Wyoming Administrative Code
Agency 020 - Environmental Quality, Dept. of
Sub-Agency 0011 - Water Quality
Chapter 2 - DISCHARGES, PERMIT REGS
Section 2-6 - Storm Water Discharges

Universal Citation: WY Code of Rules 2-6

Current through September 21, 2024

The following process shall be used in the application for development of and issuance of storm water discharge permits and for identifying storm water discharges covered by this rule.

(a) Deadlines to apply.

(i) Except as provided in Section 6(b), for any storm water discharge associated with large construction activity as described in Section 6(f) (i) or industrial activity as identified in Section 6(g) in place prior to the effective date of this rule, should have made application to the administrator by October 1, 1992; prior to initiation of the activity or in accordance with Section 4(o) (i) (B) of these regulations.

(ii) For any storm water discharge associated with large or small construction activities or industrial activities from a facility that is owned or operated by a municipality with a population of less than 100,000 that is not authorized by a general or individual permit, other than an airport, power plant, or sanitary landfill, a permit application must be submitted to the administrator by March 10, 2003.

(iii) Storm water discharges associated with small construction activity as described in Section 6(f) (ii), that are not already authorized by a storm water general or individual permit, require permit authorization as of March 10, 2003, except;
(A) Storm water discharges subject to Section 4(b) (v) which are not required to submit a NOI for coverage in accordance with the provisions of the applicable general permit, and

(B) Storm water discharges associated with small construction activity at oil and gas exploration, production, processing, and treatment operations or transmission facilities subject to the provisions of, Section 6(a) (iv) of these regulations.

(iv) Storm water discharges associated with small construction activity at oil and gas exploration, production, processing, and treatment operations or transmission facilities, require permit authorization as of March 10, 2005.

(v) For any storm water discharge associated with regulated small MS4 as described in Section 6(h) (i) and that is not authorized by a storm water general or individual permit, a permit application made pursuant to Section 6(b) (iv) must be submitted to the administrator by March 10, 2003 or within 180 days of notice, unless the administrator grants a later date, if designated under Section 6(h) (i) (C) or (D).

(vi) A permit application shall be submitted to the administrator within 60 days of notice of a storm water discharge which the administrator determines contributes to a violation of a water quality standard or is a significant contributor of pollutants to surface waters of the state or where the administrator determines that storm water controls are needed for the discharge based on wasteload allocations that are part of TMDLs that address the pollutant(s) of concern; unless permission for a later date is granted by the administrator.

(b) Individual permit application. A complete application for an individual permit must contain, at a minimum, the following information, unless the administrator determines that certain items are unnecessary in accordance with Section 6(c):

(i) General requirements of all applications:
(A) Name of the company, entity, or individual seeking a permit;

(B) Mailing address and telephone number of company, entity, or individual seeking permit;

(C) The facility name, location, and telephone number if applicable;

(D) Applicant status as federal, state, private, public, or other entity;

(E) Name and signature in accordance with the requirements of Section 14 of this chapter;

(F) Authorization of a duly authorized representative und er the Signatory Requirements of Section 14 of these rules, where applicable;

(G) Location, expressed in latitude and longitude to the nearest 15 seconds, of the facility to be covered under the permit;

(H) Location, expressed as quarter/quarter, section, township, and range, in the applicable Public Land Survey (PLS), of the facility to be covered under the permit;

(I) A description of the activities conducted by the applicant which require it to obtain an WYPDES permit;

(ii) Individual permit application requirements for industria l activities. Individual permit application requirements for industrial activities (not including large or small construction activities as described in Section 6(f). Except as provided in Section 6(b) (iii) and in Section 6(g) (iv) (M) and (N), the operator of a storm water discharge associated with industrial activity subject to this section shall provide, at a minimum:
(A) Up to four (4) SIC codes which best reflect the principal products or services provided by the facility;

(B) A site map showing topography (or indic ating the outline of drainage areas served by the outfall(s) covered in the application if a topographic map is unavailable) of the facility including: each of its drainage and dis charge structures; the drainage area of each storm water outfall; paved areas and buildings within the drainage area of each storm water outfall; each past or present area used for outdoor storage or disposal of significant materials; each existing structural control measure to reduce pollutants in storm water runoff; materials loading and access areas; areas where pesticides, herbicides, soil conditioners and fertilizers are applied; each of its hazardous waste treatment, storage or disposal facilities (including each area not required to have a RCRA permit which is used for accumulating hazardous waste under 40 CFR 262.34); each well where fluids from the facility are injected underground; springs, and other surface water bodies which receive storm water discharges from the facility;

(C) An estimate of the area of impervious surfaces (including paved areas and building roofs), the total area drained by each outfall and a narrative description of the following: significant materials that in the three (3) ye ars prior to the submittal of this application have been treated, stored or disposed in a manner to allow exposure to storm water; method of treatment, storage or disposal of such materials; materials management practices employed, in the three (3) years prior to the submittal of this application to minimize contact by these materials with storm water runoff; materials loading and access areas; the location, manner and frequency in which pesticides, herbicides, soil conditioners and fertilizers are applied; the location and a description of existing structural and non-structural control measures to reduce pollutants in storm water runoff; and, a description of the treatment the storm water receives, including the ultimate disposal of any solid or fluid wastes other than by discharge;

(D) A certification that all outfalls that should contain storm water discharges associated with industrial activity have been tested or evaluated for the presence of non-storm water discharges which are not covered by a permit. Tests for such non-storm water discharges may include smoke tests, fluorometric dye tests, analysis of accurate schematics, as well as other appropriate tests. The certification shall include a description of the method used, the date of any testing, and the on-site drainage points that were directly observed during a test;

(E) Existing information regarding significant leaks or spills of toxic or hazardous pollutants at the facility that have taken place within the three (3) years prior to the submittal of this application;

(F) Quantitative data based on samples collected during storm events and collected in accordance with Section 6(b) (ii) (G) from all outfalls containing storm water discharge associated with industrial activity for the following parameters, except when waived by the administrator under the provisions of Section 6(c) of these regulations.
(I) Any pollutant limited in an effluent guideline to which the facility is subject;

