§ 151.22 STANDARDS FOR STORMWATER POLLUTION PREVENTION PLANS FOR LAND DISTURBANCES.
   (A)   Applicability and exemptions.
      (1)   The Town will require a Stormwater Pollution Prevention Plan (SWPPP), which includes erosion and sediment control measures, pollution prevention practices and materials handling procedures, to be submitted as part of the construction plans and specifications. Any project located within the Town that involves land disturbance (with exception of items § 151.22(A)(2) and (A)(3) below) shall comply with this section. Calculation of land disturbance should follow the guidelines contained in § 151.22(C). Land disturbance falls into one of two categories with differing requirements as follows:
         (a)   Land disturbances which are one (1) or more acres shall obtain a state NPDES general permit for construction activities (currently regulated by 327 IAC 15-5 and commonly referred to as “Rule 5”) and are subject to the requirement of this section. This section also applies to disturbances of less than one (1) acre of land that are part of a larger common plan of development or sale if the larger common plan will ultimately disturb one (1) or more acres of land.
         (b)   Land disturbances which are less than one (1) acre shall submit a SWPPP that at a minimum includes the following:
            1.   Installation and maintenance of appropriate perimeter control measures. These measures are to be installed prior to land disturbance and maintained until bare soils are permanently stabilized to at least seventy percent (70%) density of permanent perennial vegetated cover. Maintain existing vegetation when possible.
            2.   Installation of a temporary construction entrance/drive. Minimize sediment and soil discharge and tracking from the disturbed area. Clean-up sediment that is either tracked or washed on to roads or into storm water conveyances (sewers, ditches, waterways, storm inlets, and the like). Cleaning surfaces shall not include flushing the area with water. Cleared sediment and soil must be collected and redistributed or disposed of in a manner that is in compliance with all applicable statutes and rules.
            3.   Establish a concrete washout area to contain residual concrete and washout waters. Water collected from washout that does not harden or evaporate must be handled as wastewater.
            4.   Bare soils are to be stabilized in areas where work is complete, or where bare soils are to be inactive for more than fifteen (15) days. Utilize soil stabilization measures that are appropriate for the season.
            5.   Adjacent areas disturbed by an individual lot operator must be repaired and stabilized with temporary or permanent surface stabilization.
            6.   Install inlet protection at all stormwater inlets that receive runoff from disturbed areas. For inlets within a road or driving lane, inlet protection must be installed below the grate with an overflow or bypass so that ponding water does not cause unsafe driving conditions.
            7.   Where construction disturbs surfaces greater than 3H:1V slope or in areas of concentrated flow, establish permanent vegetation with erosion control blanket and seeding.
      (2)   The requirements under this chapter do not apply to the following activities:
         (a)   Agricultural land disturbing activities.
         (b)   Forest harvesting activities.
         (c)   Single family residential with disturbance of less than five hundred (500) square feet.
      (3)   The requirements under this section do not apply to the following activities, provided other applicable state permits contain provisions requiring immediate implementation of soil erosion control and pollution prevention measures:
         (a)   Landfills that have been issued a certification of closure under 329 IAC 10.
         (b)   Coal mining activities permitted under I.C. 14-34.
         (c)   Municipal solid waste landfills that are accepting waste pursuant to a permit issued by IDEM under 329 IAC 10 that contains equivalent stormwater requirements, including the expansion of landfill boundaries and construction of new cells either within or outside the original solid waste permit boundary.
      (4)   For an individual lot where land disturbance is expected to be one (1) acre or more, the individual lot owner must complete their own Notice of Intent (NOI) letter, obtain Stormwater Management Plan approval, and ensure that a sufficient construction and stormwater pollution prevention plan is completed in accordance with the requirements of this chapter and other relevant ordinances.
      (5)   An individual lot with land disturbance less than one (1) acre, located within a larger permitted project site, is considered part of the larger permitted project site, and the individual lot operator must comply with the terms and conditions of the Stormwater Management Plan approved for the larger project site. The Stormwater Management Plan for the larger project site must include detailed erosion and sediment control measures for individual lots.
