CITY OF COON RAPIDS, MINNESOTA
CHAPTER 8-1200
SURFACE WATER MANAGEMENT

8-1201 Findings and Purpose. The City of Coon Rapids hereby finds that uncontrolled and inadequately planned use of wetlands, woodlands, natural habitat areas, areas subject to soil erosion, and areas containing restrictive soils adversely effects the public health, safety and general welfare by impacting water quality and contributing to other environmental problems, creating nuisances, impairing other beneficial uses of the environmental resources and hindering the ability of the City of Coon Rapids to provide adequate water, sewage, flood control, and other community services. In addition, extraordinary public expenditures may be required for the protection of persons and property in such areas and in areas which may be affected by unplanned land usage.

The purpose of this Chapter is to promote, preserve, and enhance the natural resources within the City of Coon Rapids and protect them from adverse effects occasioned by poorly sited development or incompatible activities by regulating land disturbing or development activities that would have an adverse and potentially irreversible impact on water quality and unique and fragile environmentally sensitive land; by minimizing conflicts and encouraging comparability between land disturbing and development activities and water quality and environmentally sensitive lands; and by requiring detailed review standards and procedures for land disturbing or development activities proposed for such areas, thereby achieving a balance between urban growth and development and protection of water quality and natural areas.

8-1202 Statutory Authorization. This Chapter is adopted pursuant to Minnesota Statutes Section 462.351 (1990).

8-1203 Definitions. The following definitions of words, terms, and phrases apply in this Chapter of this Code. References hereinafter to “Section” are, unless otherwise specified, references to sections of this Chapter. Unless used in a context which indicates otherwise, defined terms remain defined terms whether or not capitalized.

(1) “Applicant” means any person who wishes to obtain a building permit, zoning, or subdivision approval.
(2) “City” means the City of Coon Rapids, Minnesota. City means its elected officials, officers, employees, and agents, or any commission, committee, or subdivision acting pursuant to lawfully delegated authority.
(3) “Control Measure” means a practice or combination of practices to control erosion and attendant pollution.
(4) “Detention Facility” means a permanent natural or man-made structure, including wetland, for the temporary storage of runoff which contains a permanent pool of water.
(5) “Flood Fringe” means the portion of the flood plain outside of the flood way.
(6) “Flood Plain” means the area adjoining a watercourse or water basin that has been or may be covered by a regional flood.
(7) “Flood way” means the channel of the watercourse, the bed of water basins, and those portions of the adjoining flood plains that are reasonably required to carry and discharge flood water and provide water storage during a regional flood.
(8) “Hydric Soils” means soils that are saturated, flooded, or ponded long enough during the growing season to develop anaerobic conditions in the upper part.
(9) “Hydrophytic Vegetation” means microphytic plant life growing in water soil, or on a substrate that is at least periodically deficient in oxygen as a result of excessive water content.
(10) “Land Disturbing or Development Activities” means any change of the land surface including removing vegetative cover, excavating, filling, grading, and the construction of any structure.
(11) “Person” means any individual, firm, corporation, partnership, franchisee, association, or governmental entity.
(12) “Public Waters” means waters of the state as defined in Minnesota Statutes, Section 103G.005, subd. 15.
(13) “Regional Flood” means a flood that is representative of large floods known to have occurred generally in the state and reasonably characteristic of what can be expected to occur on an average frequency in the magnitude of a 100-year recurrence interval.
(14) “Retention Facility” means a permanent natural or man-made structure that provides for the storage of storm water runoff by means of a permanent pool of water.
(15) “Sediment” means solid matter carried by water, sewage, or other liquids.
(16) “Structure” means anything manufactured, constructed, or erected which is normally attached to or positioned on land, including portable structures, earthen structures, roads, parking lots, and paved storage areas.
(17) “Wetlands” means 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 three 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.

8-1204 Applicability. Every applicant for a building permit, subdivision approval, or a permit to allow land disturbing activities must submit a storm water management plan to the City’s Community Development Department. No subdivision approval, or grading permit to allow land disturbing activities shall be issued until approval of the storm water management plan or a waiver of the approval requirement has been obtained in strict conformance with the provisions of this Chapter.