(II) Any pollutant listed in the facility's WYPDES permit for its process wastewater (if the facility is operating under an existing WYPDES permit);

(III) Oil and grease, pH, BOD5, COD, TSS, total phosphorus, total Kjeldahl nitrogen, and nitrate plus nitrite nitrogen;

(IV) Information on the discharge required under Appendix B (a) (vi) of these regulations;

(V) Flow measurements or estimates of the flow rate, the total amount of discharge for the storm event(s) sampled, and the method of flow measurement or estimation; and

(VI) The date and duration (in hours) of the storm event(s) sampled, rainfall measurements or estimates of the storm event (in inches) which generated the sampled runoff and the duration between the storm event sampled and the end of the previous measurable (greater than 0.1 inch rainfall) storm event (in hours).

(G) Sampling storm water discharges.
(I) All samples shall be collected from the discharge resulting from a storm event that is greater than 0.1 inch and at least 72 hours from the previously measurable (greater than 0.1 inch rainfall) storm event. Where feasible, the variance in the duration of the event and the total rainfall of the event should not exceed 50 percent from the average or median rainfall event in that area.

(II) For all applicants, a flow-weighted composite shall be taken for either the entire discharge or for the first three hours of the discharge. The flow-weighted composite sample for a storm water discharge may be taken with a continuous sampler or as a combination of a minimum of three sample aliquots taken in each hour of discharge for the entire discharge or for the first three (3) hours of the discharge, with each aliquot being separated by a minimum period of 15 minutes.

(III) A minimum of one grab sample may be taken for storm water discharges from holding ponds or other impoundments with a retention period greater than 24-hours.

(IV) For a flow-weighted composite sample, only one analysis of the composite of aliquots is required.

(V) For storm water discharge samples taken from discharges associated with industrial activities, quantitative data must be reported for the grab sample taken during the first thirty minut es (or as soon thereafter as practicable) of the discharge for all pollutants specified in Section 6(b) (ii) (F).

(VI) The director may allow or establish appropriate site-specific sampling procedures or requirements, including sampling locations, the season in which the sampling takes place, the minimum duration between the previous measurable storm event and the storm event sampled, the minimum or maximum level of precipitation required for an appropriate storm event, the form of precipitation sampled (snow melt or rain fall), protocols for collecting samples under 40 CFR 13 6 of federal regulations, and additional time for submitting data on a case-by-case basis.

(VII) An applicant is expected to "know or have reason to believe" that a pollutant is present in an effluent based on an evaluation of the expected use, production, or storage of the pollutant, or on any previous analyses for the pollutant. (For example, any pesticide manufactured by a facility may be expected to be present in contaminated storm water runoff from the facility.)

(H) Operators of new sources or new discharges (as defined in Section 3) which are composed entirely of storm water must include estimates for the pollutants or parameters listed in Section 6(b) (ii) (F) instead of actual sampling data, along with the source of each estimate. Operators of new sources or new discharges composed in part or entirely of storm water must provide quantitative data for the parameters listed in paragraph Section 6(b) (ii) (F) of this section within two (2) years after commencement of discharge, unless such data has already been reported under the monitoring requirements of the WYPDES permit for the discharge.

(iii) Individual permit application requirements for large and small construction activities. When required to obtain coverage under an individual WYPDES storm water permit, the operator of an existing or new storm water discharge that is associated with large construction activity under Section 6(f) (i) or small construction activity under Section 6(f) (ii) shall, at a minimum, provide a narrative description of:
(A) The location (including a map) and the nature of the construction activity;

(B) The total area of the site and the area of the site that is expected to undergo excavation during the life of the permit;

(C) Proposed measures, including best management practices, to control pollutants in storm water discharges during construction, and a brief description of applicable state and local erosion and sediment control requirements;

(D) Proposed measures to control pollutants in storm water discharges that will occur after construction operations have been completed, including a brief description of applicable state or local erosion and sediment control requirements;

(E) The increase in impervious area after the construction addressed in the permit application is completed, the nature of fill material and existing data describing the soil or the quality of the discharge; and

(F) The name of the receiving water.

(iv) Individual permit application requirements for regulated small MS4s.
(A) The application requirements of Section 4(o) (iii); and

(B) The operator of an existing or new storm water discharge from a regulated small MS4 under Section 6(h) shall, at a minimum, provide a narrative description of:
(I) A general description of the best ma nagement practices (BMPs) that the permittee or another municipality will implement for each of the storm water minimum control measures at Section 6(j) (i);

(II) The measurable goals for each of the selected BMPs including, as appropriate, the months and years in which the permittee will undertake required actions, including interim milestones and the frequency of the action;

(III) The person or persons responsible for implementing or coordinating the permittee's storm water management program. A position, rather than an individual, may also be designated; and

(IV) A description of the funding sources expected for implementation of the permittee's program.

(v) Additional information requirements. Applicants shall provide such other information the administrator may reasonably require to determine whether to issue a permit and the administrator may require any facility subject to Section 6(b) (iii) to comply with Section 6(b) (ii). The additional information may include additional quantitative data and bioassays to assess the relative toxicity of discharges to aquatic life and requirements to determine the cause of the toxicity.

(c) Waiver of application requirements. The administrator may waive any part of the application requirements contained in Section 6(b) (ii) (F) and (H) when the applicant makes a conclusive demonstration to the administrator that certain parameters listed in Section 6(b) (ii) (F) are not reasonably likely to be present in storm water discharges associated with the industrial activity.

(d) Reporting requirements.

(i) Requirements to report monitoring results for storm water discharges associated with industrial activity or large or small construction activity which are subject to an effluent guideline shall be established on a case-by-case basis with a frequency dependent on the nature and effect of the discharge, but in no case less than one (1) a year.

