Chesapeake Bay Monitoring
"Monitoring for Management Actions"

3. program description

The OEP Chesapeake Bay Water Quality Monitoring Program is a carefully assembled group of monitoring components all guided by the same philosophy and integrated into a unified study. This integration was incorporated in the study design phase, it is in place during implementation (for example, the coordination of sampling activities), and it is a key aspect in the analysis of results. The objectives followed consistently for all components, reflecting the major management questions as described in Chapter 1, are:

  • Characterization of the existing baseline water quality conditions.
  • Detection of trends in water quality indicators.
  • Increasing the understanding of processes and causes affecting Bay water quality and the linkage between water quality and living resources.
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Before the State's recent monitoring initiatives commenced in the summer of 1984, certain segments of the Bay had been studied intensively for only brief periods of time and often only in selected seasons. In one area, chemical and physical measurements may have been taken. In other areas or times, biological measurements may have been taken. This level of effort may have been sufficient for the objectives of each of these studies but it left many gaps in our understanding of the Bay.

The newly initiated OEP water quality monitoring program closes the previously existing gaps by being comprehensive, maintaining a Bay-wide perspective and having a long-term commitment.

It is comprehensive in its approach by including the most important physical, chemical and biological measurements from a management and scientific perspective. These measurements take place in a coordinated fashion, in many cases at exactly the same times and places; data collected in this way enhances our ability to interpret linkage between monitored parameters.

Second, a Bay-wide perspective has been applied to the location of sampling stations throughout the tidal tributaries and mainstem of Chesapeake Bay. Existing programs, such as that in the Patuxent River, were enhanced and incorporated into the expanded program while those regions that lacked coverage are now included. As a result, every major tidal tributary in the State is included in the present monitoring network, as well as the mainstem from Havre de Grace at the head of the Bay to the mouth of the Potomac River at the State line. The Bay-wide coverage reaches beyond our state boundaries with similar efforts in Virginia and Pennsylvania, coordinated by the three states and EPA. Bay-wide coverage is necessary in order to effectively evaluate where and how pollution control measures are working, to identify regions in need of additional remedies and to better understand the fate and effect of pollutant inputs.

Third, this monitoring program has been constructed with a long-term perspective, as mandated by a bill passed in the 1985 State legislature which directs Maryland's OEP and Department of Natural Resources to initiate and continue monitoring of the Bay's water quality and living resources. In a system as large and complex as Chesapeake Bay, where natural year-to-year variability can make trends difficult to discern, several years of record are required to make reliable assessments from monitoring programs. Further-more, the challenge of cleaning up Chesapeake Bay is likely to continue well into the future, requiring continued vigilance as added pressures impinge upon its shores.

Each component within the overall Water Quality Monitoring Program was chosen with an ecological perspective to provide a comprehensive set of important water quality indicators. While each component individually is capable of providing an indication of Chesapeake Bay water quality, the synthesis of information from all of these elements permits much more precise and meaningful assessments to be made. Each of these components is portrayed in Figure 5 and explained briefly below.

Figure 5.  Components of the OEP Water Quality Monitoring Program in the perspective of major ecological relationships in Chesapeake Bay.

Chemical and Physical Properties - The measurement of chemical and physical variables such as salinity, dissolved oxygen, suspended sediment and nutrients, provides baseline data to characterize physical properties of the system such as stratification and provide knowledge of the levels and distributions of important pollutants. This element has the most intensive spatial and temporal coverage and forms the foundation for interpreting measurements from all other components.

Toxicants - Toxic pollutants, both metals and organic compounds, are measured in the sediments where they tend to accumulate after being discharged into the estuary. Levels in the tissues of benthic organisms are also monitored as an indicator of accumulation in the food chain.

Plankton - Plankton include the microscopic plants and animals suspended in the water column that form the base of the estuarine food web. Thus, they are directly or indirectly crucial to the success of important Bay resources such as fish and shellfish. These organisms are also responsible for the symptoms of eutrophication, such as low dissolved oxygen and decreased water clarity, that result from excessive nutrient inputs.