Every applicant for subdivision approval, or a grading permit to allow wetland disturbing activities must submit a wetland assessment report to the City’s Engineering Division. No subdivision approval or grading permit to allow wetland disturbing activities shall be issued until approval of the wetland replacement plan application or a certificate of exemption has been obtained in strict conformance with the provision of this Chapter and the Minnesota Wetland Conservation Act. This Chapter applies to all land, public or private, located within the City of Coon Rapids.

Every applicant for a building permit, subdivision approval, or a grading permit to allow land disturbing activities must adhere to erosion control measure standards and specifications contained in the MPCA publication “Protecting Water Quality in Urban Areas” or as approved by the City of Coon Rapids.

8-1205 Exemptions. The provisions of this Chapter do not apply to:

(1) any part of a subdivision or a plat for the subdivision that has been approved by the City Council on or before the effective date of this Chapter;
(2) any land disturbing activity for which plans have been approved by the watershed management organization within six months prior to the effective date of this Chapter.
(3) a lot for which a building permit has been approved on or before the effective date of this Chapter;
(4) installation of fence, sign, telephone, and electric poles and other kinds of posts or poles; or
(5) emergency work to protect life, limb, or property.

8-1206 Waiver. The City Council, upon recommendation of the Planning Commission, may waive any requirement of this Chapter upon making a finding that compliance with the requirement will involve an unnecessary hardship and the waiver of such requirements will not adversely effect the standards and requirements set forth in Section 8-1212. The City Council, may require as a condition of the waiver, such dedication or construction, or agreement to dedicate or construct as may be necessary to adequately meet said standards and requirements.

8-1207 Incorporation by Reference. The Minnesota Wetland Conservation Act is incorporated into this Chapter by reference.

8-1208 Storm Water Management Plan Approval Procedures. A written application for storm water management plan approval, along with the proposed storm water management plan, shall be filed with the Community Development Department and shall include a statement indicating the grounds upon which the approval is requested, that the proposed use is 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 ordinance. Prior to applying for approval of a storm water management plan, an applicant may have the storm water management plans reviewed by the City’s Community Development Department.

Five sets of clearly legible blue or black lined copies of all drawings and required information shall be submitted to the Community Development Department.

Storm water management and grading plan 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.

8-1209 Storm Water Management Plan. At a minimum, the Storm Water Management Plan shall contain the following information.

(1) Existing Site Map. A map of existing site conditions showing the site and immediately adjacent areas, including:

(a) the names, addresses, telephone numbers, and fax numbers of the applicant, owner, developer, surveyor, engineer and contact person;
(b) the section, township and range, north point, date and scale of drawing and number of sheets;
(c) plat names and block, lot and outlot boundaries for adjacent platted properties and full property identification numbers for adjacent unplatted properties;
(d) location and indication of demolition, relocation, or abandonment of existing structures, driveways, septic systems, alternate septic systems, and wells;
(e) existing underground and overhead utilities, easements and rights-of-way;
(f) 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;
(g) a delineation of all streams, rivers, public waters, and wetlands located on and immediately adjacent to the site, including depth of 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;
(h) 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 waters collect;
(i) a description of the soils at the site, including a map indicating soil types within the 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 describing any remedial steps to be taken by the developer to render the soils suitable;
(j) vegetative cover, such as brush, grass, and trees, and clearly delineating any vegetation proposed for removal; and
(j) the ten year and one hundred year floodplains, flood fringes and flood ways.

(2) Site Construction Plan. A site construction plan 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 to 100. Drawing sheets shall be 22 by 34 inches. A site construction plan shall include:

(a) the section, township and range, north point, date, revision number, scale of drawing, and number of sheets;
(b) signature and Minnesota registration number of the professional land surveyor or professional engineer under whose supervision the plan was prepared;
(c) locations and dimensions of all proposed land disturbing activities and any phasing of those activities;
(d) locations and dimensions of all temporary soil or dirt stockpiles;
(e) locations and dimensions of all construction site erosion control measures necessary to meet the requirements of this Chapter;
(f) schedule of anticipated starting and completion dates of each land disturbing activity including the installation of construction site erosion control measures needed to meet the requirements of this Chapter;
(g) provisions for maintenance of the construction site erosion control measures during construction;
(h) existing topography with a contour internal appropriate to the topography of the land but in no case having a contour interval greater than 2 feet;
(i) 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;
(j) all lot corner elevations and bench marks utilized;
(k) the proposed footprint and intended use of any structures or driveways to be constructed on the site;
(l) a delineation of all streams, rivers, ponds, public waters, and wetlands located on and immediately adjacent to the site, including depth of 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, the U.S. Fish and Wildlife Service, and/or the United States Army Corps of Engineers;
(m) emergency overflow routes from all low points, elevation of high point along overflow route, and directional flow arrows;
(n) a drainage plan of the developed site delineating 10 year and 100 year
design drainage area/watershed and hydrologic/hydraulic calculations verifying location and capacity of all overland drainage routes;
(o) access routes for maintenance to all inlets, outlets, manholes, and lift stations at ponding areas proposed;
(p) a clear delineation and tabulation of all areas which shall be paved or surfaced, including a description of the surfacing material to be used;
(q) 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;
(r) locations and dimensions of all permanent erosion control measures;
(s) location of any proposed septic system; and
(t) any other information pertinent to the particular project which in the opinion of the applicant or the City is necessary for the review of the project.

8-1210 Plan Review Procedure.

(1) Process. Storm water management plans for subdivisions or land disturbing activities meeting the requirements of Section 8-1209 shall be submitted by the Community Development Department to the Planning Commission for review in accordance with the standards of Section 8-1212. This review will be coordinated with review of the related subdivision, site plan or conditional use permit by the Commission. The Commission shall recommend approval, recommend approval with conditions or recommend denial of the storm water management plan. Building permit storm water management plans shall be submitted to the City’s Building Inspection Division for review and approval in accordance with the standards of Section 8-1212.
(2) Duration. Approval of a plan submitted under the provisions of this Chapter 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 Community Development Department for an extension of time to commence construction setting forth the reasons for the requested extension, the Community Development Department may grant one extension of not longer than twelve (12) consecutive months. No subsequent extensions will be permitted regardless of the one extension granted. Receipt of any request for an extension shall be acknowledged by the Community Development Department within 15 days. The Community Development Department shall make a decision on the extension within 30 days of receipt. An applicant may appeal the decision to the City Council by filing a written request with the Director of the Community Development Department within ten (10) days after receipt of the decision. The City Council will consider the appeal at its next regularly scheduled meeting which is held at least five (5) days after the Director reviews the appeal request. Any plan may be revised in the same manner as originally approved.
(3) Conditions. A storm water management plan may be approved subject to compliance with conditions reasonable and necessary to insure that the requirements contained in this Chapter are met. Such conditions may, among other matters, limit the size, kind or character of the proposed development, require the construction of structures, drainage facilities, storage basins, and other facilities, require replacement of vegetation, establish required monitoring procedures, stage the work over time, require alteration of the site design to insure buffering, and require the conveyance to the City of Coon Rapids or other public entity of certain lands or interests therein.
(4) Performance Security. As a condition of approval of any storm water management plan, the applicant shall submit an agreement to construct such required physical improvements, to dedicate property or easements, or to comply with such conditions as may have been agreed to. Such agreement shall be accompanied by a cash deposit or letter of credit to cover 150% of the estimated cost of complying with the agreement. The agreement and security shall guarantee completion and compliance with conditions within a specific time, which time may be extended in accordance with Section 8-1210(2).

The adequacy, conditions and acceptability of any agreement and security shall be determined by the City Council or any official of the City of Coon Rapids as may be designated by resolution of the City Council.

8-1211 Fees. All applications for storm water management plan approval shall be accompanied by a processing and approval fee. The processing and approval fee shall be established from time to time by resolution of the City Council.

8-1212 Approval Standards. No storm water management plan which fails to meet the standards contained in this Section shall be approved by the City Council.

