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HomeMy WebLinkAbout4B Bluff Ordinance Amendment 4646 Dakota Street SE Prior Lake, MN 55372 PLANNING COMMISSION AGENDA REPORT MEETING DATE: OCTOBER 9, 2017 AGENDA #: 4B PREPARED BY: CASEY MCCABE, COMMUNITY DEVELOPMENT DIRECTOR PRESENTED BY: CASEY MCCABE AGENDA ITEM: PUBLIC HEARING TO CONSIDER CERTAIN AMENDMENTS TO SECTION 1104 (SHORELAND REGULATIONS) OF THE PRIOR LAKE ZONING ORDI- NANCE RELATING TO BLUFF AREAS WITHIN THE SHORELAND DISTRICT DISCUSSION: Introduction The purpose of this public hearing is to consider a request by city staff to amend Section 1104 (Shoreland Regulations) of the City of Prior Lake Zoning Ordinance related to retaining walls and other structures within bluff areas. History The City of Prior Lake Zoning Ordinance defines a bluff as a topographic feature such as a hill, cliff, or embankment having the following characteristics: ➢ Part or all of the feature is located in a Shoreland area; ➢ The slope rises at least 25 feet above the ordinary high water level of the water body; ➢ The grade of the slope from the toe of the bluff to a point 25 feet or more above the ordinary high-water level averages 30% or more; and ➢ The slope must drain toward the water body. The original ordinance for bluff areas was developed in the 1990s under the pol- icies of the Minnesota Department of Natural Resources (DNR). The City of Prior Lake completed a major amendment to the bluff ordinance in 2009 with the most recent minor amendment completed in June 2016. Current Circumstances The City of Prior Lake uses preventative controls including structure setbacks, erosion control methods and storm water regulations to preserve the integrity of bluffs. These methods also minimize the visual impact of construction and pre- serve natural vegetation that stabilizes slopes and preserves wildlife habitat. The current Shoreland Regulations require engineering reports for construction activity within a bluff impact zone, which includes the bluff and the land located within 20 feet from the top of bluff. The current regulations state the applicant for a building permit and the property owner shall provide a report and calcula- tions prepared and signed by a professional engineer registered by the State of Minnesota on the bluff stability; on the impact any excavation, fill or placement 2 of structures will have on the site; and on whether the excavation, fill, or place- ment of structures will cause any slope to become unstable or will impose loads that may affect the safety of structures or slopes. The current ordinance language has caused confusion for some residents. The intent of the current ordinance was to require an engineering report for all work within a bluff impact zone; however, it was argued that the city could not require a building permit for walls under four feet in height, thus eliminating the require- ment for an engineering report, as the building code does not require a building permit for a walls under four feet. One of the primary purposes of this ordinance amendment is to clarify that an engineering report is required for all construction within a bluff impact zone. The City Attorney has proposed amended language for subsection 1104.305 of the Shoreland Regulations to eliminate the Building Permit language. The proposed subsection now states, “Engineering Reports Required: For any construction within a bluff impact zone or bluff setback, including work on any building, plat- form or structure, the following shall be provided…” Another amendment is the removal of the language which allowed the Building Official, the Community Development Director or City Engineer to waive the en- gineering report requirement. By removing this language, which has never been used, the City of Prior Lake is stating that all work conducted within a bluff will require appropriate permits and engineering reports. Conclusion The proposed ordinance amendments identify the process to construct or re- place retaining walls and other structures within a bluff, where appropriate, within the Zoning provisions of the Shoreland Regulations, as well as clarify the re- quirements the city has consistently been enforcing in bluff areas for many years. The proposed ordinance amendments have been sent to the DNR for review. City staff anticipates the DNR will support the revisions; however, any DNR com- ments will be incorporated into the final ordinance prior to City Council review. ISSUES: The purpose of the proposed amendments is to clarify the shoreland regulations related to retaining walls and other structures within a bluff. ALTERNATIVES: 1. Motion and a second to recommend the City Council approve the amend- ments to Section 1104 of the City Code as proposed, or as may be amended by the Planning Commission. 