| 4 | TOLEDO NONPOINT WORKSHOP: NONPOINT SOURCES OF POLLUTION TO THE GREAT LAKES BASIN |
Background
1998 marked the 20th anniversary of the publication of the final reports of the Commission's Pollution From Land-use Activities Reference Group (PLUARG). PLUARG produced a body of work that remains the cornerstone of current thinking about nonpoint source pollution in the Great Lakes and elsewhere. Now, 20 years after PLUARG, the Workgroup on Parties Implementation seeks to assess the status of nonpoint source pollution control in the Great Lakes basin, particularly progress by the Parties under Annexes 3 (Control of Phosphorus) and 13 (Pollution from Non Point Sources) of the Agreement. To that end, the workgroup sponsored a special session at the Great Lakes soil erosion and sediment control conference, held in Toledo, Ohio, September 16-18, 1998. The following report summarizes the findings of that session.
Session Format
The workgroup commissioned two major papers from leading experts in urban and agricultural nonpoint source pollution control. The first of these was from Mr. Tom Schueler, Executive Director of the Center for Watershed Protection, Washington, D.C., on the topic of Source and Controls of Pollutants in Urban Runoff. The second was from Professor Terry Logan, a member of the Environmental Sciences faculty at Ohio State University and a former PLUARG participant. Dr. Logan spoke on the topic Nonpoint Sources of Pollutants to the Great Lakes - 20 Years Post PLUARG.
In addition to these two speakers, the session included a panel of four experts: Dr. Trevor Dickinson, Emeritus Professor of Water Resources Engineering, University of Guelph, and a former PLUARG participant; Dr. Roger Brook, Professor of Agricultural Engineering, Michigan State University; Mr. Michael Hunter, Certified Crop Adviser, Bruce AgVise, Ontario; and Mr. Peter Johnson, Soil and Crop Advisor, Ontario Ministry of Agriculture and Food.
The session was attended by about 25 participants, and the breadth of experience within this group contributed markedly to the lively technical discussion during and following the formal presentations.
Requirements Under Agreement
Two annexes of the Agreement are relevant to the control of nonpoint sources of pollution. Annex 3 provides several key provisions relating to the control of phosphorus, including load reduction targets. Annex 13 of the Agreement, on Pollution from Nonpoint Sources, calls for the Parties to:
Annex 13 specifies a number of other requirements relating to the control of nonpoint sources, including surveillance, surveys and demonstration projects. Furthermore, Annex 13 emphasizes the importance of demonstration projects of remedial programs on pilot urban and rural watersheds to advance knowledge and enhance information and education services, including extension services, where applicable.
Progress to Date
It was pointed out at the session that progress in these areas was significant through the 1980s but has flagged over the past decade. In part, this may be because other issues, such as concern for persistent toxic organics, became prominent in the environmental agenda and eventually took precedence over issues that were generally believed to have been solved. Nevertheless, it became apparent during the workshop that nonpoint sources of pollution to the Great Lakes basin remain a serious issue, and that phosphorus levels are far from under control. Phosphorus continues to be a major source of concern in the Great Lakes basin, both because of persistent eutrophication in some areas and because control strategies have been less effective than anticipated. Similarly, soil erosion (leading to high sediment loadings to watercourses) remains a significant problem in some areas.
In view of the fact that nonpoint sources of pollution are significant in a number of Areas of Concern, and therefore that remedial actions in those areas remain to be developed, the findings of this session also have important implications for the management of Areas of Concern and for Lakewide Management Plans.
The SAB recommends the following.
Participants at the session also noted the tremendous changes that have occurred in the Great Lakes basin over the past 20 years, observing that the basin of today is significantly different from the basin of 20 years ago. These fundamental changes in the basin may be far more important than the presence or absence of controls in influencing pollution levels. Urbanization in particular has brought significant changes to natural systems, particularly in increased land surface imperviousness. These changes have in turn led to increased runoff and associated water-quality impairment. The impacts of this urban drainage on receiving waters are significant and must be included in any attempt to address nonpoint source pollution. Major improvements in urban drainage impacts may be achievable through modest land-use planning changes coupled with appropriate and well-maintained structural measures such as infiltration trenches and storm-water retention ponds. Jurisdictional issues may, however, be thorny, because effective control of urban nonpoint sources demands linkages between environmental and planning agencies at several levels of government. These linkages may be entirely absent or complicated by local political or economic forces. In urban systems, the appropriate planning unit may be much smaller than in a largely permeable agricultural watershed. Urban management systems may have to be based on sewersheds -- the areas served by individual sewer systems -- rather than on natural drainage patterns.
