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C-1ii. Pervious PaversMEMORANDUM CITYOFCHANHASSEN ` Chanhassen is a Community for Life -Providing for Today and Planning forTomorrow TO: Planning Commission FROM: Paul Oehme, Director of Public Works/City Engineer Vanessa Strong, Water Resources Coordinator MacKenzie Walters, Assistant Planner DATE: May 15, 2018 �. SUBJ: Permeable Pavers Proposed Motion: "The Chanhassen Planning Commission recommends that the City Council adopt the attached ordinance amending Chapters 7 and 20 of the City Code." SUMMARY A significant number of Chanhassen's residents live on properties that are at or above the maximum amount of lot coverage permitted for their zoning district. When these homeowners contact the city to inquire about the possibility of adding on or installing a new patio, they find that their project cannot move forward or would require a variance due to the city's lot coverage restrictions. For the last year staff has been investigating the possibility of allowing residents to utilize permeable pavements to exceed existing lot coverage caps and provide residents with an option other than requesting a lot coverage variance. Since lot coverage is linked to both stormwater management and the overall intensity of land use within the city, it is important to balance the benefits of allowing increased lot coverage with its potential consequences. The city must also make sure that any proposed change to the ordinance will satisfactorily address the issue of constrained properties. Staff believes that allowing homes located in Residential Single Family Districts (RSF) outside of the Shoreland Management District five percent additional lot coverage in the form of pervious pavement will provide flexibility for homeowners looking to improve their properties while minimizing the potential for negative impacts. This fairly conservative approach will allow the city to better understand how residents will utilize these systems, what their actual impacts will be, and the long term performance of pervious pavements within Chanhassen. If these PH 952.227.1100 • www.ci.chanhassen.nnn.us • FX 952.227.1110 7700 MARKET BOULEVARD • PO BOX 147 • CHANHASSEN • MINNESOTA 55317 Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 2 of 17 systems successfully accomplish the city's goals and do not create significant issues, a similar ordinance could be enacted for other zoning districts. BACKGROUND The Chanhassen City Council selected a review and potential update of the city's policy on pervious pavements in residential districts as a Key Fiscal Strategy for 2017. Staff contracted with Wenck Associates, Inc. to assist in determining the potential ramifications of modifying the city's existing policy. During the June 26, 2017 City Council Work Session staff presented the results of the consultant's study and internal research to the City Council. Staff was directed draft an ordinance allowing for the use of permeable pavers located in low-density residential districts outside of the Shoreland Overlay District. During the September 25, 2017 City Council Work Session staff discussed the proposed ordinance, and the City Council instructed staff to bring the proposal before the Planning Commission. During the October 17, 2017 Public Hearing, the Planning Commission expressed concerns about the long term impact of increasing residential lot coverage. They expressed concerns about both the long-term efficacy of these systems and the city's capacity to identify, inspect, and enforce maintenance agreements. The Planning Commission indicated that additional research and public input should be gathered before altering the existing policy. The Planning Commission tabled the proposed code revisions and instructed staff to bring back an ordinance that resolved the issues identified with the terms lot coverage, impervious surface, and hardcover, but which did not increase the amount of lot coverage currently allowed in residential districts. During the November 21, 2017 Public Hearing the staff presented the requested definitions only amendment to resolve the issues identified with the terms lot coverage, impervious surface, and hardcover. The Planning Commission expressed some concern that the definition of pervious pavement be made more specific to ensure that systems are adequately designed. Staff clarified that design standards would be specifically addressed when/if the city allowed pervious pavers their own category of lot coverage. The Planning Commission recommended that the City Council approve the revised definitions. During the December 11, 2017 City Council meeting staff presented on the proposed definition changes. The City Council asked if staff was still investigating potentially permitting an increase in pervious lot coverage for residential districts. Staff clarified that they were waiting for the surface water management plan to be completed and also wanted to work with residents and contractors to ensure a smooth implementation of any changes. The City Council unanimously voted to adopt the revised definitions. Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 3 of 17 On February 26, 2018 the City Council adopted a review and potential update of the city's policy on permeable pavers as a Key Financial Strategy for 2018. Issue 1: Constrained lots The most common constraint that residents encounter when they are looking into improving their property is the city's lot coverage limit. Properties tend to be at or above their lot coverage limit for one of two reasons: the lot, house, and lot cover were all created before current standards were enacted; or the builder or previous homeowner chose to maximize the property and improved it up to or in excess of the current limits. In the first instance, the city considers the property to be a non -conforming use and allows the homeowner to rearrange the existing lot cover to improve the property so long as the resulting lot coverage is less than the existing lot coverage, i.e. removing 200 square feet of driveway and installing 150 square feet of patio. In situations where small lot size prevents reasonable use of the property, staff will recommend approval of a lot coverage variance to allow for needed improvements, i.e. adding a two car garage to a property that does not have one. In the second case, the city encourages homeowners to plan their projects within the bounds established by the zoning ordinance. Property owners always have the right to request a variance; however, staff's general policy is to recommended denial of lot coverage variances for properties that meet their districts' general standards, unless extenuating circumstances are present. Allowing property owners an additional five percent lot coverage in the form of pervious pavements is a potential option for allowing the owners of some of these properties options for improving their properties without utilizing the variance process; however, it may be of limited use to homes on lots that do not meet current minimum lot area standards. Any parcel that already exceeded its lot coverage by more than five percent would not be able to take advantage of this provision to make additional improvements, and smaller parcels would be entitled to proportionally smaller amounts of increased lot coverage. In both of these situations the property owner would still likely require a variance. It is also important to note that allowing additional lot coverage is unlikely to represent a lasting solution to the issue of constrained lots. The cost of land is very high and builders tend to build the largest house possible on any given piece of property in order to increase the return on their investment. It is not uncommon for as built surveys for new houses to show lot coverage totals within a few tenths of a percentage point of the property's maximum limit. Staff believes that it is likely that builders will utilize an increased lot coverage allotment to construct larger houses with pervious paver driveways, and that new homeowners will still find themselves in a position of having a limited ability to add patios, screen porches, and sheds due the house having been built up to the property's lot coverage limit. Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 4 of 17 Similarly, homeowners who are at the current lot coverage limit may take advantage of the increased lot coverage limit to make improvements until they reach the new lot coverage limit. Once they have sold their homes, subsequent homeowners will be unable to improve their property due to the fact that previous homeowner utilized the property's allowed lot coverage. This will result in the next generation of homeowners facing the same issues with lot constraints as the current generation, albeit with a higher lot coverage limit. Staff believes the issue of constrained lots should be approached through the lens of what limits are reasonable and justifiable. The current housing market may make a higher lot coverage percentage desirable and changes in stormwater management practices and technologies may allow the city to justify increasing its permitted lot coverage; however, increasing lot coverage limits should not be expected to resolve the issue of constrained lots. Issue 2: Where to allow The city has several zoning districts which allow for detached single-family dwelling units and each district has different minimum lot sizes and maximum lot coverage limits. Staff has created a table of these districts and has listed their current standards as well as the amount of additional lot coverage they would be entitled to if they were permitted an additional five percent lot coverage in the form of pervious pavement. Districts in green are those that staff believe would be good candidates for an initial increase in permitted lot coverage, districts in yellow are those where it may be appropriate to allow expanded lot coverage at a later date, and districts in red are those where increasing lot coverage is not recommended. Permitted Lot Coverage by Zoning District Min lot area (sq. ft.) A-2 RR RSF PUDR* R-4** RLM** 108,900 108,900 15,000 11,000 15,000 9,000 Max lot coverage % 20% 20% 25% 30% 30% 35% Min lot coverage (sq. ft.) 21,780 21,780 3,750 3,300 4,500 3,150 5% additional lot coverage (sq. ft.) 5,445 5,445 750 550 750 450 Total with +5% lot coverage 1 27,225 1 27,225 1 4,500 1 3,850 1 5,250 1 3,600 *Minimum lot size is for single-family detached PUDRs, single-family attached/cluster home PUDRs have no minimum lot size. "Minimum lot size is for single-family units, twin and attached homes have different minimum lot sizes. A district by district discussion is present below, but staff is recommending that if this proposal is adopted only properties zoned residential single-family (RSF) and located outside of the shoreland management district be granted the additional five percent lot coverage. The map below shows which properties would benefit from this amendment. Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 5 of 17 Shoreline Management Distric and RSF Zoning i t 9 i W Awicultural Estate (A-2) and Rural Residential (RR) Districts: Approximately one-third of the city's acreage is located in these districts, though many properties zoned A-2 and RR are either permanent park and open space or guided for future development and rezoning. These districts are intended to be rural/agrarian in character with large amounts of green space and are limited to 20 percent lot coverage. Allowing a higher percentage of lot cover would not be in line with the districts' intent and character. The A-2 and RR parcels used for residential purposes have a minimum 2.5 -acre lot size, which means that parcels meeting their district's minimum standards are entitled to 21,780 square feet of lot cover. It is unlikely that many property owners are unable to make reasonable improvements to their property within that limit. In the event that a property has extenuating circumstances requiring additional lot coverage, the variance process seems better suited to addressing that need than a blanket five percent increase in permitted lot coverage. Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 6 of 17 Residential Single Family (RSF) Districts: About sixteen percent of the city is zoned RSF and the district has a minimum lot size of 15,000 square feet. Prior to 1986 it was possible to create lots zoned R-1, reclassified as RSF in 1986, that were as small as 11,700 square feet and before 1967 the city did not have a zoning or subdivision ordinance with which to establish a minimum lot size. This means that some of the most severely constrained parcels in the city are zoned RSF. RSF parcels are also limited to a maximum lot coverage of twenty-five percent, five percent less than can be allowed in PUDR and ten percent less than is permitted within RLM. The lot coverage constraints faced by RSF properties can be exacerbated by the fact that up until 2007 the city did not require zoning permits for patios or driveway expansions. This means that many properties ended up unknowingly exceeding their lot coverage limits when they added a patio or expanded their driveway. In some cases, this is beneficial to property owners as the city treats this additional lot coverage as a non -conforming use; however, it does prevent the owner from further improving their property unless they remove at least some of the excess lot coverage. RSF lots meeting their district's minimum lot standards are restricted to 3,750 square feet of lot cover, and with the modern trend towards large houses and three car garages this does not always allow for large patios, screened porches, sheds, sport courts, swimming pools, and other accessory uses. Allowing an extra five percent lot coverage would allow current homeowners a significant amount of additional flexibility. It could also improve the situation for substandard lots which are currently between twenty-five and thirty percent lot coverage, though many severely constrained lots will likely still need to go through the variance process. Planned Unit Development Residential (FUDR) Around twelve percent of the city is zoned PUDR and PUDRs can have wildly different minimum lot areas and permitted lot coverage depending on their individual planned unit development ordinance. Current standards for detached single-family PUDRs establish 11,000 square feet as the minimum lot area and allow up to thirty percent lot coverage; however, there are numerous historic PUDRs that with smaller lot sizes or which limit properties to twenty-five percent lot coverage. The table below provides a breakdown of the city's detached single-family PUDRs' minimum lot sizes and permitted lot coverage. Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 7of17 PUD Name Referenced zoning Min Lot Size (sq. ft.) Lot Coverage* # Units Arbor Glen 15-16 RLM 5,000 25% total site 18 Camden Ride 13-13 RLM 9,000 35% total site /25% shore 58 Chanhassen Hills 85-6 RSF 11,200 25% 172 Chanhassen Vista 86-1 RSF 11,000 30% 123 Chaparral 78-1 R-4 10,000/4,300 30% (total site) 172 Ches Mar 84-2 A-2 2.5 acres 20% as amended 4-5 Chesnutt Ride 79-2 RSF 7,400 to 20,000 sub 25-35% (by sub 236 Fox Hollow 84-1 RSF 7,400 25% total site 95 Hidden Valle 85-1 RSF 7,500 30%/25% shore 110 Lake Susan Hills 87-3 RSF 15,000 25% as amended 411 Laredo Lane 75-05 RSF 6,000 30% 21 L ore Addition 98-1 RSF 12,854 30% 8 Meadows at Long Acres 92-4 RSF 10,000 25% 112 Minnewashta Creek 78-3 RSF/RLM 8,266 to 20,000 sub 25-30% (by sub 44 Near Mountain 79-2 RSF 7,400 to 20,000 sub 25-35% (by sub 236 Pheasant Hills 83-1 RSF 1 10,000 30% 84 Preserve at Bluff Creek 06-14 RLM 8,000 30% total site 155 Preserve at Rice Lake 13-12 RLM 10,000 30% total site 16 Saratoga 77-1 R4 10,000/6,000 30% total site 35 South Lotus Lake 854 RSF 11,700 30%/25% shore 40 Springfield/Summerfield 00-3 RSF 11,000 30%/25% shore 122 Sunny Sloe ? RSF 11,300 25% total site 12 Trile Crown Estate 85-2 RSF 11,300 30% total site) 55 Trotters Ride 93-2 RSF 1 11,000 30% 49 Walnut Grove 96-4 RSF/R-4 10,400/3,400 30% total site 79 Western Hills 69-2 RSF 10,400 30% 102 Willowrid e 91-3 RSF 14,000 30%/250/() shore 38 Woods at Lon acres 93-50 RSF 11,000 25% 115 Total 2,722 *The phrase "total site "means that development as a whole was limited to thatpercent lot coverage and in most cases unused lot coverage generated by open spaces was credited to the individual parcels; the phrase "shore " refers to a different limit within the shoreland management district; and, the phrase "as amended" means that the standard will change if the referenced zoning district's standard is altered. As the table above shows most PUDRs either already have a five percent increase in lot coverage over their RSF counterparts or utilize "total site" provisions to allow individual lots to