This dataset represents the centroids of lakes, reservoirs, and wetlands that were listed as "impaired" in Iowa's 2012 Section 305(b) Water Quality Assessment and the 303(d) Impaired Waters Report. Together, these two reports are known as Iowa's 2012 Integrated Report. Waterbodies in Iowa each have specific designations based on what they are commonly used for-recreation, such as swimming or fishing; drinking water; or maintaining a healthy population of fish and other aquatic life. Every two years, Iowa must report on its progress in meeting water quality goals to the U.S. Environmental Protection Agency (EPA).
The state prepares one report called the 305(b) Water Quality Assessment or 305(b) list. This 305(b) list categorizes waterbodies to reflect: those that meet all the designated uses (category 1), those in which data availability is insufficient to determine whether any or all designated uses are being met (categories 2 and 3), and those waters in which the water quality prevents it from fully meeting its designated use, and is thus considered "impaired".
New impairments (or category 5 listings) are placed on the "303(d) Impaired Waters Report", commonly referred to as the "impaired waters list." This is named after section 303(d) of the Federal Clean Water Act and means that the stream or lake needs a water quality improvement plan written (also known by a technical name, "Total Maximum Daily Load," or "TMDL"). The water quality improvement plan outlines water quality problems, identifies sources of the problem(s), identifies needed reductions in pollutants and offers possible solutions. Water quality improvement plans are approved by the EPA and then the waters are moved from the 303(d) list back to the 305(b) list as category 4 listings (waters considered impaired, but a water quality improvement plan has been written).