City of Prescott, WI Article VII Design Standards

§ 510-39 General street design standards.

A. Compliance with statutes. In laying out a subdivision, the owner shall conform to the provision of Ch. 236, Wis. Stats., and all applicable City regulations. In all cases where the requirements of the chapter are different from the requirement of Chapter 236, the more restrictive provision shall apply.

B. Dedication. The subdivider shall dedicate land and improve streets as provided in this chapter and § 510-24. Streets shall be located with due regard for topographical conditions, natural features, existing and proposed streets, utilities and land uses and public convenience and safety. Streets shall conform to official maps adopted by the Common Council. The subdivision, certified survey parcel or land division shall be so designed as to provide each lot with satisfactory access to a public street or road.

C. Compliance with Comprehensive Master Plan and ordinances.

(1) The arrangement, character, features, and layout of land division in the City of Prescott shall be designed to comply with the standards of this chapter, the Comprehensive Master Plan, the Official Map, and/or any comprehensive utility plans or other planning documents which may pertain to the standard of design for land divisions and which have been adopted by the Common Council. Where no such planning documents have been adopted, subdivision shall be designed according to engineering and planning standards, approved by the City Engineer and applied so as to properly relate the proposed development with adjacent development, the topography natural features, public safety and convenience, and the most advantageous development of undeveloped adjacent lands. In the absence of a street being shown on the Official Map, streets shall be provided in locations determined necessary by the City Engineer and to the right-of-way widths required in this article for the classification of street required.

(2) The arrangement, character, extent, width, grade and location of all streets shall conform to the City Comprehensive Master Plan, the Official Map and to this chapter and other City planning documents and shall be considered in their relation to existing and planned streets, reasonable circulation of traffic, topographical conditions, runoff of stormwater, public convenience and safety and in their appropriate relation to the proposed uses of the land to be served by such streets.

(3) The arrangement of streets in new subdivisions shall make provision for the appropriate continuation of the same or greater width of the existing streets in adjoining areas.

D. Areas not covered by Official Map or plan. In areas not covered by the Official Map or City Comprehensive Master Plan, the layout of streets shall conform to the plan for the most advantageous development of adjoining areas of the neighborhood. Streets shall be designed and located in relation to existing and officially planned streets, topography and natural terrain, streams and lakes and existing tree growth, public convenience and safety and in their appropriate relation to the proposed use of the land to be served by such streets.

E. Proposed streets. Proposed streets shall extend to the boundary lines of the tract being subdivided unless prevented by topography or other physical conditions or unless, in the opinion of the Common Council, such extension is not necessary or desirable for the coordination of the layout of the subdivision or land division or for the advantageous development of the adjacent tracts.

F. Streets classifications. Streets shall be required and classified by the City Engineer in accordance with the City's Comprehensive Master Plan and, where not identified in said plan, in accordance with sound engineering standards, into the classifications indicated below:

(1) Arterial streets. Arterial streets shall be arranged to provide through traffic for a heavy volume of vehicles.

(2) Collector streets. Collector streets shall be arranged so as to provide ready collection of traffic from individual areas and conveyance of this traffic to the major street and highway system and shall be properly related to special traffic generators such as schools, churches and shopping centers and other concentrations of population and to the major streets into which they feed.

(3) Local/minor streets. Local streets shall be arranged to conform to the topography, to discourage use by through traffic, to permit the design of efficient storm and sanitary sewerage systems, and to require the minimum street area necessary to provide safe and convenient access to abutting property.

(4) Alleys. Alleys shall be located at rear property lines, shall discourage through traffic, shall serve fewer than 50 vehicles per day, shall be intended to provide access to off-street loading and service areas and not primary access to parcels.

G. Reserve strips. Reserve strips shall not be provided on any plat to control access to streets or alleys, except where control of such strips is placed with the City under conditions approved by the Common Council.

H. Extraterritorial streets. Streets located in the extraterritorial plat jurisdiction of the City shall provide for the dedication of the minimum widths of right-of-way in accordance with the standards adopted by the pertinent Town government in which the project is located. Other streets within the extraterritorial plat jurisdiction of the City shall meet or exceed the town road standards of § 82.50, Wis. Stats.

I. Alleys; cul-de-sac streets.

(1) Commercial and industrial. Alleys may be provided in commercial and industrial districts. The width of the right-of-way for residential alleys shall be not less than 24 feet, and the width of the right-of-way for commercial and industrial alleys shall be not less than 32 feet. Alleys shall be constructed according to base and surfacing requirements for streets.