(ii) Requirements to report monitoring results for storm water discharges associated with industrial activity or large or small construction activity (other than those required in Section 6(d) (i)) shall be established on a case-by-case basis with a frequency dependent on the nature and effect of the discharge. At a minimum, a permit for such a discharge must require:
(A) The discharger to conduct an annual inspection of the facility site to identify areas contributing to a storm water discharge associated with industrial activity or large or small construction activity and evaluate whether measures to reduce pollutant loadings identified in a storm water pollution prevention plan are adequate and properly implemented in accordance with the terms of the permit or whether additional control measures are needed;

(B) The discharger to maintain for a period of three years a record summarizing the results of the inspection, a certification that the facility is in compliance with the plan and the permit, and identification of any incidents of non-compliance;

(C) Such report and certification be signed in accordance with Section 14; and

(D) Permits for storm water discharges associated with industrial activity from inactive mining operations may, where annual inspections are impracticable, require certification once every three years, that the facility is in compliance with the permit, or alternative requirements.

(iii) Permits which do not require the submittal of monitoring result reports at least annually shall require that the permittee report all instances of non- compliance with the terms and conditions of the permit under which the storm water discharges are covered at least annually.

(e) General permit application requirements. See Section 4 for general permit application requirements for storm water discharges.

(f) Regulated construction activities. The following discharges, composed entirely of storm water and associated with construction activities, are point sources requiring an WYPDES permit.

(i) Storm water discharge associated with large construction activity means the discharge of storm water from construction activities, including clearing, grading, and excavating, that result in land disturbance of five (5) or more acres of total land area. Large construction activity also includes the disturbance of less than five (5) acres of total land area that is a part of a larger common plan of development or sale if the larger common plan will ultimately disturb five (5) acres or more.

(ii) A storm water discharge associated with small construction activity.
(A) Storm water discharge associated with small construction activity means the discharge of storm water from construction activities, including clearing, grading, and excavating, that result in land disturbance of equal to or greater than one (1) acre and less than five (5) acres. Small construction activity also includes the disturbance of less than one (1) acre of total land area that is part of a larger common plan of development or sale, if the larger common plan will ultima tely disturb equal to or greater than one and less than five (5) acres. Small construction activity does not include routine maintenance that is performed to maintain the original line and grade, hydraulic capacity, or original purpose of the facility.

(B) The administrator, at his discretion, may waive the otherwise applicable requirements in a general permit, as described in Section 4, for a storm water discharge from a small construction activity that disturbs less than five (5) acres where the value of the rainfall erosivity factor ('R' in the Revised Universal Soil Loss Equation) is less than five (5) during the period of construction activity. The rainfall erosivity factor must be determined in accordance with Chapter 2 of the Agriculture Handbook Number 703, Predicting Soil Erosion by Water: A Guide to Conservation Planning With the Revised Universal Soil Loss Equation (RUSLE), pages 21-64, dated January 1997 or a similar state-approved method. The operator or owner must certify to the administrator that the construction activity will only take place during a period when the value of the rainfall erosivity factor is less than five (5). If unforeseeable conditions occur that are outside of the control of the applicant for a waiver, and that will extend the construction activity beyond the dates initially applied for, the owner or operator must reapply for the waiver or obtain coverage under a general permit for storm water discharges. The waiver re-application or permit application must be submitted within two (2) business days after the unforeseeable condition becomes known. This waiver does not relieve the operator or owner from complying with requirements of local agencies.

(iii) Any construction activity designated by the administrator, based on the potential for contribution to a violation of a water quality standard or for significant contribution of pollutants to surface waters of the state or where the administrator determines that storm water controls are needed for the discharge based on wasteload allocations that are part of TMDLs that address the pollutants of concern.

(iv) A storm water discharge associated with small or large construction activities that are owned or operated by a municipality with a population of less than 100,000 (based on the 1990 census).

(v) For storm water discharges associated with large and/or small construction activities from point sources which discharge through a non-municipal or non-publicly owned separate storm sewer system, the director, at his discretion, may issue: a single WYPDES permit, with each discharger a co-permittee to a permit issued to the operator of the portion of the system that discharges into surface waters of the state; or, individual permits to each discharger of storm water associated with large and/or small construction activity through the non-municipal conveyance system.
(A) Each facility with a storm water discharge to a storm water discharge system that is not an MS4 shall be covered by a WYPDES permit, or a permit issued to the operator of the portion of the system that discharges to surface waters of the state, with each discharger to the non-municipal conveyance a co-permittee to that permit.

(B) Where there is more than one (1) operator of a single system of such conveyances, all operators of storm water discharges associated with industrial activity must submit applications.

(C) Any permit covering more than one (1) operator shall identify the effluent limitations, or other permit conditions, if any, that apply to each operator.

(g) Regulated industrial activities. Discharges composed entirely of storm water and associated with industrial activities are point sources requiring a WYPDES permit.

(i) "Storm water discharge associated with industrial activity" means the discharge from any conveyance which is used for collecting and conveying storm water and which is directly related to manufacturing, processing, or raw materials storage areas at an industrial plant. The term does not include discharges from facilities or activities excluded from the WYPDES program under these regulations.
(A) For the categories of industries identified in Section 6(g) (ii) (A) through (I), the term "storm water discharge associated with industrial activity" includes, but is not limited to, storm water dis charges from industrial plant yards; immediate access roads and rail lines used or traveled by carriers of raw materials, manufactured products, waste material, or by-products used or created by the facility; material handling sites; refuse sites; sites used for the application or disposal of process waste waters; sites used for the storage and maintenance of material handling equipment; sites used for residual treatment, storage, or disposal; shipping and receiving areas; manufacturing buildings; storage areas (including tank farms) for raw materials, and intermediate and final products; and areas where industrial activity has taken place in the past and significant materials remain and are exposed to storm water. For the purposes of Section 6(g), material handling activities include the storage, loading and unloading, transportation, or conveyance of any raw material, intermediate product, final product or waste product.

(B) The term excludes areas located on a plant site separate from the plant's industrial activities, such as office buildings and accompanying parking lots, as long as the drainage from the excluded areas is not mixed with storm water drained from the industrial areas described above.

