Management of Non-Point Source Pollution CE 296B

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Management of Non-Point Source PollutionCE 296B

• Department of Civil Engineering
• California State University, Sacramento

Lecture 14, March 26, 1998 Receiving Water
Impacts - Part I
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I. Receiving water impacts - Introduction

• 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.

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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
• 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.

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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.)

• Differentiating between background concentrations
  and anthropogenic concentrations.
• Establishing a priority ranking for
• Problems within a receiving water
• One receiving water from another

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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.)

• 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.

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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?

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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?

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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
• 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.

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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

• 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

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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
• 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

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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.)

• 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.

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I. Receiving water impacts - Introduction (cont.)

• 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.

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II. Traditional method for evaluating receiving
water impacts.

• 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.

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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.)

• 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.

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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.)

• 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.

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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.)

• 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.

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II. Traditional method for evaluating receiving
water impacts.

• 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.

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Discussion Break

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

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II. Traditional method for evaluating receiving
water impacts. B. Crucial problems associated
with the traditional approach. (cont.)

• 3. Measured concentrations are typically
  variable with flow rate and time of year.
• What might seem like a substantial problem on
  September 15th, might not be of any concern on
  November 15th. (Another reason for seasonally
  adjusted water quality objectives.)
• Whether action is demanded might depend heavily
  on the time the samples were taken.

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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?

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II. Traditional method for evaluating receiving
water impacts. B. Crucial problems associated
with the traditional approach. (cont.)

• 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.

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II. Traditional method for evaluating receiving
water impacts. B. Crucial problems associated
with the traditional approach. (cont.)

• 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.

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II. Traditional method for evaluating receiving
water impacts. B. Crucial problems associated
with the traditional approach. (cont.)

• 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.

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II. Traditional method for evaluating receiving
water impacts. B. Crucial problems associated
with the traditional approach. (cont.)

• 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.

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Discussion Break

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

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II. Traditional method for evaluating receiving
water impacts. B. Crucial problems associated
with the traditional approach. (cont.)

• 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.

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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?

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II. Traditional method for evaluating receiving
water impacts.

• 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.

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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.

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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