(2) Residential. Alleys shall not be approved in residential areas unless necessary because of topography or other exceptional circumstances.

(3) Dead end. Dead-end alleys are prohibited except under very unusual circumstances, and crooked and T-alleys shall be discouraged. Temporary dead-end streets shall not be over 600 feet in total length, shall provide for an eventual intersection spacing meeting the requirements of this chapter and shall provide for temporary culs-de-sac or turnarounds as approved by the City Engineer.

(4) Permanent dead-end streets; cul-de-sac streets. Permanent dead-end streets or culs-de-sac shall not be longer than 600 feet, shall have a minimum width of 60 feet and terminate with a turnaround having minimum radii of 30 feet for roadway and 40 feet for a street line.

J. Continuation. Streets shall be laid out to provide for possible continuation wherever topographic and other physical conditions permit. The use of culs-de-sac shall be held to a minimum and permanently dead-ended streets shall be prohibited. Provisions shall be made so that all proposed streets shall have a direct connection with, or be continuous and in line with, existing, planned or platted streets with which they are to connect. Proposed streets shall be extended to the boundary lines of the tract to be subdivided, unless prevented by topography or other physical conditions or unless, in the opinion of the Common Council, upon the recommendation of the Plan Commission, such extension is not necessary or desirable for the coordination of the layout of the subdivision with existing layout or the most advantageous future development of adjacent tracts.

K. Minor streets. Minor streets shall be so laid out so as to discourage their use by through traffic.

L. Frontage roads. Where a land division abuts or contains an existing or proposed arterial highway or railroad right-of-way, the subdivider shall provide a frontage road, platted access restriction along the property contiguous to such highway, or such other treatment as may be determined necessary by the City Engineer to ensure safe, efficient traffic flow and adequate protection of residential properties.

M. Private streets. Private streets shall not be approved nor shall public improvements be approved for any private street; all streets shall be dedicated for public use.

N. Width; radii of curvature; grades. All street right-of-way widths, radii of curvature and grades shall conform to the following requirements:

	Street Type	Minimum Right-of-Way Width (feet)	Minimum Radius of Curvature (feet)	Maximum Grade
	Arterial or highway	120	300	6%
	Collector	80	80	7%
	Minor	66	100	10%

O. Visibility. Streets shall afford maximum visibility and safety for motorist, bicycle, and pedestrian use and shall intersect at right angles, where practicable. A minimum sight distance with clear visibility, measured along the center line, shall be provided of at least 500 feet on major thoroughfares, 200 feet on collector-distributor streets, and 150 feet on all other streets.

P. Tangents. A tangent at least 100 feet long shall be required between reverse curves on arterial and collector streets.

Q. Vertical curves. All changes in street grades for arterials and changes in street grades for collector and local streets where the algebraic difference in the rate of grade exceeds 1% shall be connected by vertical curves. The minimum length, in feet, of the vertical curve shall be the product of the "K" value for the associated street design speed times the algebraic difference in the rate of grade.

R. Half streets. Half streets shall not be platted unless necessary to provide the full width of an existing street platted to half width. All newly platted streets shall be platted to half width. All newly platted streets shall be platted to the required width. Where a half street exists adjacent to a proposed land division, the subdivider shall endeavor to acquire and dedicate the remaining half street.

S. Intersections.

(1) Angle of intersect. Streets shall intersect each other at as nearly right angles as topography and other limiting factors of good design permit. The curved street shall intersect another street with not less than 40 feet of tangent right-of-way between the end of curvature and right-of-way of the street being intersected.

(2) Number of streets converging. The number of streets converging at one intersection shall be reduced to a minimum, preferably not more than two. Intersections of local streets shall be at least 125 feet from each other.

(3) Number of intersections: arterial streets. The number of intersections along arterial streets shall be held to a minimum. Wherever practicable, the distance between such intersections shall be not less than 1,200 feet, unless otherwise determined by the City Engineer to provide better safety.

(4) Local street spacing. Local street and frontage roads intersecting with other local streets shall be spaced no closer than 800 feet between center lines on collector streets, unless otherwise approved by the Plan Commission.

(5) Property lines at street intersections. Property lines at street intersections shall be rounded with a minimum radius of 15 feet, except that with all intersections with arterial and collector streets, the radius shall be increased to 25 feet or of a greater radius when required by the City Engineer.