(ii) The following categories of facilities are considered to be engaging in "industrial activity" for purposes of these regulations. (See Appendix A of these regulations for a brief description of the SIC codes identified in this section.)
(A) Facilities subject to federal storm water effluent limitations guidelines, new source performance standards, or toxic pollutant efflue nt standards under 40 CFR Subchapter N (except facilities with toxic pollutant effluent standards which are excluded under the "no exposure" provisions of Section 6(g) (iii));

(B) Facilities classified as Standard Industrial Classifications (SICs) 20 through 39 and 4221-25;

(C) Facilities classified as Standard Industrial Classifications 10 and 12 through 14 including active or inactive mining operations and oil and gas exploration, production, processing, or treatment operations, or transmission facilities that discharge storm water that has come into contact with any overburden, raw material, intermediate products, finished products, byproducts or waste products located on the site of such operations; (inactive mining operations are mining sites that are not being actively mined, but which have an identifiable owner/operator. Inactive mining sites do not include sites where mining claims are being maintained prior to disturbances associated with the extraction, beneficiation, or processing of mined materials, nor sites where minimal activities are undertaken for the sole purpose of maintaining a mining claim);

Areas of coal mining operations no longer meeting the definition of a reclamation area under 40 CFR 434.11(1) because the performance bond issued to the facility by the appropriate SMCRA (Surface Mining Control and Reclamation Act, 1977) authority has been released, or areas of non-coal mining operations which have been released from applicable state or federal reclamation requirements after December 17, 1990 are not considered to be engaged in "industrial activity" and do not require coverage under a WYPDES storm water permit;

(D) Hazardous waste treatment, storage, or disposal facilities, including those that are operating under interim status or a permit under Wyoming Hazardous Waste Rules and Regulations;

(E) Landfills, land application sites, and open dumps that receive or have received any industrial wastes (waste that is received from activities associated with large or small construction activity as described in Sections 6(f) (i) and 6(f) (ii) and industrial activities as described in Section 6(g) (ii)) including those that are subject to regulation under subtitle D of RCRA;

(F) Facilities involved in the recycling of materials, including metal scrap yards, battery reclaimers, salvage yards, and automobile junkyards, including but limited to those classified as Standard Industrial Classification 5015 and 5093;

(G) Steam electric power generating facilities, including coal handling sites;

(H) Transportation facilities classified as Standard Industrial Classifications 40, 41, 42 (except 4221-25), 43, 44, 45, and 5171 which have vehicle maintenance shops, equipment cleaning operations, or airport deicing operations. Only those portions of the facility that are either involved in vehicle maintenance (including vehicle rehabilitation, mechanical repairs, painting, fueling, and lubrication), equipment cleaning operations, airport deicing operations, or which are otherwise identified under Section 6(g) (ii) (A through G or I) are associated with industrial activity;

(I) Treatment works treating domestic sewage or any other sewage sludge or wastewater treatment device or system, used in the storage treatment, recycling, and reclamation of municipal or domestic sewage, including land dedicated to the disposal of sewage sludge that are located within the confines of the facility, with a design flow of 1.0 mgd or more, or required to have an approved pretreatment program under 40 CFR 403. Not included are farm lands, domestic gardens or lands used for sludge management where sludge is beneficially reused and which are not physically located in the confines of the facility, or areas that are in compliance with section 405 of the CWA;

(J) A storm water discharge associated with industrial activity from a facility that is owned or operated by a municipality with a population of less than 100,000 (based on the 1990 census);

(K) For storm water discharges associated with industrial activity from point sources which discharge through a non-municipal or non-publicly owned separate storm sewer system, the director, at his discretion, may issue: a single WYPDES permit, with each discharger a co-permittee to a permit issued to the operator of the portion of the system that discharges into surface waters of the state; or, individual permits to each discharger of storm water associated with industrial activity through the non-municipal conveyance system.
(I) Each facility with a storm water discharge to a storm water discharge system that is not an MS4 shall be covered by a WYPDES permit, or a permit issued to the operator of the portion of the system that discharges to surface waters of the state, with each discharger to the non-municipal conveyance a co-permittee to that permit.

(II) Where there is more than one (1) operator of a single system of such conveyances, all operators of storm water discharges associated with industrial activity must submit applications.

(III) Any permit covering more than one (1) operator shall identify the effluent limitations, or other permit conditions, if any, that apply to each operator;

(L) A WYPDES permit is not required for discharges of storm water runoff from mining operations or oil and gas exploration, production, processing or treatment operations or transmission facilities, composed entirely of flows which are from conveyances or systems of conveyances (including but not limited to pipes, conduits, ditches, and channels) used for collecting and conveying precipitation runoff and which are not contaminated by contact with or that has not come into contact with, any overburden, raw material, intermediate products, finished product, byproduct or waste products located on the site of such operations. This paragraph applies only to the operation of these facilities. Construction of such facilities may require a permit to discharge storm water as specified in Sections 6(f) (i) and (ii);

(M) The operator of an existing or new discharge composed entirely of storm water from an oil or gas exploration, production, processing, or treatment operation, or transmission facility is not required to submit a notice of intent in accordance with Section 4 or a permit application in accordance with Section 6(b), unless the facility:
(I) Has had a discharge of storm water resulting in the discharge of a reportable quantity for which notification is or was required pursuant to 40 CFR 117.21 or 40 CFR 302.6 at anytime since November 16, 1987; or

(II) Has had a discharge of storm water resulting in the discharge of a reportable quantity for which notification is or was required pursuant to 40 CFR 110.6 at any time since November 16, 1987; or

(III) Contributes to a violation of a water quality standard; or

(IV) Has been determined by the administrator that storm water controls are needed for the discharge based on wasteload allocations that are part of TMDLs that address the pollutants of concern.

(V) The construction of such facilities may still qualify for permit coverage under Section 6(f).

