Toward Cost Effective Planning and Management of Water Quality.
Water resources, especially those in urban areas near large rivers, lakes and estuaries, have serious management problems today. In central parts of Canada and the United States, where the climate usually provides a dependable and adequate year-round precipitation, many of the problems are associated with both surface and groundwater quality. The surface water quality problems today in this region are usually due to a combination of combined sewer overflows, non-point-source runoff from urban and rural land and river, lake, estuarine, and bay sediments contaminated with toxics such as polychlorinated biophenyls, PCBS, and various pesticides due to past uses. Groundwater quality problems today result from past agricultural chemical overuse and leaching through municipal and industrial landfalls, pipeline breaks, leaking underground storage tanks and septic tanks.
This is in contrast to the arid and semi-arid regions of the West and Southwest in the United States. The problems there are due largely to the leaching of farmland irrigation water, which contaminates downstream surface water with minerals, e.g. selenium and pesticides, and the overpumping of aquifers for both municipal and agricultural uses. Other factors, including evapotranspiration from crops and reservoirs, transbasin diversions and drought initiated low flow periods, also contribute to the problems.
Knowledge of, and response to, water quality problems in the eastern, more humid, region has evolved during the past three decades. The dominant focus during the 60's and 70's was on organic waste water from municipal and industrial point sources. Massive subsidies, in the form of construction grants, were provided by both the Canadian and US federal and provincial/state governments to municipalities to upgrade and/or expand waste water treatment plants. The result was a significant reduction in organic loadings and suspended solids to receiving waters and an increase in shell and fin fish populations in many locations. Some estuaries are still in decline. By the early 80's there was new knowledge of deformed fish and fisheating birds caused by low concentrations of toxic chemicals in the sediments and the water column of receiving waters. The bioaccumulations of toxic materials occurred in the aquatic food chain leading to unsafe body burdens in fish and birds. Advisory notices from state regulatory agencies not to eat many fish species and water fowl followed. Knowledge was gained also of the connection between upstream land use practices, both rural and urban, and downstream eutrophication and toxic contamination during the 80's.
The recent response to an improved understanding of surface and groundwater pollution in this region has been significant and partially effective. Attempts to include the ecosystem philosophy in the studies of the Great Lakes problem areas initiated by the International Joint Commission have often been made. Most of the past investments were made according to technology-based rather than water-quality-based standards. The technology-based standards are effluent regulations set according to the treatment levels that can be met today by use of proven wastewater treatment equipment and processes. Water-quality based standards, the alternative regulatory approach, have not been used much during this period. The difficulty of enforcement and the tendency for inequity among dischargers in different geographical locations have been cited as reasons for using technology-based standards (Viessman and Hammer., 1993). Wasteload allocations, the rationing of receiving water assimilative capacity, are examples of combining technology with water-quality-based standards. This regulatory policy has been used for those receiving waters already heavily polluted that could not be remediated through use of technology-based standards alone. Today, with a more complex set of pollution sources, including point, non-point, and in-place pollutants coming from both urban and rural sites throughout a watershed, as well as less money available, it may be wise to seek a new mix of technology and water-quality-based standards.
This chapter forms a progress report on recent water quality management efforts in a few areas of eastern North America. The ongoing Remedial Action Plan activity throughout the Great Lakes is indicated along with some recommendations for improvements in the analysis and planning process which include explicit consideration of cost-effectiveness. The planning and management status of one site on the Great Lakes, the Fox/Wolf River and Green Bay, Wisconsin is described in more detail. The role of stormwater and water quality modelling in some specific cases is included. Conclusions are drawn and some recommendations given.
This paper is only available in PDF Format:
View in PDF Format