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(a) General. The stormwater system, including stormwater management practices for storage, treatment and control, and conveyance facilities, shall be designed to prevent structure flooding during the 100-year, 24-hour storm event; to maintain predevelopment runoff patterns, flows, and volumes; and to meet the following criteria.
(1) Integrated practices that address degradation of water resources. The stormwater management practices shall function as an integrated system that controls flooding and minimizes the degradation of the physical, biological and chemical integrity of the water resources receiving stormwater discharges from the site. Acceptable practices shall:
A. Not disturb riparian areas, unless the disturbance is intended to support a watercourse restoration project and complies with § 1058.11;
B. Maintain predevelopment hydrology and ground water recharge on as much of the site as practicable;
C. Only install new impervious surfaces and compact soils where necessary to support the future land use; and
D. Compensate for increased runoff volumes caused by new impervious surfaces and soil compaction by reducing stormwater peak flows to less than pre-development levels.
Stormwater management practices that meet the criteria in this regulation, and additional criteria required by the Stormwater Program Manager, shall comply with this chapter.
(2) Practices designed for final use. Stormwater management practices shall be designed to achieve the stormwater management objectives of this regulation, to be compatible with the proposed post-construction use of the site, to protect the public health, safety and welfare, and to function safely with minimal maintenance.
(3) Stormwater management for all lots. Areas developed for a subdivision, as defined in § 1058.05, shall provide stormwater management and water quality controls for the development of all subdivided lots. This shall include provisions for lot grading and drainage that prevent structure flooding during the 100-year, 24-hour storm; and maintain, to the extent practicable, the pre-development runoff patterns, volumes and peaks from the lot.
(4) Stormwater facilities in water resources. Stormwater management practices and related activities shall not be constructed in water resources unless the applicant shows proof of compliance with all appropriate permits from the Ohio EPA, the U.S. Army Corps of Engineers, and other applicable federal, state and local agencies as required in this chapter, and the activity is in compliance with Chapter 1058 and § 1058.11, all as determined by the Stormwater Program Manager.
(5) Stormwater ponds and surface conveyance channels. All stormwater pond and surface conveyance designs must provide a minimum of one foot freeboard above the projected peak stage within the facility during the 100-year, 24-hour storm. When designing stormwater ponds and conveyance channels, the applicant shall consider public safety as a design factor and alternative designs must be implemented where site limitations would preclude a safe design.
(6) Exemption. The site where soil-disturbing activities are conducted shall be exempt from the requirements of this section if it can be shown to the satisfaction of the Stormwater Program Manager that the site is part of a larger common plan of development where the stormwater management requirements for the site are provided by an existing stormwater management practice, or if the stormwater management requirements for the site are provided by practices defined in a regional or local stormwater management plan approved by the Stormwater Program Manager.
(7) Maintenance. All stormwater management practices shall be maintained in accordance with inspection and maintenance agreements approved by the Stormwater Program Manager as detailed in § 1060.08.
(8) Ownership. Unless otherwise required by the city, stormwater management practices serving multiple lots in subdivisions shall be on a separate lot held and maintained by an entity of common ownership or, if compensated by the property owners, by the city. Stormwater management practices serving single lots shall be placed on these lots, protected within an easement, and maintained by the property owner.
(9) Preservation of existing natural drainage. Practices that preserve and/or improve the existing natural drainage shall be used to the maximum extent practicable. Such practices may include minimizing site grading and compaction; protecting and/or restoring water resources, riparian areas, and existing vegetation; and maintaining unconcentrated stormwater runoff to and through these areas.
(10) Preservation of wetland hydrology. Concentrated stormwater runoff from BMPs to wetlands shall be converted to diffuse flow before the runoff enters a wetland in order to protect the natural hydrology, hydroperiod and wetland flora. The flow shall be released such that no erosion occurs down slope. Practices such as level spreaders, vegetative buffers, infiltration basins, conservation of forest covers, and the preservation of intermittent streams, depressions, and drainage corridors may be used to maintain the wetland hydrology.
If the applicant proposes to discharge to natural wetlands, a hydrological analysis shall be preformed to demonstrate that the proposed discharge matches the pre-development hydroperiods and hydrodynamics.
