Management of Non-Point Source Pollution CE 296B. Department of Civil Engineering California State University, Sacramento. Lecture #3, February 5, 1998 Clean Water Act - Part II. Recall from the last lecture, In a NPDES Permit there are two key items:. Effluent Limitations
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Department of Civil Engineering
California State University, Sacramento
Lecture #3, February 5, 1998
Clean Water Act - Part II
These two items are core of the Clean Water Act (CWA) framework to achieve the goal of acquiring and keeping clean surface waters in the U.S.
It is effluent limitations and receiving water limitations that govern most management efforts for non-point source pollution.
B. The CWA requires that the effluent from applicable dischargers be regulated. This is effluent limitations. Regulations are to specify a measure of control for the quality and sometimes quantity of the effluent.
Think of this as the first line of defense.
C. The CWA requires that the beneficial uses of receiving waters not be impaired by the regulated dischargers effluent. This is receiving waters limitations. The standards for assessing if a water body is meeting beneficial uses are Water Quality Objectives.
Think of this as the last line of defense.
D. If a receiving waters beneficial uses are impaired or in danger of being impaired by a regulated dischargers effluent, more stringent control measures may be required. Of course, assigning blame is a complicated affair.
More stringent control measures are inevitably expensive.
E. An excellent example of the system of effluent and receiving water limitations is the discharge of domestic wastewater.
1. The CWA and associated regulations require secondary treatment for domestic wastewater to meet numerical effluent limits of 30 mg/L BOD5 and 30 mg/L of total suspended solids (TSS) over a 30 day period. (There are other values involved.) These are numerical effluent limits.
2. If the water quality objectives of a water body are exceeded due to a discharge of secondary effluent, the discharger may then be required to implement tertiary treatment.
This is what has happened to Santa Rosa and other communities on the Russian River.
Based on your knowledge of U.S. geography, what part of the U.S. does this system of effluent and receiving water limitations make the most sense?
What kind of system would be more appropriate for California?
A. After the 1986 Amendments to the CWA required the regulation of urban non-point source pollution, there was a desire by some to have numerical effluent limits established.
In court, in a case between the Natural Resources Defense Council (NRDC) and the USEPA, it was decided that numerical effluent limits could not be imposed. (~1989)
Instead, the implementation of Best Management Practices would constitute effluent limitations.
Legal questions aside, why would numerical effluent limitations be unreasonable for urban non-point source effluent?
What if we only consider dry weather flow?
What if we only consider wet weather flow?
B. What are Best Management Practices (BMP’s)?
They are steps that are taken to minimize the discharge of pollutants from non-point sources.
Some quick examples (out of many)are:
1. Source control type measures - “front end of the pipe”. Examples:
2. Treatment type measures - “end of the pipe”. Examples:
The term Best Management Practices is a legal one coming from the CWA.
Given how new the field of managing non-point source pollution is, is the use of the term Best a good idea?
C. What is the theory behind how BMP’s limit pollution in non-point source run-off?
A broad range of practices, when consistently and simultaneously applied, limit the ability of pollutant to enter the flow stream. It is assumed that any one practice will have a small effect. The idea is to have multiple layers of defense.
1. In some cases, the use of a material, e.g. pesticide, solvent, is minimized, reducing the chance of that material entering the flow stream. Example: Restrictions on home use of fertilizer in Tahoe Basin.
2. In some cases, how a material is used is adjusted to reduce the chance of that material entering the flow stream. Example: Proper material storage.
3. In some cases, a devise intercepts pollutants in the flow stream. Example: A detention basin.
D. What are the standards determining the adequate implementation of BMP’s?
After all, they do constitute effluent limitations.
Depending on the circumstance, there are several possibilities (in order of decreasing stringency and cost):
1. Best Available Technology (BAT)
2. Best Conventional Pollutant Control Technology (BCT)
3. Maximum Extent Practicable (MEP)
Some level of Development
In the Beginning Stages
II. How are effluent limitations defined for non-point source pollution? (cont.)
E. How well are BAT, BCT, and MEP defined?
Regulations are still being developed for all three. They are moving targets.
F. Where are BAT, BCT, and MEP applied?
1. BAT - Toxic pollutants from industrial and construction sites.
2. BCT - Conventional pollutants from industrial and construction sites.
3. MEP - All pollutants from general urban areas.
Notice two levels of separation:
1. Toxic vs. Conventional Pollutants
2. Industrial and Commercial vs. General Urban
Why the first separation?
Why the second separation?
G. How is compliance with effluent limits assessed?
Two versions, one works, one doesn’t seem to.
1. Verification, along with associated written documentation that BMP’s were indeed implemented. This works.
2. Collecting samples of effluent to determine if pollutants have been reduced. If this can be made to work, no one yet has been able to do so.
A. Recall that water quality objectives are set for a water body to meet beneficial uses.
B. Those values, both narrative and numerical, are not to be exceeded.
C. So, receiving water limitations are water quality objectives.
D. However, if receiving water limitations are exceeded, the regulated dischargers contributing to the problem need to be identified.
F. If we are considering a water body in the eastern U.S. with a point source discharge, it is a reasonable proposition to asses whether ongoing receiving water limitations are caused by that discharge. Responsible actions may then be taken.
G. What if nearly all the flow in a stream is of non-point source origin? Such as any southern California stream during a storm. Are the water quality objectives being exceeded?
Effluent, all storm water
Receiving Water, all storm water
What if some of the dischargers are regulated and some are not? Who pays?
What if the beneficial uses that are impaired are things that do not take place during rain storms? Example, contact recreation in the American River during winter storms.
A. NPDES permits for non-point source discharge from municipal areas contained receiving water language that went something like this:
“If you can demonstrate that you are making progress in the implementation of BMP’s that could lead to the meeting of water quality objectives, then you are in compliance with receiving water limitations.”
Is this in the spirit of the effluent limitations, receiving water limitations framework in the CWA?
B. Recently language was adopted for the Orange County non-point source NPDES permit that went something like this:
“where applicable water quality standards are exceeded, that discharger will be required to develop and implement a Storm Water Management Plan that describes BMPs which will reduce pollutants in storm water discharges to levels which shall not cause or contribute to an exceedance of any applicable water quality standards”
It is safe to say that this whole issue of receiving water limitations and appropriate water quality objectives is currently being debated.
Any ideas on solutions to this problem?
Some possible solutions:
1. Apply a time component to beneficial uses. When the water body is full of storm water, the beneficial uses are different that periods of low flow. One set of water quality objectives would apply during storm flow and another during low flow.
2. Link achievable beneficial uses to current land use patterns.
Some possible solutions:
3. Significantly increase the level of science used to set water quality objectives.
4. Insist that Porter-Cologne Act guidelines on how beneficial uses and water quality objectives are set be observed.
Without solutions to these problems, will dischargers be pushed in the direction of abandoning source control efforts in favor of treatment type solutions?
Treatment type solutions are extremely expensive, would that erode public support for clean water efforts?