2. Motion and a second to recommend the City Council deny the proposed amendments to Section 1104 of the City Code. 3. Motion and a second to table action and provide direction to staff and con- tinue discussion at a future meeting. RECOMMENDED MOTION: ATTACHMENTS: Alternative #1 1. Proposed Amendments to Section 1104 (Shoreland Regulations) Zoning Ordinance City of Prior Lake June 1, 2009 1104/p1 SECTION 1104 SHORELAND REGULATIONS SUBSECTIONS 1104.100: General Provisions 1104.200: Designation of Types of Land Use 1104.300: Zoning Provisions 1104.400: Shoreland Alterations 1104.500: Special Provisions for Commercial, Industrial, Public/Semi-Public, Agricultural and Forestry 1104.600: Water Supply and Sewage Treatment 1104.700: Conditional Uses 1104.800: Planned Unit Developments (PUDs) 1104.900: Development on Nonconforming Lots EXCERPT from 1104.300 Zoning Provisions 1104.303 Bluff Impact Zones: Structures and accessory facilities, excluding stairways, lifts, and landings, shall not be placed in bluff impact zones except for the following: (1) An expansion of a legally nonconforming principal structure that does not meet the bluff setback is permitted provided that: • The expansion is lateral to the existing intrusion into the setback and does not project any further into the setback than an extension of a line drawn along the edge of the existing intrusion • The expanded structure is in harmony with the general purpose and intent of the ordinance, consistent with the comprehensive plan and will not alter the essential character of the locality; and • The structural footprint of the expansion into the bluff setback shall not exceed 500 square feet. (Ord. Amd. 116-13, publ. 06/04/2016) (2) Retaining walls shall not be permitted in the bluff impact zone or bluff setback except for the following: (a) Construction on an existing retaining wall that consists of the repair or exact replacement of the existing wall, provided the grade of the land within the bluff impact zone or bluff setback and the location and size of the retaining wall do not change and the new retaining wall will create no more impact in the bluff impact zone or bluff setback than was caused by the existing retaining wall. (b) Construction of a new retaining wall that does not exceed four feet in height, construction that consists of an addition to an existing retaining wall that does not increase the height of the wall above four Zoning Ordinance City of Prior Lake June 1, 2009 1104/p2 feet, or construction that decreases the height of an existing retaining wall; provided the proposed drainage patterns and/or erosion control methods are an improvement over the existing conditions on the site as determined by the City. Construction of retaining walls under provisions (a) and (b) above shall require a grading and filling permit as well as engineering reports as required by subsection 1104.305. 1104.304 Bluff Setbacks: The required setback from the Top of Bluff is determined as follows: as measured from the Top of Bluff, the upper end of a segment at least 25 feet in length having an average slope less than 18%. 1104.305 Engineering Reports Required: On properties for which For any construction is proposed within a bluff impact zone or bluff setback, including work on any building, platform or structure, the following shall be provided: the applicant for a building permit and the property owner shall provide the following: (1) Prior to any construction, aThe applicant for a building permit on that property shall provide a report and calculations prepared and signed by a professional engineer licensed registered by the State of Minnesota on the bluff stability and the impact any excavation, fill or placement of structures will have on the site and whether the excavation, fill, or placement of structures will cause any slope to become unstable or will impose loads that may affect the safety of structures or slopes. The report shall include the following: • The global failure plane determination of the slope substantiated by at least one soil boring at an appropriate depth and location • Analysis of the land influence zone and its intersection with the failure plane based on the soil type 25’ Zoning Ordinance City of Prior Lake June 1, 2009 1104/p3 • The Engineer's recommendations for the proper design and maintenance of a drainage system so the site development will not interfere with adequate drainage for the site or adjacent properties, will not obstruct, damage or adversely affect existing sewer or drainage facilities, will not adversely affect the quality of stormwater runoff, will not adversely affect downstream properties, wetlands or bodies of water and will not result in erosion or sedimentation. • If the initial determination indicates that the load influence zone intersects or falls within the global failure plane, a global stability analysis of the bluff shall be required. (2) After construction is complete, aThe owner of the property shall submit an as- built survey and post- construction report completed by a professional engineer licensed by registered by the State of Minnesota that the final grading of the site was completed in compliance with an approved grading plan and that the recommendations contained in the engineer's report have been adhered to. (3) The