To promote the health, safety and general welfare of the citizens of Dayton, Minnesota, by requiring stormwater management practices for construction activity.

   This section is adopted pursuant to M.S. § 462.351.

   The City of Dayton hereby finds that uncontrolled land-disturbing activity at construction sites are subject to soil erosion and other pollutants which enter into receiving water bodies adversely affecting the public health, safety and general welfare by impacting water quality, creating nuisances, impairing other beneficial uses of environmental resources and hindering the ability of the City of Dayton to provide adequate water, sewage, flood control and other community services.

   The purpose of the section is to promote, preserve and enhance the natural resources within the City of Dayton and protect them from adverse effects occasioned by poorly sited development or incompatible activities by regulating land-disturbing activities that would have an adverse and potentially irreversible impact on water quality and environmentally sensitive land; by minimizing conflicts and encouraging proper installation and maintenance of best management practices (BMPs) for land-disturbing activities; and by requiring detailed review standards and procedures for land-disturbing activities proposed for such areas, thereby achieving a balance between development, redevelopment and protection of water quality and natural areas.

   For the purpose of this section, the following terms, phrases, words and their derivatives shall have the meaning stated below. When inconsistent with the context, words used in the present tense include the future tense, words in the plural number include the singular number, and words in the singular number include the plural number. The word “shall” is always mandatory and not merely directive.

   Any person who wishes to obtain a building permit, zoning or Subdivision approval.

   Erosion and sediment control and water quality management practices that are the most effective and practicable means of controlling, preventing, and minimizing the degradation of surface water, including construction-phasing, minimizing the length of time soil areas are exposed, prohibitions, and other management practices published by state or designated area-wide planning agencies.

   A permanent natural or man-made structure, including wetlands, for the temporary storage of runoff which contains a permanent pool of water.

   The release, conveyance, channeling, runoff, or drainage, of stormwater including snowmelt, from a construction site.

   All areas of the construction site where the vegetation (trees, shrubs, brush, grasses and the like) or impervious surface has been removed, thus rendering the soil more prone to erosion. This includes topsoil stockpile areas, borrow areas and disposal areas within the construction site. It does not include stockpiles or surcharge areas of gravel, concrete or bituminous. Once soil is exposed it is considered exposed soil until it meets the definition of “final stabilization.”

   All soil-disturbing activities at the site have been completed, and a uniform perennial vegetative cover with a density of 75% of the cover for unpaved areas and areas not covered by permanent structures has been established, or equivalent permanent stabilization measures have been employed. Simply sowing grass is not considered final stabilization.

   Any change of the land surface including removing vegetative cover, excavating, filling, grading and the construction of any structure.

   Any individual, firm, corporation, partnership, franchise, association or governmental entity.

   Waters of the state as defined in M.S. § 103G.00S, Subdivision 15.

   A permanent natural or man-made structure that provides for the storage of storm water runoff by means of a permanent pool of water.

   Solid matter carried by water, sewage or other liquids.

   A joint stormwater and erosion and sediment control plan that is a document containing the requirements of this section, that when implemented will decrease soil erosion on a parcel of land and off-site nonpoint pollution.

   Anything manufactured, constructed or erected which is normally attached to or positioned on land, including portable structures, earthen structures, roads, parking lots, paved storage areas, fences and retaining walls.

   As defined in M.S. § 115.01, Subdivision 22, the term waters of the state includes all streams, lakes, ponds, marches, watercourses, waterways, wells, springs, reservoirs, aquifers, irrigation systems, drainage systems and all other bodies or accumulations of water, surface or underground, natural or artificial, public or private, which are contained within, flow through or border upon the state or any portion thereof.

    Lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is covered by shallow water. For purposes of this definition, wetlands must have the following 3 attributes:

      a.   Have a predominance of Hydric soils;

      b.   Are inundated or saturated by surface or ground water at a frequency and duration sufficient to support a prevalence of Hydrophytic vegetation typically adapted for life in saturated soil conditions; and

      c.   Under normal circumstances support a prevalence of such vegetation.

   (1)   Applicability. Every applicant for a building permit, Subdivision approval, or a permit to allow land disturbing activities greater than or equal to one acre or part of a larger common plan or development greater or equal to one acre must submit a storm water pollution prevention plan to the Zoning Administrator. No building permit, Subdivision approval, or permit to allow land disturbing activities shall be issued until approval of the storm water pollution prevention plan or a waiver of the approval requirement has been obtained in strict conformance with the provisions of this section. The provisions of Subd. 6(2) of this section apply to all land, public or private.