Benthic Organisms - Benthic organisms, which live in or on the bottom sediments of Chesapeake Bay, have a prominent role in the food web as important components of fish and crab diets. They also mediate in many processes occurring where bottom sediments interface with the overlying water column. They are good indicators of Bay water quality, especially local conditions, since they occupy a relatively fixed position on the Bay bottom and respond to changes over both long and short time intervals.

Ecosystem Processes - Many of the important water quality indicators are not static measures, but rather processes or rates that reflect the dynamic nature of water quality in Chesapeake Bay. Several of these processes were chosen as a separate element of the OEP program such as sediment-water column exchanges of nutrients, oxygen and particulate matter. Other important processes such as phytoplankton growth rates and river inputs are included as part of other program elements.

Pollutant Inputs - The input of freshwater, sediment and nutrients from the major rivers and point sources control water quality to a large extent in the Bay and its tributaries. This component therefore becomes crucial to an interpretation of Bay water quality and to track the progress of management actions throughout the Chesapeake Bay basin. River input monitoring is the major new initiative in the OEP program.

In assembling the monitoring elements described above into a unified study, several design considerations were applied uniformly to insure success in achieving the program's objectives.

First, no elements were considered for monitoring unless there was a sound scientific basis for measuring the parameters that comprise a given component. Where some uncertainty existed, literature reviews and pilot studies were conducted before implementation to evaluate alternative monitoring designs.

Second, the selection of sites to be monitored for each element was designed to be representative of major regions in the mainstem and tributary estuarine system. Other considerations in site selection, once the representative nature of a location was satisfied, included important habitats, such as striped bass spawning areas, and the availability of useful historical data.

Third, frequency of monitoring was tailored to the known temporal variability for given parameters to efficiently and effectively utilize the resources available for monitoring. The more variable a parameter is through time, the more frequently it must be sampled to provide an accurate and precise measurement. For example, river loadings can undergo very rapid changes during the course of a storm and therefore conditions must be monitored several times a day during these events to provide an accurate picture of loadings. At the other end of the spectrum are sediment measurements that are more stable in character through time and are therefore sampled only once per year.

The management of information generated by the program and the reporting of results is a critical final step in the program design. Much of the effort to date in this aspect of the program has been devoted to constructing a reliable and responsive data base from which to draw upon for analysis and interpretation. All data being collected is stored on computer-based media for rapid access and manipulation. Rigorous quality assurance insures that the data collected in the field and in the lab is reliable and meets the intended needs of the program. Reporting of results from the monitoring program is also proceeding as planned. Yearly data reports have been and will continue to be forthcoming from each of the individual monitoring components in a common format; these individual reports can be viewed as the building blocks for subsequent, more synthetic data analysis efforts. In future stages of the program, when the data base is sufficient to achieve this more synthetic level of analysis, the results of individual monitoring elements will be brought together to form a comprehensive interpretation of Chesapeake Bay water quality. This synthesis of information from all the interrelated indicators of water quality, is the strength of the State's program. Following this report, at two year intervals starting in the fall of 1988, there will be a technical synthesis report of information from the monitoring program. A concise summary, distilled from this technical synthesis, will be produced by the spring of the following year. The yearly data reports from each monitoring element, and the two levels of synthesis every other year, will insure that all citizens, legislators, managers and scientists can profit from the State's assessment of Chesapeake Bay water quality.

The present suite of program components, sampling locations (Map 1) and sampling frequencies represents an efficient and cost-effective design. One could always point, however, to areas in the Bay without sampling sites for certain variables of the additional information that could be gained with more sampling trips. But, this thinking must be balanced by the benefit that such additional information would yield for the expense involved. This cost-benefit analysis was also a major factor in the selection of the monitoring program design. The current design yields a practical and technically sound program capable of reaching its objectives on a Bay-wide scale and capable of being sustained for the time necessary to reach its major objectives.

Map 1

a.    Preface
b.   Acknowledgements
1.   Introduction
2.   Understanding The Bay's Problems
3.   Program Description
4.   Chemical and Physical Properties
5.   Plankton
6.   Benthic Organisms
7.   Ecosystem Processes
8.   Pollutant Inputs
9.   Management Strategies and the Role of Monitoring
10. Glossary

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