(6) Local streets. Local streets shall not necessarily continue across arterial or collector streets, but if the center lines of such local streets approach the major streets from opposite sides within 150 feet of each other, measured along the center line of the arterial or collector streets, then the location shall be so adjusted that the adjoinment across the major or collector street is continuous and a jog is avoided.

(7) Additional sight easements. At any intersection determined by the City Engineer, restricted development easements or additional street right-of-way shall be platted to provide for adequate sight distances in every direction of travel. At a minimum, the subdivider shall grade, clear or otherwise provide for an unobstructed sight triangle at all intersections incorporating the area within a triangle formed by the intersection of the street right-of-way lines and a point on each right-of-way line being not less than 25 feet from the intersection point.

T. Street names.

(1) Duplication of existing street names by similar word, spelling, or sound shall not be permitted.

(2) Where a street maintains the same general direction except for curvilinear changes for short distances, the same name shall continue for the entire length of the street. House numbering difficulties shall be considered the determining factor in considering whether a change of name is necessary due to curvilinear changes.

(3) A street name shall be changed when required to conform to the proposed or existing house numbering base.

(4) A name which is assigned to a street which is not presently a through street, due to intervening land over which the street extension is planned, shall be continued for the separate portions of the planned through street.

(5) The following designations shall be used only in the situations indicated:

(a) "Boulevard": a street with a divided pavement, either existing or planned. If the divided pavement ends but the street continues, the same street name and suffix shall continue.

(b) "Lane": to be limited to a street one block long, not ending in a cul-de-sac.

(c) "Circle": to be limited to a cul-de-sac of nine lots or more.

(d) "Court": to be limited to a cul-de-sac of eight lots or less.

(e) "Parkway": to be limited to a street abutting a park or greenway or creek.

(6) The maximum number of street names at one intersection shall be three.

(7) Street names shall be assigned to avoid intersections which have the same exact street names.

(8) The name of any projection of a street shall remain unchanged even if the projection terminates in a cul-de-sac.

(9) The changing of a street name that does not duplicate an existing street name shall only be approved where such change will eliminate conflicts with other provisions of this subsection.

(10) Service roads and highways served by them shall have the same street name and designation.

(11) Approval of street names on a preliminary plat will not reserve the names, nor shall the City be required to accept such names at the time of final platting.

(12) A minimum number of letters is desirable in a street name. The maximum number of letters, not including the prefix or suffix, shall not exceed 12.

U. Limited-access highway and railroad right-of-way treatment. Whenever the proposed subdivision contains or is adjacent to a limited-access highway, arterial street or railroad right-of-way, the design shall provide the following treatment:

(1) Subdivision lots. When lots within the proposed subdivision back upon the right-of-way of an existing or proposed limited-access highway or a railroad, a planting strip at least 30 feet in depth shall be provided adjacent to the highway or railroad in addition to the normal lot depth. This strip shall be part of the platted lots but shall have the following restriction lettered on the face of the plat: "This strip reserved for the planting of trees and shrubs, the building of structures hereon prohibited."

(2) Commercial and industrial districts. Commercial and industrial districts shall have provided, on each side of the limited-access highway, arterial street or railroad, streets approximately parallel to and at a suitable distance from such highway or railroad for the appropriate use of the land between such streets and highway or railroad, but not less than 150 feet.

(3) Streets parallel to a limited-access highway. Streets parallel to a limited-access highway or railroad right-of-way, when intersecting a major street and highway or collector street which crosses said railroad or highway, shall be located at a minimum distance of 250 feet from said highway or railroad right-of-way. Such distance, where desirable and practicable, shall be determined with due consideration of the minimum distance required for the future separation of grades by means of appropriate approach gradients.

(4) Minor streets. Minor streets immediately adjacent and parallel to railroad rights-of-way shall be avoided, and location of minor streets immediately adjacent to arterial streets and highways and to railroad rights-of-way shall be avoided in residential areas.

§ 510-40 Specifications for preparation, construction and dedication of streets and roads.

