that characterizes populations of or- ganisms, the ecosystems within which they function, and the climatic fac- tors that perturb them. In contrast, managers are expected to make in- formed decisions and solve problems in a "timely" fashion and are often under considerable pressure to do so on political time scales that are short relative to the generation of new scientific understanding. To compound the problem, success in the science community is achieved through a process that emphasizes peer review, so there is little motivation to communicate outside the science community (except when funds are needed for research). Within the management community, success is measured, in part, by the outcome of the decision, which typically must be made before sufficient scientific information is available. The distrust that these dichotomies and lack of communication breed has two important and related consequences: (1) the management community tends to question the relevance of environ- mental research conducted by an independent science community, and (2) the science community tends to question the integrity of the management process. Free from the requirement to make management decisions, scientists are much more likely to acknowledge uncertainties and the complexities of nature. For example, consider an event that occurred in 1983, the year of the first Chesapeake Bay Agreement. A headline in the Baltimore Sun (July 17, 1983) reads "Scientists Wary About Quick Fix for Bay." The article quotes a prominent university scientist as stating in testimony before the state Assembly that "we still don't know very much about nitrogen and the Bay.... The nitrogen entering the bay from farm runoff may not be as injurious, pound for pound, as that coming from . . . sewage treatment plants.... Buffer strips may not stop much nitrogen from running off farms . . . the bay is not purely a sink [for N. which can escape the Bay in gaseous form]." This left "decision-makers upset and confused . . . some almost cursing, 'saying what is this guy trying to do to us?"' A manager with the Maryland DNR summed up the dilemma by commenting that, "Scientists, being quite honest. present so many options that no action nets taken . . . , .L ~ which Is our problem as managers who must take action." In a subsequent interview, Tom Horton of the Baltimore Sun (personal notes) quotes Secre- tary Eichbaum as saying "Ian's tIan Morris] concerned about a lack of communication between scientists and us? I know he feels that way and I think he's even right, but in most of our experiences in the bay system the -
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32 MALONE, BOYNTON, HORTON, AND STEVENSON scientists have not provided answers as to what to do. They have sat around and complicated the issue, and that's the nature of their job. So at this stage fin the management process] it's not so unusual for scientists to recede into the background. Hopefully, the information they've given us is good enough." The uncertainties and complexities (large data sets) inherent to environ- mental science have also led to, arguably, an irrational reliance on math- ematical models as predictors of ecological variability and responses to anthropogenic perturbations. This tendency of the management community to view water quality models with considerable favor is understandable. Scientists who develop the models have a vested interest in seeing them used (an example of why it is important to maintain a separation of pow- ers in terms of the generation of scientific information and its use by management). At the same time, they provide an objective means of synthesizing a great deal of information and of predicting both the causes and the consequences of eutrophication (in this case), and they take the "heat" off the decision maker (the model makes the decision). This allows the government to assess blame and institute corrective actions. Herein lies the rub. All of these are attractive (and seductive) features, but all assume that the water quality model provides an accurate representation of the real world. The current heavy reliance on the 3-D, time-dependent, coupled hydro- dynamic water quality model to set nutrient reduction goals and evaluate the success of nutrient control programs is reminiscent of the Patuxent experi- ence. Clearly, this model is significantly improved, but it is still an imper- fect cartoon of the real world. It is so tempting to ask the model a question and then believe the answer ("mirror, mirror on the wall") when the most prudent approach is to use the model results in conjunction with other sources of information (monitoring and experimental results that reveal causation). One must also keep in mind that no single model can answer all questions. For example, the current model does not address the dynamics of littoral areas, sea grasses, or food webs. Finally, models may take many years to develop, during which time the playing field and the players may change, including expectations of what the model can and cannot do. The original intent of the model may be modest (e.g., to be used as a trial-and-error tool), but as the results are simplified again and again for nontechnical audiences, expectations can and do become unrealistic. As the cost of the model increases (in terms of time and money) and the corporate memory is lost, the model begins to take on a life of its own and the predictions become reality. Thus, there is a tendency for the management community to reach the conclusion that additional scientific information is no longer needed, a tendency that can be countered by establishing a process of peri- odic scientific reevaluation of the effectiveness of management actions. ...
