(A) All measures involving erosion control practices shall be designed and installed under the guidance of a professional engineer experienced in erosion control and following the specifications and criteria under this subchapter.
(B) The design standards for storm water runoff facilities are the following:
(1) Grading, erosion control practices, sediment control practices, and waterway crossings shall meet the design criteria set forth in the most recent versions of guidance documents similar to, or as effective as those outlined in the Indiana Handbook on Erosion Control in Developing Areas from the Division of Soil Conservation, Indiana Department of Natural Resources and the Field Office Technical Guide from the Soil Conservation Service, and shall be adequate to prevent transportation of sediment, pollutants or debris from the site to the satisfaction of the city.
(2) Clearing and grading of wetlands shall not be permitted, except when in compliance with other state and federal permits obtained for the project. Clearing and grading of forested areas is to be avoided whenever possible and if not possible alternative plans for protecting forested areas or reforestation should be implemented. Clearing techniques that retain natural vegetation and the use of existing drainage patterns to avoid revising drainage basin areas shall be utilized.
(3) Clearing, except that necessary to establish sediment control devices have been installed and stabilized.
(4) (a) All storm water runoff generated from new development which involves more than one acre of land disturbance shall not discharge untreated directly into a jurisdictional wetland or local water body, or into the MS4 (municipal separate storm sewer system) without treatment to remove a minimum of the following:
1. All floatables greater than 1/8 inch in size;
2. All debris greater than 1/8 inch in size;
3. 70% of total suspended solids; and
4. Oil and grease removal to achieve no more than 20 mg/l discharge concentration.
(b) For purposes of this chapter, strip developments:
1. Are considered as one project site; and
2. Must comply with this chapter; unless the total combined disturbance on all individual lots added together is less than one acre and is not part of a larger common plan of development or sale.
(c) Where such discharges into a jurisdictional wetland are proposed, the impact of the proposal on wetland functional values shall be assessed using a method acceptable to the Army Corps of Engineers (ACE) or IDNR and IDEM. Storm water discharges to critical areas with sensitive resources (i.e., swimming beaches, groundwater recharge areas, water supply reservoirs) may be subject to additional performance criteria, or may need to utilize or restrict certain storm water management practices.
(5) Certain industrial sites are required to prepare and implement a storm water pollution prevention plan and shall file a notice of intent (NOI) under the provisions of 327 IAC 15-6 for a National Pollutant Discharge Elimination System (NPDES) general permit for industrial sites and shall implement those requirements in the city storm water control plan. The storm water pollution prevention plan requirement applies to both existing and new industrial sites.
(6) Storm water discharges from land uses or activities with higher potential pollutant loadings, known as "hotspots," shall use specific storm water treatment and pollution prevention practices applicable to the particular pollutants to be addressed.
(7) Phasing shall be required on all sites disturbing greater than 30 acres, with the size of each phase to be established at plan review.
(8) Erosion control requirements shall include the following:
(a) Soil stabilization shall be completed within 15 days of clearing or inactivity in construction.
(b) If seeding or another vegetative erosion control method is used, it shall become established within two weeks after planting or the city may require the site to be reseeded or a no vegetative erosion control option employed.
(c) The entire site must be stabilized, using a heavy mulch layer or another method that does not require germination to control erosion, when adequate growing season does not exist.
(d) Special techniques (i.e. turf reinforcement, erosion control blankets, contouring, etc.) shall be utilized on steep slopes or in drainage ways to ensure stabilization.
(e) Soil stockpiles must be stabilized or covered at the end of each workday when located within 100 feet of the property edge or a water body.
(f) Techniques shall be employed to prevent the blowing of dust or sediment from the site.
(g) Techniques that divert upland runoff past disturbed slopes shall be employed.
(9) Sediment controls requirements shall include:
(a) Settling basins, sediment traps, or tanks and perimeter controls.
(b) Settling basins that are designed in a manner that allows adaptation to provide long-term storm water management, if required by the city.
(c) Protection for adjacent properties by the use of a vegetated buffer strip in combination with perimeter controls.
(10) Waterway and watercourse protection requirements shall include:
(a) All temporary stream crossings designed shall be installed in accordance with the requirements of the latest edition of the Indiana Handbook on Erosion Control in Developing Areas if a wet watercourse will be crossed regularly during construction.
(b) Stabilization of the watercourse channel before, during, and after any in-channel work.
(c) All on-site storm water conveyance channels designed to stabilize underlying soils, prevent erosion, and conform to Indiana Handbook on Erosion Control.
(d) Stabilization adequate to prevent erosion located at the outlets of all pipes and paved channels.