A. Construction standards. All roadway construction and materials used shall be performed in accordance with the construction methods as listed in the appropriate sections of the "State of Wisconsin Department of Transportation Standard Specifications for Road and Bridge Construction," and its supplements, and this chapter, whichever is more restrictive. The design requirements of this section and § 510-39 shall be applicable to all streets and roads that are to be dedicated to the City, regardless of whether such streets or roads are part of a new subdivision or land division. Design requirements for the pavement shall be adequate for the zoning classification of the area served by the subject street. A street which divides areas with different zoning classifications shall be constructed in accordance with the requirements of the area requiring the higher-quality pavement. Any variation of this must have prior approval of the City Engineer. Combination concrete curb and gutter is required on all streets. (Refer to § 510-25 describing requirements for curbs and gutters.)[1]

[1] Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II).

B. Temporary streets. Construction of temporary streets shall require authorization of the Plan Commission.

C. Standard street improvements.

(1) Standard street improvements shall include streetlights, crushed stone base course, concrete curb and gutter, bituminous binder and surface course and, when required, walkways.

(2) The construction of standard street improvements can begin only when the construction of underground utilities has been completed and mechanical compaction test reports have been approved by the City Engineer.

(3) Upon obtaining the written approval of the City Engineer, the subdivider can proceed with the construction of the standard street improvements. Standard street improvements shall be installed to the boundary line of the subdivision unless the street culminates in a cul-de-sac, unless the topography or other physical conditions make it impossible to do so, or unless this requirement is waived, in writing, by the Plan Commission.

D. Roadway base standards.

(1) The subdivider must bring all streets and alleys to a grade established by the Common Council. All site work by City employees in determining grade shall be billed at the City rate and paid by the owner.

(2) Residential streets shall have a minimum nine-inch-thick, compacted-in-place, crushed stone roadway base. Roadway base shall consist of four-inches minimum depth of compacted, crushed stone conforming to requirements of Gradation No. 2 of Section 304, Crushed Aggregate Base Course, of "State of Wisconsin, Standard Specifications for Road and Bridge Construction," latest edition, in top layer over five inches minimum depth of compacted, crushed stone in bottom layer, which conforms to following gradation specifications:

Sieve Size (inches)	Percentage Passing by Weight
3	100%
2 1/2	90% to 100%
2	35% to 70%
1 1/2	0% to 15%
3/4	0% to 5%

(3) On commercial, arterial or other heavy-use streets, as determined by the City Engineer, a ten-inch minimum depth base course shall be constructed upon an inspected and approved subgrade, with crushed rock approximately six inches in depth conforming to the specifications in Subsection D(2) above and overlaid with one four-inch layer of crushed stone conforming to Gradation No. 2 as specified in Subsection D(2) above.

(4) In the case of commercial, arterial or other heavy-use roads, the Common Council may, in the alternative to the above standards, have the City Engineer provide specifications for such roads after researching the site(s) and conducting a soil analysis for separate pavement design analysis.

(5) In any case, the Common Council shall have the sole discretion in determining the use and construction classification to be adhered to.

(6) In all cases, the base course shall be compacted to the extent necessary to produce a condition so that there will be no appreciable displacement of material laterally and longitudinally under traffic and shall conform to line, grades and shape shown on the approved plans, profiles and cross sections. Compaction shall be to 95% modified Proctor ASTM D1557. Testing shall be conducted by nuclear density meter or as otherwise approved by the City Engineer.

(7) The subdivider shall furnish drawings which indicate the proposed grades of streets shown on the plat, and after approval of those grades by the City Engineer and adoption by the Common Council, the streets shall be graded to full width of the right-of-way of the proposed street to the subgrade elevations shown on the typical cross section. The grading is to be completed prior to installation of utilities. All stumps and trees which cannot be saved, boulders and other similar items shall be removed by the subdivider.

E. Roadway subgrade quality. All subgrade material shall have a minimum California Bearing Ratio (CBR) of three. Subgrade material having a CBR less than three shall be removed and replaced with a suitable fill material, or the pavement must be designed to compensate for the soil conditions. The soil support CBR values selected for use by the designer should represent a minimum value for the soil to be used.

F. Roadway subbase. Stable and nonorganic subbase material is required. Unstable and organic material must be subcut, removed and replaced with a suitable granular or breaker-run material approved by the City Engineer.

G. Street width; pavement thickness.

(1) Local streets shall be constructed as indicated herein; provided, however, that a greater or lesser roadway width may be required by the City Engineer where necessary to assure uniformity along the entire length of any street. The thickness of the pavement shall be four inches, applied in two separate two-inch lifts.

