(a) SWQM Plans required by this regulation shall meet the following design criteria:
(1) Storm water quantity management practices shall be designed for the ultimate use of the site and to function safely and with minimal maintenance.
(2) Proposed redevelopment project designs shall include storm water quantity management practices that are designed to result in a reduction of the rate of storm water runoff from the site.
A. “Redevelopment” refers to alterations of a property that change the footprint of a site or building which results in greater than 5,000 square feet of land disturbance except for parcels of land less than one acre used for single family residential purposes only.
(3) All storm water quantity management practices shall have easements sufficient to provide access to the Community for municipal purposes. The following conditions shall apply to all easements:
A. Easements and covenants for subdivisions shall be approved by the Community prior to approval of a final plat and shall be recorded with the County Recorder and on all property deeds. Maintenance responsibilities for such practices shall be clearly stated on the record plat.
B. Unless otherwise required by the Community Engineer, access easements to all storm water management practices shall be no less than 20 feet wide. The easement shall also incorporate the entire storm water management practice, plus an additional 15-wide band around the perimeter of the storm water management practice.
C. Unless otherwise required by the Community Engineer, storm water management practices in subdivisions, including basins, ponds, and wetlands, shall be on separate lots held and maintained by an entity capable of long term maintenance responsibility.
D. Those lots crossed by an easement are restricted against the planting within said easement of trees, shrubbery, or other woody growth; against the construction therein of buildings, fences (unless approved by the City), walls, and other structures that may obstruct the free flow of storm water 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 Community.
E. 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.
(4) When developing a Storm Water Quantity Management Plan, storm water management practices shall be used to control storm water quantity. In meeting this requirement, the following shall apply:
A. Storm water management practices shall be designed in accordance with the most recent version of the Rainwater and Land Development Manual, as specified within this regulation, and/or in accordance with specifications provided by the Community Engineer.
(5) Calculations submitted for the design of storm water quantity management practices shall demonstrate the following:
A. The peak rate of runoff from the Critical Storm and all more frequent storms occurring on the development drainage area does not exceed 75% of the peak rate of runoff from a one (1) year frequency, twenty-four (24) hour storm occurring on the same area under pre-development conditions.
B. Storms of less frequent occurrence (longer return periods) than the Critical Storm, up to the 100-year storm, have peak runoff rates no greater than 75% of the peak runoff rates from equivalent storms under pre-development conditions. Consideration of the 1, 2, 5, 10, 25, 50, and 100 – year storms in design and construction will be considered meeting this standard.
C. In the case of redevelopment, the Community may stipulate additional criteria regarding discharge rates with respect to existing storm water problems in down-stream areas.
(6) The Critical Storm for a specific development drainage area shall be determined as follows:
A. Determine, by appropriate hydrologic methods, the total volume of runoff from a one-(1) year frequency, 24-hour storm occurring on the development drainage area before and after development.
B. From the volume determined in (a), determine the percent increase in runoff volume due to development.
C. Using the percentage increase determined in (b), select the 24-hour Critical Storm from the following table:
If the Percentage of Increase in Volume of Runoff is | The Critical Storm for Peak Rate Control will be: | |
Equal to or Greater Than: | And Less Than: | |
-- | 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 |
(7) Calculation Methods.
A. The selection of a calculation method shall be based on the size of the development drainage area and the output information required.
B. The engineer selecting the calculation method and/or performing the calculations shall do so with full knowledge of the method’s limitations, applicable conditions, and degree of accuracy and shall state these in the calculations submitted to the Community Engineer for review.
C. The Community Engineer may reject any calculation method he/she deems inappropriate for the given situation.
(b) Maintenance and Inspection of Storm Water Quantity Management Practices.
(1) The Community Engineer and Law Director shall approve an inspection and maintenance agreement binding on all subsequent owners of land served by the planned storm water quantity management practices before the Community accepts the final plat of the proposed project.
(2) All inspection and maintenance agreements shall do the following:
A. Designate the party responsible for maintenance of storm water quantity management practices including mowing and ensuring outlet structures are clear and in good repair. Unless otherwise approved by the Community, this shall be an entity of common ownership within the proposed subdivision or the owner of a commercial site.
B. Prohibit unauthorized alterations of storm water quantity management practices.
C. Provide access to storm water quantity management practices for inspection by the Community to document the condition of the practices.
(3) Whenever feasible, the location, dimensions, and bearing (including the depth of capacity) of all storm water quantity management practices shall be incorporated on the final plat, prior to approval by the Community, and reference thereon shall be made to the entity or individual(s) responsible for maintenance.
(4) An as-built survey must be completed by qualified registered engineer or surveyor and submitted to the Community showing the location, detention volume (include depth and capacity) of all storm water quantity management practices.
(4) The Community may inspect storm water quantity management practices periodically.
(6) Upon finding a malfunction or other need for maintenance, the Community shall notify the responsible party of the need for maintenance.
(7) Upon notification, the responsible party shall have thirty (30) working days, or other times stipulated by the Community, to make repairs.
(8) Should repairs not be made within this time, or a plan approved by the Community for these repairs not be in place, the Community may undertake necessary repairs and assess the responsible party.
(9) One (1) inspection with a written report will be performed each year. The written report will be given to the City of Fairview Park by May 1st of each and every year after the Best Management Practice (BMP) has been completed. The City retains the authority to require that the annual inspection report be a written and stamped report from a professional engineer or other individual possessing a valid state license that authorizes them to design the type of BMP inspected.
(10) A written report from an inspector on the status of all storm water management easements for each project shall be submitted to the City of Fairview Park by May 1st of each year into perpetuity. These reports will document if restricted plantings, fences and structures are on the easement and will identify the location of the noted easement restriction violations.
(Ord. 08-14. Passed 3-3-08.)