13.35.020 Waiver – Exemptions – Mitigations.
(a) The Utilities Director may grant a waiver for one or more stormwater management requirements for projects that meet any of the following conditions:
(1) The project will discharge stormwater runoff to a stormwater management facility located off site, whether public or private, that is designed, adequately sized, constructed and maintained to achieve or exceed the required performance standard(s), inclusive of the stormwater runoff being discharged to the facility by the project. To receive this waiver, all of the following requirements shall be met:
(i) Stormwater runoff from the project shall not cause pollution, erosion, and flooding at any location between the project and the off-site facility, and shall not enter a stream, lake, or wetland prior to treatment by the off-site facility.
(ii) The off-site facility must be fully functional and operating in accordance with this chapter prior to construction of the project. If the off-site facility or any conveyances located downstream of the project must be improved to meet these requirements, the applicant shall provide design plans detailing the necessary improvements and their achievement of the required standard(s). Improvements to off-site facilities shall adhere to, without exception, this chapter, Chapter 13.30 TMC, and the City of Topeka stormwater BMP design policy handbook. The applicant is solely responsible for coordination of all necessary improvements with the owner(s) of the facility(s) and for ensuring said improvements are made in accordance with these requirements.
(iii) The applicant shall obtain a legally binding written agreement signed by the owner(s) of the off-site facility acknowledging and authorizing the discharge of stormwater runoff from the project to the off-site facility(s) and clearly establishing the party responsible for the long-term operation and maintenance of the facility in keeping with Chapter 13.40 TMC. This agreement shall be recorded by the applicant with the Shawnee County Register of Deeds.
(2) An engineering study determines that installing a stormwater management facility in order to meet the stormwater management standards will cause adverse impact to water quality, or cause a negative impact to a downstream channel or property.
(3) The stormwater quantity performance standard may be waived for a redevelopment if an engineering study demonstrates there is no net increase in stormwater runoff peak flow and volume from current conditions for the stormwater quality design storm events established in the City of Topeka stormwater BMP design policy handbook.
(b) In order to receive a waiver, the Director may require the applicant to provide an engineering study which substantiates the criteria required to receive said waiver. The study shall be prepared by a professional civil engineer licensed in the State of Kansas and shall be performed in keeping with the City of Topeka stormwater BMP design policy handbook. For waivers provided under subsection (a)(1) of this section, provision of the approved as-built plan for the off-site stormwater management facility may be sufficient for this purpose.
(c) A waiver from compliance with one or both performance standards shall not be construed as a waiver or exemption from all other requirements in this chapter.
(d) Acceptable mitigation measures may be required in order to prevent deterioration of existing culverts, bridges, dams, and other structures, degradation of biological functions or habitat, accelerated stream bank or stream bed erosion or siltation, and increased threat of flood damage to public health, life, and property. Such mitigation measures may include, but are not limited to:
(1) The purchase and donation of privately owned lands, or the granting of an easement to be dedicated for preservation or reforestation.
(2) The creation of a stormwater management facility or other drainage improvement on previously developed properties, public or private, that currently lack stormwater management facilities.
(3) Granting an easement or dedicating land to the City to be used for the construction of an off-site stormwater management facility. Such easement shall be granted prior to issuance of any building permit.
(e) Site plans for construction or reconstruction of single-family and two-family dwellings on individual lots are exempt from this chapter if any of the following conditions apply:
(1) Are located in a residential subdivision that was platted prior to August 29, 2011; or
(2) Are located in a residential subdivision served by a stormwater management facility that is/was designed, adequately sized, constructed and maintained to achieve or exceed the required performance standard(s) for the subdivision in its fully developed condition; or
(3) Are designed to safely direct stormwater runoff generated by building rooftops to a vegetated channel or vegetated area before discharge to a street, gutter, water body, or the municipal stormwater system. The design must ensure stormwater runoff will not cause vegetation damage, soil erosion, and flooding on, or downstream of, the property.
(f) Developments or redevelopments for which a subdivision plat or site plan is not required shall be exempted from the requirements of this chapter.
(g) An exemption from this chapter shall not be construed as a release from on-site drainage improvements that may be necessary to avoid on-site or off-site flooding or erosion or are required in accordance with building and construction codes, nor from providing adequate erosion prevention and sediment control measures to protect adjoining property owners, local waterways, and public right-of-way. (Ord. 20262 § 3, 10-6-20; Ord. 20089 § 110, 10-17-17.)