(N) The operator of an existing or new discharge composed entirely of storm water from a mining operation is not required to submit a permit application unless the discharge has come into contact with any overburden, raw material, intermediate products, finished product, byproduct or waste products located on the site of such operations; and

(O) Facilities that have been determined, by the administrator, to have the potential to contribute to a violation of a water quality standard or contribute pollutants to surface waters of the state that are part of a TMDL that address the pollutant(s) of concern.

(iii) Discharges composed entirely of storm water are conditionally excluded from storm water permitting by way of not meeting the definition of "storm water discharges associated with industrial activity" if there is "no exposure" of industrial materials and/or activities to precipitation, snowmelt and/or runoff, and the discharger satisfies the conditions in Section 6(g) (iii) (A through D). "No exposure" means that all industrial materials and activities are protected by a storm resistant shelter to prevent exposure to precipitation, snowmelt, and/ or runoff. Industrial materials or activities include, but are not limited to, material handling equipment or activities, industrial machinery, raw materials, intermediate products, by-products, final products, or waste products. Material handling activities include the storage, loading and unloading, transportation, or conveyance of any raw material, intermediate product, final product or waste product.
(A) To qualify for this exclusion, the operator must:
(I) Provide a storm resistant shelter to protect industrial materials and activities from exposure to precipitation, snow melt, and runoff;

(II) Complete and sign, in accordance with Section 14 of these regulations, a certification that there are no discharges of storm water contaminated by exposure to industrial materials and activities fr om the entire facility, except as provided in Section 6(g) (iii) (B);

(III) Submit the signed, updated certification to the administrator once every five (5) years;

(IV) Allow the administrator, and/or his authorized representative, upon the presentation of credentials, to inspect the facility to determine compliance with the "no exposure" conditions;

(V) Allow the administrator to make any "no exposure" inspection reports available to the public upon request;

(VI) For facilities that discharge through an MS4, submit a copy of the certification of "no exposure" to the MS4 operator, as well as allow inspection and public reporting by the MS4 operator, upon request; and

(VII) Have adequate protections in place to assure that storm water discharges associated with industrial activity do not occur from secondary containment facilities.

(B) To qualify for this exclusion, a storm resistant shelter is not required for:
(I) Drums, barrels, tanks, and similar containers intended for the outdoor storage of the contained material, that are tightly sealed, provided those containers are not deteriorated and do not leak ("sealed" means banded or otherwise secured and without operational taps or valves), and are not otherwise a source of industrial pollutants;

(II) Adequately maintained vehicles used in material handling, that are not otherwise a source of industrial pollutants; and

(III) Final products, other than products that would be mobilized in storm water discharge (e.g., rock salt).

(C) The exclusion is subject to the following limitations:
(I) Storm water discharges from construction activities identified as small or large in Section 6(f) are not eligible for this conditional exclusion.

(II) This conditional exclusion from the requirement for a state WYPDES permit is available on a facility-wide basis only, not for individual outfalls.

(III) If circumstances change and industrial materials or activities become exposed to precipitation, snow melt, and/or runoff, the conditions for this exclusion no longer apply. In such cases, the discharge becomes subject to enforcement for unpermitted discharge. Any conditionally excluded discharger who anticipates such a change in circumstances must apply for and obtain permit authorization prior to the change of circumstances.

(IV) Notwithstanding the provisions of this paragraph, the administrator retains the authority to require permit authorization (and deny this exclusion) upon making a determination that the discharge causes, has a reasonable potential to cause, or contributes to an instream excursion above an applicable water quality standard, including designated uses.

(D) The "no exposure" certification requires the submission of the following information, at a minimum, to aid the administrator in determining if the facility qualifies for the no exposure exclusion:
(I) The legal name, address and phone number of the discharger;

(II) The facility name and address, the county name and the location description using the public land survey system quarter/quarter, section, township, and range where the facility is located;

(III) The certification must indicate that none of the following materials or activities are, or will be in the foreseeable future, exposed to precipitation, snow melt, and/or runoff:
(1.) Using, storing or cleaning industrial machinery or equipment, and areas where residuals from using, storing or cleaning industrial machinery or equipment remain and are exposed to storm water;

(2.) Materials or residuals on the ground or in storm water inlets from spills/leaks;

(3.) Materials or products from past industrial activity;

(4.) Material handling equipment (except adequately maintained vehicles);

(5.) Materials or products during loading/unloading or transporting activities;

(6.) Materials or products stored outdoors (except final products intended for outside use, e.g., new cars, where exposure to storm water does not result in the discharge of pollutants);

(7.) Materials contained in open, deteriorated or leaking storage drums, barrels, tanks, and similar containers;

(8.) Materials or products handled/stored on roads or railways owned or maintained by the discharger;

(9.) Waste material (except waste in covered, non-leaking containers, e.g., dumpsters);

(10.) Application or disposal of process wastewater (unless otherwise permitted); and

(11.) Particulate matter or visible deposits of residuals from roof stacks/vents not otherwise regulated, i.e., under an air quality control permit, and evident in the storm water outflow.

(IV) All "no exposure" certifications must include the following certification statement, and be signed in accordance with the signatory requirements of Section 14 of these regulations:

"I certify under penalty of law that I have read and understand the eligibility requirements for claiming a condition of "no exposure" and obtaining an exclusion from state WYPDES storm water permitting; and that there are no discharges of storm water contaminated by exposure to industrial activities or materials from the industrial facility identified in this document (except as allowed under Wyoming Water Quality Rules and Regulations, Chapter 2 Section 6(g) (iii) (B)) . I understand that I am obligated to submit a no exposure certification form once every five (5) years to the administrator and, if requested, to the operator of the local MS4 into which this facility discharges (where applicable). I understand that I must allow the administrator, or MS4 operator where the discharge is into the local MS4, to perform inspections to confirm the condition of no exposure and to make such inspection reports publicly available upon request. I understand that I must obtain coverage under a state WYPDES permit prior to any point source discharge of storm water from the facility. I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based upon my inquiry of the person or persons who manage the system, or those persons directly involved in gathering the information, the information submitted is to the best of my knowledge and belief true, accurate and complete. I am aware there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations."