Building Official, the Community Development & Natural Resources Director and the City Engineer may waive the engineer's report requirement for replacement decks, new decks or additions to existing decks, replacement retaining walls, stairways, lifts and landings, water-oriented accessory structures, and additions or new structures not exceeding 480 square feet in size under the following conditions: a. An inspection of the site does not indicate any obvious erosion conditions. b. There is no history of bluff failure on the site or on the adjacent lots. (Ord. Amd. 116-13, publ. 06/04/2016) EXCERPT from 1104.400 Shoreland Alterations 1104.402 Topographic Alterations/Grading And Filling: (1) The exact replacement of an existing retaining walls within a bluff impact zone is permitted, provided the grade of the land within the bluff impact zone and the location and size of the retaining wall do not change and the new retaining wall will create no more impact in the bluff impact zone than was caused by the existing retaining wall. (1) Grading, and filling and excavation, including the import or export of materials, is not permitted within the bluff impact zone is not permitted. However, the movement or grading of existing materials within the bluff impact zone may be permitted subject to approval of a grading and filling/building permit. This movement of existing grade may involve the modification of existing retaining walls or placement of retaining walls as long as the following conditions are met: a. Any new retaining walls cannot exceed 4 feet in height. b. Any additional height to existing walls cannot increase the height of Zoning Ordinance City of Prior Lake June 1, 2009 1104/p4 the wall above 4 feet. c. Walls which exist over 4 feet in height may decrease in height but may not increase in overall height. d. Proposed drainage patterns and/or erosion control methods shall indicate an improvement over the existing conditions on the site. e. Grading, filling, and excavations in all areas within the Shoreland District which are necessary for the construction of structures, sewage treatment systems and driveways under validly issued construction permits for these facilities do not require the issuance of a separate grading and filling permit, except as provided in subsection (2) below. However, the grading and filling standards in this subsection must be incorporated into the issuance of permits for construction of structures, sewage treatment systems and driveways. (Ord. Amd. 116-13, publ. 06/04/2016) (32) Notwithstanding subsections (1) and (2) above, in addition to any other required permit, a grading and filling permit will be required for: a. AnyThe movement of more than 10 cubic yards of material or impact to more than 500 square feet of area on steep slopes or and within the bluff impact zone. or shore impact zone or shoreland district; orand b. AnyThe movement of more than 50 cubic yards of material or impact to more than 500 square feet within outside of the shoreland district. (43) The following considerations and conditions must be adhered to during the issuance of construction permits, grading and filling permits, conditional use permits, variances and subdivision approvals: a. Grading or filling in any wetland must be done in accordance with the Wetland Conservation Act. b. Alterations shall be designed and conducted in a manner that ensures only the smallest amount of bare ground is exposed for the shortest time possible; c. Erosion control best management practices shall be used, where necessary, for temporary bare soil coverage, and a permanent vegetation cover shall be established as soon as possible: d. Methods to minimize soil erosion and to trap sediments before they reach any surface water feature shall be used. e. Altered areas shall be stabilized to acceptable erosion control standards consistent with the Public Works Design Manual. Zoning Ordinance City of Prior Lake June 1, 2009 1104/p5 f. Fill or excavated material shall not be placed in a manner that creates an unstable slope; g. Plans to place fill or excavated material on steep slopes shall be reviewed by qualified professionals for continued slope stability and shall not create finished slopes of 4:1 or greater: h. Fill or excavated material shall not be placed in bluff impact zones: i. Any alterations below the ordinary high waterhigh-water level of public waters shall first be authorized by the Commissioner of Natural Resources under Minnesota Statutes, Section 103G.241. j. Alterations of topography shall only be allowed if they are accessory to permitted or conditional uses and do not adversely affect adjacent or nearby properties; and k. Placement of natural rock riprap, including associated grading of the shoreline and placement of a filter blanket, is permitted if the finished slope does not exceed 3 feet horizontal to 1 foot vertical, the landward extent of the riprap is within 10 feet of the ordinary high-water level, and the height of the riprap above the ordinary high-water level does not exceed 3 feet.