[Amended 9-14-2020 by Ord. No. 04-20]

(2) Collector streets shall be constructed as indicated herein; provided, however, that a greater or lesser roadway width may be required by the City Engineer where necessary to assure uniformity along the entire length of any street. The thickness of the pavement shall be four inches, applied in two separate two-inch lifts.

[Amended 9-14-2020 by Ord. No. 04-20]

(3) Arterial streets shall be constructed as indicated herein; provided, however, that a greater or lesser roadway width may be required by the City Engineer where necessary to assure uniformity along the entire length of any street. The thickness of the pavement shall be four inches, applied in two separate two-inch lifts.

[Amended 9-14-2020 by Ord. No. 04-20]

(4) When drainage ditches are utilized in a land division outside of the public service area, concrete curbs and gutters shall not be required, and streets shall be constructed as prescribed by the City Engineer. The thickness of the pavement shall be determined and prescribed by the City Engineer in accordance with the functional classification of the proposed street and soil subgrade data available.

H. Roadway culverts and bridges. Roadway culverts and bridges shall be constructed as directed by the City Engineer and sized utilizing the methods listed in Chapter 13, entitled "Drainage," of the "Facilities Development Manual" of the Wisconsin Department of Transportation. All roadway culverts shall be provided with concrete or metal apron endwalls. All culverts shall be designed to pass a ten-year, twenty-four-hour-duration storm event.

I. Driveways.

(1) Curbs shall not be interrupted by openings for driveways or other accessways to private property unless the number and location of such interruptions have been approved by the Plan Commission.

(2) When allowed, curb openings for driveways within the public service area shall be no less than 14 feet nor more than 24 feet in width unless the opening is intended to afford access to a commercially zoned parcel. The width of any driveway opening intended to afford access to commercial property shall not be more than 35 feet, unless otherwise prescribed by the City Engineer.

(3) Driveways outside of the public service area shall be no less than 12 feet in width, shall have a culvert at the ditch line, and shall, in all other respects, comply with the requirements of any ordinance regulating driveways adopted by the pertinent adjacent town.

(4) The culverts shall be placed in the ditch line at elevations that will assure proper drainage, and they shall be provided with concrete or metal endwalls.

J. Topsoil, grass, seed, fertilizer and mulch. All disturbed areas (ditches, backslopes) within the road right-of-way not provided with pavement and shouldering material shall be restored utilizing four inches of topsoil and good-quality grass seed, fertilizer and mulch. Ditches along the roadway with greater than a two-percent slope shall be protected by erosion control materials such as hay bales, sod, erosion control mats, etc.

K. Drainage improvements. All new roads and streets shall be provided with stormwater retention areas and storm sewers in order to provide for proper drainage.

L. Continuity and transitions.

(1) All street pavement widths on streets continued from previously developed or platted streets shall, wherever practical, provide for the greater of either the existing or required pavement type, width, grade and cross slope.

(2) Where it is necessary to provide for a transition of pavement width and/or type between new and existing streets, the transition shall occur in a safe manner at an intersection. In width transitions, the ratio of the transition length to width shall not be less than 40:1 unless the City Engineer determines that special circumstances prevent use of such ratio, in which case the minimum transition ratio shall be 20:1.

M. Curb and gutter. Combination concrete curb and gutter is required on all streets. Refer to § 510-25 describing requirements for curbs and gutters.

N. Post-construction traffic limited. No vehicular traffic shall be permitted on the pavement for a minimum period of between 24 and 72 hours following paving, as determined necessary by the City Engineer to protect the new pavement.

§ 510-41 Block design standards.

A. Length; arrangement. The lengths, widths and shapes of blocks shall be appropriate for the topography and the type of development contemplated, but block length (measured in the long dimension from street center line to street center line) shall not be less than 500 feet nor exceed 1,200 feet nor have less than sufficient width to provide for two tiers of lots of appropriate depth between street lines. A block shall be so designated as to provide two tiers of lots, unless it adjoins a railroad, major thoroughfare, river or park, where it may have a single tier of lots. Culs-de-sac may be used where the interblock spacing of adjacent streets exceeds the appropriate depth of two tiers of lots.

B. Pedestrian pathways. Pedestrian pathway easements not less than 10 feet wide, with a five-foot sidewalk, may be required by the Common Council, upon the recommendation of the Plan Commission, through the center of a block more than 900 feet long, where deemed essential to provide circulation or access to schools, playgrounds, shopping centers, transportation and other community facilities.

