The purpose of this section is to provide requirements and criteria to prevent and manage stormwater pollution and to diminish adverse impacts to health, safety, property, and the general welfare of the citizens of the City of Grand Island through regulating stormwater runoff from areas of development and redevelopment to the maximum extent practicable as required by the Federal Clean Water Act, 33.U.S.C. § 1251 et seq. (as amended to date), the Nebraska Environmental Protection Act, Neb. Rev. Stat. § 81-1501 et seq. (as amended to date) and the rules and regulations promulgated under such Acts. This chapter will also promote the public welfare by guiding and regulating the design, construction, and maintenance of areas of development and redevelopment. Additional criteria can be found in the City of Grand Island Post-Construction Stormwater Guidance Manual.
A. Post-Construction Requirement of Permanent BMPs/STFs.
1. Land development that meets the requirements of Section 40-11 (A)(1) must address stormwater runoff quality through the use of permanent BMPs/STFs. Permanent BMPs/STFs shall be provided for in the drainage plan for any subdivision plat, annexation plat, development agreement, subdivision agreement or other local development plan.
2. Structural BMPs/STFs located on private property shall be owned and operated by the owner(s) of the property on which the BMP is located; unless the City of Grand Island agrees in writing that a person or entity other than the owner shall own or operate such BMP/STF. As a condition of approval of the BMP/STFs, the owner shall also agree to maintain the BMP/STF in perpetuity to its design capacity unless or until the City of Grand Island shall relieve the property owner of that responsibility in writing. The obligation to maintain the BMP/STF shall be memorialized on the subdivision plat, annexation plat, development agreement, subdivision agreement or other form acceptable to the City of Grand Island and shall be recorded with the City of Grand Island Public Works Department.
3. The preferred Structural BMPs/STFs that are acceptable in the City of Grand Island and its 2 mile jurisdictional boundary without additional review by the Public Works Director are: Bioswales, Rain Gardens, Permeable Pavement, Green Roofs, Retention Ponds, and Detention Ponds (Provided the detention Ponds include treatment areas to improve water quality; i.e. a treatment forebay and filtration strip). If there are other stormwater treatment measures a developer would like to use, plans for those measures will need to be submitted to and approved in writing by the Director of Public Works, prior to construction and development.
4. A Post Construction Stormwater Management Plan (PCSWMP) shall be submitted to the planning department for transmittal to the Public Works Director on a form or format specified by the director, as part of any preliminary plat application required under Sec. 33-7; if not already submitted as part of a preliminary plat process. For any significant redevelopment, a post-construction stormwater management plan shall be submitted along with the permit application for any activity requiring a building permit under Sec. 33-6.
(1) For all developments that have not had a preliminary plat approved prior to January 1, 2019, the post-construction stormwater management plan, at a minimum, shall include Low Impact Development (LID) STFs to provide for water quality control of the first one-half inch of runoff from the site. The director may also require this minimum control level for replats that significantly increase the amount of impervious area in a preliminarily platted subdivision, which was approved prior to July 1, 2018.
(2) For all developments with plats preliminarily approved after July 1, 2018 and for significant redevelopment projects, the post-construction stormwater management plan, at a minimum shall include the STF or STFs selected, the STF design, schedules and procedures for inspection and maintenance of the STFs, and where it is reasonably practicable, include STFs for water quality control of the first one-half inch of runoff from the site. Provisions for STFs are set forth in the Grand Island Post-Construction Stormwater Management Guide. For significant redevelopment projects that involve replacement of building structures without significant disturbance of existing parking or other pervious areas, BMPs for water quality control of the first one-half inch of runoff from the site shall not be required. For significant redevelopment projects involving an outlot parcel that is part of a greater existing development, the calculation of the area requiring control of the first one-half inch of runoff shall be based only on the impervious area of the project site that is being added or disturbed within the out lot parcel.
B. Exemptions from the Post-Construction Storm Water Management Plan. Systems designed to accommodate only one single family dwelling unit, duplex, triplex, or quadraplex, provided the single unit
is not part of a larger common plan of development or sale, are exempt from the requirements in this Ordinance to submit a Post-Construction Storm Water Management Plan. Additional policies and procedures for the development and implementation requirements for BMPs/STFs can be found in the City of Grand Island Post-Construction Stormwater Management Guide.
C. Completion of Permanent BMPs/STFs. Upon completion of a project, the City of Grand Island shall be provided a written certification stating that the completed project is in compliance with the approved Final Drainage Plan. All applicants are required to submit “as built” plans for any permanent BMPs once final construction is completed and must be signed by a professional engineer licensed in the State of Nebraska.
D. Ongoing Inspection and Maintenance of Permanent BMPs/STFs.
1. The owner of site must, unless an on-site stormwater management facility or practice is dedicated to and accepted by the City of Grand Island, execute an inspection and maintenance agreement, that shall be binding on all subsequent owners of the permanent BMPs/STFs.
2. Permanent BMPs/STFs included in a Drainage Plan which is subject to an inspection and maintenance agreement must undergo ongoing inspections to document maintenance and repair needs and to ensure compliance with the requirements of the agreement, the plan and this Ordinance.
(1) All BMPs/STFs must be inspected by the owner, using an approved inspection form, (Appendix B of the Grand Island Post-Construction Guidance Manual), for maintenance and repair requirements at a minimum, once per quarter.
(2) All BMPs/STFs shall be inspected, by a qualified employee of the City of Grand Island, twice per year to ensure owner compliance with the design of the BMP/STF and to ensure maintenance and repair actions are adequately monitored.
3. The maintenance agreement shall also provide that if, after notice by the City to correct a violation requiring maintenance work, satisfactory corrections are not made by the owner(s) or occupant within a reasonable period of time (30 days maximum), and the City may perform all necessary work to place the facility in proper working condition. The owner(s) or occupant of the facility shall be assessed the cost of the work and any lawful penalties.