(b) Stormwater conveyance design criteria. All stormwater management practices shall be designed to convey stormwater to allow for the maximum removal of pollutants and reduction in flow velocities. This shall include but not be limited to:
(1) Stream relocation or enclosure. The Stormwater Program Manager may allow the enclosure or relocation of water resources only if the applicant shows proof of compliance with all appropriate permits from the Ohio EPA, the U.S. Army Corps of Engineers, and other applicable federal, state and local agencies as required in § 1060.07 of this regulation, and the activity is in compliance with Chapter 1058, all as determined by the Stormwater Manager. At a minimum, stream relocation designs must show how the project will minimize changes to the vertical stability, floodplain form, channel form, and habitat of upstream and downstream channels on and off the property;
(2) Off-site stormwater discharges. Off-site stormwater runoff that discharges to or across the applicant’s development site shall be conveyed through the stormwater conveyance system planned for the development site at its existing peak flow rates during each design storm. Off- site flows shall be diverted around stormwater quality control facilities or, if this is not possible, the stormwater quality control facility shall be sized to treat the off-site flow. Comprehensive Stormwater Management Plans will not be approved until it is demonstrated to the satisfaction of the Stormwater Program Manager that off-site runoff will be adequately conveyed through the development site in a manner that does not exacerbate upstream or downstream flooding and erosion;
(3) Sheet flow. The site shall be graded in a manner that maintains sheet flow over as large an area as possible. The maximum area of sheet flow shall be determined based on the slope, the uniformity of site grading, and the use of easements or other legally-binding mechanisms that prohibit re-grading and/or the placement of structures within sheet flow areas. In no case shall the sheet flow length be longer than 300 feet, nor shall a sheet flow area exceed one and one-half acres. Flow shall be directed into an open channel, storm sewer, or other stormwater management practice from areas too long and/or too large to maintain sheet flow, all as determined by the Stormwater Program Manager;
(4) Open channels. Unless otherwise allowed by the City Engineer, drainage tributary to stormwater management practices shall be provided by an open channel with landscaped banks and designed to carry the ten-year, 24-hour stormwater runoff from upstream contributory areas;
(5) Open drainage systems. Open drainage systems shall be preferred on all new development sites to convey stormwater where feasible. Storm sewer systems shall be allowed only when the site cannot be developed at densities allowed under zoning or where the use of an open drainage system affects public health or safety, all as determined by the Stormwater Program Manager. The following criteria shall be used to design storm sewer systems when necessary.
A. Storm sewers shall be designed such that they do not surcharge from runoff caused by the five-year, 24-hour storm, and that the hydraulic grade line of the storm sewer stays below the gutter flow line of the overlying roadway, or below the top of drainage structures outside the roadway during a ten-year, 24-hour storm. The system shall be designed to meet these requirements when conveying the flows from the contributory area within the proposed development and existing flows from off-site areas that are upstream from the development.
B. The minimum inside diameter of pipe to be used in public storm sewer systems is 12 inches. Smaller pipe sizes may be used in private systems, subject to the approval.
C. All storm sewer systems shall be designed taking into consideration the tailwater of the receiving facility or water resource. The tailwater elevation used shall be based on the design storm frequency. The hydraulic grade line for the storm sewer system shall be computed with consideration for the energy losses associated with entrance into and exit from the system, friction through the system, and turbulence in the individual manholes, catch basins and junctions within the system.
D. The inverts of all curb inlets, manholes, yard inlets and other structures shall be formed and channelized to minimize the incidence of quiescent standing water where mosquitoes may breed.
E. Headwalls shall be required at all storm sewer inlets or outlets to and from open channels or lakes.
(6) Water resource crossings. The following criteria shall be used to design structures that cross a water resource in the city.
A. Water resource crossings other than bridges shall be designed to convey the stream’s flow for the minimum 25-year, 24-hour storm.
B. Bridges, open bottom arch or spans are the preferred crossing technique and shall be considered in the planning phase of the development. Bridges and open spans should be considered for all state scenic rivers, cold-water habitat, exceptional warm-water habitat, seasonal salmonid habitat streams and Class III headwater streams. The footers or piers for these bridges and open spans shall not be constructed below the ordinary high water mark.
C. If a culvert or other closed bottom crossing is used, 25% of the cross-sectional area, or a minimum of one foot of box culverts and pipe arches, must be embedded below the channel bed.
D. The minimum inside diameter of pipes to be used for crossings shall be 12 inches.
E. The maximum slope allowable shall be a slope that produces a ten-fps velocity within the culvert barrel under design flow conditions. Erosion protection and/or energy dissipaters shall be required to properly control entrance and outlet velocities.
F. All culvert installations shall be designed with consideration for the tailwater of the receiving facility or water resource. The tailwater elevation used shall be based on the design storm frequency.
G. Headwalls shall be required at all culvert inlets or outlets to and from open channels or lakes.
H. Streams with a drainage area of five square miles or larger shall incorporate floodplain culverts at the bankfull elevation to restrict head loss differences across the crossing so as to cause no rise in the 100-year storm event.
I. Bridges shall be designed such that the hydraulic profile through a bridge shall be below the bottom chord of the bridge for either the 100-year, 24-hour storm, or the 100-year flood elevation as determined by FEMA, whichever is more restrictive.
(7) Overland flooding. Overland flood routing paths shall be used to convey stormwater runoff from the 100-year, 24-hour storm event to an adequate receiving water resource or stormwater management practice such that the runoff is contained within the drainage easement for the flood routing path and does not cause flooding of buildings or related structures. The peak 100-year water surface elevation along flood routing paths shall be at least one foot below the finished grade elevation at the structure. When designing the flood routing paths, the conveyance capacity of the site’s storm sewers shall be taken into consideration;
(8) Compensatory flood storage mitigation. All fill proposed to be placed in a designated Flood Hazard Mitigation area shall be in accordance with Chapter 1476; and
(9) Velocity dissipation. Velocity dissipation devices shall be placed at discharge locations and along the length of any outfall to provide non-erosive flow velocity from the structure to a water resource so that the natural physical and biological characteristics and functions of the water resource are maintained and protected.
(c) Stormwater quality control.
(1) Direct runoff to a BMP. The site shall be designed to direct runoff to one or more of the following stormwater management practices. These practices are listed in Table 2 of this regulation and shall be designed to meet the following general performance standards:
A. Extended conveyance facilities that slow the rate of stormwater runoff; filter and biodegrade pollutants in stormwater; promote infiltration and evapotranspiration of stormwater; and discharge the controlled runoff to a water resource;
B. Extended detention facilities that detain stormwater; settle or filter particulate pollutants; and release the controlled stormwater to a water resource;
C. Infiltration facilities that retain stormwater; promote settling, filtering, and biodegradation of pollutants; and infiltrate captured stormwater into the ground. The Stormwater Program Manager may require a soil engineering report to be prepared for the site to demonstrate that any proposed infiltration facilities meet these performance standards;
D. For sites less than five acres, but greater than one acre and not part of a common plan of development, where one or more acres are disturbed, the Stormwater Program Manager may approve other BMPs if the applicant demonstrates that these BMPs meet the objectives of this regulation as stated in division (c)(6) of this section;
E. For sites greater than five acres, or less than five acres but part of a larger common plan of development or sale which will disturb five or more acres, the Stormwater Program Manager may approve other BMPs if the applicant demonstrates to the Stormwater Program Manager’s satisfaction that these BMPs meet the objectives of this regulation as stated in division (c)(6) of this section, and has prior written approval from the Ohio EPA; and
F. For the construction of new roads and roadway improvement projects by public entities (i.e., the state, counties, townships, cities or villages), the Stormwater Program Manager may approve BMPs not included in Table 2 of this regulation, but must show compliance with the current version of the Ohio Departments of Transportation’s Location and Design Manual, Volume Two, Drainage Design.
NOTE: In division (c)(2) of this section, the size of the water quality volume (WQv) orifice can be limited to two and one-half inches in extended detention ponds when drainage areas are too small to allow a practical WQv orifice size.
(2) Criteria applying to all stormwater management practices. Practices chosen must be sized to treat the water quality volume (WQv) and to ensure compliance with Ohio Water Quality Standards (O.A.C. Chapter 3745-1).
A. The WQv shall be equal to the volume of runoff from a 0.75-inch rainfall event and shall be determined according to one of the following methods:
1. Through a site hydrologic study approved by the Stormwater Program Manager that uses continuous hydrologic simulation; site-specific hydrologic parameters, including impervious area, soil infiltration characteristics, slope, and surface routing characteristics; proposed best management practices controlling the amount and/or timing of runoff from the site; and local long-term hourly records; or
2. Using the following equation:
WQv = C*P*A/12
where terms have the following meanings:
WQv = water quality volume in acre-feet
C = runoff coefficient appropriate for storms less than one inch
P = 0.75-inch precipitation depth
A = area draining into the stormwater practice, in acres
Runoff coefficients required by the Ohio Environmental Protection Agency (Ohio EPA) for use in determining the water quality volume can be determined using the list in Table 1 or using the following equation to calculate the runoff coefficient, if the applicant can demonstrate that appropriate controls are in place to limit the proposed impervious area of the development:
C = 0.858i3 - 0.78i2 + 0.774i + 0.04, where:
i = fraction of the drainage area that is impervious
Table 1: Runoff Coefficient Based on the Type of Land Use | |
Land Use | Runoff Coefficient
|
Industrial and commercial | 0.8 |
High-density residential (>8 dwellings/acre) | 0.5 |
Medium-density residential (4 to 8 dwellings/acre) | 0.4 |
Low-density residential (<4 dwellings/acre) | 0.3 |
Open space and recreational areas | 0.2 |
Where land use will be mixed, the runoff coefficient should be calculated using a weighted average. For example, if 60% of the contributing drainage area to the stormwater treatment structure is low density residential, 30% is high density residential, and 10% is open space, the runoff coefficient is calculated as follows (0.6)(0.3) + (0.3)(0.5) + (0.1)(0.2) = (0.35) | |
B. An additional volume equal to 20% of the WQv shall be incorporated into the stormwater practice for sediment storage. This volume shall be incorporated into the sections of stormwater practices where pollutants will accumulate.
C. Stormwater quality management practices shall be designed such that the drain time is long enough to provide treatment and protect against downstream bank erosion, but short enough to provide storage available for successive rainfall events as defined in Table 2.
Table 2: Draw Down Times for Stormwater Management Practices | |
Best Management Practice | Drain Time of WQv |
Infiltration facilities* | 24 - 48 hours |
Extended conveyance facilities (vegetated swales, filter strips) | |
Vegetated filter strip with berm | 24 hours |
Enhanced water quality swale | 24 hours** |
Flow through design | 24 hours |
Extended detention facilities | |
Extended dry detention basins*** | 48 hours |
Wet detention basins + | 24 hours |
Pocket wetland^ | 24 hours |
Constructed wetlands (above permanent pool) | 24 hours |
Bioretention* | 40 hours |
Sand and other media filtration | 40 hours |
* The WQv shall completely infiltrate within 48 hours so there is no standing or residual water pool. ** Sized to pass a hydrograph with a volume equal to the WQv, a duration of two hours, peak rainfall intensity of one inch/hour at a depth of no more than 3 inches and have a minimum hydraulic residence time of 5 minutes. The use of this criterion is limited to sites where the total area disturbed is 5 acres or less. Prior approval from the Stormwater Program Manager is necessary to use this practice. For sites greater than 5 acres or less than 5 acres but part of a larger common plan of development or sale which will disturb 5 or more acres, prior written approval is required from the Ohio EPA. *** The use of a forebay and micropool is required on all extended dry detention basins. Each is to be sized at a minimum 10% of the WQv. + Provide both a permanent pool and an extended detention volume above the permanent pool, each sized with at least 0.75*WQv. ^ A pocket wetland must have a wet pool equal to the WQv, with 25% of the WQv in a pool and 75% in marshes. The EDV above the permanent pool must be equal to the WQv. | |
D. Each practice shall be designed to facilitate sediment removal, vegetation management, debris control, and other maintenance activities defined in the inspection and maintenance agreement for the site.
NOTE: This table is similar to that found in the Ohio EPA Construction General Permit. It has been reordered to match recommended BMP categories and additional description of the “drain time” for vegetated swales and filter strips has been added. The “Flow-Through Design” BMP is an Ohio EPA alternative practice and does require additional approvals from the Community and Ohio EPA depending the development site size, and can be removed from the table if necessary.
(3) Additional criteria applying to infiltration facilities.
A. Infiltration facilities shall only be allowed if the soils of the facility fall within hydrologic soil groups A or B, if the seasonal high water table is at least three feet below the final grade elevation, and any underlying bedrock is at least six feet below the final grade elevation.
B. All runoff directed into an infiltration basin must first flow through a pretreatment practice such as a grass channel or filter strip to remove coarser sediments that could cause a loss of infiltration capacity.
C. During construction, all runoff from disturbed areas of the site shall be diverted away from the proposed infiltration basin site. No construction equipment shall be allowed within the infiltration basin site to avoid soil compaction.
(4) Additional criteria applying to extended conveyance facilities.
A. Facilities shall be lined with fine turf-forming, flood-tolerant grasses.
B. Facilities designed according to the extended conveyance detention design drain time shall:
1. Not be located in areas where the depth to bedrock and/or seasonal high water table is less than three feet below the final grade elevation; and
2. Only be allowed where the underlying soil consists of hydrologic soil group (HSG) A or B, unless the underlying soil is replaced by at least a two and one-half foot deep layer of soil amendment with a permeability equivalent to a HSG A or B soil and an underdrain system is provided.
C. Facilities designed according to the flow through design drain time shall:
1. Only be allowed on sites where:
a. The total area disturbed is five acres or less;
b. The discharge rate from the BMP will have negligible hydrologic impacts to received waters as described in division (c)(6)B. of this section;
c. Prior written approval is given by the Stormwater Program Manager; and
d. For sites greater than five acres or less than five acres but part of a larger common plan of development or sale which will disturb five or more acres, prior written approval has been given by the Ohio EPA.
2. Be designed to slow and filter runoff flowing through the turf grasses with a maximum depth of flow no greater than three inches; and
3. Be designed to have a minimum hydraulic residence time of five minutes.
D. Concentrated runoff shall be converted to sheet flow, or a diffuse flow using a plunge pool, flow diffuser or level spreader, before entering an extended conveyance facility designed according to the flow-through drain time.
(5) Additional criteria for extended detention facilities.
A. The outlet shall be designed to not release more than the first half of the water quality volume in less than one-third of the drain time. The outlet shall be designed to minimize clogging, vandalism, maintenance and promote the capture of floatable pollutants.
B. The basin design shall incorporate the following features to maximize multiple uses, aesthetics, safety and maintainability.
1. Basin side slopes above the permanent pool shall have a run to rise ratio of 3:1 or as approved by the Stormwater Program Manager in order to satisfy the intent of this chapter.
2. The perimeter of all permanent pool areas deeper than four feet shall be surrounded by an aquatic bench that extends at least eight feet and no more than 15 feet outward from the normal water edge. The eight-foot wide portion of the aquatic bench closest to the shoreline shall have an average depth of six inches below the permanent pool to promote the growth of aquatic vegetation. The remainder of the aquatic bench shall be no more than 15 inches below the permanent pool to minimize drowning risk to individuals who accidentally or intentionally enter the basin, and to limit growth of dense vegetation in a manner that allows waves and mosquito predators to pass through the vegetation. The maximum slope of the aquatic bench shall be ten (H) to one (V). The aquatic bench shall be planted with hearty plants comparable to wetland vegetation that are able to withstand prolonged inundation.
3. A forebay designed to allow larger sediment particles to settle shall be placed at basin inlets. The forebay and micropool volume shall be equal to at least 10% of the water quality volume (WQv).
NOTE: Division (c)(6) below identifies the criteria that are currently be used by the Ohio EPA to assess the equivalency of alternative practices that are not listed in Table 2.
(6) Criteria for the acceptance of alternative post-construction BMPs. The applicant may request approval from the Stormwater Program Manager for the use of alternative structural post- construction BMPs if the applicant shows to the satisfaction of the Program Manager that these BMPs are equivalent in pollutant removal and runoff flow/volume reduction effectiveness to those listed in Table 2. If the site is greater than five acres, or less than five acres but part of a larger common plan of development or sale which will disturb five or more acres, prior approval from the Ohio EPA is necessary. To demonstrate the equivalency, the applicant must show the following.
A. The alternative BMP has a minimum total suspended solid (TSS) removal efficiency of 80%, using the Level II Technology Acceptance Reciprocity Partnership (TARP) testing protocol.
B. The water quality volume discharge rate from the selected BMP is reduced to prevent stream bed erosion, unless there will be negligible hydrologic impact to the receiving surface water of the state. The discharge rate from the BMP will have negligible impacts if the applicant can demonstrate one of the following conditions.
1. The entire water quality volume is recharged to ground water.
2. The development will create less than one acre of impervious surface.
3. The development project is a redevelopment project with an ultra-urban setting, such as a downtown area, or on a site where 100% of the project area is already impervious surface and the stormwater discharge is directed into an existing storm sewer system.
4. The stormwater drainage system of the development discharges directly into a large river of fourth order or greater or to a lake, and where the development area is less than 5% of the water area upstream of the development site, unless a total maximum daily load (TMDL) has identified water quality problems in the receiving surface water of the state.
(d) Stormwater quantity control. The comprehensive stormwater management plan shall describe how the proposed stormwater management practices are designed to meet the following requirements for stormwater quantity control for each watershed in the development.
(1) The peak discharge rate of runoff from the critical storm and all more frequent storms occurring under post-development conditions shall not exceed the peak discharge rate of runoff from a one-year, 24-hour storm occurring on the same development drainage area under pre-development conditions.
(2) Storms of less frequent occurrence (longer return periods) than the critical storm, up to the 100-year, 24-hour storm shall have peak runoff discharge rates no greater than the peak runoff rates from equivalent size storms under pre-development conditions. The one-, two-, five-, ten-, 25-, 50- and 100-year storms shall be considered in designing a facility to meet this requirement.
(3) The critical storm for each specific development drainage area shall be determined as follows:
A. Determine, using a curve number-based hydrologic method that generates hydrographs, or other hydrologic method approved by the Stormwater Program Manager, the total volume (acre-feet) of runoff from a one-year, 24-hour storm occurring on the development drainage area before and after development. These calculations shall meet the following standards:
1. Calculations shall include the lot coverage assumptions used for full build out as proposed;
2. Calculations shall be based on the entire contributing watershed to the development area;
3. Curve numbers for the pre-development condition must reflect the average type of land use over the past ten years and not only the current land use; and
4. To account for future post-construction improvements to the site, calculations shall assume an impervious surface such as asphalt or concrete for all parking areas and driveways, regardless of the surface proposed in the site description.
B. From the volume determined in division (d)(3)A. of this section, determine the percent increase in volume of runoff due to development. Using the percentage, select the 24-hour Critical Storm from Table 3.
Table 3: 24-Hour Critical Storm | ||
If the Percentage of Increase in Volume of Runoff is: | The Critical Storm will be: | |
Equal to or Greater Than: | and Less Than: | |
— | 10 | 1 year |
For example, if the percent increase between the pre- and post-development runoff volume for a one-year storm is 35%, the critical storm is a five-year storm. The peak discharge rate of runoff for all storms up to this frequency shall be controlled so as not to exceed the peak discharge rate from the one-year frequency storm under pre-development conditions in the development drainage area. The post-development runoff from all less frequent storms need only be controlled to meet pre- development peak discharge rates for each of those same storms. | ||
(e) Stormwater management on redevelopment projects. Comprehensive Stormwater Management Plans for redevelopment projects shall reduce existing site impervious areas by at least 20%. A one-for-one credit towards the 20% net reduction of impervious area can be obtained through the use of pervious pavement and/or green roofs.
(1) Where site conditions prevent the reduction of impervious area, stormwater management practices shall be implemented to provide stormwater quality control facilities for at least 20% of the site’s impervious area.
(2) When a combination of impervious area reduction and stormwater quality control facilities are used, the combined area shall equal or exceed 20% of the site.
(3) Where projects are a combination of new development and redevelopment, the total water quality volume that must be treated shall be calculated by a weighted average based on acreage, with the new development at 100% water quality volume and redevelopment at 20%.
(4) Where conditions prevent impervious area reduction or on-site stormwater management for redevelopment projects, practical alternatives as detailed in § 1060.10 may be approved by the Stormwater Program Manager.
(Ord. 88-2012, passed 6-25-2012; Ord. 26-2013, passed 3-25-2013)
(a) When the city determines that site constraints compromise the intent of this chapter, off-site alternatives may be used that result in an improvement of water quality and a reduction of stormwater quantity. Such alternatives shall meet the following standards:
(1) Shall achieve the same level of stormwater quantity and quality control that would be achieved by the on-site controls required under this regulation;
(2) Implemented in the same hydrologic unit code (HUC) 14 watershed unit as the proposed development project;
(3) The mitigation ratio of the water quality volume is 1.5 to 1 or the water quality volume at the point of retrofit, whichever is greater;
(4) An inspection and maintenance agreement as described in § 1060.08(d)(10) is established to ensure operations and treatment in perpetuity; and
(5) Obtain prior written approval from Ohio EPA.
(b) Alternative actions may include, but are not limited to the following. All alternative actions shall be approved by the Stormwater Program Manager:
(1) Fees, in an amount specified by the city to be applied to community-wide stormwater management practices;
(2) Implementation of off-site stormwater management practices and/or the retrofit of an existing practice to increase quality and quantity control;
(3) Stream, floodplain or wetland restoration; and
(4) Acquisition or conservation easements on protected open space significantly contributing to stormwater control such as wetland complexes.
(Ord. 88-2012, passed 6-25-2012; Ord. 26-2013, passed 3-25-2013)
Access to stormwater management practices as required by the Stormwater Program Manager for inspections and maintenance shall be granted by easements. The following provisions shall apply to all easements.
(a) Easements shall be included in the inspection and maintenance agreement submitted with the comprehensive stormwater management plan.
(b) Easements shall be approved by the city prior to approval of a final plat and shall be recorded with the Lorain County Auditor. Easements granted after approval of the plat by the city shall be recorded as a separate document with the Lorain County Recorder.
(c) Unless otherwise required by the City Engineer or Stormwater Program Manager, access easements between a public right-of-way and all stormwater management practices shall be no less than 25 feet wide. The easement shall also incorporate the entire practice plus an additional 25-foot wide band around the perimeter of the stormwater management practice. Based on the review of the BMP or stormwater management practice being considered, and in accordance with an agreed upon maintenance plan for the BMP or stormwater management practice, the easement width may be reduced as recommended and approved by the Stormwater Program Manager.
(d) The easement shall be graded and/or stabilized as necessary to allow maintenance equipment to access and manipulate around and within each facility, as defined in the inspection and maintenance agreement for the site.
(e) Easements to structural stormwater management practices shall be restricted against the construction therein of buildings, fences, walls and other structures that may obstruct the free flow of stormwater and the passage of inspectors and maintenance equipment; and against the changing of final grade from that described by the final grading plan approved by the city. Any re-grading and/or obstruction placed within a maintenance easement may be removed by the city at the property owners’ expense.
(Ord. 88-2012, passed 6-25-2012; Ord. 26-2013, passed 3-25-2013)
To receive final inspection and acceptance of any project, or portion thereof, the following must be completed and provided to the Stormwater Program Manager.
(a) Final stabilization must be achieved and all permanent stormwater management practices must be installed and made functional, as determined by the Stormwater Program Manager and per the approved comprehensive stormwater management plan.
(b) An as-built certification, including a survey and inspection, must be sealed, signed and dated by a professional engineer and a professional surveyor with a statement certifying that the stormwater management practices, as designed and installed, meet the requirements of the comprehensive stormwater management plan approved by the Stormwater Program Manager. In evaluating this certification, the Stormwater Program Manager may require the submission of a new set of stormwater practice calculations if he or she determines that the design was altered significantly from the approved comprehensive stormwater management plan. The as-built survey must provide the location, dimensions and bearing of such practices and include the entity responsible for long-term maintenance as detailed in the inspection and maintenance agreement.
(c) A copy of the complete and recorded inspection and maintenance agreement as specified in § 1060.08 must be provided to the Stormwater Program Manager.
(Ord. 88-2012, passed 6-25-2012; Ord. 26-2013, passed 3-25-2013)
(a) The city shall inspect stormwater management practices periodically. Upon finding a malfunction or other need for maintenance, the city shall provide written notification to the responsible party, as detailed in the inspection and maintenance agreement, of the need for maintenance.
(b) Upon notification, the responsible party shall have five calendar days, or other mutually agreed upon time, to makes repairs or submit a plan with detailed action items and established time lines. Should repairs not be made within this time, or a plan approved by the Stormwater Program Manager for these repairs not be in place, the city may undertake the necessary repairs and assess the responsible party.
(Ord. 88-2012, passed 6-25-2012; Ord. 26-2013, passed 3-25-2013)
The comprehensive stormwater management plan review, filing, and inspection fee is part of a complete submittal and is required to be submitted to the city before the review process begins. The Stormwater Program Manager shall establish a fee schedule based upon the actual estimated cost for providing these services.
(Ord. 88-2012, passed 6-25-2012; Ord. 26-2013, passed 3-25-2013)
The applicant may not direct runoff through any water quality structures or portions thereof that would be degraded by construction site sediment until the entire area tributary to the structure has reached final stabilization as determined by the Stormwater Program Manager. This occurs after the completion of the final grade at the site, after all of the utilities are installed, and the site is subsequently stabilized with vegetation or other appropriate methods. The developer must provide documentation acceptable to the Stormwater Program Manager to demonstrate that the site is completely stabilized. Upon this proof of compliance, the water quality structure(s) may be completed and placed into service. Upon completion of installation of these practices, all disturbed areas and/or exposed soils caused by the installation of these practices must be stabilized within two days.
(Ord. 88-2012, passed 6-25-2012; Ord. 26-2013, passed 3-25-2013)
No person shall violate or cause or knowingly permit to be violated any of the provisions of this chapter, or fail to comply with any of such provisions or with any lawful requirements of any public authority made pursuant to this chapter, or knowingly use or cause or permit the use of any lands in violation of this chapter or in violation of any permit granted under this chapter.
(a) Sites that are in violation with the requirements on this chapter as, determined by the Stormwater Program Manager, shall be required to take immediate actions to correct the violations. Sites that do not comply within a reasonable amount of time, as determined by the Stormwater Program Manager, shall be subject to immediate actions such as withholding of inspections including building inspections or underground utility site inspections, stop work orders, cease and desist orders, and final inspections for occupancy permits or plat approval. Sites subject to such actions cannot resume work until all violations are corrected to the satisfaction of the Stormwater Program Manager and such restrictions are suspended in writing. In cases where a violation notice has been issued for a site, the owner/agent shall be granted a reasonable amount of time, not to exceed five calendar days to respond, in writing, to the violations and provide a timeline to complete the necessary corrections. The Stormwater Program Manager shall review and approve the appropriate timelines as he or she feels is appropriate for the violations under review. Responsible parties that object to such actions can appeal to such determination in accordance with § 1060.17 herein.
(b) In the event that the provisions of this chapter and the provisions of Chapter 1058 of this code of ordinances, or the provisions of an approved SWP3 plan, the more restrictive provisions shall prevail. Any activities or actions taken in accordance with the provisions of Chapter 1058 or through an approved SWP3 plan shall not constitute a violation of this chapter.
(Ord. 88-2012, passed 6-25-2012; Ord. 26-2013, passed 3-25-2013)
Any person aggrieved by any order, requirement, determination or any other action or inaction by the city in relation to this chapter may appeal to the court of common pleas. Such an appeal shall be made in conformity with the appropriate standards of the Ohio Revised Code. Written notice of appeal shall be served on the city.
(Ord. 88-2012, passed 6-25-2012; Ord. 26-2013, passed 3-25-2013)
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