1. 1 Management of Non-Point Source Pollution CE 296B Department of Civil Engineering California State University, Sacramento Lecture #14, March 26, 1998 Receiving Water Impacts - Part I

2. 2 A.A central need of the overall effort to manage non-point source pollution is to discover the impacts that pollution is having on receiving waters. This is important to: 1.Focus efforts, and finite resources, on pollution that is causing the problem. 2. Identify potential changes to land use policy that might help preserve the quality of water bodies in the future. 3.Better identify aspects of water quality, both qualitatively and quantitatively, that affect beneficial uses. I.Receiving water impacts - Introduction

3. 3 B.Fundamental problems exist in assessing the impact of non-point source pollution on receiving waters. Some of the problems exist everywhere and some are unique to arid climates such as California. 1.Problems that exist everywhere: Differentiating between the effect of non-point source pollution from point source pollution, particularly when common constituents exist. Differentiating beneficial from detrimental impacts of a particular constituent. I.Receiving water impacts - Introduction (cont.)

4. 4 Differentiating between background concentrations and anthropogenic concentrations. Establishing a priority ranking for: –Problems within a receiving water –One receiving water from another I.Receiving water impacts - Introduction (cont.) B.Fundamental problems exist in assessing the impact of non-point source pollution on receiving waters. Some of the problems exist everywhere and some are unique to arid climates such as California. 1.Problems that exist everywhere: (cont.)

5. 5 2.Problems unique to arid climates: Substantial use of receiving water for irrigation. Dramatic changes in flow rate from wet to dry season. Normal pattern of successive drought years alternating with flood years. I.Receiving water impacts - Introduction (cont.) B.Fundamental problems exist in assessing the impact of non-point source pollution on receiving waters. Some of the problems exist everywhere and some are unique to arid climates such as California. (cont.)

6. 6 Discussion Break What are some of the problems in assessing receiving water impacts with respect to seasonal flow rate changes? What are some of the problems in assessing receiving water impacts with respect to flow rate changes associated with alternating drought and flood conditions? How about differentiating detrimental effects associated with natural phenomena vs. human impacts?

7. 7 Discussion Break Take as correct the assumption that the problems associated with determining the magnitude of a receiving water bodies impairment and in correctly assessing the causes, particularly in apportioning blame, are fundamental. This is not news. What effect has this had on the drafting of environmental laws and the regulations those laws promulgated?

8. 8 C.Currently two primary schools of thought exist on how to assess the quality of a receiving water and the impact that pollution, point and non-point has had on those waters: 1.The traditional approach. Setting beneficial uses, establishing the water quality standards required to meet those uses, and then testing the waters to see if those standards are met. If the standards are not met, figure out who is responsible. I.Receiving water impacts - Introduction (cont.)

9. 9 2.The environmental indicator approach. In brief, this is, from several different different perspectives examining the overall health of the receiving water body. Much more later, but some indicators are: The diversity of species present, at several different levels Flooding frequency I.Receiving water impacts - Introduction (cont.) C.Currently two primary schools of thought exist on how to assess the quality of a receiving water and the impact that pollution, point and non-point has had on those waters:

10. 10 D.An EPA report to Congress in 1988 on the health of the nations receiving waters indicated that for: 1.Rivers and streams 70 % of the river miles were fully supporting designated uses. 20% of the river miles were partially supporting designated uses. 10% of the river miles were not supporting designated uses I.Receiving water impacts - Introduction (cont.)

11. 11 2.Lakes (excluding the Great Lakes, but including Lake Champlain!!!) 74% of the lake area fully supporting the designated uses. 17% of the lake area partially supporting the designated uses. 10% of the lake area did not support the designated uses. I.Receiving water impacts - Introduction (cont.) D.An EPA report to Congress in 1988 on the health of the nations receiving waters indicated that for: (cont.)

12. 12 E.So what we would like to do by assessing receiving water impacts is: 1.Insure that those water bodies that are fully supporting beneficial uses continue to do so. 2.Make reasonable progress in restoring beneficial uses to the other water bodies. What we need from the assessment of receiving water impacts is information to guide our efforts. I.Receiving water impacts - Introduction (cont.)

13. 13 A.Steps taken to assess receiving water impacts the traditional way might be as follows: 1.Assign historical, present, and potential beneficial uses to the water body. 2.Assign water quality standards (objectives) to meet the beneficial uses. 3.Determine the background concentrations of the constituents associated with the water quality objectives. An assumption, false as it turn out, is that background concentrations are constant. II.Traditional method for evaluating receiving water impacts.

14. 14 4.Measure concentrations and compare those assessments with: Background levels Water quality objectives 5. Measure effluent concentrations of regulated dischargers, point and non-point. 6. Determine how much of the elevated concentrations are due to point source discharges. II.Traditional method for evaluating receiving water impacts. (cont.) A.Steps taken to assess receiving water impacts the traditional way might be as follows: (cont.)

