The first section of this memo contains several related amendments to address the landscaping and GI for impervious surface goals:

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1 Birchline Planning LLC Memo To: Dave DeAngelis, Village of Elm Grove From: Juli Beth Hinds, AICP RE: Menomonee Codes Project: Elm Grove Impervious Cover Date: July 5, 2013 Below (at long last) are some initial options for Elm Grove to consider. These are intended to address the goals of (1) providing options for calculating the extent to which impervious cover limits can be increased when specific green infrastructure practices are used, including green roofs; and (2) developing standards for reviewing and approving landscape-based stormwater management practices. The first section of this memo contains several related amendments to address the landscaping and GI for impervious surface goals: (1) Add landscape standards that encourage the use of landscaped areas for stormwater management and water quality to Section (C), Site Specific Stormwater Management Plan and (C), Site Regulations. (2) Add substitution factors for green infrastructure practices and impervious/building cover to a new Section (C), Site Regulations, with a cross-reference in Section (3) Add a new provision at (A)(4) allowing the Village to seek independent technical review of landscaping and stormwater control plans in cases where a tradeoff is proposed, to ensure that the functions represented are likely to be performed, similar to the existing language in (D) which enables the Village to charge fees for consultant review of subdivisions (4) Add a definition of impervious surface to Section (SW Management; definitions) which should apply throughout the municipal code (5) Add definitions of GI stormwater control measures and practices to Section apply throughout the municipal code. The remaining sections provide some options for landscaping, permeable surfacing, and other miscellaneous amendments. **To support landscaping plan review and provide support for the Plan Commission and Village on species selection, I am suggesting use of a guidance document drawn from the attached plant list and parking lot bioretention guides. We would love feedback from Elm Grove on wheher these would be helpful outputs from the codes project! I. IMPERVIOUS COVER LIMITS AND GREEN INFRASTRUCTURE amendments to 325 ARTICLE III. STORMWATER MANAGEMENT Vermont Office 5 Taft Avenue Rutland VT California Office & Mailing Address Carmel Country Road #70 San Diego CA birchlineplanningllc@gmail.com

2 Purpose. The purpose of this article is to promote the public health, safety and general welfare of this community and to diminish threats ot the environment by: A. E. Reducing stream channel erosion and sedimentation F. Promote the use of landscape-based stormwater control measures and practices, rainwater harvesting measures, and permeable surfacing, where consistent with sound engineering and landscape practices Definitions. The definitions used in this article are as follows: (Add the following definitions) AMENDED SOIL AREAS. Amended soil areas are those landscaped portions of a site where decomposed organic material has been incorporated into the soil to improve its performance for infiltration and vegetation, enabling the area to function as a vegetated control measure 1. BIORETENTION AREA or RAIN GARDEN. A bioretention area or rain garden is an excavated area that is back-filled with an prepared or amended soil mixture, covered with a mulch layer and planted with a diversity of woody or herbaceous vegetation, to which storm water is directed to promote infiltration and evapotranspiration 2. CISTERN. Roof runoff collection systems that detain water in above-ground or underground storage tanks, ranging in capacity from one hundred to 10,000 gallons 3. GREEN ROOF. An engineered roofing system that includes vegetation planted in a growing medium above an underlying waterproof membrane material, designed to reduce the volume of storm water runoff from building roofs 4. IMPERVIOUS SURFACE. Any pavement or structural element that prevents rain, surface water runoff, or melting snow from infiltrating into the ground below, including, but not limited to roofs and paved roads, driveways, and parking lots 5. PERMEABLE SURFACING. A material or materials and accompanying subsurface treatments designed and installed specifically to allow stormwater to penetrate into the material, thereby reducing the volume of storm water runoff from the surfaced area. Permeable surfacing may include without limitation paver blocks, grasscrete or similar structural support materials, and permeable concrete or asphalt. POCKET WETLANDS. Pocket wetlands are small (typically under 1,00 SF in area) constructed wetlands designed to reduce peak flows and runoff volumes, and remove pollutants via settling and biouptake 6. 1 Adapted from MMSD LID descriptions 2 From WI DNR post-construction stormwater technical sheets 3 Adapted from MMSD LID descriptions 4 Adapted from MMSD LID descriptions 5 From MMSD Chapter 13