exceed the twenty-five percent lot coverage. Those that are limited to a flat twenty-five percent lot coverage are older subdivisions where many of the constrained lots can be expected to be non -conforming due to the installation of patios and other impervious surface before the 2007 zoning permit requirement, and this means that a five percent increase in lot coverage is unlikely to provide significant relief. Additionally, many PUDRs' zoning ordinances specify smaller setbacks, provide for HOA owned lots with public amenities, or otherwise attempt to balance the smaller lot sizes. These factors combined with the fact that individuals living in these neighborhoods have self-selected a community designed around smaller lot sizes means that it is appropriate to Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 8 of 17 limit PUDRs to their existing standards. In cases where extenuating circumstances necessitate increased lot coverage, the variance process can be utilized to grant relief. Mixed Low Density Residential District (R-4) Less than half of a percent of the city falls within this zoning district which allows for both detached single-family and two-family dwellings. Single-family homes within these districts have a minimum lot size of 15,000 square feet and are allowed up to thirty percent lot coverage. Since the lot size is the same as the RSF districts and the permitted lot coverage is already five percent higher than the RSF districts, it is unlikely that there are many constrained lots within this zoning category. In cases where extenuating circumstances necessitate increased lot coverage, the variance process can be utilized to grant relief. Residential Low and Medium Density Residential Districts (RLM) Just over seven -tenths of a percent of the city is zoned RLM. The RLM district was created in 2006 to allow for smaller lot subdivisions with a higher ratio of lot coverage in exchange for developers dedicating permanent open space to the city. Single-family dwellings within this district have a minimum lot size of 9,000 square feet and are allowed up to thirty-five percent lot coverage. Residents choose to buy houses in this district because they are interested in smaller lots and denser neighborhoods; however, even with the increased lot coverage percentage there is less space for accessory structures. Since these are all newer subdivisions and very few homes were built before the existing zoning permit requirements were enacted, these districts should not have constrained or non -conforming lots. In cases where extenuating circumstances necessitate increased lot coverage, the variance process can be utilized to grant relief rather than allowing all of these properties forty percent lot coverage. Shoreland Management Districts All areas within 1,000 feet of the ordinary high water level of a lake or within 300 feet of a river or stream are regulated by the city's Shoreland Management District ordinance. The city administers the Shoreland Management District on behalf of the Department of Natural Resources (DNR), and the DNR's policies limit the city's ability to modify its Shoreland Management District Ordinance. The DNR considers pervious pavers and similar technologies to constitute impervious surface/lot cover, and the city cannot increase the Shoreland Management District's residential lot coverage allowance beyond twenty-five percent. This means that all detached single-family properties within the Shoreland Management District will continue to be limited to twenty-five percent lot coverage even if their underlying zoning district's lot coverage limit is increased. Bluff Creek Overlay District (BCOD): Due to the importance and ecological sensitivity of the Bluff Creek Corridor, the existing provisions limiting lot coverage to twenty-five percent on slopes with a grade between twenty- Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 9of17 five and ten percent should be left intact. Since development within the primary and secondary zone is very heavily restricted there are only a few detached single-family properties that could potentially be constrained by these provisions. The unique and non -conforming nature of all these properties means that the variance process is the best way to address any potential lot coverage increases within this area. Issue 3: Cumulative Impact Changing the city's policy regarding pervious pavements has the potential to significantly impact the city, especially if these systems encounter issues and do not work as intended. To provide context for a discussion on the potential cumulative impact of these systems staff has created the following table. Districts in green are those that staff believe would be good candidates for an initial increase in permitted lot coverage, districts in yellow are those where it may be appropriate to allow expanded lot coverage at a later date, and districts in red are those where increasing lot coverage is not recommended. It should be noted that due to the restriction within the Shoreland Management District over 40 percent of the city's residential properties would not be able to take advantage of the proposed pervious pavement amendment. Total In Shoreland Out of Shoreland Zoning square feet Acreage % of City Square feet Acreage % in shore Square Feet Acreage % out shore 5% of area A2 134,906,824 3,097 20.98% 49,572,494 1,138 36.75% 85,334,330 1,959 63.25% 4,266,716 RR 81,381,968 1,868 12.66% 32,758,696 752 40.25% 48,623,272 1,116 59.75% 2,431,164 R4 3,069 679 70 0.48% 363,629 8 11.78% 2,706,050 62 88.22% 135,302 R8 519,356 12 0,08% 379,366 9 73.11 % 139 990 3 