(11) Construction site access requirements shall include:
(a) A temporary access road provided at all sites consisting of stone or other non-erosive material that will allow soil in wheels to be removed on-site.
(b) Other measures required by the city to ensure that sediment is not tracked onto public streets by construction vehicles or washed into storm drains.
(12) Storm water conveyance facilities shall be designed to convey storm water and allow for the maximum removal of pollutants and reduction in flow velocities. This shall include, but not be limited to:
(a) Maximizing of flow paths from inflow points to outflow points.
(b) Protection of inlet and outfall structures.
(c) Elimination of erosive flow velocities.
(d) Providing of underdrain systems, where applicable.
(13) The use of non-structural storm water treatment practices is encouraged in order to minimize the reliance on structural practices.
(14) The following criteria shall apply to stabilization and revegetation efforts:
(a) Reseeding must be done with an annual or perennial cover crop accompanied by placement of straw mulch or its equivalent of sufficient coverage to control erosion until such time as the cover crop is established over 90% of the seeded area.
(b) Replanting with native woody and herbaceous vegetation must be accompanied by placement of straw mulch or its equivalent of sufficient coverage to control erosion until the plantings are established and are capable of controlling erosion.
(c) Any area of revegetation must exhibit survival of a minimum of 75% of the cover crop throughout the year immediately following revegetation. Revegetation must be repeated in successive years until the minimum 75% survival for one year is achieved.
(d) In addition to the above requirements, a landscaping plan must be submitted, as part of the post construction plan, with the final design describing the vegetative stabilization and management techniques to be used at a site after construction is completed. This landscaping plan will explain not only how the site will be stabilized after construction, but who will be responsible for the maintenance of vegetation at the site and what practices will be employed to ensure that adequate vegetative cover is preserved.
(15) Storm water drainage from adjacent areas that naturally pass through the site shall be controlled by diverting it around disturbed areas. Alternatively, the existing channel must be protected and/or improved to prevent erosion or sedimentation from occurring.
(16) Where appropriate, any combination of storage, filtering, or vegetative practices to reduce the impact of pollutants in storm water runoff on receiving waters shall be used. In addition to the combination of practices, the following requirements shall be utilized:
(a) Infiltration practices will not be allowed in wellhead protection areas.
(b) Discharges from an MS4 area will not be allowed directly into sinkholes or fractured bedrock without treatment that results in the discharge meeting Indiana ground water quality standards as referenced in 327 IAC 2-11.
(c) Any storm water practice that is a Class V injection well must ensure that the discharge from such practices meets Indiana ground water quality standards as referenced in 327 IAC 2-11.
(d) As site conditions allow, the rate at which water flows through the MS4 conveyances shall be regulated to reduce outfall scouring and stream bank erosion.
(e) As site conditions allow, a vegetated filter strip of at least ten feet width shall be maintained along unvegetated swales and ditches.
(f) New retail gasoline outlets, new municipal, state, federal, or institutional refueling areas, or outlets and refueling areas that replace their existing tank systems are required to design and install appropriate practices to reduce lead, copper, zinc, and polyaromatic hydrocarbons in storm water runoff.
(17) Buffer strips and Setback Requirements:
(a) Buffer strips shall be maintained for a minimum of 50 feet, measured horizontally, from the high water mark on a river, lake, stream or drainage way which appears as a continuous or dotted blue line on 7.5 minute series (topographical) USGS Quadrangle Maps showing the development area.
(b) An additional setback shall be maintained for 25 feet, measured horizontally, beyond the buffer strip, in which all impervious cover shall be prohibited. Grading, filling and earthmoving shall be minimized within the setback.
(c) No septic tanks or septic tank drain fields shall be permitted within the buffer or the setback.
(18) Open Space Development Requirements. If open space development is utilized to minimize land disturbing activities and provide post construction stormwater quality benefits, the following requirements shall be met:
(a) Application.
1. The provisions of this division apply to all residential zones with a density less than or equal to eight dwelling units per acre.
2. The minimum size of an open space development shall be five acres.
3. Open space is a by-right form of development and shall not require a special exception or additional review.
(b) Design Criteria
1. The total number of residential units allowable within an open space development shall not exceed the number of units that would otherwise be allowed in the zoning district using conventional development. The total number of units allowed shall be determined using the following formula:
T = BD x [A - (U+R)]
Where:
T = Total Units (dwelling units)
BD = Base Density (dwelling units/acre)
A = Total Site Area (acres)
U = Unbuildable Land as defined in § 157.004 (acres).