(h) Regulated small municipal separate storm sewer systems. Discharges composed entirely of storm water from regulated small municipal separate storm sewer systems (MS4s) are point sources requiring a WYPDES permit.

(i) Regulated small MS4s include:
(A) Systems located in an urbanized area as determined by the latest Decennial Census by the Bureau of the Census. (If the small MS4 is not located entirely within an urbanized area, only the portion that is within the urbanized area is regulated);

(B) Publicly owned systems similar to MS4s in municipalities, such as:
(I) Systems at military bases, and large education, hospital or prison complexes, if they are designed for a maximum daily user population (residents and individuals who come there to work or use the facilities) of at least 1,000, and are located in an urbanized area.

(II) Separate storm sewer systems associated with highways and thoroughfares within the boundary of an urbanized area.

(C) Small MS4s designated by the administrator, where the designation is pursuant to the following:
(I) The administrator shall evaluate, at a minimum, any small MS4 located outside of an urbanized area serving a jurisdiction with a population density of at least 1,000 people per square mile and a population of at least 10,000 (based on the latest Decennial Census by the Bureau of the Census), to determine whether or not storm water discharges from the MS4 result in or have the potential to result in exceedances of water quality standards, including impairment of designated uses, or other significant water quality impacts, including habitat and biological impacts. The evaluation shall use the following elements, at a minimum:
(1.) Relationship to sensitive waters. For purposes of this section, sensitive waters means any class 1, 2AB, 2A or any impaired or threatened waters listed on the most recent 303 (d) list;

(2.) High growth potential. For purposes of this section a growth rate of 10% per decade or more will be considered a high rate of growth, the administrator may also consider other factors such as, but not limited to, sustainability of population increase, future projected growth, initial population size and population density.

(3.) Size of population and population density. Whether the MS4 is an MS4 that is not in an urbanized area and has a population of at least 10,000 and a population density of 1,000 people per square mile;

(4.) Contiguity to an urbanized area; and

(5.) Significant contribution of pollutants, based on credible data, to surface waters of the state.

Based on this evaluation, if the administrator determines that storm water discharges from the MS4 result in or have the potential to result in exceedances of water quality standards, including impairment of designated uses, or other significant water quality impacts, including habitat and biological impacts, the administrator shall designate the MS4 as a regulated small MS4 to be covered under a state WYPDES storm water discharge permit. However, the MS4 may provide information to the administrator on its existing storm water quality control programs, including any that are analogous to the six (6) minimum control measures under Section 6(j) (i) (B). If the administrator determines that the MS4 has adequate controls for its storm water discharges, (i.e., is already implementing the applicable portions of the six (6) minimum measures), it will not be designated as a regulated small MS4 at that time.

(II) Other MS4s. The administrator may evaluate any other small MS4s other than those described in subsections (I) and (III) of this section, in order to determine whether or not storm water discharges from a small MS4 result in or have the potential to result in exceedances of water quality standards, including impairment of designated uses, or other significant water quality impacts, including habitat and biological impacts. The administrator will place a high priority on evaluating small MS4s with a combined permanent and seasonal population (as determined by the official Census population plus the number of commercially advertised bed accommodations that will allow for an overnight stay, as listed through the chamber of commerce, or any local resort or property management companies) of over 10,000. Based on this evaluation, the administrator may designate the small MS4 as a regulated small MS4 to be covered under a state WYPDES storm water discharge permit at any time, as appropriate, using the elements shown in Section 6(h) (i) (C) (I) above.

(III) The administrator shall designate any small MS4 that contributes substantially to the pollutant loadings of a physically interconnected municipal separate storm sewer that is designated as a regulated small MS4 to be covered under a state WYPDES storm water discharge permit.

(IV) Small MS4s may be designated by the administrator based upon Section 6(h) (ii) (C).

(V) For any small MS4 that has been evaluated as per subsections (I) or (II) above, the administrator reserves the right to re-evaluate the MS4 if circumstances change or new information becomes available.

(D) A storm water discharge that the administrator determines contributes to a violation of a water quality standard or is a significant contributor of pollutants to surface waters of the state. This designation may include a discharge from any conveyance or system of conveyances used for collecting and conveying storm water runoff or a system of discharges from municipal separate storm sewers, except for those discharges from conveyances which do not require a permit under Section 6(g) (iii) (L) or irrigation return flow whic h is exempted from the definition of point source in this regulation.

The administrator may designate discharges from a MS4 on a system-wide or jurisdiction-wide basis. In making this determination the administrator may consider the following factors:

(I) The location of the discharge with respect to surface waters of the state;

(II) The size of the discharge;

(III) The quantity and nature of the pollutants discharged to surface waters of the state; and

(IV) Other relevant factors.

(E) The administrator may designate discharges from municipal separate storm sewers where the administrator determines that storm water controls are needed for the discharge based on wasteload allocations that are part of TMDLs that address the pollutants of concern.

(F) The administrator may issue permits for municipal separate storm sewer systems designated in Section 6(h) (i) (C) (D) or (E) on a system-wide basis, jurisdiction-wide basis, watershed basis or other appropriate basis, or may issue permits for individual discharges.

(ii) The administrator may waive permit coverage for a small MS4 with a population under 1,000 within the urbanized area where both of the following criteria have been met:
(A) Its discharges are not known to be contributing substantially to the pollutant loadings of a physically interconnected regulated MS4 (see Section 6(h) (i) (C) (III)); and

(B) The small MS4 does not discharge any pollutant(s) that have been identified as a cause of impairment of any water body to which it discharges and storm water controls are not needed based on wasteload allocations that are part of a local watershed plan or an EPA approved TMDL that addresses the pollutant(s) of concern.

(C) A small MS4 waived under this section may be designated if circumstances change or new information becomes available.

(iii) Whether or not a discharge from a municipal separate storm sewer is subject to regulation under this Section 6(h) shall have no bearing on whether the owner or operator of the discharge is eligible for funding under Title II, Title III or Title VI of the CWA.