3 3 RAIN BARREL. Rain barrels are structures for the collection of roof runoff in containers typically ranging from 50 to 100 gallons in size, with subsequent release to landscaped areas 7. STORMWATER TREE. Stormwater trees are those trees selected and installed (either with or without an engineered box or structure) as integral components of stormwater management plan, at points or sites where the tree(s) will have the effect of increasing the coverage of tree canopies to provide stormwater interception and evapotranspiration, stormwater uptake, and increased infiltration. VEGETATED CONTROL MEASURES. The term Vegetated control measures refers to vegetated swales, bioretention areas, rain gardens, amended soil landscape areas, pocket wetlands, stormwater trees, or similar practices, that are designed and intended to provide stormwater treatment and control and to promote evapotranspiration and infiltration of stormwater. VEGETATED SWALES. Vegetated swales are stormwater conveyance systems routing stormwater flows through vegetated areas a natural elongated depression or a constructed channel. A vegetated infiltration swale differs from a conventional drainage channel or ditch in that it is constructed specifically to promote infiltration Site-specific stormwater management plan. A. General (1) The stormwater management plan shall be prepared by (2) The plan shall consist of narrative descriptions and explanations (3) The plan shall incorporate the landscaping and grading plan for the site and indicate clearly the location and size of all landscaped and vegetated areas, green roofs, rainwater storage systems and areas of permeable surfacing that are intended to provide stormwater treatment or control functions. (4) The applicant shall pay a fee equal to the actual cost to the Village for the review of plans by consultants engaged by the Village in the course of review of the stormwater management plan application 8. B. Existing site conditions. The plan shall include a map and description of the existing conditions of the site concerned, including: (1) A map of the site (2) The hydrologic and hydrologic characteristics (3) The location of areas where stormwater may collect or percolate into the ground. (4) Groundwater elevations (5) Soils by hydrologic group (6) Existing vegetative ccover type and condition, including the location and caliper (dbh) of all mature trees. (7) Location and extent of impervious surfaces, including type and condition of the surfaces 6 Adapted from MMSD LID descriptions 7 Adapted from MMSD LID guidance 8 Mirrors language in (C), Subdivision, Administrative and other fees

4 4 (8) Locations and outlines of all buildings (9) Location of all receiving bodies of surface water (10) Location and extent of the one-hundred-year (11) Information regarding current water quality objectives (12) Locations of points of discharge of stormwater runoff (13) Locations, sizes and elevations of all existing storm sewers (14) Locations of any existing water supply wells C. Proposed post-development and redevelopment site conditions. The plan shall describe the alterations proposed to be made to the site and the resulting proposed post-development and redevelopment conditions. The proposed site conditions plan shall incorporate the proposed landscaping and grading plan and indicate clearly where landscaped areas, vegetated control measures, rain barrels or cisterns, green roofs, or permeable materials are intended to perform stormwater treatment and control functions. The description shall include (1) Proposed changes in the planimetry of the site (2) The location and outline of all proposed buildings or other structures, clearly indicating: a. the size and location of areas of green roof practices, b. locations where building drainage is to be directed to a vegetated control measure, and c. the location, size and specifications for any rainwater harvesting systems proposed. (3) Changes in the location, extent and type of impervious surfaces, identifying clearly the location and size of any proposed areas of permeable surfacing and the type of material proposed. (4) The location and extent of areas where vegetation is to be disturbed or planted The landscaping plan for the property. Plant species should be consistent with [GUIDANCE REFERENCE], as kept on file with the Village [DEPARTMENT]. Landscaping plans shall include: a. The location, type and dimensions of all proposed vegetated control measures, including amended soil areas and stormwater trees, indicating the flow paths and area draining to each vegetated control measure; b. The location and general type of planting (e.g. natural lawn, trees, tree boxes, ornamental plantings, turfgrass, etc.) of those landscaped areas not intended to function as vegetated control measures (5) Changes in the drainage flow paths into, through and out of the site and related changes in drainage basin boundaries; (6) The location, elevations and sizes of all other proposed minor and major stormwater management facilities; the former, including all storm sewers and inlets, and the latter, including curbed roadways, roadway ditches, culverts, storage facilities and interconnected flow paths, all elevations being referred to the National Geodetic Vertical Datum of (7) The location, size, and general specifications for any rainwater harvesting or green roof systems proposed as part of the stormwater management plan, including the location and extent of areas proposed to drain to cisterns or rain barrels. D. Anticipated impacts. The plan shall contain a description of the following E. Proposed stormwater management facilities and measures. The plan shall include a definitive description of the stormwater management facilities and measures proposed to be used for the control of the quantity and quality of the anticipated stormwater runoff from the proposed development, redevelopment or property subdivision. The measures and descriptions may include:

5 5 (1) For detention and retention facilities: (2) For conveyance facilities: (3) Areas to be used for percolation into the groundwater reservoir Areas or stormwater control measures, including permeable surfacing and vegetated control measures, designed specifically to promote infiltration of stormwater into the groundwater table. (4) Provisions for the control of erosion (5) Measures to abate any potential pollution of surface and ground waters, including any source control measures necessitated for the proposed land use (e.g. waste containment, outdoor storage area covers, etc.). (6) Installation and materials specifications for all permeable surfacing, including the type of material proposed, structural strength, and subsurface profile. (7) Planting and design plans for vegetated control measures, including proposed planting types, soil or planting media and depths, and specifications for any proposed drainage or lining; or standards and specifications for stormwater trees or tree boxes. (8) Detailed drawings and plans for any proposed rainwater harvesting measures and green roof systems, including structural specifications, soil depths, planting types, drainage measures, and the location and extent of areas proposed to drain to rain barrels or cisterns. (9) Volume reduction calculations [question to staff: have there been any issues w/this area?] F. Hydrologic computations G. Construction schedule and costs Stormwater discharge criteria. A. The conveyance and storage facilities incorporated into the site-specific stormwater management system plan required under this article, including permeable surfacing, rainwater harvesting, green roofs, stormwater trees and vegetated control measures, shall be designed as an integral part of existing stormwater systems, provided that there is no downstream flooding. In the event that there is downstream flooding, the Village Engineer may require site-specific measures that will not increase downstream storm flows. B. Design criteria and standards for stormwater management measures shall be made available by the Village Clerk in cooperation with the Village Engineer. Use of design guidance promulgated by the Milwaukee Metropolitan Sewerage District and Wisconsin Department of Natural Resources is encouraged for vegetated stormwater control measures, rainwater harvesting, and permeable surfacing.

6 6 2. Landscaping regulations Site regulations. A. All lots shall abut upon a public street or have other Village-approved access. B. All principal structures shall be located on a lot and only one principal structure shall be located, erected or moved onto a lot in all residential districts. The Plan Commission may permit more than one structure per lot in other districts where more than one principal structure is needed for the orderly development of the parcel. When additional structures are permitted, the Plan Commission may impose additional yard requirements, landscaping requirements or parking requirements, or may require a minimum separation distance between principal structures. C. (Reserved) Lot Coverage Calculations and Stormwater Management Maximum lot coverage by all buildings and impervious surfaces shall be as set forth in the individual district regulations in Sections through , as modified in a Planned Development Overlay approval under Section However, in conjunction with an approved Stormwater Management Plan, the maximum lot coverage may be increased by up to [ten percent of the maximum for the underlying district or five thousand SF, whichever is less] 910 through the use of specific stormwater practices that reduce the amount of connected impervious cover, per Table below. The area of the stormwater control measure shall be determined using the outside perimeter of the area wholly occupied by the stormwater control measure or permeable surfacing. Amended Soil Areas Bioretention or Rain Garden Cistern Green roof Permeable surfacing Pocket wetlands Rain barrel Stormwater tree Vegetated swale Percent of area of the stormwater control measure that may be counted as permeable 25% of the area of the amended soil area 25% of the area of the bioretention area or rain garden 25% of the roof or impervious area draining to the cistern 50% of the area of the green roof 25% of the area of permeable surfacing 25% of the area 25% of the roof area draining to the rain barrel 25% of the impervious area draining to the stormwater tree 10% of the area of the vegetated swale D. No building permit shall be issued for a lot which abuts a public street dedicated to only a portion of its proposed width and located on that side thereof from which the required dedication has not been secured. E. Lots abutting more restrictive district boundaries shall provide side and rear yards not less than those required in the more restrictive abutting district. The setbacks on the less restrictive district shall be modified for a distance of not more than 60 feet from the district boundary line so as to equal the average of the street yards required in both districts. 9 What is the maximum in a PDO? Would the Village prefer to establish a maximum number per zoning district and if so, should this be included in the PDO section as well? 10 If a parcel is 20,000 SF with a maximum impervious cover of 70% (14,000 SF), the total allowable increase would be the lesser of either 10% [(14,000 SF + (10%*20,000 SF)) = 16,000 SF], potentially including a maximum of 5,000 SF per parcel to avoid very large additional areas on larger parcels.