26.89% 6,999 R12 1,591510 37 0.25% 1144,989 26 72.05% 446,521 10 27.95% 22,326 RLM 4,57Q,S94 Jos 0.71% 1,513,578 35 33.08% 3,057,016 70 66.92% 152,851 RSF 103,668,358 2,380 16.12% 56.686,256 1,301 54.67% 46,982,102 1,079 45.33"'0 2,349,105 PUDR 75 189 414 1,726 11.69% 28,933 318 664 38.48% 46,256,096 1 062 61.52% 2,312,805 Total 404 897 702 9,295 62.97% 171,352,326 3,933 42.32% 233,545,376 5 362 57.68% 11 677,269 If the city allows RSF properties outside of the Shoreland Management District to add five percent lot coverage in the form of pervious pavement it would allow up to 2.3 million square feet of new lot coverage. This is roughly equivalent to 600 new houses with 3,750 square feet of lot cover or a 180 -acre subdivision with thirty percent development wide lot coverage. Of course, not every property will take advantage of the proposed ordinance and homeowners that do add pervious pavers will not all reach their lot coverage limit; however, the proposed amendment could lead to a very significant amount of green space being converted into lot coverage. That additional lot coverage, even if it is in the form of pervious pavements, has the potential to impact stormwater management on a citywide scale. Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 10 of 17 Issue 4: Stormwater Implications Permeable Interlocking Concrete Pavers (PICP) are typically used in areas with light traffic at commercial and residential sites such as low -speed roads, parking lots, driveways, sidewalks, plazas, and patios PICP has become the preferred permeable pavement option over pervious concrete and asphalt applications in recent years due in part to the use in smaller residential or retrofit applications, and lower material and installation costs and maintenance. Research has demonstrated that PICP is an effective method for reducing stormwater runoff and pollutants from urbanized areas. Properly designed, installed, and maintained PICP can have design life surface infiltration rates exceeding 100 in./hour in type A soils according to industry literature. Stringent design, installation and maintenance is imperative to ensure proper performance. Staff must ensure that in residential areas, the systems be designed and installed properly, and be maintained as needed to prevent creating additional stormwater issues in existing neighborhoods with insufficient stonnwater treatment capacity. It is essential that these systems are designed in line with industry -accepted guidelines, installed by certified installers, and a maintenance agreement be recorded against the property. The stormwater utility fee, which is based upon lot coverage, will be updated in 2019 to adjust for the increase in lot coverage. Issue 5: Implementation Design, installation, and maintenance standards would be at the discretion of appropriate city staff. The MPCA Stormwater Manual suggests using the design, installation, and maintenance guidance for PICP as referenced by the Interlocking Concrete Pavement Institute (ICPI). The ICPI's website is www.icpi.org. It includes information for design professionals and installers regarding industry standards and specifications, installation guidelines and maintenance. Many certified installers are available in the metro area. Staff will reference ICPI for design, installation, and maintenance guidance. Pervious pavers are not effective at infiltration in C and D soils. These soils are common in the city. To achieve the long-term effectiveness of these systems and significantly reduce the chance of erosion issues being generated by PICP the city will require that systems provide for rate and volume control for the first 0.5" of treatment area and follow the current version of The City of Chanhassen Standard Specification and Detail Plates. Treatment area includes the total square feet of pervious pavement system plus the total square feet of impervious surface draining directly to the pervious pavement system. Staff is proposing requiring a building permit to evaluate and approve proposed designs. Maintenance agreements: Staff recommends that applicants receiving a permit to use PICP be required to execute a recordable Maintenance Agreement setting forth maintenance requirements consistent with the ICPI recommendations. The maintenance agreement will also include enforcement procedures. It is not cost effective, nor does the city have sufficient staffing to Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 11 of 17 annually inspect or track maintenance of small Best Management Practices. Proper design, installation, and review is the best method available to ensure long-term effectiveness. ALTERNATIVES 1) Do nothing. Maintain current policy and continue to treat pervious pavements as impervious surface. Use variance process to grant relief as appropriate. 2) Amend Chapters 7, and 20 to allow five percent additional lot coverage in the form of pervious pavements within the Single Family Residential District (RSF) outside of the Shoreland Management District. 