15. 15 7. Calculate, by difference, the contribution from non-point (diffuse) sources. 8. If concentrations are measurably greater than background, but less than water quality objectives, determine the pollutant most likely to cause a problem in the future and focus on that as an issue. II.Traditional method for evaluating receiving water impacts. (cont.) A.Steps taken to assess receiving water impacts the traditional way might be as follows: (cont.)

16. 16 9.If concentrations exceed water quality objectives, regulated dischargers will have to reduce the amount of pollutants they discharge. 10.Based on the trends observed in concentration measurements, determine the quantitative improvements pollution management efforts are having. II.Traditional method for evaluating receiving water impacts. (cont.) A.Steps taken to assess receiving water impacts the traditional way might be as follows: (cont.)

17. 17 B.Crucial problems associated with the traditional approach. 1.Evaluation of receiving water impacts via the traditional approach take place at a individual moments in time. The picture of a long period of time, what really matters for many beneficial uses, is not well considered. 2.Background concentrations are not constant. Substantial changes occur with flow rate and time of year. II.Traditional method for evaluating receiving water impacts.

18. 18 Discussion Break What are some of the reasons that background concentrations, if they can be determined at all, are not constant?

19. 19 3. Measured concentrations are typically variable with flow rate and time of year. What might seem like a substantial problem on September 15 th, might not be of any concern on November 15 th. (Another reason for seasonally adjusted water quality objectives.) Whether action is demanded might depend heavily on the time the samples were taken. II.Traditional method for evaluating receiving water impacts. B.Crucial problems associated with the traditional approach. (cont.)

20. 20 Discussion Break The flow rate in most rivers and streams in California is regulated by dams. How might the operator of a dam affect the assessment of receiving water impacts?

21. 21 4.The impact that constituents can have on many beneficial uses is far more complicated than the current water quality objectives approach assumes. An excellent example of this are effect metals concentrations have on aquatic life. As we have seen, a fraction of total metals present have a toxic effect. Just measuring metals concentration tells us nothing about the fish. II.Traditional method for evaluating receiving water impacts. B.Crucial problems associated with the traditional approach. (cont.)

22. 22 5.An even more complicated situation is the effect on dissolved oxygen concentrations. The text covers this with some thoroughness, a good example is: If BOD type pollution is reduced, the heterotrophic organism population will decrease. These organisms are predators of algae. If nutrients are not reduced as well, algae blooms will lead to high daytime dissolved oxygen concentrations and low nighttime concentrations. II.Traditional method for evaluating receiving water impacts. B.Crucial problems associated with the traditional approach. (cont.)

23. 23 6.The effluent concentrations from point source discharges might be relatively constant, but the effluent concentrations from non-point source discharges will be highly variable. Determining the quantitative contribution from the non-point source discharge is problematical. II.Traditional method for evaluating receiving water impacts. B.Crucial problems associated with the traditional approach. (cont.)

24. 24 7.The traditional approach for evaluating receiving water impacts directs solutions to be technology driven, end-of-pipe approaches. 8.Only concentrations are measured, aspects that can have a profound effect on the receiving water such as the size of peak flows are not included in the environmental side of the equation. II.Traditional method for evaluating receiving water impacts. B.Crucial problems associated with the traditional approach. (cont.)

25. 25 Discussion Break How does the traditional approach to assessing receiving water impacts encourage the use of technology driven, end-of-pipe solutions?

26. 26 9.Determining if management efforts have produced statistically significant changes in pollutant concentrations in receiving waters is problematical at best. Consider the following scenario: Management efforts have significantly reduced metals concentrations in non-point source effluent. During a drought year, the contribution from mine drainage and POTW effluent is elevated along with metals concentrations. II.Traditional method for evaluating receiving water impacts. B.Crucial problems associated with the traditional approach. (cont.)

27. 27 Discussion Break What other scenarios, particular to arid climates such as California might make it very difficult to detect differences in receiving water pollutant concentrations?

28. 28 C.Benefits of the traditional method for evaluating receiving water impacts: 1.The traditional method does conform with the law, both the Federal Clean Water Act and the California Porter-Cologne Act. 2.The reliance on concentration measurements is at least somewhat understandable to the public. II.Traditional method for evaluating receiving water impacts.

29. 29 A Preview of the Alternative Approach to Assessing Receiving Water Impacts Environmental Indicators - I The idea is to take a holistic approach to the examination of the water body. To be included is aspects of the watershed. This method is being developed using EPA funding with most of the current work being tested in Ohio and Maryland. It has no standing in the law and is by no means perfect, but does have some promise and the support of senior EPA officials.

30. 30 A Preview of the Alternative Approach to Assessing Receiving Water Impacts Environmental Indicators - II Six different categories of indicators are evaluated simultaneously, they are: –Water quality indicators –Physical and hydrological indicators –Biological indicators –Social indicators –Programmatic indicators –Site indicators