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CHESAPEAKE BAY CASE STUDY 33 Overcoming Inertia Clearly, financial incentives in the form of federal and state funding for such actions as the construction of STPs and the implementation of BMPs have played an important role in controlling nutrient loading to surface waters. However, the authorizing legislation and subsequent appropriations are often responses to an environmental catastrophe. In a recent study of the process of environmental governance, Morris and Bell (1988) argue the case that a "major event" is required to stimulate policymakers and manag- ers to take action on environmental issues. They suggested that, in the Chesapeake Bay region, this event was the Chesapeake Bay Study itself. Our analysis certainly supports this contention. By pulling together large numbers of scientists and decision makers from throughout the Bay and its watershed, the EPA Bay Study marked a significant departure from the course of the 1960s and 1970s. Under the auspices of the EPA, it gave rise to a governance structure that would involve citizens, government officials, and scientists in the oversight of environmental research, formulation of policy, and implementation of that policy throughout the entire Bay and its watershed (the Chesapeake Executive Council, Citizens Advisory Commit- tee, Science and Technology Committee, and Implementation Committee). This spawned a decade of research and management activity that was un- precedented in the United States, and ushered in an era that would lead to a more systemwide perspective as the significance of nonpoint sources and water movements through drainage basins and the estuaries of the Bay be- came increasingly apparent. Our analysis also suggests that Tropical Storm Agnes was an event of similar impact, which, in effect, set the stage for the EPA Bay Study. Agnes alerted a broad cross-section of the population, including scientists and managers, to the systemwide susceptibility of the Bay to inputs from land. Until Tropical Storm Agnes arrived in 1972, research tended to focus on local problems, a tendency exacerbated by the funding priorities of manage- ment agencies that emphasized the effects of power plants, oil spills, and dredging. Pritchard (July 1, 1970, Baltimore Sun) states that, "The empha- sis on thermal pollution is obscuring the real threat to the Bay, nutrient pollution." This 200-year storm captured the attention of the entire popula- tion of the Chesapeake region, including state and federal agencies, elected officials, concerned citizens, and the scientific community. In a terrible way, Agnes reconnected millions of urban and suburban dwellers to nature. People were made keenly aware that they did not just live on a street or in a town, but also in the drainage basin of a creek, in the valley of a river. The storm dramatized how we had changed the very nature of the watershed in just a few decades, stripping the vegetation that once covered it and ab- sorbed and slowed the runoff of rainfall, paving it for roads and parking, .
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34 MALONE, BOYNTON, HORTON, AND STEVENSON and roofing it over with homes. One effect of these land-use patterns was to channel the water that fell with a destructive force never seen before. In retrospect, it is clear that, although the storm delivered a "bullet to the Bay's heart," land use in the watershed had been "loading the gun and softening up the victim for many decades." The precedent-setting 1981 Patuxent Charrette and the Chesapeake Bay Agreements that followed illustrate the importance of achieving a consen- sus involving a broad cross-section of a region's social fabric. Events leading up to the Patuxent Charrette and the Charrette itself underscore some of the ingredients needed to achieve a consensus on the nature of the problem and the actions that need to be implemented to solve the problem. Among the more important of these are leadership, trust, and financial in- centives. A few powerful individuals had to have more than a passing interest in the problem; they needed to understand the problem well enough to justify action in the context of competing political, economic, and social forces. Such leadership was clearly demonstrated by the actions of Senator Mathias, who formulated the legislation that led to the EPA Bay Program; by