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HomeMy WebLinkAbout3314 ORDINANCE NO. 3 3 14 AN ORDINANCE OF THE CITY OF AUBURN, WASHINGTON, ESTABLISHING A NEW CHAPTER OF THE AUBURN CITY CODE AND REQUIRING A DRAINAGE PLAN TO BE SUBMITTED IN CONJUNCTION WITH CERTAIN PERMITS, SPECIFYING THE CONTENTS THEREOF. WHEREAS, an expanding population and increased development of land, coupled with inadequate drainage controls, has led to drainage and runoff problems; and WHEREAS, these drainage and runoff problems contribute to increased sedimentat;on in ponds, creeks, and streams, thereby degrading water quality; and WHEREAS, these drainage and runoff problems also contribute to water quality degradation through excessive discharge of nutrients, metals, oil and grease, toxic materials, and other detrimental substances; and WHEREAS, inadequate surface and subsurface drainage planning and practices lead to crosion and property damage, and risk to life; and WHEREAS, excess water runoff on streets and highways poses a safety hazard to both lives and property; and WHEREAS, the Auburn City Council finds that future problems could be avoided if developers, both private and public, provide for adequate drainage of their property. NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF AUBURN, WASHINGTON, DO ORDAIN AS FOLLOWS: There is hereby created a new chapter of the Auburn City Code entitled "Drainage Plans." Section 1. PURPOSES. The Auburn City Council finds that this chapter is necessary in order to promote sound development policies and construction procedures which respect and preserve the City of Auburn's water courses; to minimize water quality degradation and control the sedimentat;on of creeks, streams, ponds, lakes and other water bodies; to protect property owners adjacent to devleoping and developed land from increased runoff rates which could cause crosion of abutting property; to protect downstream owners; to preserve and Ordinance No. 3314 Page One 9-21-78 enhance the suitability of waters for contact recreation and fishing; to preserve and enhance the aesthetic quality of the waters; to maintain and protect valuable groundwater resources; to minimize adverse effects of alterations in goundwater or quantities, locations, and flow patterns; to ensure the safety of City of Auburn roads and rights of way; and to decrease drainage related damage to public and private property. Section 2. DEFINITIONS. (1) "Procedures Manual" shall mean the manual of technical and administrative procedures established by the Engineering and Planning Departments which delineates methods to be used, the level of detail of analysis required, and other details for implementation of the provisions of this Ordinance. (2) "Comprehensive Drainage Plan" refers to a detailed analysis for each drainage basin which compares the capabilities and needs for runoff accomodation due to various combinations of development, land use, structural and nonstructural management alternatives. The plan recommends the form, location and extent of quantity and quality control measures which optimally would meet the legal constraints, water quality standards, and community standards, as well as identifying the institutional and funding requirements for plan implementation. (3) "Computations" shall mean calculations, including coefficients and other partinent data, made to determine the frainage plan with rates of flow of water given in cubic feet per second and cubic meters per second (cms). (4) "Design Storm" shall refer to that rainfall event which is selected by the Engineering Department for purposes of design, specifying both the return period in years and the duration in hours. (5) "Detention facilities" shall mean facilities designed to hold runoff while gradually releasing it at a predetermined maximum rate. (6) "Developer" shall mean the individual(s) or corporation(s) applying for the permits or approvals described in Section 3 (1) of this chapter. (7) "Developmental coverage" shall mean all developed surface areas within the subject property including, but not limited to, rooftops, driveways, carports, accessory buildings, parking areas, and any other impervious surfaces. Ordinance No. 331 4 Page Two 9-21-78 During construction, "developmental coverage" shall include the above in addition to the full extent of any alteration of previously occurring soils, slope or vegetation due to grading, temporary storage, access areas, or any other short-term causes. (8) "Drainage area" shall mean the watershed contributing water runoff to and including the subject property. (9) "Drainage plan" shall mean a plan for collection, transport, treatment, and discharge or recycle of water within the subject property. (lO) "Drainage treatment/abatement facilities" shall mean any facilities installed or constructed in conjunction with a drainage plan for the purpose of treatment or abatement of urban runoff, excluding retention or detention facilities. (11) "Natural location" of drainage systems shall refer to the location of those channels, swales, and other non-man-made conveyance systems as defined by the first documented topographic contours existing for the subject property, either from maps or photograps, or such other means as appropriate. (12) "Peak discharge" shall mean the maximum surface water runoff rate (cfs and cms) determined for the design storm. (13) "Planned unit development" shall 'refer to residential developments which are planned and/or developed in several stages but submitted together for approvals, and which typically consist of clusters of multi-unit structures interspersed with areas of common open space. (14) "Receiving bodies of water" shall mean creeks, streams, lakes and other bodies of water into which waters are directed, either naturally, in man- made ditches, or in closed conduit systems. (15) "Retention facilities" shall mean facilities designed to hold water for a considerable length of time and then consume it by evaporation, plant transpiration, or infiltration into the soil. (16) "Subject property" shall mean the tract of land which is the subject of the permit and/or approval action, as defined by the full legal description of all parcels involved in the proposed development. Ordinance No. 3314 Page Three 9-21-78 Section 3. SUBMISSION OF A DRAINAGE PLAN. (1) All developers applying for any of the following permits and/or