In order to reduce property damage, minimize siltation and soil erosion, and to minimize the hazards of personal injury and loss of life due to flooding, and in order to provide for basic protections to the quality of water in the various streams, drainage channels, ponds and reservoirs in the zoning jurisdiction of the City of Marysville, these regulations set forth below shall hereinafter be applicable to all the following instances, except as noted.
(a) Subdivision of land, where the total platted area exceeds two (2) acres, and/or where the total impermeable surface area upon full development, including streets, parking lots, buildings, drives and sidewalks is estimated to exceed one half (1/2) acre; development for multiple-family dwellings; development for more than two (2) dwelling units on a lot or adjoining lots; development of all residential districts allowed under Article 10 of the Uniform Land Development Code; and commercial, industrial or other types of non-residential development having a total site impermeable surface area of more than one half (1/2) acre, including, but not limited to such features as roofs, driveways and sidewalks.
(b) Such regulations shall not apply to:
(1) Construction of any building or future improvements on a site, which have been previously provided with approved stormwater management control facilities as a part of a larger unit of development.
(2) Remodeling, repair, replacement and improvements to any existing structure or facility that does not cause an increase in the impermeable surface area by more than one half (1/2) acre.
(3) Development where it can be demonstrated by a study, conducted by an engineer, duly licensed by the State of Kansas, that the detention of stormwater runoff or other measures referenced herein would be detrimental to the drainage basin or would provide no benefit to development downstream. Only such specified measure(s) shall be rendered inapplicable to the subject development.
(4) Development in the C-1 and C-2 districts.
(Ord. 1822; Code 2020)
Developers shall submit, along with the preliminary plat, or plans for development of a site or building, a storm water management plan, prepared by an engineer duly licensed by the State of Kansas, describing in sufficient detail the measures which will be employed to comply with the regulations contained under Section 15-303. No building permit shall be issued by the City nor shall a final plat be approved by the Planning Commission until such plans has been approve by the City.
(Ord. 1822; Code 2020)
Notwithstanding applicable Federal and State stormwater quality requirements imposed during construction, the following measures shall be applied, relating to post construction stormwater management.
(a) The quantity of impervious surface shall be minimized as practical for the proposed principal use.
(b) Best management practices (BMP) shall be employed to minimize off-site stormwater runoff, increase on-site infiltration, encourage natural filtration, simulate natural drainage patterns and minimize off-site discharge of pollutants to surface water. BMP may include measures such as detention and retention basins, recharge trenches, porous paving and piping, control terraces, rain gardens and swales, flattening of drainage slopes or other measures having widespread acceptance or endorsed by the Kansas Department of Health and Environment.
(c) The calculated peak rate of stormwater run-off that would be directed off-site upon full development of a proposed subdivision or after the proposed development of a single tract, shall not exceed the peak rate of stormwater run-off that exists prior to such development. Calculations shall take under consideration any contributing runoff from areas adjacent to or upstream from the site. The peak rate of stormwater runoff shall be determined upon application of the design criteria based upon standard engineering practices by a licensed professional engineer.
(d) Where on-site measures to reduce the peak runoff rate to pre-development levels are deemed to be impractical, determination of required offsite improvements shall be made by an engineer, duly licensed by the State of Kansas, and shall be made at the expense of the developer. The Planning Commission shall review and recommend Governing Body approve of one of the following approaches:
(1) Offsite measures, including detention on public right-of-way or on property owned by others, where suitable approvals and agreements running with the land are in place, setting forth financial responsibilities for the construction of such measures and setting forth the party responsible for their continued maintenance.
(2) Offsite improvements to stormwater facilities and channels owned by private parties, where suitable approvals and agreements running with the land are in place setting forth financial responsibilities for the construction of such improvements and setting forth the party responsible for their continued maintenance by the developer.
(3) Offsite improvements to stormwater facilities and channels owned by the City or another public agency at no cost to the City, provided that the Governing Body approves such alterations to City owned public facilities, or that any necessary approvals required from other public agencies are secured.