C. Street tree planting strip easements. Tree planting strip easements shall be provided for on both sides of all streets when the street terrace is insufficient. The minimum easement width shall be 10 feet and shall be adjacent to the front property line. Street trees shall be maintained by the adjacent property owner in accordance with City ordinances.

§ 510-42 Lot design standards.

A. Size.

(1) The size, shape and orientation of lots shall be appropriate for the location of topography of the land division and for the type of development contemplated, provided that no lot shall be smaller in area than the minimum lot size for the appropriate zone as established by the City Zoning Code.[1]

[1] Editor's Note: See Ch. 635, Zoning.

(2) Lot dimensions, shape and size shall provide for conformance to the requirements of the Zoning Code for the permitted land use(s) without the need for the granting of Zoning Code variances by the Zoning Board of Appeals. Excessive depth in relation to width shall be avoided.

B. Commercial or industrial lots. Depth and width of properties reserved or laid out for commercial or industrial purposes shall be adequate to provide for the off-street service and parking facilities required by the type of use and development contemplated, as required by the City Zoning Code.

C. Minimum lot frontage. All lots on curved streets and culs-de-sac shall have a minimum of 50 feet of platted frontage on a public street to allow access by emergency and service motor vehicles unless part of a planned unit development approved by the Common Council. In any case, minimum lot width at building setback line shall be in conformance with the requirements of the Zoning Code. Alley frontage (public or private) shall not constitute meeting this minimum frontage requirement.

D. Corner lots. Corner lots for residential use shall have extra width to permit full building setback from both streets or as required by applicable zoning regulations.

E. Access to public streets. Every lot shall front or abut on a public street.

F. Side lots. Side lot lines shall be substantially at right angles to straight street lines or radial to curved street lines. Lot lines shall follow City boundary lines.

G. Double and reversed frontage lots. Double frontage and reversed frontage lots shall be avoided except where necessary to provide separation of residential development from traffic arteries or to overcome specific disadvantages of topography and orientation.

H. Natural features. In the dividing of any land, regard shall be shown for all natural features, such as tree growth, watercourses, historic spots or similar conditions which, if preserved, will add attractiveness and stability to the proposed development.

I. Land remnants. All remnants of lots below minimum size left over after dividing of a larger tract must be added to adjacent lots or a plan shown as to future use rather than allowed to remain as unusable parcels.

J. Large lots. In case a tract is divided and results in parcels of more than twice the minimum lot size provided for by the City Zoning Code for the zoning district in which the land is located, such parcels shall be so arranged to permit redividing into parcels in accordance with this chapter and with the Zoning Code.

K. Trunk highway proximity. All lots adjacent to state trunk and federal highways shall be platted with additional depth necessary to provide for a building setback line not less than 50 feet from the nearer right-of-way line or 110 feet from the center line, whichever is more restrictive. (Reference Ch. Trans 233, Wis. Adm. Code.) The subdivider may appeal this requirement to the City Engineer. Upon written request of the City Engineer; the Wisconsin Department of Transportation is hereby authorized to then determine building setback requirements equal to or less than those required above in all land divisions (including certified surveys) adjacent to state and federal highways in accordance with the authority granted in the Administrative Code. The required building setback line and additional lot depth shall be platted so as to accommodate such required building setbacks.

L. Easement allowance. Lots containing pedestrian or drainage easements shall be platted to include additional width in allowance for the easement.

M. Drainageway and watercourses. Lots abutting upon a watercourse, drainageway, channel or stream shall have such additional depth or width as required by the City Engineer to obtain building sites that are not subject to flooding from a post-development, one-hundred-year, twenty-four-hour-duration storm event.

§ 510-43 Drainage and stormwater management system.

A. Purpose. The following provisions in this section are established to preserve and provide properly located public sites and facilities for drainage and stormwater management as the community develops and to insure that the costs of providing and developing such public sites are equitably apportioned on the basis of serving the need for the management of increased stormwater quantities resulting from land development.

B. Drainage system required.

(1) As required by § 510-29, a drainage system shall be designed and constructed by the subdivider to provide for the proper drainage of the surface water of the land division and the drainage area of which it is a part. A final plat shall not be approved until the subdivider shall submit plans, profiles and specifications as specified in this section, which have been prepared by a registered professional engineer and approved or modified by the Common Council, upon the recommendations of the Plan Commission and City Engineer. Drainage systems shall be designed to accommodate a ten-year storm event.

(2) Lots shall be laid out so as to provide positive drainage away from all buildings, and individual lot drainage shall be coordinated with the general storm drainage pattern for the area. Drainage shall be designed so as to avoid concentration of storm drainage water from each lot to adjacent lots.

(3) The Plan Commission shall not recommend for approval any subdivision plat which does not provide adequate means for stormwater or floodwater runoff. Any stormwater drainage system will be separate and independent of any sanitary sewer system. Storm sewers, where necessary, shall be designed in accordance with all governmental regulations, and a copy of design computations for engineering capacities shall accompany plans submitted by the planning engineer for the final plat. When calculations indicate that curb capacities are exceeded at a point or that stormwater will extend more than 10 feet beyond the face of the curb, no further allowance shall be made for flow beyond that point, and basins shall be used to intercept flow at that point.

C. Drainage system plans.

(1) The subdivider shall submit to the City at the time of filing a preliminary plat a preliminary drainage plan or engineering report on the ability of existing watercourse channels' storm sewers, culverts and other improvements pertaining to drainage or flood control within the subdivision to handle the additional runoff which would be generated by the development of the land within the subdivision. Additional information shall be submitted to adequately indicate that provision has been made for disposal of surface water without any damage to the developed or undeveloped land downstream or below the proposed subdivision. The report shall also include:

(a) Estimates of the quantity of stormwater entering the subdivision naturally from areas outside the subdivision.

(b) Quantities of flow at each inlet or culvert.

(c) Location, sizes and grades of required culverts, storm drainage sewers and other required appurtenances.

(2) A grading plan for the streets, blocks and lots shall be submitted by the subdivider for the area within the subdivision.

(3) The design criteria for storm drainage systems shall be based upon information provided by the City Engineer.

(4) Material and construction specifications for all drainage projects (i.e., pipe, culverts, seed, sod, etc.) shall be in compliance with specifications provided by the City Engineer.

D. Drainage system requirements. The subdivider shall install all the storm drainage facilities indicated on the plans required in Subsection A of this section necessary to serve, and resulting from, the phase of the land division under development:

(1) Street drainage. All streets shall be provided with an adequate storm drainage system. The street storm system shall serve as the minor drainage system and shall be designed to carry street, adjacent land and building stormwater drainage. Stormwater shall not be permitted to be run into the sanitary sewer system within the proposed subdivision or to run across street intersections.

(2) Off-street drainage. The design of the off-street major drainage system shall include the entire watershed affecting the land division and shall be extended to a watercourse or ditch adequate to receive the storm drainage. When the drainage system is outside of the street right-of-way, the subdivider shall make provisions for dedicating an easement, pursuant to Subsection F, to the City to provide for the future maintenance of said system.

E. Protection of drainage systems. The subdivider shall adequately protect all ditches to the satisfaction of the City Engineer. Ditches and open channels shall be seeded, sodded or paved depending upon grades and soil types. (Generally, ditches or channels with grades up to 1% shall be seeded, those with grades up to 4% shall be sodded and those with grades over 4% shall be paved or lined with riprap.)

F. Drainage easements.

(1) Where a land division is traversed by a watercourse, drainageway, channel or stream:

(a) There shall be provided a stormwater easement or drainage right-of-way conforming substantially to the lines of such watercourse and such further width or construction, or both, as will be adequate for the purpose and as may be necessary to comply with this section; or

(b) The watercourse or drainageway may be relocated in such a manner that the maintenance of adequate drainage will be assured and the same provided with a stormwater easement or drainage right-of-way conforming to the lines of the relocated watercourse and such further width or construction, or both, as will be adequate for the purpose and may be necessary to comply with this section; or

(c) Wherever possible, drainage shall be maintained in an easement by an open channel with landscaped banks and adequate width for maximum potential volume flow.

(2) In all cases, such easements shall be of a minimum width established at the high water mark plus 10 feet.

G. Dedication of drainageways. Whenever a parcel is to be subdivided or consolidated and embraces any part of a drainageway identified on a City Comprehensive Stormwater Management Plan, Comprehensive Master Plan and/or Official Map or any portion thereof, such part of said existing or proposed public drainageway shall be platted and dedicated by the subdivider as an easement or right-of-way in the location and at the size indicated along with all other streets and public ways in the land division. Whenever any parcel is to be subdivided or consolidated and is part of a drainage district established under the authority of Ch. 88, Wis. Stats., the subdivider shall petition the Circuit Court to transfer the jurisdiction of that portion of the drainage district being subdivided or consolidated to the City in accordance with § 88.83, Wis. Stats.