approvals shall submit for approval a drainage plan with their application and/or request: (a) Grading permit. (b) Substantial development permit required under RCW 90.58 (Shoreline Management Act). (c) Subdivision approval. (d) Short subdivision approval. (Industrial and Commercial) (e) Conditional Use Permits. (f) Building permits where the permit relates to 5,000 or more square feet of development coverage within the property, or where development is in a critical area. (g) Planned unit development. (2) Commencement of construction work under any of the above permits or applications shall not begin until such time as final approval of the drainage plan is obtained in accordance with Section 7 of this chapter. (3) The same plan submitted during one permit/approval process may be subsequently submitted with further required applications. The plan shall be supplemented with such additional information that is requested by the Engineering Department or required by the provisions of the Compliance Manual. (4) The plan requirement established in this section shall apply except when the developer demonstrates to the satisfaction of the Engineering and Planning Departments that the proposed activity or development: (a) Will neither seriously nor adversely impact the water quality conditions or any affected receiving bodies of water, and (b) Will not alter the surface discharge location, alter the drainage pattern on adjoining properties, alter drainage patterns, increase the discharge, nor cause any other adverse effects in the drainage area, and Ordinance No. 3314 Page Four 9-21 °78 10-9-78 (page 4 only) (c) Will not alter the subsurface drainage patterns, flowrates, and discharge points, nor result in any significant adverse effects to property or residents.. Section 4. CONTENTS OF A DRAINAGE PLAN. All persons applying for any of the permits and/or approvals contained in Section 3 of the Auburn City Code shall provide a drainage plan for surface and pertinent subsurface water flows entering, flowing within, and leaving the subject property both during and after construction. The detailed form and contents of the drainage plan shall be prepared by a registered professional Civil Engineer and shall be prepared in accordance with procedures established by the Engineering and Planning Departments, or in the Procedures Manual. The Procedures Manual will set forth the manner of presenting the following required information: (a) Background computations for sizing drainage facilities: (1) Depiction of the drainage area on a topographical map of approved scale and contour interval, with acreage of the site, development, and developmental coverage indicated. (2) Indication of the peak discharge and volume of surface water currently entering and leaving the subject property due to the design storm. (3) Indication of the peak discharge and volume of runoff which will be generated due to the design storm within the subject property if the development or proposed activity is allowed to proceed. (b) Proposed measures for handling the computed runoff at the detail level specified in the Procedures Manual. (c) Proposed measures for controlling runoff during construction. The requirements of this section may be modified at the discretion of the Auburn City Engineering Department in special cases requiring more information, with the concurrence of the Planning Department. Section 5. MANDATORY REQUIREMENTS FOR DRAINAGE IMPROVEMENTS. (1) (a) Surface water entering the subject property shall be received Ordinance No. 3314 Page Five 9-21-78 at the naturally occurring locations and surface water exiting the subject property shall be discharged at the natural locations with adequate energy dissipators within the subject property to minimize downstream damage and with no diversion at any of these points; and (b) The design storm peak discharge from the subject property may not be increased by the proposed development; and (c) Retention/detention facilities must be provided in order to maintain surface water discharge rates at or below the existing design storm peak discharge; and (d) Where open channel construction is used to handle drainage within the subject property, a minimum of fifteen (15) feet will be provided between any structures and the top of the bank of the defined channel. (1) In open channel work the water surface elevation will be indicated on the plan and profile drawings. The con- figuration of the finished grades constituting the banks of the open channel will also be shown on the drawings. (2) Proposed cross section of the channel will be shown with stable side slopes as approved by the Engineering Department. (3) The water surface elevation of the flow for the design storm will be indicated on the cross section. (c) When a closed system is used to handle drainage within the subject property, the system will be a minimum of ten (10) feet from all structures. (2) To the extent possible, approved measures for controlling runoff during construction should comply with the above provisions. (3) Variances from the requirements of Section 5 (1) may be permitted only after a determination by the Engineering and Planning Departments, using the Comprehensive Drainage Plan (if available) and/or employing the following criteria: (a) Sufficient capacity of downstream facilities under design conditions. Ordinance No. 331 4 Page Six 9-21-78 (b) Maintenance of the integrity of the receiving waters; (c) Possibility of adverse effects of retention/detention; (d) Utility of regional retention/detention facilities; (e) Capability of maintenance of the system; and (f) Structural integrity of abutting foundations and structures. Request for variances shall be filed in writing with the Engineering Department and shall adequately detail the basis for granting an exemption. Section 6. DEVELOPMENT IN CRITICAL AREAS. Development which would increase the volume or rate of discharge due to any storm from the subject property shall not be permitted in areas designated as critical areas by the Engineering and Planning Departments. Critical areas are those in which existing flooding, drainage, erosion, and/or instability conditions present an imminent likelihood of harm to the welfare and safety of the surrounding community, or to the integrity of the surface or groundwater system. Development shall not be permitted in these critical areas