(1) Site Dewatering. Water Pumped from the site shall be treated by temporary sedimentation basins, grit chambers, sand filters, upflow chambers, hydro-cyclones, swirl concentrators, or other controls as appropriate. Water may not be discharged in a manner that causes erosion or flooding of the site, or receiving channels, or a wetland.
(2) Waste and Material Disposal. All waste and unused building materials (including garbage, debris, cleaning wastes, wastewater, toxic materials, or hazardous materials) shall be properly disposed of off-site and not allowed to be carried by runoff into a receiving channel or storm sewer system
(3) Tracking. Each site shall have graveled roads, access drives, and parking areas of sufficient width and length to prevent sediment from being tracked onto public or private roadways. Any sediment reaching a public or private road shall be removed by street cleaning (not flushing) before the end of each workday.
(4) Drain Inlet Protection. All storm drain inlets shall be protected during construction until control measures are in place with a straw bale, silt fence or equivalent barrier meeting accepted design criteria, standards and specifications contained in the MPCA Publication “Protecting Water Quality in Urban Areas.”
(5) Site Erosion Control. The following criteria apply only to construction activities that result in runoff 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. Sheet flow runoff from adjacent areas greater than 10,000 square feet in area shall also be diverted around disturbed areas, unless shown to have resultant runoff rated of less than 0.5 ft./sec. across the disturbed area for the one year storm. Diverted runoff shall be conveyed in a manner that will not erode the conveyance and 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 subsection i and ii or i and iii below:

i) all disturbed ground left inactive for fourteen or more days shall be stabilized by seeding or sodding (only available prior to September 15) or by mulching or covering or other equivalent control measure.
ii) for sites with more than ten acres disturbed at one time, or if a channel originates in the disturbed area, one or more temporary or permanent sedimentation basins shall be constructed. Each sedimentation basin shall have a surface area of at least one percent of the area draining to the basin and at least three feet of depth and constructed in accordance with accepted design specifications. Sediment shall be removed to maintain a depth of three feet. The basin discharge rate shall also be sufficiently low as to not cause erosion along the discharge channel or the receiving water.
iii) For sites with less than ten acres disturbed at one time, silt fence, straw bales, or equivalent control measures shall be placed along all sideslope and downslope 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, straw bales, or equivalent control measures must include a maintenance and inspection schedule

(d) Any soil or dirt storage piles containing more than ten cubic yards of material should not be located with a downslope drainage length of less than 25 feet from the toe of the pile to a roadway or drainage channel. If remaining for more than seven days, the piles shall be stabilized by mulching, vegetative cover, tarps, or other means. Erosion from piles which will be in existence for less than seven 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 seven days, and storm drain inlets must be protected with straw bale or other appropriate filtering barriers.

8-1213 Storm Water Management Criteria for Permanent Facilities.

(1) An applicant shall install or construct, on or for the proposed land disturbing or development activity, all storm water management facilities necessary to manage increased runoff so that the two-year, ten-year, and 100-year storm peak discharge rates existing before the proposed development shall not be increased and accelerated and channel erosion will not occur as a result of the proposed land disturbing or development activity. An applicant may also make an in-kind or monetary contribution to the development and maintenance of community storm water management facilities designed to serve multiple land disturbing and development activities undertaken by the City or one or more persons, including the applicant.
(2) The applicant shall give consideration to reducing the need for storm water management facilities by incorporating the use of natural topography and land cover such as wetlands, ponds, natural swales, and depressions as they exist before development to the degree that they can accommodate the additional flow of water without compromising the integrity or quality of the wetland or pond.
(3) The following storm water management practices shall be investigated in developing a storm water management plan in the following descending order of preference:

(a) natural infiltration of precipitation on-site;
(b) flow attenuation by use of open vegetated swales and natural depressions;
(c) storm water retention facilities; and
(d) storm water detention facilities.

(4) A combination of successive practices may be used to achieve the applicable minimum control requirements specified in subsection (3) above. Justification shall be provided by the applicant for the method selected.