(i) Petitions.

(i) Any operator of a municipal separate storm sewer system may petition the director to require a separate WYPDES permit for any discharge into the municipal separate storm sewer system.

(ii) Any person may petition the director to require a WYPDES permit, where one does not already exist, for a discharge which is composed entirely of storm water which contributes to a violation of a water quality standard or is a significant contributor of pollutants to surface waters of the state.

(iii) Any person may petition the director for the designation of a small MS4 as defined in these regulations.

(iv) The owner or operator of a municipal separate storm sewer system may petition the director to reduce the Census estimates of the population served by such separate system to account for storm water discharged to combined sewers as defined by 40 CFR 35.2005(b) (11) that is treated in a publicly owned treatment works. In municipalities in which combined sewers are operated, the Census estimates of population may be reduced proportional to the fraction, based on estimated lengths, of the length of combined sewers over the sum of the length of combined sewers and municipal separate storm sewers where an applicant has submitted the WYPDES permit number associated with each discharge point and a map indicating areas served by combined sewers and the location of any combined sewer overflow discharge point.

(v) The director shall make a final determination on any petition received under this section within 90 days after receiving the petition with the exception of petitions to designate a small MS4, in which case the director shall make a final determination on the petition within 180 days after receipt of the petition.

(j) Conditions for municipal storm water permits.

(i) An individual permit issued under Section 6 or general permit authorization issued under Section 4 to a regulated small MS4 shall contain the following requirements, at a minimum:
(A) The MS4 permit will require that the regulated small MS4 develop, implement, and enforce a storm water management program designed to reduce the discharge of pollutants from the MS4 to the maximum extent practicable, to protect water quality, and to satisfy the appropriate water quality requirements of the Wyoming Environmental Quality Act (W.S. 35-11-301 to 35-11-311) . The storm water management program must include the minimum control measures described in Section 6(j) (i) (B). Implementation of BMPs consistent with the provisions of the storm water discharge permit required pursuant to this section constitutes compliance with the standard of reducing pollutants to the maximum extent practicable.

The initial permit for the regulated small MS4 will specify a time period of up to five (5) years from the date of permit issuance for development and implementation of the program.

(B) Minimum control measures.
(I) Public education and outreach on storm water impacts. The permittee must implement a public education program to:
(1.) Distribute educational materials to the community or conduct equivalent outreach activities about the impacts of storm water discharges on water bodies and the steps that the public can take to reduce pollutants in storm water runoff; and

(2.) Inform public employees, businesses and the general public of impacts associated with illegal discharges and improper disposal of waste.

(II) Public involvement/participation. The permittee must, at a minimum, comply with any applicable state and local public notice requirements when implementing the storm water management programs required under the permit. Notice of all public hearings should be published in a community publication or newspaper of general circulation to provide opportunities for public involvement that reach a majority of citizens through the notification process.

(III) Illicit discharge detection and elimination. The permittee must develop, implement and enforce a program to detect and eliminate illicit discharges (as defined in Section 3) into the permittee's small MS4.
(1.) The permittee must:
a. Develop, if not already completed, a storm sewer system map, showing the location of all municipal storm sewer outfalls and the names and location of all surface waters of the state that receive discharges from those outfalls;

b. To the extent allowable under state or local law, effectively prohibit, through ordinance or other regulatory mechanism, non-storm water discharges into the storm sewer system, and implement appropriate enforcement procedures and actions; and

c. Develop and implement a plan to detect and address non-storm water discharges, including illicit discharges and illegal dumping, to the system.

The plan must include the following three components: procedures for locating priority areas likely to have illicit discharges; procedures for tracing the source of an illicit discharge; and procedures for removing the source of the discharge.

(2.) The permittee shall address the following categories of non-storm water discharges or flows (i.e., illicit discharges) only if the permittee identifies them as significant contributors of pollutants to the permittee's small MS4 discharges: landscape irrigation, lawn watering, diverted stream flows, irrigatio n return flow, rising groundwaters, groundwater infiltration (as defined at 40 CFR 35.2005(20)) , pumped groundwater, springs, flows from riparian habitats and wetlands, water line flushing, discharges from potable water sources, foundation drains, air conditioning condensation, water from crawl space pumps, footing drains, individual residential car washing, dechlorinated swimming pool discharges, and street wash water (discharges or flows from fire fighting activities are excluded from the effective prohibition against non-storm water and need only be addressed where they are identified as significant sources of pollutants to surface waters of the state).

(IV) Construction site storm water runoff control.
(1.) The permittee must develop, implement, and enforce a program to reduce pollutants in any storm water runoff to the MS4 from construction activities that result in a land disturbance of greater than or equal to one acre. Reduction of pollutants in storm water discharges from construction activity disturbing less than one acre must be included in the program if that construction activity is part of a larger common plan of development or sale that would disturb one acre or more. If the administrator waives requirements for storm water discharges associated with a small construction activity in accordance with Section 6(f) (ii) (B), the permittee is not required to develop, implement, and/or enforce its program to reduce pollutant discharges from such a site.

(2.) The program must be developed and implemented to assure adequate design, implementation, and maintenance of BMPs at construction sites within the MS4 to reduce pollutant discharges and protect water quality. The program must include the development and implementation of, at a minimum:
a. An ordinance or other regulatory mechanism to require erosion and sediment controls, as well as sanctions to ensure compliance, to the extent allowable under state or local law;

b. Requirements for construction site operators to implement appropriate erosion and sediment control BMPs;

c. Requirements for construction site operators to control waste such as discarded building materials, concrete truck washout, chemicals, litter, and sanitary waste at the construction site that may cause adverse impacts to water quality;

d. Procedures for site plan review which incorporate consideration of potential water quality impacts;

e. Procedures for receipt and consideration of information submitted by the public, and

f. Procedures for site inspection and enforcement of control measures.

