Developments in Sediment Control

Jan. 1, 2010

Many new things are happening in the erosion and sediment control industry. A new report released by the National Research Council in late 2008 states that the EPA’s stormwater program needs a significant overhaul to improve its effectiveness and the quality of urban streams. In addition, a new proposed rule regarding effluent limitations guidelines and standards for construction and development was published in the Federal Register on November 28, 2008, for public comment. These two documents have the potential to change the industry significantly in the coming years.

National Research Council Report
The EPA recognized a number of problems with the stormwater program as it is currently implemented. First, there is limited information available on the effectiveness and longevity of many best management practices (BMPs), thereby contributing to uncertainty of their performance. Second, the requirements for monitoring vary depending on the regulating entity and the type of activity. Finally, state and local stormwater programs are plagued by a lack of resources for reviewing stormwater pollution prevention plans (SWPPPs) and for conducting regular compliance inspections. For all these reasons, the EPA believes the stormwater program has suffered from poor accountability and uncertain effectiveness at improving the quality of the nation’s waters.

In light of these challenges, the EPA requested the advice of the National Research Council’s Water Science and Technology Board on its stormwater permitting program. The following tasks guided the council:

  • Clarify the mechanisms by which pollutants in stormwater discharges affect ambient water-quality criteria and define the elements of a “protocol” to link pollutants in stormwater discharges to ambient water-quality criteria.
  • Consider how useful monitoring is for both determining the potential of a discharge to contribute to a water-quality-standards violation and for determining the adequacy of  SWPPPs.
  • Assess and evaluate the relationship between different levels of SWPPP implementation and in-stream water quality, considering a broad range of BMPs.
  • Make recommendations for how to best stipulate provisions in stormwater permits to ensure that discharges will not cause or contribute to exceedances of water-quality standards.
  • Assess the design of the stormwater-permitting program implemented under the Clean Water Act.

The following is a summary of the council’s findings:

  • Radical changes to the EPA’s stormwater program are necessary to reverse degradation of freshwater resources and ensure progress toward the Clean Water Act’s goal of “fishable and swimmable” waters.
  • To provide meaningful regulation, all stormwater and other wastewater discharge permits should be based on watershed boundaries instead of political boundaries.
  • The program should integrate stormwater management and land management practices; it should focus less on chemical pollutants in the stormwater and more on the increased flow  of water.
  • The EPA should adopt a watershed-based permitting system that would encompass all discharges-including stormwater and wastewater-that could impact waterways in a particular drainage basin, rather than having many separate permits.
  • Responsibility and authority for implementing watershed-based permits should be centralized with a lead municipality that would work in partnership with other municipalities. In addition, lead municipalities should receive enhanced funding to compensate for increased responsibility.
  • The federal government needs to provide more financial support to state and local efforts to regulate stormwater.

These findings raise many questions as to what lies ahead in how stormwater will be regulated. The full report is approximately 624 pages and goes into detail on all these points and more. If you are interested in reading the report in full, you can find it online at

Proposed Rule for Limitations Guidelines
In other news, the EPA is proposing a regulation that would strengthen the existing regulatory program for discharges from construction sites by establishing technology-based effluent limitations guidelines. The full title of the document published in the Federal Register is “Effluent Limitations Guidelines and Standards for the Construction and Development Point Source Category.”

The EPA has developed effluent guidelines for all types of industrial discharges, including manufacturing, agriculture, and service industries. As required by the Clean Water Act, the EPA publishes an Effluent Guideline Program Plan every other year to announce the agency’s plans to develop new effluent guidelines and revise existing ones. Effluent guidelines are technology-based national regulations that control the discharge of pollutants to surface waters and to publicly owned treatment works (POTWs).

The EPA began work on developing effluent guidelines for the construction and development (C&D) industry and listed C&D in the 2000 and 2002 effluent guidelines plans. The EPA even proposed several options for C&D back in 2002 but withdrew the proposal two years later. The EPA was sued by the Natural Resources Defense Council and Waterkeeper Alliance and the states of New York and Connecticut over the agency’s failure to promulgate effluent guideline regulations for the C&D industry.

The court found that EPA has a mandatory duty to promulgate effluent guidelines for an industrial category listed in the biennial effluent guidelines plan. The court ordered EPA to publish proposed regulations in the Federal Register by December 1, 2008, and to publish final regulations for the C&D category by December 1, 2009. EPA has met the deadline on publishing a proposed regulation.

National effluent guideline regulations typically specify the maximum allowable levels of pollutants that may be discharged by facilities within an industrial category or subcategory. Even though the limits are based on the performance of specific technologies, the guidelines do not usually require the industry to use these technologies, but rather allow the industry to use any effective alternatives to meet the numerical pollutant limits. Effluent guidelines may also be based on BMPs.

The proposed rule for establishment of effluent guidelines for the C&D industry was published in the Federal Register on November 28, 2008, and comments were to be received on or before February 26, 2009. The following is a summary of the scope of the proposed rule.

The proposed rule would establish a set of non-numeric effluent limitations requiring dischargers to provide and maintain effective erosion control measures, sediment control measures, and other pollution prevention measures to minimize and control the discharge of pollutants in stormwater and other wastewater from construction sites. The rule would specify particular minimum BMPs to meet the effluent limitations requiring effective erosion control and pollution prevention. This is very similar to requirements in the current regulations.

In addition, reflecting current requirements in the EPA Construction General Permit (CGP), sites disturbing 10 or more acres at one time would be required to install a sediment basin to contain and settle sediment from stormwater runoff. The proposed rule would require minimum standards of design for sediment basins; however, alternatives that control sediment discharges in a manner equivalent to sediment basins would be authorized where approved by the permitting authority.

