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The post-construction water quality plan developed to meet this chapter will be coordinated and combined with the riparian and wetland setback plan and the construction site conservation plan that are developed for the same site. These plans will be titled and numbered in one consecutive sequence to make a comprehensive storm water management plan for the site. The comprehensive storm water management plan so developed will serve as the storm water pollution prevention plan (SWP3) required by Ohio EPA as part of the NPDES storm water permit for general construction.
(Ord. 1357-09. Passed 8-18-09.)
The intent of this chapter is to:
(a) Allow development while reducing damage to receiving water resources and drainage systems that may be caused by new development or redevelopment activities.
(b) Protect and maintain the receiving stream's physical, chemical, biological characteristics and stream functions.
(c) Provide perpetual management of storm water runoff quality and quantity.
(d) Establish consistent technically feasible and operationally practical standards to achieve a level of storm water quantity and quality control that will minimize damage to public and private property and degradation of water resources, and will promote and maintain the health, safety, and welfare of the residents of the Community.
(e) Control storm water runoff resulting from soil disturbing activities.
(f) Preserve, to the maximum extent practicable (MEP), the natural drainage characteristics of the building site.
(g) Preserve, to the maximum extent practicable (MEP), natural infiltration and groundwater recharge, and maintain subsurface flow that replenishes water resources, wetlands, and wells.
(h) Assure that storm water quality controls are incorporated into site planning and design at the earliest possible stage.
(i) Reduce the need for costly treatment and mitigation for the damage to and loss of water resources that are the result of inadequate storm water quality control.
(j) Reduce the long-term expense of remedial projects needed to address problems caused by inadequate storm water quality control.
(k) Require the incorporation of water quality protection that encourages and promotes habitat preservation into the construction of storm water management practices.
(l) Ensure that all storm water quality practices are properly designed, constructed, and maintained.
(Ord. 1357-09. Passed 8-18-09.)
(a) Where this chapter imposes a greater restriction upon land than is imposed or required by other Community provisions of law, ordinance, contract or deed, the provisions of this chapter shall prevail.
(b) If a court of competent jurisdiction declares any clause, section, or provision of this chapter invalid or unconstitutional, the validity of the remainder shall not be affected thereby.
(c) This chapter shall not be construed as authorizing any person to maintain a private or public nuisance on their property. Compliance with the provisions of this chapter shall not be a defense in any action to abate such nuisance.
(d) Failure of the Community to observe or recognize hazardous or unsightly conditions or to recommend corrective measures shall not relieve the owner from the responsibility for the condition or damage resulting therefrom, and shall not result in the Community, its officers, employees, or agents being responsible for any condition or damage resulting there from.
(Ord. 1357-09. Passed 8-18-09.)
This chapter applies to development areas having new or relocated projects involving highways, underground cables, pipelines, subdivisions, industrial projects, commercial projects, building activities on farms, redevelopment of urban areas and all other land uses not specifically exempted. This chapter does not apply to:
(a) Land-disturbing activities related to producing agricultural crops or silviculture operations regulated by the Ohio Agricultural Sediment Pollution Abatement Rules (1501: 15-03-01 to 1501: 15-03-09 of the Ohio Administrative Code) and existing at the time of passage of this chapter.
(b) Strip mining operations regulated by Ohio R.C. Chapter 1513 and existing at the time of passage of this chapter.
(c) Surface mining operations regulated by Ohio R.C. Chapter 1514 and existing at the time of passage of this chapter.
(d) Linear construction projects (e.g. pipeline or utility line installation) which do not result in the installation of impervious surface and are independent of other construction projects (not part of a larger common plan of development or sale). However, linear construction projects must be designed to minimize the number of stream crossings and the width of disturbance.
(e) Transportation projects that are subject to industry specific Ohio EPA rules are exempt from these rules.
(f) It is not the role of the Community to point out each and every part of the rules and how to implement them on the individual job sites. It is the project owner's responsibility to be proactive in meeting the intent, purpose and requirements of these regulations.
(Ord. 1357-09. Passed 8-18-09.)
In implementing these regulations the Community engineer or other Community officials may consult with the local county SWCD, state and federal agencies and other technical experts as necessary. Any costs associated with such consultations may be assessed to the applicant or his or her designated representative.
(Ord. 1357-09. Passed 8-18-09.)
In order to control post-construction water quality damage and damage to public and private lands, the owner of each development area shall be responsible for developing a post-construction storm water management plan.
(a) This plan will be combined with the construction site conservation plan and the riparian setback and wetland setback plans that are also developed for the site.
(b) This plan will contain a description of controls appropriate for each construction operation covered by these regulations, and the operator will implement such controls in a timely manner.
(c) The BMPs used to satisfy the condition of these regulations shall meet the standards and specifications in the current edition of the Ohio Rain Water and Land Development manual, ODOT post-construction storm water standards, or other manual that is acceptable to the community engineer or Ohio EPA.
(d) The plan must make use of the practices that preserve the existing natural condition to the maximum extent practicable (MEP).
(e) To meet the post-construction requirements of this regulation, the post-construction water quality plan must contain a description of the post-construction best management practices (BMPs) that will be installed during construction for the site and the rationale for their selection. The rationale must address the anticipated impacts on the channel and floodplain morphology, hydrology, and water quality.
(f) This plan will identify the person or entity responsible for continued maintenance of all vegetative and/or mechanical BMPs for both the construction and post-construction phases of the development.
(g) Long-term maintenance requirements and schedules of all BMPs for both the construction and post-construction phases of the development will be identified.
(h) This plan will contain long-term maintenance inspection schedules, including the printed name and contact point of the post-construction landowner (e.g., president of the homeowners association, store manager, apartment complex manager, etc.).
(i) This plan will identify the person or entity financially responsible for maintaining the permanent inspection and maintenance of permanent storm water conveyance and storage structures and other conservation practices.
(j) The method of ensuring that funding will be available to conduct the long-term maintenance and inspections of all permanent storm water, soil erosion and sediment control and water quality practices will be identified.
(k) (1) The post-construction plan will also contain the following information depending on the size of the development sites as well as any additional information required by the Community engineer.
(2) Development sites smaller than five acres. A development site that will disturb one or more, but less than five acres of land and is not a part of a larger common plan of development or sale which will disturb five or more acres of land shall identify:
A. Storm Water Issues. A statement as to how the decreased storm water quality that will be caused by the planned development project will be handled.
B. Structural BMPs. Structural (designed) post-construction storm water treatment practices shall be incorporated into the permanent drainage system for the site.
C. Property Sized BMPs. The BMP(s) chosen must be sized to treat the water quality volume (WQ) and ensure compliance with Ohio's water quality standards in OAC Chapter 3745-1. The WQ shall be equivalent to the volume of runoff from a 0.75 inch rainfall and shall be determined according to one of the two following methods:
1. Through a site hydrologic study approved by the local municipal permitting authority that uses continuous hydrologic simulation and local long-term hourly precipitation records, or
2. Using the following equation:
WQ = C * P * A/12 where:
WQ = water quality volume in acre-feet
C = runoff coefficient appropriate for storms less than one inch (see Table 1)
P = 0.75 inch precipitation depth
A = area draining into the BMP in acres
Table 1 Runoff Coefficients Based on the Type of Land Use
Land Use | Runoff Coefficient |
Industrial & 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 |
D. Where the land use will be mixed, the runoff coefficient should be calculated using a weighted average. For example, if sixty percent of the contributing drainage area to the storm water treatment structure is Low Density Residential, thirty percent is High Density Residential, and ten percent is Open Space, the runoff coefficient is calculated as follows: (0.6)(0.3) + (0.3)(0.5) + (0.1)(0.2) = 0.35.
E. An additional volume equal to twenty percent of the WQ shall be incorporated into the BMP for sediment storage and/or reduced infiltration capacity. The BMPs will be designed according to the methodology included in the Ohio Rainwater and Land Development manual, ODOT post-construction storm water standards, or other manual that is acceptable to Ohio EPA.
F. BMPs shall be designed such that the drain time is long enough to provide treatment, but short enough to provide storage available for successive rainfall events as described in Table 2 below.
Table 2: Target Draw Down (Drain) Times for Structural Post-Construction Treatment Control Practices
Best Management Practice | Drain Time of WQ |
Infiltration | 14 – 18 hours |
Vegetated Swale and Filter Strip | 24 hours |
Extended Detention Basin (Dry Basins) | 48 hours |
Retention Basin (Wet Basins)* | 24 hours |
Constructed Wetlands (above permanent pool) | 24 hours |
Media Filtration, Bioretention | 40 hours |
*Provide both a permanent pool and extended detention volume above the permanent pool, each sized at 0.75 WQ. | |
G. The owner may request approval from the Community Engineer to use alternative structural post-construction BMPs if the owner can demonstrate, in a way that is acceptable to Ohio EPA rules and regulations, that the alternative BMPs are equivalent in effectiveness to those listed in Table 2 above. The use of alternative or vendor supplied post-construction BMPs should be limited to redevelopment projects where justification is provided that the traditional BMPs in Table 2 are technically and economically infeasible.
H. Construction activities shall be exempt from this condition if it can be demonstrated that the WQ is provided within an existing structural post-construction BMP that is part of a larger common plan of development or sale or if structural post-construction BMPs are addressed in a regional or local storm water management plan.
I. For redevelopment projects (i.e., developments on previously developed property), post-construction practices shall either ensure a twenty percent net reduction of the site impervious area, provide for treatment of at least twenty percent of the WQ, or a combination of the two.
J. Site Description.
1. The prior land uses of the site.
2. The nature and type of construction activity (e.g., low density residential, shopping mall, highway, etc.).
3. Total area of the site and the area that is expected to be disturbed (i.e., grubbing, clearing, excavating, filling or grading, including off-site borrow, fill or spoil areas and off-site utility installation areas).
4. Amount of the impervious area and percent imperviousness created by the construction activity.
5. Name and/or location of the immediate receiving stream or surface water(s) and the first subsequent named receiving water and the major river watersheds in which it is located.
K. A vicinity sketch locating:
1. The development area.
2. The larger common plan of development or sale.
3. All pertinent surrounding natural features within 200 feet of the development site including, but not limited to:
a. Water resources such as wetlands, springs, lakes, ponds, rivers and streams (including intermittent streams with a defined bed and bank).
b. Conservation easements.
c. Other sensitive natural resources and areas receiving runoff from the development.
L. The existing and proposed topography shown in the appropriate contour intervals as determined by the Community Engineer (generally one-foot contours are used).
M. The location and description of existing and proposed drainage patterns and facilities, including any allied drainage facilities beyond the development area and the larger common plan of development or sale.
N. Existing and proposed watershed boundary lines, direction of flow and watershed acreage.
O. The person or entity responsible for continued maintenance of all permanent vegetative and/or mechanical post-construction water quality conservation practices (BMPs).
P. The location of any existing or planned riparian and/or wetland setback areas on the property.
(Ord. 1357-09. Passed 8-18-09.)
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