(V) Post-construction storm water management in new development and redevelopment.
(1.) The permittee must develop, implement, and enforce a program to address storm water runoff from new development and redevelopment projects that disturb greater than or equal to one acre, including projects less than one acre that are part of a larger common plan of development or sale, that discharge into the small MS4. The program must ensure that controls are in place that would prevent or minimize water quality impacts.

(2.) The permittee must:
a. Develop and implement strategies which include a combination of structural and/or non-structural BMPs appropriate for the community;

b. Use an ordinance or other regulatory mechanism to address post-construction runoff from new development and redevelopment projects to the extent allowable under state or local law; and

c. Ensure adequate long- term operation and maintenance of BMPs.

(VI) Pollution prevention/good housekeeping for municipal operations. The permittee must develop and implement an operation and maintenance program that includes an employee training component and has the ultimate goal of preventing or reducing pollutant runoff from municipal operations. The program must also inform public employees of impacts associated with illegal discharges and improper disposal of waste from municipal operations. The program must prevent and/or reduce storm water pollution from facilities such as streets, roads, highways, municipal parking lots, maintenance and storage yards, fleet or maintenance shops with outdoor storage areas, salt/sand storage locations and snow disposal areas operated by the permittee, waste transfer stations, and from activities such as park and open space maintenance, fleet and building maintenance, street maintenance, ne w construction of municipal facilities, and storm water system maintenance, as applicable.

(C) If an existing qualifying local program requires the permittee to implement one or more of the minimum control measures of Section 6(j) (i) (B), the administrator may include conditions in the permit that direct the permittee to follow that qualifying program's requirements rather than the requirements of Section 6(j) (i) (B). A qualifying local program is a local or state municipal storm water management program that imposes, at a minimum, the relevant requirements of Section 6(j) (i) (B). The permit may be reopened and modified to include the requirement to implement a minimum control measure if the other entity fails to implement it.

(D) The permittee must comply with any more stringent effluent limitations in the permit, including permit requirements that modify, or are in addition to, the minimum control measures, based on an approved TMDL or equivalent analysis. The administrator may include more stringent limitations based on a TMDL or equivalent analysis that determines such limitations are needed to protect water quality.

(E) The permittee must comply with other applicable state WYPDES permit requirements, standards and conditions established in the individual or general permit, developed consistent with the provisions of Section 6(b) or Section 4, as appropriate.

(F) A permittee may rely on another entity to satisfy its state WYPDES permit obligations to implement a minimum control measure, or component thereof if:
(I) The other entity, in fact, implements the control measure;

(II) The particular control measure, or component thereof, is at least as stringent as the corresponding WYPDES permit requirement; and

(III) The other entity agrees to implement the control measure on behalf of the permittee. The permittee must specify in reports submitted under Section 6(j) (i) (G) (iii) that it relies on another entity to satisfy some of its permit obligations. If the permittee is relying on another entity, subject to these regulations, to meet all of its permit obligations, including the obligation to file periodic reports, it must note that fact in its NOI. The permittee remains responsible for compliance with its permit obligations if the other entity fails to implement the control measure (or component thereof).

(G) Evaluation and assessment.
(I) Evaluation. The permittee shall evaluate program compliance, the appropriateness of its identified BMPs, and progress towards achieving its identified measurable goals. A summary of this evaluation shall be included in the permittee's annual report.

(II) Record keeping. The permittee must keep records required by the permit for at least three (3) years. The permittee must submit their records to the administrator only when specifically asked to do so. The permittee must make the records, including a description of the permittee's storm water management program, available to the public at reasonable times during regular business hours. (The permittee may assess a reasonable charge for copying. The permittee may require a member of the public to provide advance notice.)

(III) Reporting. The permittee shall submit annual reports to the administrator for the permittee's first permit term. For subsequent permit terms, reports must be submitted in years two (2) and four (4) unless the administrator requires more frequent reporting. The permittee's report must include:
(1.) The status of compliance with permit conditions, an assessment of the appropriateness of the permittee's identified BMPs and progress towards achieving the permittee's identified measurable goals for each of the minimum control measures;

(2.) Results of information collected and analyzed, including monitoring data, if any, during the reporting period;

(3.) A summary of the storm water activities the permittee plans to undertake during the next reporting cycle;

(4.) A change in any identified BMPs or measurable goals for any of the minimum control measures; and

(5.) Notice that the permittee is relying on another governmental entity to satisfy some of the permittee's permit obligations (if applicable).

(H) Any additional requirements as determined to be necessary by the administrator.

(ii) The administrator may determine monitoring requirements for the permittee in accordance with state monitoring plans appropriate to the permittee's watershed.

(k) Qualifying programs. Qualifying state or local programs associated with municipal storm water permits.

(i) For storm water discharges associated with small construction activity identified in Section 6(f) (ii) (A), the administrator may include permit conditions that incorporate qualifying state or local erosion and sediment control program requirements by reference. A qualifying state or local erosion and sediment control program is one that includes:
(A) Requirements for construction site operators to implement appropriate erosion and sediment control best management practices;

(B) Requirements for construction site operators to control waste such as discarded building materials, concrete truck washout, chemicals, litter, and sanitary waste at the construction site that may cause adverse impacts to water quality;

(C) Requirements for construction site operators to develop and implement a storm water pollution prevention plan. (A storm water pollution prevention plan includes site descriptions, descriptions of appropriate control measures, copies of approved local requirements, maintenance procedures, inspection procedures, and identification of non-storm water discharges); and

(D) Requirements to submit a site plan for review that incorporates consideration of potential water quality impacts.

(ii) For storm water discharges from large construction activity identified in Section 6(f) (i), the administrator may include permit conditions that incorporate qualifying state or local erosion and sediment control program requirements by reference. A qualifying state or local erosion and sediment control program is one that includes the elements listed in Section 6(k) (i), and any additional requirements necessary to achieve the applicable technology-based standards of "best available technology" and "best conventional technology" based on the best professional judgment of the permit writer.

Disclaimer: These regulations may not be the most recent version. Wyoming may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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