7 7 F. Buffer yard required. Any business or industrial use that abuts a residential parcel shall provide a minimum buffer yard of 20 feet between the business use and all single-family and two- family residential districts. The purpose of the buffer yard is to screen the business activity or multifamily residential activity from the single- or two-family residential environment in such a manner that: (1) If a buffer yard is composed entirely of plant materials, it shall be of sufficient depth and height and contain sufficient plant species as to provide dense effective visual screening within two years and during all seasons of the year. If the buffer yard landscaping and grading is part of an approved stormwater management plan, applicants are encouraged to use a combination of fencing, architectural walls, and plantings to provide an effective visual screen without interfering with use of the landscaped area for stormwater management. Plant selection from the [GUIDANCE DOCUMENT] is encouraged. (2) Where architectural walls or fences are used, sufficient landscaping shall be used in conjunction with such wall or fence to create an attractive view from the residential side. Any wall or fence shall not be less than four nor more than six and one-half feet in height and shall comply with the requirements set forth for fences in D(6)(g) of this chapter. (3) Pursuant to G, all public off-street parking areas which abut single-family residential development shall be provided with a continuous landscaped screen consisting of either dense landscaping or a wall or fence of appropriate height, sufficiently opaque to prevent the penetration of headlight glare into the abutting single-family residential development. If the landscaped screen area is part of an approved stormwater management plan, applicants are encouraged to use fencing or architectural walls in combination with plantings to provide an effective visual screen without interfering with the use of the landscaped area for stormwater management. (4) All landscaping shall be maintained by the owner or operator to the satisfaction of the Building Board. Maintenance of native vegetation or plantings in vegetated stormwater control measures shall be consistent with maintaining the area s water quality and stormwater management functions, following practices outlined in [GUIDANCE DOCUMENT]. (5) No lighting shall be permitted on or in any part of the buffer yard, and no lighting installed elsewhere on the parcel shall direct any rays onto adjacent residential properties. (6) No signs shall be permitted on or in any part of the buffer yard AEffect on existing provisions; greater restrictions to apply. 3. PLANNED DEVELOPMENT OVERLAY DISTRICT Planned Development Overlay District. A. B. C. D. Dimensional and stormwater management requirements.

8 8 (1) PDO Districts shall comply at all times with MMSD District Rules and Regulations Chapter 13 relating to stormwater management requirements within the underlying zoning district. (2) PDO Districts may, however, deviate from the requirements of the underlying zoning district with respect to maximum building height, yard areas, lot dimensions, setbacks and parking requirements, and with maximum lot coverage requirements to the extent allowable under (C). E, F G. Procedural requirements. (b) A general development plan including: [1] A legal description of the boundaries of all property included in the proposed PDO District and its relationship to surrounding properties, including existing topography on the site with contours at no greater than two-foot intervals as part of an ALTA survey. [2] A detailed site plan for the entire PDO District showing: [a] The type, size, arrangement, including respective use(s) and location of any individual lots, building sites and proposed structures on each individual lot. [b] The location of open space areas and areas reserved or dedicated for private or public uses, including, but not limited to, easements and drainageways. [c] Landscaping, including the proposed location, caliper and species of all new and retained trees, general planting plan for landscaped areas; location, size, type and planting plan of vegetated control measures; location and size of proposed lawn or turfgrass areas; exterior lighting; and signage. Planting plans for vegetated stormwater control measures should be drawn from the [GUIDANCE DOCUMENT]. [d] The location of public and private roads, driveways and parking facilities and the calculations used to justify the number of spaces proposed. [e] The existing and proposed location of public and private sanitary sewer and water supply facilities. [f] The existing and proposed location of all other public and private utilities or other easements. [g] Characteristics of soils related to contemplated specific uses. Stormwater management features, including the location, size and type of all vegetated control measures, permeable surfacing, and green roofs, and the location and size of any areas proposed to drain to a cistern or rain barrel. (2) The Village Plan Commission, in making its preliminary and final recommendations, and the Village Board, in making its decision on any proposed PDO District, shall consider the following criteria: (a) The development will not be contrary to the general welfare and economic prosperity of the community. (b) The stormwater management and landscaping plan for the proposed site is being provided with adequate drainage facilities provides integrated and effective protection for surface and storm waters, consistent with the Village s stormwater management standards in Section J. Development agreement contents and demonstration of consent. 4. loading, parking and access Article IV. Loading, Parking and Access Parking requirements.