3) Amend Chapters 7, and 20 to allow five percent additional lot coverage in the form of pervious pavements outside of the Shoreland Management District. Staff believes that alternative two will provide relief to some of the most constrained properties in the city while minimizing the potential for negative impacts. The city can expand the use of pervious pavements as appropriate once it has had a chance to evaluate the impact of this policy change on a smaller section of the city. Staff proposes the following changes be made to the City Code: Sec. 7-19. - Plans and specifications. The building official may require that plans and specifications, required by the Minnesota State Building Code, include a survey of the lot upon which the proposed building or construction is to be done, prepared and attested by a registered surveyor. An original signature is required on the certificate of survey. The survey shall provide the following information unless otherwise approved by the administrative authority: (1) Scale of drawing and north arrow; (2) Legal description of property; (3) Dimensions and bearing of front, rear and side property lines; (4) Front, rear and side yard setback dimensions of all proposed structures; (5) Location of all existing structures on the property, boulevards, streets and right-of- way, including but not limited to, sanitary and storm manholes, hydrants, catch basins, power poles, phone boxes, fences and any encroachments; (6) Outside dimensions of proposed structure(s) including decks, porches, retaining walls (include elevations at bottom of footing and top of wall), stoops, stairs, cantilevers, fireplaces, bay and bow windows, egress window wells; Planning Commission Permeable Pavers – City Code Amendment May 15, 2018 Page 12 of 17 (7) Location of a benchmark stake established by the surveyor at the front setback line within 20 feet of the proposed structure. Maintenance of the benchmark stake once established by the surveyor shall be the responsibility of the permit applicant; (8) Location of stakes established by the surveyor on side property lines at: a. Front setback line. b. Front building line. c. Rear building line. The maintenance of these stakes once established by the surveyor shall be the responsibility of the permit applicant. (9) Location of first floor elevation of buildings on adjacent lots. Vacant adjacent lots shall be labeled as such; (10) Location of all easements of record, including but not limited to, tree preservation, wetland conservation, cross -access, etc.; (11) Existing and proposed elevations at the following locations: a. Each lot corner. b. Top of curb or centerline of roadway at each lot line extension. c. Center of proposed driveway at curb. d. Grade at corners of proposed structure. e. Lowest floor level, top of block, garage slab. (12) Indication of direction of surface water drainage by arrows. (13) Tree removal, tree preservation and grading plan if required by the development contract; (14) Wetland boundaries with ordinary high water level and 100 -year flood elevation if applicable; (15) Driveway grade (minimum -0.50 percent, maximum—ten percent); (16) All trees in excess of six inches in diameter (diameter measured at four feet above grade); (17) All custom -graded lots and lots deviating from the approved grading plan shall require an as -built survey submitted to the city prior to issuing a certificate of occupancy; (18) Wetland buffer areas and wetland or lake setback dimensions; (19) Other information as required by the city; (20) Location and type of erosion and sediment control measures to be installed by permit holder. (21) Calculation of the amount and percentage of the lot coverage for the lot or parcel broken out by impervious surfaces and pervious pavement, if present. Sec. 20-109. - Applications. Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 13 of 17 Application for a site plan review shall be made to the city planner on forms provided by the city and shall be filed 30 days in advance of the planning commission meeting, at which it is to be considered. Prior to filing an application for site plan review, the applicant shall attend a conference with city staff. The primary purpose of the conference shall be to provide the applicant with an opportunity to gather information and obtain guidance on the general merits of the proposal and its conformity to the provisions of the comprehensive plan and the City Code before incurring substantial expense. Incomplete or deficient applications shall not be scheduled for a meeting unless the community development director has determined that official action is warranted. The application shall also include: (1) Evidence of ownership or an interest in the property; (2) The application fee; (3) Complete site plans, signed by a registered architect, civil engineer, landscape architect or other design professional, to include the following. (4) General: a. Name of project. b. Name, address and telephone number of applicant, engineer, and owner of record. c. Legal description (certificate of survey will be required). d. Date proposed, north arrow, engineering scale, number of sheets, name of drawer. e. Vicinity map showing relationship of the proposed development to surrounding streets, rights-of-way, easements and natural features. f. Description of intended use of the site, buildings and structures, including type of occupancy and estimated occupancy load. g. Existing zoning and land use. h. Tabulation box indicating: 1. Size of parcel in acres and square feet. 2. Gross floor area of each building. 3. Percent of site covered by building. 4. Percent of lot coverage on site broken out by impervious surface and pervious pavement. 5. Percent of site covered by parking area. 6. Projected number of employees. 7. Number of seats if intended use is a restaurant or place of assembly. 8. Number of parking spaces required. 9. Number of parking spaces provided including handicapped. 10. Height of all buildings and structures and number of stories. Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 14 of 17 11. Breakdown of the building area allocated for specific uses, e.g., manufacturing, office, retail, showroom, warehouse, etc. Sec. 20-615. - Lot requirements and setbacks. The following minimum requirements shall be observed in an "RSF" District subject to additional requirements, exceptions and modifications set forth in this chapter and chapter 18: (1) The minimum lot area is 15,000 square feet. For neck or flag lots, the lot area requirements shall be met after the area contained within the "neck" has been excluded from consideration. (2) The minimum lot frontage is 90 feet, except that lots fronting on a cul-de-sac "bubble" shall be 90 feet in width at the building setback line. The location of this lot is conceptually illustrated below. Lob whom ftoaftp is Frontage Measured at Setback Line (3) The minimum lot depth is 125 feet. (4) Lot width on neck or flag lots and lots accessed by private streets shall be 100 feet as measured at the front building setback line. The location of these lots is conceptually illustrated below. Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 15 of 17 NECK/FLAG LOTS FRONT LOT LINE 1 t 1 f 100' LOT WIDTH f / _ ! f ! LOT , Z WIDTH ! t NecklFla Lots (5) The maximum lot coverage for all structures and paved surfaces is "5 30 percent, of which no more than 25 percent can be impervious surfaces. For flag/neck lots neither the area within the neck, nor the impervieiis surfaeelot coverage of the driveway within the neck shall be included within the calculation of the lot area or lot coverage of the lot. (6) The setbacks are as follows: a. For front yards, 30 feet. b. For rear yards, 30 feet. c. For side yards, ten feet. (7) The setbacks for lots served by private streets and/or neck lots are as follows: a. For front yard, 30 feet. The front yard shall be the lot line nearest the public right- of-way that provides access to the parcel. The rear yard lot line is to be located opposite from the front lot line with the remaining exposures treated as side lot lines. On neck lots the front yard setback shall be measured at the point nearest the front lot line where the lot achieves a 100 -foot minimum width. b. For rear yards, 30 feet. c. For side yards, ten feet. (8) The maximum height is as follows: a. For the principal structure, three stories/35 feet. b. For accessory structures, 20 feet. Planning Commission Permeable Pavers – City Code Amendment May 15, 2018 Page 16 of 17 (Ord. No. 80, Art. V, § 5(5-5-5),12-15-86; Ord. No. 90, § 1, 3-14-88; Ord. No. 127, § 3, 3-26- 90; Ord. No. 145, § 2,4-8-91; Ord. No. 240, § 18,7-24-95; Ord. No. 324, § 23,7-9-01; Ord. No. 377, § 81, 5-24-04; Ord. No. 409, § 4,1-9-06; Ord. No. 619, § 7, 2-27-17) Editor's note— Section 2 of Ord. No. 145 purported to amend § 20-615(6)b. pertaining to accessory structures; such provision were contained in § 20-615(7)b., subsequent to amendment of the section by Ord. No. 127. Hence, the provisions of Ord. No. 145, § 2, were included as amending § 20-615(7)b. Sec. 20-921–Pervious Pavement Properly designed, installed, and maintained pervious pavements have the capacity to allow for stormwater detention and/or infiltration. When not properly designed, installed, and maintained pervious pavements fail to facilitate the detention and/or infiltration of stormwater. Additionally, pervious pavements contribute to the creation of heat islands and do not provide the same surface water management benefits as native vegetative cover. For these reasons, it is necessary to regulate the lot coverage, design, installation, and maintenance of these systems. 1) Lot Coverage: Pervious pavements are considered to constitute lot coverage; however, when built to the standards espoused in this section they do not constitute impervious surfaces. Systems not built to the standards espoused in this section are considered to constitute impervious surfaces. 2) Location Restrictions: a. Pervious pavements may not be installed in areas where trash or garbage receptacles will be stored. 3) Design and Installation: a. A building permit is required for the instillation of pervious pavement systems. b. Pervious pavement systems must be designed to provide for rate and volume control for the first half inch (0.511) of treatment area and follow the current version of The City of Chanhassen Standard Specification and Detail Plates. Treatment area includes the total square footage of the pervious pavement system plus the total square footage of impervious surface draining directly to the pervious pavement system. c. To meet the city's definition of pervious pavement the system must: 1) be designed in compliance with standards established by the Interlocking Concrete Pavement Institute (ICPI); 2) be installed by an ICPI certified installer; and, 3) be designed to meet or exceed the standards listed in paragraph (b). d. The City Engineer may permit pervious pavement technologies other than permeable interlocking concrete pavers, so long as the City Engineer determines: 1) they are functionally equivalent or better; 2) the system is designed in compliance with accepted guidelines and is installed by an Planning Commission Permeable Pavers — City Code Amendment May 15, 2018 Page 17 of 17 appropriately certified installer; and, 3) the system will meet or exceed the standards listed in paragraph (b). 4) Maintenance: a. The owner of a pervious paver system must enter into a maintenance agreement with the city to ensure the system performs as designed in perpetuity. This agreement must conform to the manufactures guidelines, and stipulate the frequency and type of maintenance to be performed. 