R = Road and Utility Right of Way (acres)
2. Frontage distance, rear, front and side yard setbacks may be reduced to 50% of the requirements in the base zoning, subject to the following rules:
A. The frontage distance shall be no less than ten feet.
B. Front and rear yard setbacks shall be no less than ten feet.
C. Side yard setbacks shall be a minimum of five feet. This requirement may be waived if the regulations of the City Fire Department are met.
3. Lot size may be reduced to 25% of base density but no smaller than 1/8 of an acre.
4. Irregular lot shapes and shared driveways are permitted in open space design.
5. Shared septic systems may be permitted provided that the requirements of the Lawrence County Health Department are met, including appropriate provisions for legal obligations related to maintenance and replacement.
6. The number of exterior parking spaces required for a residential open space development shall be two spaces per dwelling unit. Parking may be provided either on-street or in driveways.
(c) Open Space Requirements.
1. The total area of dedicated open space shall equal the amount by which all dwelling unit lots are reduced below the base zoning and shall meet the requirements outlined in Table 1.
Table 1. Open Space Required for Various Densities | |
Base Density (du/ac) | Open Space Required (% of buildable area) |
>1 | 35% |
0.5<BD<1 | 40% |
0.2<BD<0.5 | 45% |
<0.2 | 50% |
2. The following activities or land uses may not be counted as a part of designated open space:
A. Land considered unbuildable per § 157.004.
B. Existing rights-of-way and utility easements.
C. Setbacks and lawns.
3. The following areas shall be high priorities for inclusion in designated open space:
A. Buffer strips for rivers, lakes, streams and drainage ways.
B. High quality forest resources.
C. Individual trees.
D. Critical habitat areas.
E. High quality soil resources.
4. At least 75% of designated open space shall be contiguous, with no portion less than 100 feet wide unless lot dimensions are less.
5. At least 50% of designated open space shall be designated as "green space" as defined in § 157.004 and shall be maintained in a natural, undisturbed condition.
6. Reasonable effort must be made to locate green space adjacent to green space in an adjoining property(s) to the satisfaction of the city.
7. Limited access to green space may be allowed in the form of a walking or hiker/biker path, the total area of which must be no more than 2% of the total green space area.
8. The remaining designated open space may be "community space" and may be used for passive or active recreation, or the location of storm water management facilities.
A. If used for storm water management, all design, construction, maintenance, and public safety requirements shall be met, using the design criteria set forth in this chapter.
B. If used for active recreation, impervious cover shall not exceed 5% of this area.
(d) Open Space Management.
1. The boundaries of designated open space areas, recreation areas, storm water management facilities, and green space shall be clearly delineated on plans, including record plats, and marked in the field with signage approved by the city to distinguish these areas from private property.
2. Development in designated open spaces in the future is prohibited. Ownership of open space shall be designated through one of the following options:
A. Ownership by the individual lot owners as a homeowner's association. The deed to each lot shall include a proportionate share of the common open space. Each lot owner shall be required to be a member of a homeowner's association, which shall be formed prior to conveyance of the first lot. The assessment of dues or fees for structural improvements requires the affirmative vote of no less than two-thirds of the homeowners' association membership.
B. Conservation Easement. If owned by a separate entity, a conservation easement shall be established for the area as defined in division C. below and shall be given to the city. A conservation easement, established as defined in division C. below, may be transferred to an established, designated land trust organization, among whose purposes it is to conserve open space and/or natural resources. This option is recommended for natural open space areas. Such transfer is allowable, provided that:
i. The organization is acceptable to the city and is a bona fide conservation organization with perpetual existence;
ii. The conveyance contains appropriate provision for proper reverter or retransfer in the event that organization becomes unwilling or unable to continue carrying out its functions;
iii. A maintenance agreement acceptable to the homeowners' association is entered into by the developer and the organization.
C. The conservation easement shall:
i. Protect open space from future development and environmental damage by restricting the area from any future building and against the removal of soil, trees, and other natural features, except as is consistent with conservation or recreational uses or uses accessory to permitted uses;
ii. Provide that residents have access to the open space at all times;
iii. Dictate whether open space is for the benefit of residents only, or may be open to residents of the city.
(e) An open space management entity shall assure that the open space will be protected in perpetuity from all forms of development, except as shown on approved development plan, and that it will never be changed to another use. The management entity shall:
1. Prescribe all allowable and unallowable uses and activities within such open space;
2. Provide detailed standards and schedules for maintenance of the open space, including vegetative management; and
3. Allow for county or municipal maintenance of open space in the event that maintenance specified under a homeowner's agreement is not complied with.
(19) All design standards not incorporated herein which are contained in 327 IAC 15-13 are hereby incorporated by reference.
(Ord. 35-2004, passed 10-12-04; Am. Ord. 37-2005, passed 10-11-05) Penalty, see § 157.999