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Introduction In open fields, forests, and wetlands, most rain is absorbed by the soil or is taken up by plants and trees. In developed areas, rain that falls on impermeable roofs, parking lots, streets, and lawns is not absorbed. Instead, it travels down roadways, settles in gutters and ditches, and flows through storm drains to finally end up in rivers, lakes, and wetlands. Rainwater that enters a surface water body, by flowing either overland or through a storm sewer system, is called storm water or storm water runoff. Storm water runoff is one of the leading causes of pollution in rivers and lakes. In both urban and agricultural settings, it can dissolve and transport a variety of chemicals, fertilizers, pesticides, and litter picked up while traveling overland. Identifying sources of storm water pollution and keeping them from coming in contact with runoff is the best and most economical way to protect the quality of the nation's waters. The purpose of this Fact Sheet is to describe the nature and occurrence of storm water pollution, its environmental effects, and ways to address this important water quality problem. The Fact Sheet also discusses regulations and policies applicable to Air Force activities, the Air Force Installation Storm Water Program Guide, and sources for more information. Applicable Policies, Instructions, and Regulations The Clean Water Act is the principal federal legislation that addresses water pollution issues. The Clean Water Act (CWA) has regulated the discharge of pollutants from "point sources," such as industrial processes and sewage treatment plants, to waters of the U.S. since 1972. These discharges are subject to permitting under the National Pollutant Discharge Elimination System (NPDES) Program section of the CWA. In 1987, amendments to the CWA directed the Environmental Protection Agency (EPA) to develop regulations specific to discharges of storm water runoff associated with industrial activities. This change in the statute came about as a result of the "National Urban Runoff Program Study" which indicated that storm water runoff from cities and industrial activities (including construction activities) carried pollutants to our nation's water bodies. Most states have been delegated the authority to administer the federal NPDES storm water permit program, including the review of applications and the issuance of permits. Rules promulgated for the 1987 Amendments to the CWA regarding storm water discharges are found in Title 40 Code of Federal Regulations (CFR) Parts 122-124. These rules establish an application process for obtaining NPDES storm water discharge permits and categorizes storm water discharges as either "Phase I" or "Phase II." Phase I storm water discharges are those having the greatest potential to contaminate runoff and include industrial sectors such as manufacturing, transportation, landfills, certain wastewater treatment facilities, hazardous waste treatment/storage/disposal areas, large municipal separate storm sewer systems (MS4s), and large construction sites (over 5 acres). Phase II storm water discharges are those not addressed under Phase I of the program and include runoff from golf courses, housing areas, small construction sites (between 1 and 5 acres), large parking areas, gas stations, and MS4s serving populations less than 100,000. Under EPA's storm water regulations and general permits applying to Phase I discharges, Air Force installations have several industrial categories/processes that may require permitting including aircraft, plating, transportation, and solid/liquid waste stream management systems and activities. EPA published its final rule for Phase II storm water discharges in Vol-64, No. 235 of the Federal Register on 8 December 1999 (copies available from PRO-ACT) that require NPDES permits. Provisions of the final rule include "various exemptions" that allow certain sources to be excluded from the NPDES program based on their lack of impact on water quality, as well as the inclusion of sources not normally regulated based on their localized impact on water quality. Finally, EPA is conditionally excluding from the NPDES storm water program those industrial facilities whose activities pose "no exposure" to storm water. EPA hopes the final rule will be a more cost-effective approach to reducing the negative environmental impacts associated with storm water discharges. They also hope it will bring about increased utilization of general permits, a greater variety in watershed protection approaches, an increase in the use of available methods for public participation, and will be cost-effective. Permit enforcement begins in the year 2001. Executive Order 12088, "Federal Compliance with Pollution Control Standards," 13 October 1978, requires the Air Force to take all necessary actions to prevent, control, and abate environmental pollution at all Air Force installations and to comply with applicable federal environmental regulations. Air Force Policy Directive (AFPD) 32-70, "Environmental Quality," 20 July 1994, states "The Air