   (2)   Exemptions. The provisions of this section do not apply to:

      a.   Any part of a Subdivision if a plat for the Subdivision has been approved by the City Council on or before the effective date of this section;

      b.   A lot for which a building permit has been approved on or before the effective date of this section;

      c.   Installation of fence, sign, telephone, and electric poles and other kinds of posts or poles.

      d.   Emergency work to protect life, limb or property.

      e.   Tilling, planting, or harvesting of agricultural, horticultural or silvicultural (forestry) crops.

   (1)   Application. A written application for Storm Water Pollution Prevention Plan approval, along with the proposed Storm Water Pollution Prevention Plan, shall be filed with the City and shall include a statement indicating the grounds upon which the approval is requested, that the proposed use permitted by right or as an exception in the underlying zoning district, and adequate evidence showing that the proposed use will conform to the standards set forth in this section. Prior to applying for approval of a Storm Water Pollution Prevention Plan, an applicant may have the Storm Water Pollution Prevention Plan reviewed by the appropriate departments of the City.

   Two sets of clearly legible blue or black lined copies of drawings and required information shall be submitted to the Zoning Administrator and shall be accompanied by a receipt from the City Clerk evidencing the payment of all required fees for processing and/or financial securities in accordance with the City. Drawings shall be prepared to a scale appropriate to the site of the project and suitable for the review to be performed. At a minimum, the scale shall be 1 inch equals 100 feet.

   (2)   Storm Water Pollution Prevention Plan. At a minimum, the Storm Water Pollution Prevention Plan shall contain the following information:

      a.   Existing site map. A map of existing site conditions showing the site and immediately adjacent areas, including:

         1.   The name and address of the applicant, the section, township and range, north point, date and scale of drawing and number of sheets;

         2.   Location of the tract by an insert map at a scale sufficient to clearly identify the location of the property and giving such information as the names and numbers of adjoining roads, railroads, utilities, Subdivisions, towns and districts or other landmarks;

         3.   Existing topography with a contour interval appropriate to the topography of the land but in no case having a contour interval greater than 2 feet;

         4.   A delineation of all streams, rivers, public waters and wetlands located on and immediately adjacent to the site, including depth of water, a description of all vegetation which may be found in the water, a statement of general water quality and any classification given to the water body or wetland by the Minnesota Department of Natural Resources, the Minnesota Pollution Control Agency, and/or the United States Army Corps of Engineers;

         5.   Location and dimensions of existing storm water drainage systems and natural drainage patterns on and immediately adjacent to the site delineating in which direction and at what rate storm water is conveyed from the site, identifying the receiving stream, river, public water, or wetland, and setting forth those areas of the unaltered site where storm water collects;

         6.   A description of the soils of the site, including a map indicating soil types of areas to be disturbed as well as a soil report containing information on the suitability of the soils for the type of development proposed and for the type of sewage disposal proposed and describing any remedial steps to be taken by the applicant to render the soils suitable;

         7.   Vegetative cover and clearly delineating any vegetation proposed for removal; and

         8.   100-year floodplain, flood fringes and floodways.

      b.   Site construction plan. A site construction plan including:

         1.   Locations and dimensions of all proposed land disturbing activities;

         2.   Locations and dimensions of all temporary soil or dirt stockpiles;

         3.   Locations and dimensions of all construction site erosion control measures and best management practices (BMPs) necessary to meet the minimum BMP requirements listed in Subd. 9 of this section;

         4.   Schedule of anticipated starting and completion date of each land disturbing activity including the installation of construction site erosion control measures needed to meet the requirements of this section; and

      c.   Plan of final site conditions. A plan of final site conditions on the same scale as the existing site map showing the site changes including:

         1.   Finished grading shown at contours at the same interval as provided above or as required to clearly indicate the relationship of proposed changes to existing topography and remaining features;

         2.   A landscape plan, drawn to an appropriate scale, including dimensions and distances and the location, type, size and description of all proposed landscape materials which will be added to the site as part of the development;

         3.   A drainage plan of the developed site delineating in which direction and at what rate storm water will be conveyed from the site and setting forth the areas of the site where storm water will be allowed to collect;

         4.   The proposed size, alignments and intended use of any structures to be erected on the site;

         5.   A clear delineation and tabulation of all areas which shall be paved or surfaced, including a description of the surfacing material to be used; and

         6.   Any other information pertinent to the particular project which in the opinion of the applicant is necessary for the review of the project.

      d.   A copy of MPCA Permit Number for discharging storm water from construction activity (MN R 100001).