Senator Fowler, whose environmental concerns led to a nutrient manage- ment plan for the Patuxent River basin; and by the state governors who had the foresight to look beyond their borders in agreeing to clean up the Bay. The Patuxent case in particular illustrates the need for trust. It is unlikely that a truly comprehensive nutrient management plan for the Patuxent River basin would have been agreed upon if it were not for a clear definition of the problem, the establishment of common goals, the existence of indepen- dent scientific advice, and mutual respect among the participating parties. In this regard, the university was viewed by Senator Fowler and his associ- ates as a source of information from a disinterested party, an "honest bro- ker." This was critical, as was the presence of managers within the Mary- land state government who were willing to listen and even fund research that could (and did) produce evidence that the state and the EPA were wrong in insisting that N loading was not a problem (D'Elia, 1987; D'Elia et al., 1986~. The main impact of these actions and the "major" events that gave rise to them was to raise the plight of the Bay to a new level of public and political consciousness. In this context, it is important to note that, al- though there were (and are) few who would take exception to the course set by the 1983 Bay Agreement, important decisions were made on the basis of relatively little scientific information decisions that would have profound social and economic consequences. Agreements were consummated by high- ranking government officials based on perceptions and the "common sense" of the day. The impact of the EPA Bay Study was not related as much to new scientific information as it was to the large number and diversity of individuals and institutions involved in the process. The real genius of the Or
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CHESAPEAKE BAY CASE STUDY 35 study was in synthesizing and disseminating existing environmental infor- mation and scientific understanding, and in providing the political climate needed to galvanize decision makers throughout the Bay's multistate water- shed. The process itself, rather than the information it produced, led to the Bay Agreement and launched an unprecedented period of legislative, man- agement, public, and research activity. NOTES 1. The degradation of water quality occurs when assimilation capacity is exceeded. The degradation is expressed by such phenomena as accumulations of algal biomass, noxious algal blooms, decreases in water clarity, depletion of oxygen, and related losses of plant, animal, and insect life. 2. Environmental research is defined as activities that generate technical information about nutrient enrichment upon which the management of nutrient inputs can be based. Management is considered to be primarily a government activity that includes the formulation of environ- mental policy, regulations, and agreements. 3. The term anthropogenic is generally used to identify sources of pollutants that stem from human activities manufacturing, farming, waste disposal, etc. For purposes of this analysis, anthropogenic nutrient inputs include inputs from point sources (such as wastewater discharges) and diffuse sources (for example, runoff from agricultural development, atmo- spheric deposition). 4. Hurricane Agnes caused devastating coastal flooding from Florida to New York. By the time the storm reached Chesapeake Bay, it had been downgraded to the level of a tropical storm. 5. A massive nuisance bloom of blue-green algae in the upper Potomac in 1983 was attrib- uted to a combination of events that resulted in the release of excess phosphorus from the sediments (Jaworski, 1990). REFERENCES American Society of Limnology and Oceanography. 1972. Nutrients and eutrophication: the limiting-nutrient controversy. Proceedings of the 1971 Symposium on Nutrients and Eutrophication. Lawrence, Kansas: Allen Press. Bayley, S., H. Rabin, and C. H. Southwick. 1968. Recent decline in the distribution and abundance of eurasian milfoil in Chesapeake Bay. Chesapeake Science 9:173-181. Bayley, S., V. D. Stotts, P. F. Springer, and J. Steenis. 1978. Change in submerged aquatic macrophyte populations at the head of Chesapeake Bay. 1958-1975. Estuaries 1:171- 182. Boynton, W. R., W. M. Kemp, and C. G. Osborne. 