      (6)   It will be the responsibility of the project site owner to obtain Stormwater Management Plan approval and ensure that a sufficient construction plan is completed and submitted to the Town in accordance with the requirements of this section and other relevant ordinances. It will be the responsibility of the project site owner to ensure compliance with this section during the construction activity and implementation of the construction plan, and to notify the Town with a sufficient Notice of Termination (NOT) letter upon completion of the project and stabilization of the site. However, all persons engaging in construction and land disturbing activities must comply with the requirements of this section.
      (7)   For land disturbing projects owned or operated by the Town, construction plans must be submitted to the Stormwater Department and County Soil and Water Conservation District (SWCD) for review and approval. If the Town does not receive either a notice of deficiency or an approval within thirty-five (35) days of the submittal, the plans will be considered adequate.
   (B)   Policy on stormwater pollution prevention. Effective stormwater pollution prevention on construction sites is dependent on a combination of preventing movement of soil from its original position (erosion control), intercepting displaced soil prior to entering a waterbody (sediment control), and proper on-site materials handling and pollution prevention practices. The developer must submit to the Town a SWPPP with detailed erosion and sediment control plans as well as a narrative describing materials handling and storage, and construction sequencing. The following principles apply to all land-disturbing activities and should be considered in the preparation of a stormwater pollution prevention plan within the Town.
      (1)   Minimize the potential for erosion by designing a development that fits the topography and soils of the site. Deep cuts and fills in areas with steep slopes should be avoided whenever possible, and natural contours should be followed as closely as possible.
      (2)   Existing natural vegetation should be retained and protected wherever possible. Areas immediately adjacent (within thirty-five (35) feet of top of bank) to watercourses and lakes also should be left undisturbed wherever possible.
      (3)   Unvegetated or vegetated areas with less than seventy percent (70%) cover that are scheduled or likely to be left inactive for fifteen (15) days or more must be temporarily or permanently stabilized with measures appropriate for the season to reduce erosion potential. Alternative measures to site stabilization may be acceptable if the project site owner or their representative can demonstrate they have implemented and maintained erosion and sediment control measures adequate to prevent sediment discharge from the inactive area. Vegetated areas with a density of less than seventy percent (70%) shall be restabilized using appropriate methods to minimize the erosion potential.
      (4)   All practices on a site should be conducted in a logical sequence so that the smallest practical area of land will be exposed for the shortest practical period of time during land disturbing activities.
      (5)   The length and steepness of designed slopes should be minimized to reduce erosion potential. Drainage channels and swales must be designed and adequately protected so that their final gradients and resultant velocities will not cause erosion in the receiving channel or at the outlet. Guidance for determining acceptable velocities and energy dissipation is provided in HEC-14.
      (6)   Sediment-laden water which otherwise would flow from the project site shall be treated by erosion and sediment control measures appropriate to minimize sedimentation.
      (7)   A stable construction site access shall be provided at all points of construction traffic ingress and egress to the project site.
      (8)   Stormwater runoff leaving a project site must be discharged in a manner that is consistent with applicable state or federal law.
      (9)   Appropriate measures shall be implemented to prevent wastes or unused building materials, including garbage, debris, packaging material, fuels and petroleum products, hazardous materials or wastes, cleaning wastes, wastewater, substances from being carried from a project site by runoff or wind. Identification of areas where concrete truck washout is permissible must be clearly posted at appropriate areas of the site. Wastes and unused building materials shall be managed and disposed of in accordance with all applicable state statutes and regulations. Proper storage and handling of materials such as fuels or hazardous wastes, and spill prevention and cleanup measures shall be implemented to minimize the potential for pollutants to contaminate surface or groundwater or degrade soil quality.