In rural areas, economic forces on agriculture have forced a move toward intensive farming, often in large-scale operations quite different from the traditional family farm. Two effects have arisen from this move. First, livestock operations have tended to move toward confined animal feeding operations, which produce large volumes of manure and related waste waters, such as wash waters. If not properly managed, these concentrated waste sources can have a dramatic impact on local receiving waters. A second influence in agricultural portions of the basin has been the gradual implementation of soil conservation practices, such as conservation tillage or no-till, throughout the basin. Some regions have embraced these practices more enthusiastically than others. Several participants noted that, because of high local acceptance, or topographic, soil or crop factors, we appear to be approaching the limits of acceptance and/or effectiveness of available soil conservation technology in some areas. These comments underscored the need for local measures tailored to local needs throughout the basin. Conservation tillage clearly remains a powerful tool in some parts of the basin, but where it has been fully implemented and nonpoint source pollution remains a problem, other measures, for instance advanced treatment systems, may be appropriate.
In both urban and rural systems, microorganisms emerged as an issue of particular concern, especially following recent outbreaks of Cryptosporidium that may have arisen from animal wastes. The full range of microbiological pathogens, their biology and pathways, and appropriate control/treatment methods are still largely unknown, but are likely to be important avenues for future investigation. The urgency of this issue has increased in recent years because of drinking water impairments at several locations in the Great Lakes basin, revealing inadequate protection, control and treatment capabilities.
The SAB recommends the following.
In contrast to rising concern about pathogens, pesticide use was viewed by participants as much less problematic than it was even a decade ago, in part because of the advent of new products with very short half-lives and low persistence, also because of improved pesticide storage, handling and user training programs.
In addition to known and emerging pollutant sources, participants raised the issue of uncertainties in climate change and weather patterns, and their potential to impact the distribution and abundance of water resources. New technologies, such as precision agriculture (discussed below), may help us do the right thing at the right time in responding to climate and weather change, but only if those technologies are economically feasible, understood and used by farm operators.
Although we now have much better general information about the nature and importance of sources, most of this information is derived from inference and not from direct measurement. In fact, we have few direct measurements of loads, especially the detailed chemistry (for instance of phosphorus species) that may be relevant in assessing the effectiveness of proposed controls. As governments scale down their monitoring and surveillance efforts, these data are becoming scarcer and older. Without strong data, we lack proof of cause and effect relationships, and therefore cannot make sound management decisions with confidence. Computer models of agricultural systems, for instance, too often rely on inadequate data to make predictions that are influential in guiding (possibly erroneous) management decisions. The paucity of good data on nonpoint source loads and their impacts on environmental decisions has contributed to confusion about appropriate actions and endpoints and is a major obstacle to further progress on commitments under the Agreement.
The SAB recommends the following.
Emerging Technologies
Comments from panelists and participants alike indicated that we are now reasonably well informed about the general characteristics of sources, with the notable exception of microorganisms, and the limits of control technologies. Many of the actions recommended for phosphorus control under Annex 3 have been implemented throughout the basin. We appear to be approaching the limits of acceptance and/or effectiveness of available soil conservation technology in some regions where nonpoint source pollution is still not adequately controlled. In these areas, more aggressive measures, for instance using emerging technologies drawn from industrial and municipal systems, may be necessary. In all cases, measures must be planned and managed on a local basis, in response to the needs of the local system. The Level 1 and Level 2 actions identified in Annex 3 apparently are not, in themselves, any longer sufficient for the control of nonpoint sources. Instead, it will be necessary to develop new technologies and to couple those new approaches with existing methods and improved land-use planning.
Emerging technologies for control of nonpoint source pollution generally take two forms: modification of technologies in use in other industrial or municipal sectors; and optimization of nutrient and soil management through new microprocessor technologies. Control at source was considered by participants to be critical. It is, however, clear that we cannot rely on existing technologies, however well implemented and maintained, to resolve the nutrient and sediment loads arising from nonpoint sources of pollution. Both in the urban and in the rural environment, future progress must depend on a combination of technology and land-use planning on a watershed or subwatershed basis. It is likely that farmers will need financial incentives to risk new technologies or lower fertilizer and pesticide inputs. In some areas (for example, precision agriculture), technology development may be proceeding faster than our ability to implement it effectively. It is unlikely that the agricultural community will be able to fund the necessary education, economic incentive programs and agronomic research. This is an area where government support could be instrumental in helping this technology to reach its full potential.
Although government regulation has been an effective tool for the control of industrial and municipal point sources, it has been less effective in managing nonpoint source pollution, in part because of the diffuse nature of sources and the problem of assigning ownership. Traditionally, farmers have enjoyed the right to farm, with associated exemptions from many controls that would apply in other sectors. Farm operators are therefore likely to resist government regulation strenuously, arguing that controls must be on a site-by-site basis and developed in the context of local economic and environmental conditions. Economic incentives and education/extension programs have been and are likely to continue to be critical in encouraging progress in control of agricultural nonpoint sources.
The SAB recommends the following.
In the view of the Science Advisory Board, the Commission has an important and central role to play in alerting the Parties and individual Great Lakes jurisdictions to the need for continued action on phosphorus, sediment and pathogen control. It is clear that obligations under Annex 13 of the Agreement cannot be met with the present level of effort. New technologies combined with improved land-use planning will be necessary to meet targets and continue the progress achieved to date.
The SAB recommends the following.