   (1)   Process. Storm Water Pollution Prevention Plans meeting the requirements of Subd. 7 and minimum BMP requirements of Subd. 9 will be reviewed by the Zoning Administrator or designated representative which may approve, approve with conditions, or deny the Storm Water Pollution Prevention Plan. If the Storm Water Pollution Prevention Plan is part of a large Subdivision, the City may require the SWPPP be reviewed by the Planning Commission. The Planning Commission may approve, approve with conditions, or deny the Storm Water Pollution Prevention Plan. Following Planning Commission action, the Storm Water Pollution Prevention Plan shall be submitted to the City Council at its next available meeting. City Council action on the Storm Water Pollution Prevention Plan must be accomplished within 120 days following the date the application for approval is filed with the City.

   (2)   Duration. Approval of a plan submitted under the provisions of this section shall expire one year after the date of approval unless construction has commenced in accordance with the plan. However, if prior to the expiration of the approval, the applicant makes a written request to the City for an extension of time to commence construction setting forth the reason for the requested extension, the planning department may grant one extension of not greater than 1 single year. Receipt of any request for an extension shall be acknowledged by the City within 15 days. The City shall make a decision on the extension within 30 days of receipt. Any plan may be revised in the same manner as originally approved.

   (3)   Condition. A Storm Water Pollution Prevention Plan may be approved subject to compliance with conditions reasonable and necessary to insure that the requirements contained in the section are met. Such conditions may, among other matters, limit the size, kind or character of the proposed development, require replacement of vegetation, establish required monitoring procedures, stage the work over time, or require alteration of the site design to insure buffering.

   (4)   Financial security. Prior to approval of any Storm Water Pollution Prevention Plan, the applicant shall submit a financial security in the amount specified by the current City fee and security structure. The securities shall guarantee completion and compliance with conditions within a specific time, which time may be extended in accordance with Subd. 8(2). The adequacy, conditions and acceptability of any financial security shall be determined by the City Council or any official of the City of Dayton as may be designated by resolution of the City Council.

   (1)   No Storm Water Pollution Prevention Plan which fails to meet the standards contained in this section shall be approved by the City Council or designated representative.

   (2)   Site dewatering. Water pumped from the site shall be treated by temporary sedimentation basins, grit chambers, sand filters, upflow chambers, hydrocyclones, swirl concentrators or other appropriate controls as appropriate. Water may not be discharged in a manner that causes erosion, scour, or flooding of the site or receiving channels or a wetland.

   (3)   Construction site waste.

      a.   Solid waste. Collected sediment, asphalt and concrete millings, floating debris, paper, plastic, fabric, construction and demolition debris and other wastes must be disposed of properly and must comply with MPCA disposal requirements.

      b.   Hazardous materials. Oil, gasoline, paint and any hazardous substances must be properly stored, including secondary containment, to prevent spill, leaks or other discharge. Restricted access to storage areas must be provided to prevent vandalism. Storage and disposal of hazardous waste must be in compliance with MPCA regulations.

      c.   Liquid waste. All other non-storm water discharges (concrete truck washout, vehicle washing, maintenance spills and the like) conducted during the construction activity shall not be discharged to the municipal storm sewer, wetlands, natural drainageways, or waters of the state.

   (4)   Tracking. Vehicle tracking of sediment onto paved surfaces must be removed by street sweeping as needed to prevent discharge of sediment-laden water from entering the City storm sewer system.

   (5)   Drain inlet protection. All storm drain inlets shall be protected during construction until final establishment has been accomplished or until approval from the City.

   (6)   Site erosion control. The following criteria (a. through c.) apply only to construction activities that result in storm water leaving the site.

      a.   Channelized runoff from adjacent areas passing through the site shall be diverted around disturbed areas, if practical. Otherwise, the channel shall be protected as described below. Sheetflow runoff from adjacent areas greater than 10,000 square feet in area shall also be diverted around disturbed areas, unless shown to have resulted runoff rates of less than 0.5 ft./sec. across the disturbed area for the 1-year storage. Diverted runoff shall be conveyed in a manner that will not cause erosion, scour or flooding of the conveyance at receiving channels.

      b.   All activities on the site shall be conducted in a logical sequence to minimize the area of bare soil exposed at any one time.

      c.    Runoff from the entire disturbed area on the site shall be controlled by meeting either subsections (6)(c)1. and 2. or (6)(c)2. and 3. below:

         1.   All exposed soil areas with a continuous positive slope within 200 lineal feet of a surface water, must have temporary erosion protection or permanent cover for the exposed soil areas year round, according to the following table of slopes and time frames:

 

 

         2.   For sites with more than 10 acres disturbed at one time, or if a channel originates in the disturbed area, one or more temporary or permanent sedimentation basin shall be constructed. Each sedimentation basin shall have a surface area of at least 1% of the area draining to the basin and at least 3 feet of depth and constructed in accordance with accepted design specifications. Sediment shall be removed to maintain a depth of 3 feet. The basin discharge rate shall also be sufficiently low as to not cause erosion, scour or flooding along the discharge channel or the receiving water.

