d. Discharge characterization.
(1) Monthly mean rain and snow fall estimates (or summary of weather bureau data) and the monthly average number of storm events.
(2) Existing quantitative data describing the volume and quality of discharges from the municipal storm sewer, including a description of the outfalls sampled, sampling procedures, and analytical methods used.
(3) A list of water bodies that receive discharges from the municipal separate storm sewer system, including downstream segments, lakes, and estuaries, where pollutants from the system discharges may accumulate and cause water degradation and a brief description of known water quality impacts. At a minimum, the description of impacts shall include a description of whether the water bodies receiving such discharges have been:
(a) Assessed and reported in § 305(b) of the CWA reports submitted by the state, the basis for the assessment (evaluated or monitored), a summary of designated use support and attainment of the State Water Control Law and the CWA goals (fishable and swimmable waters), and causes of nonsupport of designated uses;
(b) Listed under § 304(l)(1)(A)(i), (1)(A)(ii), or (l)(1)(B) of the CWA that is not expected to meet water quality standards or water quality goals;
(c) Listed in State Nonpoint Source Assessments required by § 319(a) of the CWA that, without additional action to control nonpoint sources of pollution, cannot reasonably be expected to attain or maintain water quality standards due to storm sewers, construction, highway maintenance, and runoff from municipal landfills and municipal sludge adding significant pollution (or contributing to a violation of water quality standards);
(d) Identified and classified according to eutrophic condition of publicly owned lakes listed in state reports required under § 314(a) of the CWA (include the following: a description of those publicly owned lakes for which uses are known to be impaired; a description of procedures, processes, and methods to control the discharge of pollutants from municipal separate storm sewers into such lakes; and a description of methods and procedures to restore the quality of such lakes);
(e) Areas of concern of the Great Lakes identified by the International Joint Commission;
(f) Designated estuaries under the National Estuary Program under § 320 of the CWA;
(g) Recognized by the permit applicant as highly valued or sensitive waters;
(h) Defined by the state or U.S. Fish and Wildlife Service's National Wetlands Inventory as wetlands; and
(i) Found to have pollutants in bottom sediments, fish tissue or biosurvey data.
(4) Results of a field screening analysis for illicit connections and illegal dumping for either selected field screening points or major outfalls covered in the permit application. At a minimum, a screening analysis shall include a narrative description, for either each field screening point or major outfall, of visual observations made during dry weather periods. If any flow is observed, two grab samples shall be collected during a 24-hour period with a minimum period of four hours between samples. For all such samples, a narrative description of the color, odor, turbidity, and the presence of an oil sheen or surface scum, as well as any other relevant observations regarding the potential presence of nonstormwater discharges or illegal dumping shall be provided. In addition, a narrative description of the results of a field analysis using suitable methods to estimate pH, total chlorine, total copper, total phenol, and detergents (or surfactants) shall be provided along with a description of the flow rate. Where the field analysis does not involve analytical methods approved under 40 CFR Part 136, the permit applicant shall provide a description of the method used, including the name of the manufacturer of the test method along with the range and accuracy of the test. Field screening points shall be either major outfalls or other outfall points (or any other point of access such as manholes) randomly located throughout the storm sewer system by placing a grid over a drainage system map and identifying those cells of the grid that contain a segment of the storm sewer system or major outfall. The field screening points shall be established using the following guidelines and criteria:
(a) A grid system consisting of perpendicular north-south and east-west lines spaced 1/4 mile apart shall be overlaid on a map of the municipal storm sewer system, creating a series of cells;
(b) All cells that contain a segment of the storm sewer system shall be identified; one field screening point shall be selected in each cell; major outfalls may be used as field screening points;
(c) Field screening points should be located downstream of any sources of suspected illegal or illicit activity;
(d) Field screening points shall be located to the degree practicable at the farthest manhole or other accessible location downstream in the system, within each cell; however, safety of personnel and accessibility of the location should be considered in making this determination;
(e) Hydrological conditions; total drainage area of the site; population density of the site; traffic density; age of the structures or buildings in the area; history of the area; and land use types;
(f) For medium municipal separate storm sewer systems, no more than 250 cells need to have identified field screening points; in large municipal separate storm sewer systems, no more than 500 cells need to have identified field screening points; cells established by the grid that contain no storm sewer segments will be eliminated from consideration; if fewer than 250 cells in medium municipal sewers are created, and fewer than 500 in large systems are created by the overlay on the municipal sewer map, then all those cells that contain a segment of the sewer system shall be subject to field screening (unless access to the separate storm sewer system is impossible); and
(g) Large or medium municipal separate storm sewer systems that are unable to utilize the procedures described in subdivisions 1 d (4) (a) through (f) of this subsection because a sufficiently detailed map of the separate storm sewer systems is unavailable shall field screen no more than 500 or 250 major outfalls respectively (or all major outfalls in the system, if fewer); in such circumstances, the permit applicant shall establish a grid system consisting of north-south and east-west lines spaced 1/4 mile apart as an overlay to the boundaries of the municipal storm sewer system, thereby creating a series of cells; the permit applicant will then select major outfalls in as many cells as possible until at least 500 major outfalls (large municipalities) or 250 major outfalls (medium municipalities) are selected; a field screening analysis shall be undertaken at these major outfalls.
(5) Information and a proposed program to meet the requirements of subdivision 2 c of this subsection. Such description shall include: the location of outfalls or field screening points appropriate for representative data collection under subdivision 2 c (1) of this subsection, a description of why the outfall or field screening point is representative, the seasons during which sampling is intended, and a description of the sampling equipment. The proposed location of outfalls or field screening points for such sampling should reflect water quality concerns (see subdivision 1 d (3) of this subsection) to the extent practicable;