Finally, reflecting the best available technology (BAT) and new source performance standards (NSPS) levels of control, for certain large sites located in areas of high rainfall energy and with soils with significant clay content, discharges of stormwater from the site would be required to meet a numeric effluent limit on the allowable level of turbidity. The numeric turbidity limit is 13 nephelometric turbidity units (NTUs). The technology basis for the turbidity limit is active treatment systems, which consist of polymer-assisted clarification followed by filtration. There are no requirements in the proposed rule for sampling of the stormwater discharge from a construction site.

Active treatment systems are typically used in conjunction with other sediment controls to improve pollutant removals, especially to improve pollutant removals of fine-grained and slowly settling or non-settleable particles and turbidity contained in stormwater. Unless sufficient detention time is provided or additives reimplemented, particles such as clays and fine silts contained in stormwater discharges from construction sites typically cannot be effectively removed by conventional stormwater BMPs that rely solely on gravity settling.

The EPA has identified several demonstrated technologies capable of achieving significant reductions of these particles. Electrocoagulation, polymer clarification, and chitosan-enhanced filtration treatment technologies are demonstrated as being capable of achieving low levels of turbidity in stormwater discharges.

Electrocoagulation treatment uses an electrical field to disturb the natural electrical charges of the colloidal particles suspended in stormwater, enabling the particles to coagulate and flocculate, thereby facilitating gravity settling.

Polymer clarification can operate as a batch process whereby a polymer is added to stormwater contained in a basin. The polymer causes clays and other fine particles to flocculate and gravity-settle.

Chitosan-enhanced filtration is a process that adds a polymer (one produced from the chitin in crab shells) to the stormwater to promote flocculation. The flocculated stormwater is then passed through one or more filtration steps and, if permit conditions are met, can be discharged.

The use of polymers for flocculation and sediment settling is a fairly new tool being used on construction sites. Although the rule proposed by the EPA mentions the possibility of overuse of polymers in these active treatment systems, it dismisses the risk by saying the EPA is not aware of any studies indicating that polymer addition to treat stormwater from construction sites using active treatment systems has been found to pose a significant risk to water quality at those facilities. The problem with this logic is that polymers currently are not a “required” tool to facilitate sediment settling; after the rule goes into effect, they will be a required tool, and many more construction sites will be required to use polymers, therefore adding new distributors and appliers to the market. This will cause persons who are unknowledgeable or do not care about the harmful effects of polymers to overapply them, so they discharge into receiving streams and adhere to fish and other aquatic organisms, causing aquatic toxicity. Some polymers have been shown to bind to fish gills resulting in mechanical suffocation.

It is in the best interest to everyone in the industry to properly educate all users of polymers and to create a certification, allowing only those with the proper education and certification to sell and apply polymers for sediment control on construction sites. The use of polymers, while providing a good sediment control system, must be monitored closely to reduce or eliminate the possible added pollution and environmental degradation it would cause if excess amounts are released into a receiving stream.

Best Available Technology
The report produced by the National Research Council and the new proposed rule for effluent limitations guidelines have a common theme, and that is the use of best available technology. As stated in the National Research Council report, performance characteristics are starting to be established for most structural and some nonstructural BMPs, but additional research is needed on the relevant hydrologic and water-quality processes within the BMPs across different climates and soil conditions.

Such typical data as long-term load reduction efficiencies and pollutant effluent concentrations can be found in the International Stormwater BMP Database ( However, understanding of the processes involved in each BMP is in its infancy, making modeling of these BMPs difficult. Seasonal differences, the time between storms, and other factors all affect pollutant loadings emanating from BMPs. Additional research is needed that moves away from the use of percent removal and toward better simulation of BMP performance. Research is particularly important for nonstructural BMPs, which may be more effective, have longer life spans, and require less maintenance than structural BMPs. The EPA should be the leader in BMP research, both directly by improving its internal modeling efforts and also by funding state efforts to monitor and report back on the success of BMPs in the field. There has been a huge inflow of new technology and products available to use for the control of erosion and sediment discharge. All products should be tested against existing data for similar devices. They must meet or exceed existing baseline standards set by the EPA. Testing should be consistent with the production of relevant data.

What’s Missing?
One aspect missing from both the National Research Council’s report and the new proposed effluent limitations guidelines is enforcement.Without consistent and across-the-board enforcement of the regulations, they will be as ineffective as the stormwater regulatory program is currently. In many places around the country, the regulations are not much more than words on paper. As stated in the proposed effluent limitations guidelines, 45% of assessed lake acres and 32% of assessed square miles of estuaries show impairments. Improper control of stormwater discharges from construction activities is among the many contributors of sediment, which is one of the major remaining water-quality problems throughout the United States. Sediment is the leading cause of water-quality impairment for streams and rivers. Turbidity or suspended solids impair 695,133 miles of streams nationwide, and 376,832 acres of lakes and reservoirs have been documented as impaired by turbidity or suspended solids nationwide.

Would those numbers be the same if the current National Pollutant Discharge Elimination System (NPDES) permit program for construction activity, which has been in effect since 1992, had been properly enforced, if substantial fines had been issued years ago, and if orders to stop work had been given out on a regular basis? As you drive across the country today, you can see clear evidence that enforcement is lacking from the number of construction sites that are completely out of compliance. Construction sites in every state have trackout of sediment, lack of a compliant SWPPP on site, and no regular inspection and maintenance of BMPs. Will these problems stop with the new proposed guidelines or with changes to the NPDES program as suggested in the National Research Council report? No-without enforcement, they are just words on paper. The two things this industry needs more than more regulations and reports are education and enforcement. Then let’s see how productive the NPDES program is.

About the Author

Shirley Morrow

Writer Shirley D. Morrow, CPESC, CISEC, is president of ABC’s of BMP’s, located in Spring Hill, KS.