Force will prevent future pollution by reducing use of hazardous materials and releases of pollutants into the environment to as near zero as feasible." The AFPD also directs that any spent waste that cannot be reused or recycled will be disposed of in an environmentally safe manner consistent with the requirements of all applicable laws. AFI 32-7041, "Water Quality Compliance," 13 May 1994, implements the water quality requirements of AFPD 32-70. It applies to generating, collecting, treating, reusing, and discarding: domestic and industrial wastewater, storm water, non-point source runoff, sewage sludge, and water treatment residuals. The AFI states that the Clean Water Act and EPA regulations form the basis of the Water Quality Compliance Program, which requires Air Force compliance with permit standards under the National Pollutant Discharge Elimination System (NPDES) and other applicable federal, state, and local water quality regulations. To this end, the AFI explains how to assess, attain, and sustain compliance with: the Clean Water Act; other federal, state and local environmental regulations; and related Department of Defense (DoD) and Air Force directives. (NOTE: Water quality compliance requirements at installations outside the U.S. and its territories are addressed in AFI 32-7006, "Environmental Program in Foreign Countries," Chapter 4 of DoD's "Overseas Environmental Baseline Guidance Document" [OEBGD], and in country-specific Final Governing Standards [FGS]). Common Storm Water Pollutants Oil and Grease - Oil from vehicles, storage tanks, and machinery, as well as grease from dining hall waste can be carried by storm water into surface waters. Oil and grease float on the water's surface and block sunlight needed by underwater fish and plants. Oil and grease can also damage stream habitat and sensitive spawning areas when it settles and clings to sand and gravel particles. Heavy Metals - Heavy metals, such as lead, zinc, and mercury, are ingredients in many commonly used products like batteries, fuels, paints, pesticides, and cleaners (e.g. algaecides). Heavy metals can also be found in industrial-strength materials like rubber. When these products are spilled or improperly discarded, or when materials containing heavy metals break down, they leave behind pollutants that can be readily transported (in dissolved or undissolved form) into streams by storm water. Heavy metals can be toxic to fish and other aquatic life in streams. Nutrients - Nutrients like phosphorus and nitrogen are transported into streams when storm water picks up fertilizer and animal manure residues on the ground in agricultural areas. Excessive amounts of nutrient buildup in surface water bodies can disrupt the normal ecosystem. Chemicals - Toxic chemicals, especially organic chemicals found in fuels, paints, cleaning products, and pesticides, have a wide range of toxic effects on fish and aquatic life, including causing tumors and skin lesions and disrupting reproductive functions. Chemicals can enter storm water through improper storage practices and through misapplication. Mud and Sediment - When storm water flows across the land, and in particular construction sites and unplanted fields, it picks up loose particulate matter that is carried into streams. It can then settle to the bottom of the stream bed in a process commonly called sedimentation. When too much sediment accumulates on stream beds, it damages fish-spawning areas, alters habitats where bottom-dwelling organisms live and reproduce, and interferes with fish migration. In addition, dirt and sand often pick up oil and grease in their path, which introduces additional chemical contaminants that are toxic to fish and other aquatic organisms. Litter - Debris that overflow from waste receptacles and litter thrown onto the ground are readily carried by storm water into streams and rivers. They can harm fish and aquatic life directly or indirectly by hindering sunlight penetration in much the same manner as oil and grease. Abnormal pH - When storm water mixes with chemicals or chemical products that are acidic or alkaline, the pH of the water will change. Acidic or alkaline conditions in streams can harm fish, especially sensitive juvenile fish, and other aquatic plants and organisms. Coliform Bacteria - At high levels, naturally occurring coliform bacteria from human and animal wastes can contaminate water. It is very important to prevent the accumulation of human and animal waste in areas drained by storm water collection systems; however, the majority of coliform bacteria contamination in water results from uncontrolled overflows from major wastewater treatment works. Air Force Activities That Can Pollute Storm Water Many routine activities occur on most Air Force installations that, if not managed properly, have the potential to cause storm water pollution. Some of these activities include:
Prevention of Storm Water Pollution There are many approaches to the prevention and control of storm water pollution, ranging from simple measures taken on an individual basis, to larger scale plans instituted installation-wide.