1980. Nutrient fluxes across the sediment- water interface in the turbid zone of a coastal plain estuary. Pp. 93-109 in Estuarine Perspectives, V. S. Kennedy, ed. New York: Academic Press. Boynton, W. R., W. M. Kemp, and C. W. Keefe. 1982. A comparative analysis of nutrients and other factors influencing estuarine phytoplankton production. Pp. 69-90 in Estuarine Comparisons, V. S. Kennedy ed. New York: Academic Press. Bunker, S. M., and G. V. Hodge. 1982. The legal, political and scientific aspects of the Patuxent River nutrient control controversy. 8th Annual Coastal Society Conference, Baltimore, Md. Carpenter, J. H., D. W. Pritchard, and R. ~ _ C. Whaley. 1969. Observations of eutrophication
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36 MALONE, BOYNTON, HORTON, AND STEVENSON and nutrient cycles in some coastal plain estuaries. Pp. 210-221 in Eutrophication: Causes, Consequences, Correctives. Proceedings of the 1967 International Symposium on Eutrophication, University of Wisconsin. Washington, D.C.: National Academy of Sci- ences. Chesapeake Bay Commission. 1985. Choices for the Chesapeake: The first biennial review of the action agenda. Report to the General Assemblies of Maryland and Virginia. Chesapeake Research Consortium. 1976. The Effects of Tropical Storm Agnes on the Chesa- peake Bay Estuarine System. Publ. No. 54. Baltimore, Md.: Johns Hopkins University Press. Chesapeake Research Consortium. 1977. Proceedings of the Bi-State Conference on the Chesapeake Bay, April 27-29, 1977. Publ. No. 61 Clark, L. J., D. K. Donnelly, and O. Villa. 1973. Nutrient enrichment and control require- ments in the upper Chesapeake Bay. EPA Report No. 903/9-73-002-a. Clark, L. J., V. Guide, and T. H. Pheiffer. 1974. Summary and conclusions: Nutrient transport and accountability in the lower Susquehanna River basin. Tech. Report 60: Annapolis Field Office, Region III, Environmental Protection Agency. D'Elia, C. F., J. G. Sanders and W. R. Boynton. 1986. Nutrient enrichment studies in a coastal plain estuary: phytoplankton growth in large-scale continuous cultures. Canadian Journal of Fisheries and Aquatic Sciences 43:397~06. D'Elia, C. F. 1987. Nutrient enrichment of Chesapeake Bay. Environment 29:6-33. Eichbaum, W. 1984. The Chesapeake Bay: Major research program leads to innovative implementation. Environmental Law Reporter 14:10237-10245. Fisher, D. C., and M. Oppenheimer. 1991. Atmospheric nitrogen deposition and the Chesa- peake Bay estuary. AMBIO 20:102-108. Flemer, D. A., D. H. Hamilton, J. A. Mihursky and C. W. Keefe. 1969. The effects of thermal loading and water quality on estuarine primary production. An interpretive report for the period August 1968 to August 1969 to the U.S. Department of the Interior, Office of Water Resources Research, Washington, D.C. Heinle, D. R., D. H. Hamilton, and D. A. Flemer. 1970. A unified approach to research on Chesapeake Bay. Chesapeake Biological Laboratory, Ref. No. 70-32. Heinle, D. R., C. F. D'Elia, J. L. Taft, J. S. Wilson, M. Cole-Jones, A. B. Caplins, and L. E. Cronin. 1980. Historical review of water quality and climatic data from Chesapeake Bay with emphasis on effects of enrichment. Report to EPA, CRC Publ. No. 84, UMCEES Ref. No. 80- 1 SCBL. Hydroscience, Inc. 1975. Wasteload Allocation Study. Maryland Department of Natural Resources, Water Resources Administration, Annapolis, Md. Jaworski, N. A. 1981. Sources of nutrients and the scale of eutrophication problems in estuaries. Pp. 83-110 in Estuaries and Nutrients, B. J. Neilson and L. E. Cronin, eds. Totowa, N.J.: Humana Press. Jaworski, N. A. 1990. Retrospective of the water quality issues of the upper Potomac estuary. Aquatic Science 3:11-40. Jaworski, N. A., D. W. Lear, and J. A. Aalto. 1969. A technical assessment of current water quality conditions and factors affecting water quality in the upper Potomac estuary. U.S. Department of the Interior Tech. Rep. No. 5. Jaworski, N. A., D. W. Lear, and J. A. Aalto. 1972. Nutrient management in the Potomac estuary. Pp. 246-273 in Nutrients and Eutrophication, G.E. Likens, ed. American Soci- ety of Limnology and Oceanography. Lawrence, Kansas: Allen Press. Jaworski, N. A., P. M. Groffman, A. A. Keller and J. C. Prager. 1992. A wastewater nitrogen and phosphorus balance: The upper Potomac River basin. Estuaries 15:83-95. Kemp, W. M., and W. R. Boynton. 1984. Spatial and temporal coupling of nutrient inputs to , ...