         3.   For sites with less than 10 acres disturbed at one time, silt fences or equivalent control measures shall be placed along all side slopes and down slope sides of the site. If a channel or area of concentrated runoff passes through the site, silt fences shall be placed along the channel edges to reduce sediment reaching the channel. The use of silt fences or equivalent control measures must include a maintenance and inspection schedule.

      d.   Any soil or dirt storage piles containing more than 10 cubic yards of material should not be located with a downslide drainage length of less than 25 feet from the toe of the pile to a roadway or drainage channel. If remaining for more than 7 days, they shall be stabilized by mulching vegetative cover, tarps or other means. Erosion from piles which will be in existence for less than 7 days shall be controlled by placing straw bales or silt fence barriers around the pile. In-street utility repair or construction soil or dirt storage piles located closer than 25 feet of a roadway or drainage channel must be covered with tarps or suitable alternative control. If exposed for more than 7 days, the storm drain inlets must be protected with an appropriate filtering barrier.

   (7)   Inspection and maintenance. All stormwater management BMPs shall be inspected by the applicant weekly or after every .5-inch rain event. If sediment has reached 1/3 the capacity of the sediment control practice, appropriate maintenance or replacement of the BMP must be completed to ensure maximum effectiveness.

   Work will be considered complete when all exposed soil areas have undergone final stabilization, as defined in Subd. 5, is constructed to finish grade and is in conformance with all permit conditions of approval to the satisfaction of the City. The applicant or representative shall notify the City when the land-disturbing operations are ready for final inspection. Final approval shall not be given until all work, including installation of all drainage facilities and their protective devices, and all erosion control measures, have been completed and final stabilization has occurred in accordance with this subdivision.

    (1)   Right of entry. The applicant shall promptly allow the City and its authorized representatives, upon presentation of credentials, to:

      a.   Enter upon the permitted site for the purpose of obtaining information, examination of records, conducting investigations, inspections or surveys;

      b.   Bring such equipment upon the permitted site as is necessary to conduct such surveys and investigations;

      c.   Examine and copy any books, papers, records or memoranda pertaining to activities or records required to be kept under the terms and conditions of this permitted site;

      d.   Inspect the storm water pollution control measures;

      e.   Sample and monitor any items or activities pertaining to storm water pollution control measures; and/or

      f.   Any temporary or permanent obstruction to the safe and easy access of such an inspection shall be promptly removed upon the inspector's request. The cost of providing such access shall be borne by the applicant.

   (2)   Warning letter. If upon inspection by the City or designated representative, the applicant fails to implement the erosion and sediment control practices outlined in the approved stormwater pollution prevention plan or minimum BMP standards outlined in Subd. 5, the City will notify the applicant with a letter of warning which outlines the issues of noncompliance and a timeline for completion of any work to bring the site into compliance.

   (3)   Action against the financial security. If appropriate actions by the applicant have not been completed within 7 days after notification by the City, the City may act against the financial security if any of the conditions listed below exist. The City shall use funds from this security to finance any corrective or remedial work undertaken by the City or a contractor under contract to the City and to reimburse the City for all direct cost incurred in the process of remedial work including, but not limited to, staff time and attorney's fees.

      a.   The applicant ceases land disturbing activities and/or filling and abandons the work site prior to completion of the City-approved grading plan.

      b.   The applicant fails to conform to any city approved grading plan and/or the storm water pollution control plan as approved by the City, or related supplementary instructions.

      c.   The techniques utilized under the storm water pollution control plan fail within 1 year of installation.

      d.   The applicant fails to reimburse the City for corrective action taken.

      e.    Emergency action under part (4) below.

   (4)   Emergency action. If circumstances exist such that noncompliance with this section poses an immediate danger to the public health, safety and welfare, as determined by the City Engineer, the City may take emergency preventative action. The City shall also take every reasonable action possible to contact and direct the applicant to take any necessary action. Any cost to the City may be recovered from the applicant's financial security.

   Any person, firm or corporation violating any provision of this section shall be fined not less than $5 nor more than $500 for each offense, and a separate offense shall be deemed committed on each day during or on which a violation occurs or continues.

(Ord. 2007-03, passed 4-10-07)