      (10)   Public or private roadways shall be kept cleared of accumulated sediment that is a result of runoff or tracking. Bulk clearing of accumulated sediment shall not include flushing the area with water. Cleared sediment shall be redistributed or disposed of in a manner that is in accordance with all applicable statutes and regulations.
      (11)   Collected runoff leaving a project site must be either discharged directly into a well-defined, stable receiving channel, or diffused and released to the adjacent property without causing an erosion or pollutant problem to the adjacent property owner.
      (12)   Natural features, including wetlands and sinkholes, shall be protected from pollutants associated with stormwater runoff.
      (13)   Required postings.
         (a)   The project site owner shall post a notice near the main entrance of the project site. For linear projects sites, such as a pipeline or highway, the notice must be placed in a publicly accessible location near the project field office. The notice must be maintained in a legible condition and contain the following information:
            1.   Copy of the completed IDEM NOI and the National Pollutant Discharge Elimination System (NPDES) permit number issued by IDEM, where applicable.
            2.   Name, company name, telephone number, e-mail address (if available), and address of the project site owner or a local contact person.
            3.   Location of the construction plan.
         (b)   This permit and posting of the notice does not provide the public with any right to trespass on a project site for any reason, nor does it require that the project site owner allow members of the public access to the project site.
      (14)   All stormwater quality measures must be designed and installed under the guidance of a trained individual (refer to definitions section or according the requirements of the NPDES general permit).
   (C)   Calculations and design standards and specifications.
      (1)   In calculating the total area of land disturbance, for the purposes of determining applicability of this section to the project, the following guidelines should be used:
         (a)   Off-site construction activities that provide services (for example, road extensions, sewer, water, and other utilities) to a land disturbing project site, must be considered as a part of the total land disturbance calculation for the project site, when the activity is under the control of the project site owner.
         (b)   Strip developments will be considered as one (1) project site and must comply with this chapter unless the total combined disturbance on all individual lots is less than one (1) acre and is not part of a larger common plan of development or sale.
         (c)   To determine if multi-lot project sites are regulated by this chapter, the area of land disturbance shall be calculated by adding the total area of land disturbance for improvements, such as, roads, utilities, or common areas, and the expected total disturbance on each individual lot, as determined by the following:
            1.   For a single-family residential project the total lot must be calculated as being disturbed.
            2.   To calculate lot disturbance on all other types of project sites, such as industrial and commercial project sites, a minimum of one (1) acre of land disturbance must be used as the expected lot disturbance, unless the lots are less than one (1) acre in size, in which case the total lot must be calculated as being disturbed.
      (2)   The calculation methods as well as the type, sizing, and placement of all stormwater pollution prevention measures for construction sites shall meet the design criteria, standards, and specifications outlined in the Indiana Stormwater Quality Manual and the Town of Brownsburg Construction Standards.
   (D)   Submittal requirements. For those projects meeting the requirements of this section, a construction stormwater pollution prevention plan is required in addition to the submittal requirements listed in § 151.20. This plan must include the following information:
      (1)   IDEM NOI form along with the information required by the NOI form.
      (2)   Proof of publication in a newspaper of general circulation, in the affected area, that notified the public that a construction activity is to commence. The publication must include language required by the NPDES general permit.
      (3)   Construction plans and SWPPP shall contain the information required by 327 IAC 15-5-6.5 “Requirements for Construction Plans” or other NPDES permit requirements. SWPPP figures shall also contain the following:
         (a)   Contour lines with maximum one (1) foot contour interval;
         (b)   Stormwater infrastructure and facilities;
         (c)   Open conveyances;
         (d)   Flood routing path and ponding locations in accordance with § 151.21(I).
      (4)   SWPPP sequencing shall consider various phases of construction activities and may require more than one SWPPP plan sheet. Possible phases of construction include: initial clearing, earth moving activities, hauling of borrow or fill soils, current site conditions, installation of infrastructure, final stabilization, off-site work associated with the project and the like.
(Ord. 2017-28, passed 10-12-17)