until such time as the existing community hazard is alleviated and it is adequately demonstrated that the proposed development will not cause a recurrence of the problem nor the occurrence of any new drainage-related problem. The Engineering and Planning Departments may also designate as critical any area in which comparable problems would occur in the future due to any increase in volume or peak discharge. The requirements of this section shall apply regardless of any variance under Section 3, item (3). Where applications of the provisions of this section will deny all reasonable uses of the property, the restrictions on development contained in this section may be waived for the subject property, provided that the resulting development shall be subject to all the remaining terms and conditions of the chapter. All decisions based on the provision of this section shall be compatible with the Comprehensive Drainage Plan (if available) for the basin in which the subject property is located. For development in areas designated as critical, the developer shall provide information regarding volume and rate of discharge for a range of storms as specified in the Procedures Manual. Ordinance No. 3314 Page Seven 9-21-78 Section 7. REVIEW AND APPROVAL OF THE PLAN. All storm drainage plans prepared in connection with any of the permits and/or approvals listed in Section 3 shall be submitted for review by and approval of the Engineering and Planning Departments, in accordance with the procedures established in the Procedures Manual. At the time of approval of the drainage plan for the subject property, a schedule for inspection of construction and facilities will be established by the Engineering Department. Section 8. ESTABLISHMENT OF REGIONAL FACILITIES. In the event that public benefits would accrue due to modification of the drainage plan for the subject property to better implement the recommendations of the Comprehensive Drainage Plan, the Engineering Department or the Planning Department may recommend that the City of Auburn should assume responsibility for the further design, construction, operation, and maintenance of drainage facilities on the subject property. Such decision shall be made concurrently with review and approval of the plan as specified in Section 7. In the event that the City decides to assume responsibility for design, construction, operation, and maintenance of the facilities, the developer will be required to contribute a prorata share to the construction cost of the facilities. The developer may be required to supply additional information at the request of the Engineering Department to aid in the determination by the City. Guidelines for implementing this section will be defined in the Procedures Manual or by the Engineering and Planning Departments. Section 9. OPERATION AND MAINTENANCE PROCEDURES. It will be the responsibility of the developer to make arrangements with the occupants or owners of the subject property for assumption of operation and maintenance in a manner subject to the approval of the Engineering Department or in accordance with the Procedures Manual. The City may inspect the facilities in order to ensure continued use of the facilities for the purposes for which they were built and in accordance with Ordinance No. 3314 Page Eight 9-21-78 these arrangements. Failure to maintain the facilities in good working order shall be cause for a written request to maintain the retention/detention facilities after inspection by City forces. If after 30 days, no remedial measures are taken by the property owner, the City may initiate legal action against the property owner. Section lO. APPLICABILITY TO GOVERNMENTAL ENTITIES. All municipal corporations and governmental entities shall be required to submit a drainage plan and comply with the terms of this chapter when developing and/or improving land including, but not limited to, road building and widening, within the areas of the City of Auburn. It is recognized that many other city, county, state, and federal permit conditions may apply to the proposed action and that compliance with the provisions of this chapter does not constitute compliance with such other requirements. Section ll. APPEALS. If the property owner feels the requirements imposed by the Engineering Department are inconsistent with storm drainage handling procedures for the area, they may appeal to the Street Committee of the Auburn City Council and present in writing their reasons for a revision to the requirements as imposed upon their development. The Street Committee's ruling shall be binding on the property owner. Section 12. PROTECTION OF PUBLIC/PRIVATE RIGHTS. Implementation of any provision of this chapter shall not cause nor be construed as an infringement of the rights of individuals, municipalities, or corporations other than the developer seeking a permit or approval as described in Section 3. Section 13. EFFECTIVE DATE. The requirements of this chapter shall apply to all plats receiving preliminary approval subsequent to the effective date of this Ordinance. In the case of all additional actions enumerated in Section 3 of this Ordinance, the terms of this chapter shall apply where final action by the City has not been taken prior to the effective date of this Ordinance. Ordinance No. 3314 Page Nine 9-21-78 Section 14. SEVERABILITY. If any provision of this chapter or its application to any person or property is held invalid, the remainder of the chapter or the application of the provision to other persons or circumstances shall not be affected. Section 15. FEE SCHEDULE. A storm sewer permit fee to cover plan checking, inspection, as-built drawings and processing of permit information shall be charged for all develop- ment except single family residential. The permit fee shall be based on the amount of impervious area on the developed site and shall be as follows: 5000 square feet or less No fee 5000 to 10,000 square feet $ 50.00 10,001 to 50,000 square feet $ 75.00 50,001 square feet or more $100.00 Section 16. This Ordinance shall take effect and be in force five (5) days from and after its passage, approval and publication, as provided by law. INTRODUCED: OCTOBER 16, 1978 PASSED: OCTOBER 16, 1978 APPROVED: OCTOBER 16, 1978 mAYOR ~ ATTEST: APPRO D A~/~T~~.FORM'~~ · City Attorney PUBLISHED: OCTOBER 20, 1978 Ordinance No. 3314 Page Ten and Last 9-21-78