API PUBL 4756-2006 pdf free download

API PUBL 4756-2006 pdf free download.Interim Permitting Manual— Navigating NPDES Permit Issues on Impaired Waters.
Water Quality Standards Water quality standards serve as the foundation of the listing process for impaired waters (also called the 303(d) process), because waters can only be listed if they are not meeting the state’s water quality standards. If the standards applicable to your receiving water are not appropriate, the basis of any impairment determination will be flawed. The Clean Water Act (CWA) sets forth the components of water quality standards as follows: … Such revised or new water quality standard shall consist of the designated uses of the navigable waters involved and the water quality criteria for such waters based upon such uses. … 1 Water quality standards therefore include designated uses and specific water quality criteria necessary to protect those uses. As discussed in more detail below, criteria may be numeric or narrative (e.g., “no toxics in toxic amounts”). In addition, the state’s antidegradation policy is considered to be part of its water quality standards. 2 States are required to adopt water quality standards applicable to waters within their jurisdictions, and to evaluate those waters to determine whether the standards are being met. As discussed in more detail below, waters that are not meeting standards will be considered impaired, and generally will be scheduled for TMDL development. Designated Uses The CWA includes goals for the nation’s water quality: that all waters should provide for the protection and propagation of fish, shellfish, and wildlife, and recreation in and on the water. 3 These goals are often interpreted as a requirement that all waters be “fishable” and “swimmable.” The CWA specifies that states must take the fishable/swimmable goals—and several other uses—into consideration when establishing their water quality standards: Such standards shall be such as to protect the public health or welfare, enhance the quality of water and serve the purposes of this chapter. Examples of subcategorization also include secondary contact recreation. Finally, states may adopt seasonal uses: States may adopt seasonal uses as an alternative to reclassifying a water body or segment thereof to uses requiring less stringent water quality criteria. If seasonal uses are adopted, water quality criteria should be adjusted to reflect the seasonal uses, however, such criteria shall not preclude the attainment and maintenance of a more protective use in another season. 8 Examples of seasonal uses include recreational uses such as full body contact recreation, which may be applicable only during summer months. Waters can—and frequently do—have multiple designated uses. For example, a waterbody may be designated for all of the following uses: warm water fishery, primary contact recreation, public water supply, industrial water supply, and agriculture. Be sure you identify all the uses designated for your receiving water, so you can better understand how your waterbody was assessed. You should be able to obtain this information by looking at the state water statutes or regulations, which are generally available on your state environmental agency’s water website. You may also find useful information concerning your state’s water quality standards on EPA’s Water Science web page. 9 When you are evaluating the uses designated for your receiving water, remember that a water can be designated for a use even if it is not currently attaining—or has never attained—that particular use: Designated uses are those uses specified in water quality standards for each water body or segment whether or not they are being attained.