8-1214 Design Standards. Storm water detention facilities constructed in the City of Coon Rapids shall be designed according to the most current technology as reflected in the MPCA publication “Protecting Water Quality in Urban Areas,” and shall contain, at a minimum, the following design factors:

(1) a permanent pond surface area equal to two percent of the impervious area draining to the pond, or one percent of the entire area draining to the pond, whichever amount is greater;
(2) an average permanent pool depth of four to ten feet;
(3) a permanent pool length-to-width ratio of 3:1;
(4) a minimum protective shelf extending ten feet into the permanent pool with a slope of 10:1, beyond which slopes should not exceed 3:1;
(5) all storm water detention facilities shall have a device to keep oil, grease, and other floatable material from moving downstream as a result of normal operations;
(6) storm water detention facilities for new development must be sufficient to limit peak flows in each subwatershed to those that existed before the development for the 10 year storm event. All calculations and hydrologic models/information used in determining peak flows shall be submitted along with the storm water management plan;
(7) all storm water detention facilities must have a forebay to remove course-grained particles prior to discharge into a watercourse or storage basin.

8-1215 Wetlands.

(1) Runoff shall not be discharged directly into wetlands without presettlement of the runoff.
(2) Wetlands must not be drained or filled, wholly or partially, unless replaced by restoring or creating wetland areas of at least equal public value. Replacement must be guided by provisions of the Wetland Conservation Act of 1991.

8-1216 Steep Slopes. No land disturbing or development activities shall be allowed on slopes of 18% or more.

8-1217 Catch Basins. Any newly installed and rehabilitated catch basins shall be provided with a sump area for the collection of coarse-grained material. Such basins shall be cleaned when they are half filled with material.

8-1218 Drain Leaders. All newly constructed and reconstructed buildings will route drain leaders to pervious areas wherein the runoff can be allowed to infiltrate. The flow rate of water exiting the leaders shall be controlled so no erosion occurs in the pervious areas.

8-1219 Inspection and Maintenance. All storm water management facilities shall be designed to minimize the need of maintenance, to provide access for maintenance purposes and to be structurally sound. All storm water management facilities shall have a plan of operation and maintenance that assures continued effective removal of pollutants carried in storm water runoff. It shall be the responsibility of the applicant to obtain any necessary easements or other property interests to allow access to the storm water management facilities for inspection and maintenance purposes. The City may require a developer to enter into a contract providing for access to perform maintenance and inspection to public or private storm waste management facilities.

8-1220 Models/Methodologies/Computations. Hydrologic models and design methodologies used for the determination of runoff and analysis of storm water management structures shall be approved by the Director of Public Works. Detention facilities shall be designed in accordance with NURP wet detention basin design criteria. Plans, specification, and computations for storm water management facilities submitted for review shall be sealed and signed by a registered professional engineer. All computations shall appear on the plans submitted for review, unless otherwise approved by the Director of Public Works.

8-1221 Watershed Management Plans/Groundwater Management Plans. Storm water management plans shall be consistent with adopted watershed management plans and groundwater management plans prepared in accordance with Minnesota Statutes Sections 103B.231 and 103B.255 respectively, and as approved by the Minnesota Board of Water and Soil Resources in accordance with state law.

8-1222 Easements.

(1) If a storm water management plan involves direction of some or all runoff from the site, it shall be the responsibility of the applicant to obtain from adjacent property owners any necessary easements or other property interests concerning flowage of water.
(2) Easements are required for all landlocked ponding areas to the basin’s 100 year storm high water level elevation.
(3) Easements are required for all outleted basins, swales, ditches, and overflow routes to the basin’s 100 year storm high water level elevation.
(4) If the storm sewer is to be installed less than 10 feet deep within private property, the easement shall be a minimum of 20 feet wide. If the storm sewer is 10 feet or greater, the easement shall be twice as wide as the depth.
(5) Easements necessary for maintenance vehicle access are required for all of the above where not directly accessible from a public road.

8-1223 Penalty. Any person, firm or corporation violating any provision of this ordinance shall be guilty of a misdemeanor and a separate offense shall be deemed committed on each day during or on which a violation occurs or continues.

8-1224 Severability. If any section, subsection, sentence, clause, phrase, or portion of this Chapter is for any reason held invalid or unconstitutional by any court or administrative agency of competent jurisdiction, such portion shall be deemed a separate, distinct, and independent provision and such holding shall not affect the validity of the remaining portions thereof. [Revised 12/05/00, Ordinance 1719]