9 9 B. Location of off-street parking shall conform to the following standards:... (3) Notwithstanding restrictions contained in , the Plan Commission may grant an exception to the general requirement that off-street parking shall not be permitted in street yards and/or side yards if the Plan Commission determines that the conditions on the property are such that parking in the street yards and/or side yards is reasonably necessary to provide adequate parking and is adequately landscaped to avoid adverse impact on adjoining parcels or to the district where the parcel is located. F. Surfacing. (1) All off-street parking areas shall be surfaced with asphalt, concrete, or permeable brick pavers, or other permeable surfacing approved in a Stormwater Management Plan pursuant to Section , and shall be drained so as to dispose of all surface water accumulated in the parking area in such a way as to preclude drainage of water onto adjacent properties or toward structures. The design and use of perimeter and island landscaping for stormwater management is strongly encouraged; curbing or wheel stops may be varied to allow stormwater inflow in accordance with an approved Stormwater Management Plan. (2) Surfacing, including permeable surfacing as noted above, shall be in accordance with engineering standards and specifications approved by the Village Manager, and surfacing shall be completed within one year after the date of the permit. (3) Any parking area for more than five vehicles shall have the aisles and spaces clearly marked. (4) Areas of the parking lot designated for snow storage shall be clearly noted on the plan. The use of areas of permeable surfacing for snow storage is encouraged. Vegetated stormwater control areas approved in a Stormwater Management Plan shall not be used for snow storage unless specifically approved by the Village Engineer. G. Landscaping. [RENUMBER SECTION; incorporate 10 & 11 from (6)] (1) A landscaping and drainage plan shall be required for all public off-street parking areas. Perimeter and internal landscape areas are encouraged to be designed and utilized for stormwater management in accordance with [GUIDANCE DOCUMENT] and [PLANT LIST], and any approved Stormwater Management Plan for the property. To ensure landscaped areas are suitably designed for stormwater management, the Plan Commission shall have the authority at its discretion to require technical review of landscape design and plant selection. (2) Parking lots of over 24 vehicles shall have a minimum of one tree island not less than 180 square feet for each 24 parking stalls or an equivalent number of perimeter plantings or tree rows that are designed as part of an overall landscape plan acceptable to the Plan Commission. (13) All public off-street parking areas which abut single-family residential development shall be provided with a continuous screening from headlights through the use of a combination of decorative fencing and landscaping. (24) Curbed end Landscaped islands of a minimum of 100 square feet shall be provided when two or more drive aisles exist in a parking lot or where traffic control is needed to delineate the path for pedestrians or motor vehicles. A combination of curbing or wheel stops shall be utilized to protect landscaped areas from vehicles. (5) Large parking areas shall be treated with decorative screens consisting of building wall extensions, plantings, fencing berms or other innovative means so as to screen parking areas. (36) The location of landscape areas, plant materials, protection afforded the plantings, including curbing and provisions for maintenance, shall be subject to approval by the Plan Commission. All plans for such proposed parking areas shall include a topographic survey or grading plan which shows existing and proposed grades and location of improvements. The preservation of existing trees, shrubs and other