Individual Efforts
Storm Water Pollution Prevention Plans (SWPPPs)
The Storm Water Program Manager should be aware of other regulations, programs, and plans that contain information pertinent to the Storm Water Program and should be reviewed when writing and updating a SWPPP. The following is a partial list (refer to the Installation Storm Water Program Management Guide for more detailed information) of other installation environmental plans and programs that will help identify sources of storm water pollution and/or appropriate BMPs:
Non-structural BMPs, also known as good housekeeping practices, are operating procedures that prevent the generation of storm water pollution and include:
Preventive Maintenance - Pipes, pumps, storage tanks, and storm water management devices require periodic maintenance to ensure equipment and structures are in good condition and will not pollute storm water. Replace worn gaskets and valves before leaks occur, and remove trash and residue from overflowing containers and receptacles.
Routine Inspections - To ensure equipment, machinery, vehicles, and tanks are not leaking, perform routine visual inspections and integrity tests. Conduct inspections in areas prone to leaks and in material storage, processing, and waste generation areas. Routinely monitor storage tanks, trash containers, and equipment for rust and wear.
Spill Response Planning - Put in place well designed spill prevention and cleanup procedures. The plan should identify all potential spill areas and have procedures developed for avoiding and responding to spills that do occur.
Erosion Control Measures - Use sediment and erosion control practices anywhere soil has been disturbed, particularly in construction and demolition areas. Minimize erosion by maintaining planted areas and designing landscape to reduce the amount of soil and dirt exposed to storm water runoff.
Structural BMPs are engineered controls that remove pollutants from storm water and usually include specially constructed devices/systems. Traditionally, structural BMPs included storm water ponds that collect storm water runoff and used oil-grit or oil-water separators to filter out oil and sand (a.k.a. grit) from storm water runoff in parking lots. More recently, new structures that manage and reduce pollution in storm water have been designed and constructed to use innovative techniques. For example, BMPs often rely on the natural filtering capacity of the ground and the absorption capabilities of plants to help with the removal of pollutants. Some filter pollutants from storm water by using natural and man-made materials such as straw bales, semi-porous plastic filter fabric, and silt fences. Common examples are:
Retention Structures - These are pond-like storm water control structures that act like natural ponds by slowing the flow of water and storing storm water behind an embankment. They may serve the dual purpose of collecting and recirculating process water from a building. These structures filter pollutants from storm water before discharging it into a storm drain or stream. Heavier suspended matter and pollutants are allowed to settle out of the storm water. This method is less effective in removing dissolved pollutants and microorganisms.
Infiltration Structures - These storm water control structures catch storm water and help it filter into the ground. Pollutants are removed from runoff that would otherwise discharge directly into a stream. These devices may include man-made materials like filter fabric, perforated pipes, or natural elements like certain types of soil, gravel, and sand to physically remove pollutants from storm water. Unlike retention structures that store and release storm water to surface water bodies, infiltration structures direct the flow of storm water into channels and other designated areas that permit storm water to gradually soak deeper into the ground. Infiltration structures are effective in removing suspended solids, bacteria, undissolved nutrients, oil and grease, and floating wastes; however, they are less effective at removing dissolved nutrients, some toxic pollutants, and chlorides (road salts).
Vegetative Structures - These are storm water management structures that rely on natural plantings and vegetation to remove pollutants such as suspended matter, undissolved metals, and bacteria from storm water. Some plants can readily absorb certain pollutants without apparent harm. For example, sunflowers and cattails can absorb low levels of dissolved metals without toxic effects. Natural wetlands and bogs are also very effective at filtering pollution from storm water. Grassed swales and filter strips are two types of storm water control structures that rely on plants and the ground surface to remove and filter pollutants from storm water.
A general summary of the Installation Storm Water Program Management Guide, highlighting the key features of each section, is presented below:
Regulatory Background
Storm Water Program Management
Technical Implementation
Resources
Appendices
Copies of the Installation Storm Water Program Management Guide may be downloaded from HQ AFCEE's World Wide Web (WWW) site, http://www.afcee.brooks.af.mil/EQ/swguide.htm, or from PRO-ACT.
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