(e) Where the amount of storage capacity can be increased to provide a benefit to the public, as in cases where a channel draining other properties and streets passes through the subject property, negotiations for public participation in the cost of development may be feasible.
(Ord. 1822; Code 2020)
All stormwater conduits, channels, basins, inlets, etc., must be capable of accommodating the calculated peak of stormwater discharge, assuming full development of the upstream catchment basin, as determined by an engineer, duly licensed by the State of Kansas. Construction of all such facilities shall be in accordance with City standards and shall be subject to inspection by the City for compliance therewith. Where stormwater facilities can be upsized to create a benefit to the public, negotiations for public participation in the cost of development may be feasible.
(Ord. 1822; Code 2020)
The developer shall furnish the City with a certification by an engineer, duly licensed by the State of Kansas, that the stormwater control measures are complete, having the required storage capacity, and that all stormwater facilities are fully functional, prior to the development of any land, the runoff from which is to be addressed by the control measure, in the case of a subdivision; or prior to occupancy of a building, in the case of other developments.
(Ord. 1822; Code 2020)
In cases where a defined open drainage course serving an upstream basin or ten (10) or more acres passes beside or through a property proposed to be subdivided or developed, a stream protection corridor shall be provided, wherein no buildings or structures shall be sited, and no soil shall be disturbed, except as needed to furnish utilities, or to meet the above requirements. The purpose of the corridor is to provide for sufficient vegetation to absorb, filter and slow the speed of stormwater entering the drainage course. Removal of trees, shrubs and ground cover in such corridors shall be minimized unless suitably replaced within sixty (60) days of construction. Restoration of vegetation shall be addressed in the developer’s stormwater management plan for the site. The width of the required corridor shall be measured from the ordinary high water mark of the open drainage course, defined as the edge of vegetation, where delineated, or the edge of the channel required to accommodate a two year storm, where not delineated. The width of the required corridor from the ordinary high water mark of the open drainage course shall be in accordance with the following table:
Contributing Drainage Area Minimum Buffer Width
10 to 40 acres 30 feet
40 to 160 acres 50 feet
160 to 2,200 acres 60 feet
Greater than 2,200 acres 100 feet
(Ord. 1822; Code 2020)
All stormwater management systems shall have an operation and maintenance plan (O&M plan) to ensure that systems function as designed. This plan shall be reviewed and approved at the same time as the stormwater management plan required under Section 15-302 above.
(a) The O&M plan shall, at a minimum, include:
(1) Contact information regarding the owner of the stormwater management system.
(2) Contact information regarding the party responsible for operation and maintenance
(3) A schedule for inspection and maintenance
(4) The routine and non-routine maintenance tasks to be undertaken
(5) An inspection and maintenance log sheet to record the results of the inspection.
(b) The City reserves the right to inspect and to require the owner to perform maintenance on private stormwater management systems, or other stormwater facilities on private property. Maintenance of such systems and facilities shall ordinarily be the responsibility of the property owner and shall include all necessary and proper maintenance including without limitations:
(1) Debris removal and cleaning
(2) Cutting of vegetation
(3) Repair of erosion
(4) Removal of silt
(5) Maintenance of structural facilities.
(c) Where it is determined that the public is to own and maintain stormwater management systems or other stormwater facilities, governing body acceptance of the necessary easement(s) is required.
(Ord. 1822; Code 2020)
The performance standards and design criteria set forth herein establish minimum requirement which must be implemented with good engineering practice and workmanship. Use of the requirement contained herein shall not constitute a representation, guarantee or warranty or any kind by the City, or its officers and employees, nor shall approval of a stormwater management plan imply that the land uses permitted will be free from damages caused by stormwater runoff. The requirements of this Article were established to consider historical records of average rainfall and engineering and scientific methods. However, larger storms may occur or stormwater run-off heights may be increased by manmade or natural causes. The provisions of the Article, therefore, shall not be deemed to create liability on the part of the City or any officer or employee thereof with respect to any legislative or administrative decision lawfully made hereunder.
(Ord. 1822; Code 2020)