Roaring Brook Consultants, Inc.

Engineering a Better Future

National Pollutant Discharge Elimination System (NPDES) - Part II

In 2003, Phase 2 of the NPDES started. This phase includes smaller communities, industries and construction sites. Included in Phase 2 are:

• Cities and towns which have a density of 1000 per sq. mile in the storm sewer watershed
• Broader range of industries
• Construction activities of one (1) or more acres

The requirements imposed on each of the sectors vary. In this discussion we will not be exploring the industrial segment, since each type of industry has it’s own individual concerns. To avoid the need of an individual permit for every one of these small entities, a General permit was created. The General permit is for storm water discharges only, any other type of discharge, such as industrial process water which will need the appropriate permit for that type of discharge. The General permit was first issued in 2003 and is due to expire in 2008. The new permit is currently under development. The basics of the permits will most likely stay the same, except that the reporting and analysis sections maybe expanded under the new 2008 permit. The following I a discussion of the current permit requirements.

The number of states who have gained delegated status has increased and in this region New Hampshire and Massachusetts are the only undelegated states. In these two states Individual and General permits are administered by the EPA regional office.

A Notice of Intent (NOI) is filed by the town, property owner, developer or other entity responsible for the work. The NOI is a one-page form that simply states that the provisions of the General permit will be followed. Prior to submitting the NOI a Storm Water Management Plan (SWMP) for a municipality or a Storm Water Pollution Prevention Plan (SWPPP) for a construction site or industrial facility must be prepared. The plans elaborate on how the responsible entity will meet the requirements of the general permit. Both the SWMP and SWPPP are to be signed by the person responsible for its implementation prior to starting any work. This is the person who has authority to initiate work and to pay for it.

The Municipal Separate Storm Sewer System (MS4) communities have to meet six (6) minimum requirements. They are:

1. Public education and outreach;
2. Public participation and involvement
3. Illicit discharge detection and elimination;
4. Construction site runoff control – temporary and permanent;
5. Post-construction runoff control, and
6. Pollution prevention and Good Housekeeping

How the municipality will meet these requirements is detailed in the SWMP. The first two requirements deal with educating and involving the public. Educating the public to change their habits and expectations will take time. The EPA knows that there is no one size fits all approach, if something doesn’t work effectively, modify the approach and try again. Three citizens attending an information night in a city of 10,000 is not an effective public education program. The annual report from the MS4 community should address what was done and what will be done next year.

Illicit discharge detection and elimination can be a time consuming endeavor. Bacteria is discovered at the stormwater outlet. Where did it come from? Who is the responsible polluter? This needs to be tracked down and the source removed from the stormwater flow.

Each locality is expected to monitor the construction and post construction activities that qualify under the permit. In the state of Maine the towns can either adopt their own control methods or by direct reference include the states program.

The last two items on the list of minimum requirements stress the need for continuing monitoring, maintenance and repair of permanent Best Management Practices (BMPs), also known as Storm water management practices (SMPs). Permanent BMPs would include such things as treatment ponds, buffers, catchbasins, etc. Building the treatment pond is good, but it has to be maintained so that it functions properly for the long term. Street sweeping and removing grit and sediment from catchbasin sumps are ongoing prevention and housekeeping tasks. Inspection and repair/maintenance of the installed BMPs is critical to the continued functioning of these practices. The goal of the CWA was to restore and maintain the water quality. Routine inspections can be performed by the responsible municipal department, but this is one more thing that needs to be prioritized among many other duties. An independent inspection by a third party, whose priority is performing the inspection, ensures that it happens on a routine schedule

The SWPPP for a construction site needs to include the following:

• Narrative description
• Potential pollutants
• Size of site, percent of imperviousness, runoff calculations
• Non-storm water management measures
• Permanent post-construction control measures
• Waste management and disposal measures
• Provisions for maintenance, inspection and repair of BMPs

The narrative describes the project and the property. Silt and sediment are obvious potential pollutants, however; others are present on many construction sites. These might include spills while refueling vehicles, spills while servicing the portable toilets on the site, leachates from treated lumber stored uncovered, there are many more potential sources. The problem is not that they exist it is when they are not managed.

The plan needs to include all of the drainage calculations of the pre-development and post-development conditions. Details of the sizing of ponds, buffers, swales and other BMPs need to be included. Temporary erosion control measures, such as silt fence, temporary seeding, mulching and other BMPs need to be described.

Non-stormwater management measures would include such procedures as where to refuel equipment, providing adequate containment around refueling stations and tanks (if present), areas stabilized for cement truck washing. All these and other operations unique to each site need to be addressed. Store small equipment and fuel under a roof. You don’t want a State or EPA inspector to able to trace an oil slick in the brook back to your inadequately stored gas can.

The SWPPP needs to be clear about who will maintain the permanent BMPs once the construction phase of the project is complete. The buffers installed during the construction phase are intended to filter runoff for the long term. The treatment pond installed during the construction phase needs to be maintained so that 20 years later the pond is still treating the stormwater. In a residential subdivision the municipality is often the ultimate owner of the permanent BMPs, but often it is a Condominium Association or Homeowners Association. The municipality may have the expertise within their staff to inspect the BMPs, an Association will most likely not, this is where an independent inspector can fill the void. An independent inspector is a knowledgeable individual who can identify existing and potential problems with the BMPs.

Waste management on the project is also important. How are materials stored? Is the dumpster open to the weather so that rain entering it can leach nutrients and other deleterious materials from the contents? Provide a procedure to cover the dumpster with a tarp each night so rainwater is kept out.

The final item is maintenance, inspection and repair. The SWPPP should include a log for recording inspections of the BMPs. Typical inspection frequency would be weekly or after a significant storm. Personally I think the inspection is best before the storm so problems can get fixed before sediment is washed off the site into the neighboring pond. The plume of silt laden water will lead any inspector back to your project. If something is broken, fix it and note the repair in the log. If the silt fence has blown out at the same spot four times already, try something new. We all know, including the regulatory inspectors that this is not a perfect science and everything doesn’t always work as designed. The regulators do expect that if something doesn’t work that efforts will be made to correct the problem. The SWPPP is supposed to be a growing document, just be sure to document the changes within the SWPPP. The ultimate goal is to have a project that does not pollute the environment.

The contractor is responsible for performing and documenting the inspections. Any repairs or maintenance needs to documented as well. When a state or EPA inspector comes onto the site they will want to see the SWPPP and the inspection and maintenance log. The inspections are to be performed by a knowledgeable person, which often means that amongst all the other duties, the project supervisor needs to dedicate time to do the weekly inspections. An independent inspection by a third party, whose priority is performing the inspection, ensures that it happens on a routine schedule, without taking valuable time from the project supervisor.

A detailed discussion of industrial SWPPPs has been left out. Each type of industry requires specific unique processes, which is beyond the scope of this document. The basics of the SWPPP for a construction plan would still apply.

In summary, the intent of all the plans and permits is to improve and maintain the quality of our water. This is in best interest of everyone. Drinking water, fish habitats, safe recreational areas all need clean water. If educating the public keeps 10 gallons of waste oil out of the storm sewer, then the plan is working.

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