B. Management Measure for Chemical and Pollutant Control

1. Limit application, generation, and migration of toxic substances;
2. Ensure the proper storage and disposal of toxic materials; and,
3. Apply nutrients at rates necessary to establish and maintain vegetation without causing significant nutrient runoff to surface waters.

1. Applicability

This management measure is intended to be applied by States to the construction of new dams, as well as to construction activities associated with the maintenance of dams. Dams are defined as constructed impoundments which are either:

• 25 feet or more in height and greater than 15 acre-feet in capacity, or
• 6 feet or more in height and greater than 50 acre-feet in capacity.

This management measure addresses fuel and chemical spills associated with dam construction, as well as concrete washout and related construction activities. Under the Coastal Zone Act Reauthorization Amendments of 1990, States are subject to a number of requirements as they develop coastal NPS programs in conformity with this measure and will have some flexibility in doing so. The application of management measures by States is described more fully in Coastal Nonpoint Pollution Control Program: Program Development and Approval Guidance, published jointly by the U.S. Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA) of the U.S. Department of Commerce.

2. Description

The purpose of this management measure is to prevent downstream contamination from pollutants associated with dam construction activities.

Although suspended sediment is the major pollutant generated at a construction site (USEPA, 1973), other pollutants include:

• Pesticides - insecticides, fungicides, herbicides, rodenticides;
• Petrochemicals - oil, gasoline, lubricants, asphalt;
• Solid wastes - paper, wood, metal, rubber, plastic, roofing materials;
• Construction chemicals - acids, soil additives, concrete-curing compounds;
• Wastewater - aggregate wash water, herbicide wash water, concrete-curing water, core-drilling wastewater, or clean-up water from concrete mixers;
• Garbage;
• Cement;
• Lime;
• Sanitary wastes; and
• Fertilizers.

A complete discussion of these pollutants can be found in Chapter 4 of this guidance.

3. Management Measure Selection

This management measure was selected because most erosion and sediment control practices are ineffective at retaining soluble NPS pollutants on a construction site. Many of the NPS pollutants, other than suspended sediment, generated at a construction site are carried offsite in solution or attached to clay particles in runoff (USEPA, 1973). Some metals (e.g., manganese, iron, and nickel) attach to sediment and usually can be retained onsite. Other metals (e.g., copper, cobalt, and chromium) attach to fine clay particles and have greater potential to be carried offsite. Insoluble pollutants (e.g., oils, petrochemicals, and asphalt) form a surface film on runoff water and can be easily washed away (USEPA, 1973).

A number of factors that influence the pollution potential of construction chemicals have been identified (USEPA, 1973). These include:

• The nature of the construction activity;
• The physical characteristics of the construction site; and
• The characteristics of the receiving water.

Dam construction sites are particularly sensitive areas and have the potential to severely impact surface waters with runoff containing construction chemical pollutants. Because dams are located on rivers or streams, pollutants generated at these construction sites have a much shorter distance to travel before entering surface waters. Therefore, chemicals and other NPS pollutants generated at a dam construction site should be controlled.

4. Practices

As explained more fully at the beginning of this chapter and in Chapter 1, the following practices are described for illustrative purposes only. State programs need not require the implementation of these practices. However, as a practical matter, EPA anticipates that the management measure set forth above generally will be implemented by applying one or more management practices appropriate to the source, location, and climate. The practices set forth below have been found by EPA to be representative of the types of practices that can be applied successfully to achieve the management measure described above.

Practices for the control of erosion and sediment loss are discussed in Chapter 4 of this guidance and should be considered applicable to this management measure.

• a. Develop and implement a spill prevention and control plan. Agencies, contractors, and other commercial entities associated with the dam construction project that store, handle, or transport fuel, oil, or hazardous materials should have a spill response plan, especially if large quantities of oil or other polluting liquid materials are used.

Spill procedure information should be posted, and persons trained in spill handling should be onsite or on call at all times. Materials for cleaning up spills should be kept onsite and easily available. Spills should be cleaned up immediately and the contaminated material properly disposed of. Spill control plan components should include (Peters, 1978):

• Stopping the source of the spill;
• Containing any liquid;
• Covering the spill with absorbent material such as kitty litter or sawdust, but do not use straw; and
• Disposing of the used absorbent properly.

• b. Maintain and wash equipment and machinery in confined areas specifically designed to control runoff.

Thinners or solvents should not be discharged into sanitary or storm sewer systems, or surface water systems, when cleaning machinery. Use alternative methods for cleaning larger equipment parts, such as high-pressure, high-temperature water washes or steam cleaning. Equipment-washing detergents can be used and wash water discharged into sanitary sewers if solids are removed from the solution first. Small parts should be cleaned with degreasing solvents that can then be reused or recycled. Do not discharge or otherwise dispose of any solvents into sewers, or into surface waters.

Washout from concrete trucks should be disposed of into:

• A designated area that will later be backfilled;
• An area where the concrete wash can harden, can be broken up, and can then be placed in a dumpster; or
• A location not subject to surface water runoff and more than 50 feet away from a receiving water.

Never dump washout directly into surface waters or into a drainage leading to surface waters.

• c. Establish fuel and vehicle maintenance staging areas located away from surface waters and all drainages leading to surface waters, and design these areas to control runoff.

• d. Store, cover, and isolate construction materials, refuse, garbage, sewage, debris, oil and other petroleum products, mineral salts, industrial chemicals, and topsoil to prevent runoff of pollutants and contamination of ground water.

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