5) District restrictions: a. Planned Unit Developments Residential Districts (PDDR) are limited to the lot coverage specified by their ordinance and/or compliance table. For PUDRs created before [insert date] the terms hardcover, hard surface, impervious surface, and similar phrases shall be understood to mean lot cover inclusive of both pervious pavements and impervious surfaces, and in no circumstance shall the failure of the ordinance or compliance table to mention pervious pavements be understood to mean that pervious pavers are not subject to the lot cover, hardcover, hardscape, or similarly identified limits that govern the PUDR. b. Shoreland Management District restricts properties zoned Single Family Residential District (RSF) to 25 percent lot coverage. ATTACHMENTS 1) Pervious Pavement Ordinance G:TLAN\City Code\2018\PC PH 5-15-18\Pervious PavementsTermeable Pavers Round2 PC.doc CITY OF CHANHASSEN CARVER AND HENNEPIN COUNTIES, MINNESOTA ORDINANCE NO. [insert number] AN ORDINANCE AMENDING CHAPTER 7, BUILDING AND BUILDING REGULATIONS AND CHAPTER 20, ZONING OF THE CHANHASSEN CITY CODE THE CITY COUNCIL OF THE CITY OF CHANHASSEN, MINNESOTA ORDAINS: Section 1. Section 7-19(21) of the Chanhassen City Code is amended to read as follows: (21) Calculation of the amount and percentage of the lot coverage for the lot or parcel broken out by impervious surfaces and pervious pavement, if present. Section 2. Section 20-109(4)(h)(4) of the Chanhassen City Code is amended to read as follows: 4. Percent of lot coverage on site broken out by impervious surface and pervious pavement. Section 3. Section 20-615(5) of the Chanhassen City Code is amended to read as follows: (5) The maximum lot coverage for all structures and paved surfaces is 30 percent, of which no more than 25 percent can be impervious surfaces. For flag/neck lots neither the area within the neck, nor the lot coverage of the driveway within the neck shall be included within the calculation of the lot area or lot coverage of the lot. Section 4. The Chanhassen City Code is amended by adding Section 20-921 to read as follows: Sec. 20-921 —Pervious Pavement Properly designed, installed, and maintained pervious pavements have the capacity to allow for stormwater detention and/or infiltration. When not properly designed, installed, and maintained pervious pavements fail to facilitate the detention and/or infiltration of stormwater. Additionally, pervious pavements contribute to the creation of heat islands and do not provide the same surface water management benefits as native vegetative cover. For these reasons, it is necessary to regulate the lot coverage, design, installation, and maintenance of these systems. 1) Lot Coverage: Pervious pavements are considered to constitute lot coverage; however, when built to the standards espoused in this section they do not constitute impervious surfaces. Systems not built to the standards espoused in this section are considered to constitute impervious surfaces. 2) Location Restrictions: a. Pervious pavements may not be installed in areas where trash or garbage receptacles will be stored. 3) Design and Installation: a. A building permit is required for the instillation of pervious pavement systems. b. Pervious pavement systems must be designed to provide for rate and volume control for the first half inch (0.5") of treatment area and follow the current version of The City of Chanhassen Standard Specification and Detail Plates. Treatment area includes the total square footage of the pervious pavement system plus the total square footage of impervious surface draining directly to the pervious pavement system. c. To meet the city's definition of pervious pavement the system must: 1) be designed in compliance with standards established by the Interlocking Concrete Pavement Institute (ICPI); 2) be installed by an ICPI certified installer; and, 3) be designed to meet or exceed the standards listed in paragraph (b). d. The City Engineer may permit pervious pavement technologies other than permeable interlocking concrete pavers, so long as the City Engineer determines: 1) they are functionally equivalent or better; 2) the system is designed in compliance with accepted guidelines and is installed by an appropriately certified installer; and, 3) the system will meet or exceed the standards listed in paragraph (b)• 4) Maintenance: a. The owner of a pervious paver system must enter into a maintenance agreement with the city to ensure the system performs as designed in perpetuity. This agreement must conform to the manufactures guidelines, and stipulate the frequency and type of maintenance to be performed. 5) District restrictions: a. Planned Unit Developments Residential Districts (PUDR) are limited to the lot coverage specified by their ordinance and/or compliance table. For PUDRs created before [insert date] the terms hardcover, hard surface, impervious surface, and similar phrases shall be understood to mean lot cover inclusive of both pervious pavements and impervious surfaces, and in no circumstance shall the failure of the ordinance or compliance table to mention pervious pavements be understood to mean that pervious pavers are not subject to the lot cover, hardcover, hardscape, or similarly identified limits that govern the PUDR. b. Shoreland Management District restricts properties zoned Single Family Residential District (RSF) to 25 percent lot coverage. Section 5. This ordinance shall be effective immediately upon its passage and publication. PASSED AND ADOPTED this [xx] day of [Month], 2018 by the City Council of the City of Chanhassen, Minnesota Todd Gerhardt, City Manager Denny Laufenburger, Mayor 2 (Summary Ordinance [insert number] published in the Chanhassen Villager on [insert date])