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CHESAPEAKE BAY CASE STUDY 37 estuarine primary production: The role of particulate transport and decomposition. Bulle- tin of Marine Science 35:522-535. Kemp, W. M., R. R. Twilley, J. C. Stevenson, W. R. Boynton, and J. C. Means. 1983. The decline of submerged vascular plants in upper Chesapeake Bay: Summary of results concerning possible causes. Journal of the Marine Technology Society 17:78-89. Ketchum, E. H. 1969. Eutrophication of estuaries. Pp. 197-209 in Eutrophication: Causes, Consequences, Correctives. Proceedings of the 1967 International Symposium on Eutrophication, University of Wisconsin. Washington, D.C.: National Academy of Sciences. Lomax, K., and J. C. Stevenson. 1981. Diffuse Source Loadings from Flat Coastal Plain Watersheds: Water Movement and Nutrient Budgets. Annapolis, Md.: Tidewater Admin- istration, Maryland Department of Natural Resources. Maryland Sea Grant College Program and Virginia Sea Grant College Program. 1992. Dis- solved Oxygen in the Chesapeake Bay: A Scientific Consensus. College Park, Md.: Maryland Sea Grant College. Morris, I., and W. H. Bell. 1988. Coastal seas governance: an international project for management policy on threatened coastal seas. Maryland Law Review 47:481-496. National Research Council. 1969. Eutrophication: Causes, Consequences, Correctives. Pro- ceedings of the 1967 International Symposium on Eutrophication, University of Wiscon- sin. Washington, D.C.: National Academy of Sciences. Neilson, B. J., and L. E. Cronin, eds. 1981. Estuaries and Nutrients. Totowa, N.J.: Humana Press. Nixon, S. W., and M. E. Q. Pilson. 1983. Nitrogen in estuaries and coastal marine ecosys- tems. Pp. 565-648 in Nitrogen in the Marine Environment, E. J. Carpenter and D. G. Capone, eds. New York: Academic Press. Officer, C. B., and J. H. Ryther. 1977. Secondary sewage treatment versus ocean outialls: An assessment. Science 197:1056-1060. Officer, C. B., R. B. Biggs, J. L. Taft, L. E. Cronin, M. A. Tyler, and W. R. Boynton. 1984. Chesapeake Bay anoxia: Origin, development, and significance. Science 223:22-27. Orth, R. J., and K. A. Moore. 1983. Chesapeake Bay: An unprecedented decline in submerged aquatic vegetation. Science 222:51-53. Pritchard, D. W. 1969. Dispersion and flushing of pollutants in estuaries. Journal of the Hydraulics Division, Proceedings of the American Society of Civil Engineers 95:115- 124. Ryther, J. H., and W. M. Dunstan. 1971. Nitrogen, phosphorus, and eutrophication in the coastal marine environment. Science 171: 1008-1013. Schindler, D. W. 1974. Eutrophication and recovery in experimental lakes: Implications for lake management. Science 184: 897-899. Schindler, D. W. 1977. Evolution of phosphorus limitation in lakes. Science 195:260-262. Seliger, H. H., J. A. Boggs, and W. H. Biggley. 1985. Catastrophic anoxia in the Chesapeake Bay in 1984. Science 228:70-73. Smith, D. E., M. Leffler, and G. Mackiernan, eds. 1992. Oxygen Dynamics in the Chesapeake Bay. Maryland Sea Grant, College Park, Md. Southwick, C. H., and F. W. Pine. 1975. Abundance of submerged vascular vegetation in the Rhode River from 1966-1973. Chesapeake Science 16:147-151. Staver, K., R. Brinsfield, and J. C. Stevenson. 1987. Strategies for reducing nutrient and pesticide movement from agricultural land in the Chesapeake region. In Toxic Sub- stances in Agricultural Water Supply and Drainage. Proceedings of National Meeting, U.S. Committee on Irrigation and Drainage, Denver, Colo. Staver, K., R. Brinsfield, and J. C. Stevenson. 1989. The effect of best management practices on nitrogen transport into Chesapeake Bay. In Toxic Substances in Agricultural Water
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Representative terms from entire chapter: