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(a) Runoff Rate: The peak runoff rate from the development area shall not be greater after development than it was before development. The applicant shall provide calculations proving no increase in the runoff rates from the one (1), two (2), five (5), ten (10), twenty-five (25), fifty (50) and one hundred (100) year storms.
(b) Runoff Volume: Increases in the runoff volume shall be offset by further restricting runoff rates. Based on the increase in runoff volume, the applicant shall determine the critical storm for the development area. The runoff rate from the critical storm shall be restricted to the one (1) year pre- development storm runoff rate. The critical storm shall be calculated as follows:
(1) Determine the total volume of runoff from a one-year frequency, twenty-four hour storm, occurring on the development area before and after development.
(2) From the volumes in paragraph (1) determine the percent of increase in volume of runoff due to development according to the equation (Q after divided by the Q before) X 100 and, using this percentage, select the critical storm from this table:
Table 4: Critical Storm Selection
The Percentage Increase in Volume Of Runoff is: | ||
Equal To Or Greater Than | And Less Than | The 24-hour "Critical Storm" For Discharge Will Be |
0 | 10 | 1 Year |
10 | 20 | 2 Years |
20 | 50 | 5 Years |
50 | 100 | 10 Years |
100 | 250 | 25 Years |
250 | 500 | 50 Years |
500 | --- | 100 Years |
(c) Detention Or Retention Basin Exemption For Redevelopment Or For Expansion Of Existing Facilities:
(1) For any development regulated by this ordinance, the construction of a detention or retention basin may not be required for the development if the post-development peak discharge for a 100 year frequency twenty-four (24) hour storm increases the existing peak discharge by one (1) cubic foot per second or less using the TR-55 method of calculation or other method approved by the Community Engineer. The Community Engineer can waive this requirement if existing storm sewers and drainage structures can safely handle the expected increase in flow.
(2) Only one (1) exemption will be allowed per parcel. Any subsequent expansion must provide for detention or retention and must include the previously exempted area.
(d) Where the Community Engineer determines that site constraints exist in a manner that compromises the intent of this ordinance to improve the management of storm water runoff as established in this section, practical alternatives may be used to result in an improvement of water quality and/or a reduction of storm water runoff. Such alternatives must be in keeping with the intent and likely cost of those measures that would otherwise be required to meet the objectives of this section. When possible, all practical alternatives shall be implemented within the drainage area of the proposed development project. Practical alternatives can include, but are not limited to:
(1) Fees shall be paid in an amount specified by the Community Engineer. These fees shall be applied by the Community to storm water management practices that reduce existing storm water runoff.
(2) Implementation of off-site storm water management practices.
(3) Watershed or stream restoration.
(4) Retrofitting of an existing storm water management practice.
(5) Other practices approved by the Community Engineer in keeping with the intent of this section.
(e) Table 4b: Infiltration Post Construction Practices with Maximum Drain Times
Table 4b Infiltration Post-Construction Practices with Maximum Drain Times
Infiltration Practices | Maximum Drain Time of WQv |
Bioretention Area/Cell 1,2 | 24 hours |
Infiltration Basin 2 | 24 hours |
Infiltration Trench 3 | 48 hours |
Permeable Pavement - Infiltration 3 | 48 hours |
Underground Storage - Infiltration 3,4 | 48 hours |
1. Bioretention soil media shall have a permeability of approximately 1 - 4 in/hr. Meeting the soil media specifications in the Rainwater and Land Development manual is considered complaint with this requirement. Bioretention cells must have underdrains unless in-situ condition allow for the WQv (surface ponding) plus the bioretention soil (to a depth of 24 inches) to drain completely within 48 hours.
2. Infiltrating practices with the WQv stored aboveground (bioretention, infiltration basin) shall fully drain the WQv within 24 hours to minimize nuisance effects to standing water and to promote vigorous communities of appropriate vegetation.
3. Subsurface practices designed to fully infiltrate the WQv (infiltration trench, permeable pavement with infiltration, underground storage with infiltration) shall empty within 48 hours to recover storage for subsequent storm events.
4. Underground storage systems with infiltration must have adequate pretreatment of suspended sediments included in the design and documented in the SWP3 in order to minimize clogging of the infiltrating surface. Pretreatment shall concentrate sediment in a location where it can be readily removed. Examples include media filters situated upstream of the storage or other suitable alternative approved by Ohio EPA. For infiltrating underground systems, pretreatment shall be eighty percent (80%) effective at capturing total suspended solids according to the testing protocol established in the Alternative Post-Construction BMP Testing Protocol.
(Ord. 2022-17. Passed 3-22-22.)
(a) Ohio Dam Safety Laws: The provisions of the Ohio Dam Safety Laws shall be followed. Proof of compliance with the Ohio Dam Safety Law administered by the ODNR Division of Water shall be, but is not limited to, a copy of the ODNR Division of Water permit number or a copy of the project approval letter from the ODNR Division of Water or a letter from the site owner explaining why the Ohio Dam Safety Law is not applicable. The written proof will be provided to the Community Engineer before a construction permit will be issued.
(b) NPDES Permits: The provisions of the National Pollutant Discharge Elimination System (NPDES) Permits, issued by the Ohio EPA, shall be followed. Proof of compliance shall be, but is not limited to, a copy of the Ohio EPA NPDES Permit number or a letter from the site owner explaining why the NPDES Permit is not applicable. The written proof will be provided to the Community Engineer before a construction permit will be issued.
(c) Federal and State Wetland Permits: The provisions of the U.S. Army Corps of Engineers dredge and fill permits for federally-protected wetlands shall be followed. The provisions of Ohio EPA's Isolated Wetlands Permits shall also be followed. Wetlands and other waters of the United States shall be delineated by protocols accepted by the U.S. Army Corps of Engineers and the Ohio EPA at the time of the application of these regulations. Written proof of compliance with both permit programs will be provided to the Community Engineer before a construction permit will be issued. Proof of compliance shall be, but is not limited to, the following:
A copy of the U.S. Army Corps of Engineers Individual Permit, if required for the project, showing project approval and any restrictions that apply to site activities; or a site plan showing that any proposed fill of waters of the United States conforms to the general and specific conditions specified in the applicable Nationwide Permit; or a letter from the site owner verifying that a qualified professional has surveyed the site and found no wetlands or other waters of the United States. Such a letter shall be noted on site plans submitted to the Community.
(Ord. 2022-17. Passed 3-22-22.)
No person shall violate, or cause, or knowingly permit to be violated, any of the provisions of these regulations, or fail to comply with any such provisions or with any lawful requirements of any public authority made pursuant to these regulations, or knowingly use or cause or permit the use of any lands in violation of these regulations or in violation of any permit granted under these regulations. (Ord. 2022-17. Passed 3-22-22.)
(a) All permanent storm water, soil erosion, other wastes control, and water quality practices not specifically waived by the Community shall be constructed prior to the granting of the Final Plat Approval. Upon the request of the owner, the Community may defer the construction or installation of a permanent storm water, soil erosion, sediment, or other wastes control or water quality practice prior to the approval of the final plat where, in the Community Engineer's judgment, such proper construction or installation is not immediately necessary for the protection of the public health and safety; and where the prior installation or construction of such improvement would constitute an undue hardship on the owner because in the case of new vegetation or weather conditions, or because in the case of concrete, building construction could cause cracking and excessive wear and tear on new structures. In such event, the Community shall require a Security Bond, Escrow Account, Certified Check or Cash to guarantee that such deferred improvements will be properly constructed or installed within an agreed specified time, but not to exceed six (6) months after the filing of such final plat.
(b) The owner will provide a maintenance guarantee for all permanent improvements, and soil erosion, wastes controls, and water quality practices.
(c) The Community shall require a Security Bond, Escrow Account, Certified Check or Cash to guarantee that the planned temporary and permanent soil erosion, sediment, and other wastes controls and water quality practices will be constructed and removed in a timely manner, as determined by the Community Engineer.
(1) The Guarantee. The guarantee of both performance and maintenance will be in the form of a Security Bond, Escrow Account, Verified Check or Cash. The Security Bond, Escrow Account, Verified Check or Cash will be used by the Community to complete any guaranteed construction or removal of improvements or temporary and permanent soil erosion, sediment, and other wastes control practices that are not adequately completed, maintained or removed by the owner in a timely manner, as determined by the Community Engineer. The Security Bond, Escrow Account, Verified Check or Cash will be in the total amount of both the performance guarantee and the maintenance guarantee. Ohio municipalities and counties may require performance bonds or other guarantees for water management improvement as stated in the Ohio R.C. Chapter 711.101.
A. Security Bond, Escrow Account, Verified Check or Cash shall be deposited with the Community prior to review by the Community Engineer and/or its consultants to cover professional services of the Community Engineer, Building Commissioner, Zoning Inspector and/or other experts required by the Community Engineer, Community Council, Mayor or Review Boards.
B. No soil disturbing activities shall be permitted until a Security Bond, Escrow Account, Verified Check or Cash has been posted to the satisfaction of the Community Engineer sufficient for the Community to perform the obligations otherwise to be performed by the owner or person responsible for the development area as stated in this regulation, and to allow all work to be performed as needed in the event that the owner or person responsible for the development area fails to comply with the provisions of this regulation. The Security Bond, Escrow Account, Verified Check or Cash shall be released only after all work required by this regulation has been completed to the satisfaction of the Community Engineer and all permit and inspection fees required by these regulations have been paid in full.
C. No project subject to this regulation shall commence without the Construction Site Conservation Plan having been approved by the Community Engineer.
(2) Performance Guarantee. The furnishing of a performance guarantee will be maintained in an amount of not less than one hundred twenty percent (120%) of the estimate approved by the Community Engineer, of installation of the deferred improvements.
(3) Maintenance Guarantee. The maintenance guarantee shall be maintained for a period of not less than two (2) years after final acceptance of the storm water, soil erosion, sediment, and other wastes control practices in an amount equal to twenty percent (20%) of the estimate approved by the Community Engineer, of the construction and, where necessary, removal of such practices.
(4) Time Extension. The Community Engineer may extend for cause the time allowed for the installation of the improvements for which the performance guarantee has been provided with the receipt of a written request from the owner.
(5) Completion. Upon completion of the construction of improvements or temporary and/or permanent, soil erosion, sediment, and other wastes control practices and the removal of the temporary soil erosion, sediment, and other wastes control practices for which the performance guarantee has been provided the owner shall notify the Community Engineer of this fact.
(6) Inspection. The Community will not release the Security Bond, Escrow Account, Verified Check or Cash guarantee until the Community Engineer has inspected the site to ensure that the guaranteed item(s) have been completed and/or removed.
(7) Slow Release Devices. Performance and maintenance guarantees will be maintained on the temporary sediment removal slow release devices installed in detention and retention basins until the entire site has reached final soil stabilization. Final stabilization in single-family residential developments is when ninety percent (90%) of the homes are constructed with their lawns completely installed and any remaining unbuilt lots having been permanently stabilized with a uniform ground cover at a growth density of eighty percent (80%) or better.
(8) Release. The Construction Maintenance Guarantee shall not be released by the Community until all temporary soil erosion and sediment control practices that are no longer needed have been removed, properly disposed of and any trapped sediment has been stabilized.
(Ord. 2022-17. Passed 3-22-22.)
(a) This plan will be combined with the Post-Construction Water Quality plans that have also been developed for the site.
(b) Plans developed by the site owners and approved by the Community in accordance with this regulation do not relieve the site owner of responsibility for obtaining and complying with all other necessary permits and/or approvals from federal, state, county, and local agencies and departments. If requirements vary, the most stringent requirement shall be followed. Plans submitted to the Community Engineer for review and approval shall be accompanied by all other required permits and documentation relevant to the project, including but not limited to the permits required and issued by the US Army Corps of Engineers, Ohio EPA and ODNR Division of Water.
(c) Three (3) sets of the plans and necessary data required by this regulation shall be submitted to the Community Engineer with text material being submitted on eight and one-half by eleven (8.5 by 11) inch paper and drawings on no larger than twenty-four by thirty-six (24 by 36) inch sized paper. Submittals shall include:
(1) At the preliminary plan approval request, the preliminary plans only need to show all of the following existing and planned features: streams, water bodies, wetlands, riparian and wetland setback areas, permanent BMPs and storm water management detention and retention basins.
(2) At the improvement plan approval request, the entire Comprehensive Storm Water Management Plan must be submitted.
(d) The Community Engineer shall review the plans, and shall approve or return these with comments and recommendations for revisions within thirty (30) working days after receipt of the plan as described above. A plan rejected because of deficiencies shall receive a report stating specific problems. At the time of receipt of a revised plan, another thirty (30) day review period shall begin.
(e) Approved plans shall remain valid for two (2) years from the date of approval. After two (2) years the plan(s) approval automatically expires.
(f) No soil disturbing activity shall begin before all necessary local, county, state and federal permits have been granted to the owner or operator.
(g) The Community will do construction inspections until the site reaches final stabilization as determined by the Community Engineer.
(Ord. 2022-17. Passed 3-22-22.)
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