10 10 natural vegetation in the parking area may be included in the calculation of the required minimum landscape area. Article VIII. Performance Standards Site plan and building plan approval. D. Procedure for site and building plan review and approval. (1) Application. (b) Existing and proposed grades, stormwater management basins and drainage systems and structures with topographic contours at intervals not exceeding two feet. The Zoning Administrator may waive the grading map in situations where there will be no alteration of existing grades. (j) Landscape plan showing all new plantings and retained existing plant materials. The landscape plan shall include the number, species and size of materials at installation. (6) Criteria for site and building plan reviews. The Building Board and Plan Commission will use the following criteria in reviewing site and building plans. (a) Landscape and site treatment. [1] Where natural or existing topographic patterns contribute to beauty and do not detract from the utility of a development, they shall be preserved and developed. [2] Landscape treatment shall be provided to enhance architectural features, improve appearance, screen parking areas and miscellaneous structures, provide wildlife habitat, provide shade and enhance the streetscape. Vegetated stormwater control measures approved in conjunction with a Stormwater Management Plan under Section shall be counted as landscape areas for purpose of this ordinance. [3] Unity of design shall be achieved by repetition of certain plant varieties and other materials and by coordination with landscaping or materials on adjacent developments. The integration of ornamental landscaping with natural areas and vegetated stormwater controls is encouraged. [4] Plant materials shall be selected on the basis of size at maturity, hardiness, tolerance for site specific environmental conditions, screening value, wildlife habitat values and all season appearance. [5] The use of plant materials listed in [GUIDANCE DOCUMENT] that enhance stormwater infiltration and control is strongly encouraged. Use of plants that are indigenous to the area shall be encouraged. [6] Nonnative plants that are considered a nuisance or invasive species, such as purple loose strife, honeysuckle and buckthorn shall not be used as plant materials. [7] Plant specimens shall be of sufficient size and quality to provide screening and landscape benefits within three growing seasons from the time of planting. Trees planted in front yard areas or in other highly visible areas where they serve as a visual screen, should be at least two inches in diameter and eight feet high at the time of planting. Evergreens should be a minimum of six feet high at the time of planting. Shrubs should be balled and burlapped and a minimum of 18 inches high at the time of planting. [8] Irregular clusters of vegetation are generally preferable to isolated specimens or regularly spaced rows of plantings. [9] In locations where they will be susceptible to injury by pedestrian or motor traffic, plants shall be protected by appropriate curbs, wheel stops, tree guards or other devices. [10] Parking lot landscaping is required in conformance with the standards in (G) **MOVE TO (G) [10] Planting in parking lot islands is required to break up large expanses of parking stalls. Parking lots of over 24 vehicles shall have a minimum of one tree island not less than 180 square feet for each 24 parking

11 11 stalls or an equivalent number of perimeter plantings or tree rows that are designed as part of an overall landscape plan acceptable to the Plan Commission. [11] Large parking areas shall be treated with decorative screens consisting of building wall extensions, plantings, berms or other innovative means so as to screen parking areas. [11] Dumpsters, trash handling areas, outdoor storage yards, animal runs, and similar areas that may contribute bacteria or trash shall be fully enclosed to prevent trash and debris from escaping. Such areas must be drained to a sanitary sewer or other area specifically designed to prevent drainage and runoff from entering surface waters or the storm drainage system. [12] Screening of service yards and other places that tend to be unsightly shall be accomplished by use of walls, fencing, planting or combinations of these. Screening shall be equally effective in winter and summer. Screens shall be compatible and harmonious with the landscaping and site treatments on neighboring properties. [13] Prohibition of disturbing steep slopes. Steeply sloped terrain with a natural grade of 25% or more may not be regraded, built upon or otherwise disturbed. The Planning Commission and Building Board may grant an exception to this requirement where the area proposed for disturbance is an isolated area no more than 20,000 square feet in size, and provided that such disturbance is necessary for the development to occur and does not alter the overall topographical character of the site. 5. OTHER RECOMMENDED AMENDMENTS Erosion control. Recommend adding requirement to demarcate the limits of disturbance on a site before construction starts Permit and control plan required (D) Permits, (3) Permit conditions (j) Clearly demarcate the limits of disturbance on the site prior to commencing construction. 2. Reduce total allowable extent of residential driveways Driveways. (1) Openings for vehicular ingress and egress shall not exceed 35 feet in width at the street right-of-way for commercial properties and 24 feet at the street right-of-way for residential properties. The width at the edge of the roadway shall be determined by the Department of Public Works.