H. Dedication/preservation of stormwater management facilities.

(1) The subdivider is responsible for the entire cost of the drainage basin at the time of construction. The drainage basin requirements for the area needed for this project and future other developments would be determined at this time. If a future developer seeks to develop included property, such developer would be responsible for a percentage of the original cost of the drainage basin, payable to the original developer.

(2) The subdivider shall dedicate sufficient land area for the storage of stormwater to meet the needs to be created by the proposed land development and in accordance with the standards for on-site detention and as determined by the City Engineer. Whenever a proposed stormwater management facility (e.g., detention or retention basin) shown on the Comprehensive Stormwater Management Plan (if applicable), Comprehensive Master Plan and/or Official Map is located, in whole or in part, within the proposed land division, ground areas for providing the required storage capacity in such proposed public facility shall be dedicated to the public to the requirements of the Comprehensive Master Plan and/or Official Map.

I. Storm drainage facilities.

(1) The subdivider, at his cost, shall install all drainage facilities identified in the erosion control plan or determined by the City Engineer as being necessary for the management of all lands and roadways within the development. In addition, drainage capacity through the development from other areas shall be provided in accordance with a comprehensive surface water management study, if applicable. All required storm drainage facilities shall be constructed and operational prior to acceptance of any dedications and/or public improvements served by the storm drainage facilities.

(2) The subdivider shall submit to the City Engineer for his review and approval a report on the ability of existing watercourse channels, storm sewers, culverts and other improvements pertaining to drainage or flood control within the land division to handle the additional runoff which would be generated by the development of the land within the land division. Additional information shall be submitted to adequately indicate that provision has been made for disposal of surface water without any damage to the developed or undeveloped land downstream or below the proposed land division. The report shall also include:

(a) Estimates of the quantity of stormwater entering the land division naturally from areas outside the land division.

(b) Quantities of flow at each inlet or culvert.

(c) Location, sizes and grades of required culverts, storm drainage sewers and other required appurtenances.

(3) A grading plan for the streets, blocks and lots shall be submitted by the subdivider for the area within the land division.

(4) The design criteria for storm drainage systems shall be reviewed by the City Engineer and approved or modified.

(5) Material and construction specifications for all drainage projects (i.e., pipe, culverts, seed, sod, etc.) shall be in compliance with standards and specifications provided by City ordinance and/or the City Engineer.

J. Minor drainage system. The subdivider shall install all minor drainage system components necessary to reduce inconvenience and damages from frequent storms. Minor drainage components shall include all inlets, piping, gutters, channels, ditching, pumping and other facilities designed to accommodate the post-development runoff resulting from a ten-year, twenty-four-hour rainfall event as determined in the most current edition of the Natural Resources Conservation Service Technical Release 55 (TR-55). Temporary accumulations of storm runoff from ponding or flowing water, in or near minor system components, shall be permitted, providing that such accumulations do not encroach on any traffic lane of any collector or arterial street, nor on the center 16 feet of any local street, except on cul-de-sac or permanently dead-end streets serving fewer than 10 dwelling units, where such accumulations may not overtop the curb. In drainageways and drainageway easements, accumulations of water shall not inundate beyond the limits of the drainageway or drainageway easement. Cross-street drainage channels (valley gutters) shall not be permitted.

K. Major drainage system. The subdivider shall install all major drainage system components necessary to reduce inconvenience and damages from infrequent storms. Major system components shall include large channels and drainageways, streets, easements and other paths and shall be capable of accommodating post-development runoff in excess of that accommodated by minor system components resulting from twenty-four-hour rainfall events for storms with return frequencies greater than 10 years up to and including the one-hundred-year return event (as identified in TR-55). On local and collector streets and drainageways and drainage easements, accumulations of water shall not inundate any buildings at the ground line, unless such buildings are floodproofed. On arterial streets and in commercial zoning districts, accumulations of water shall not inundate any buildings at the ground line, unless such buildings are floodproofed, and the depth of water at the street crown shall not exceed six inches to permit operation of emergency vehicles.

L. Drainage piping systems.

(1) Unless otherwise approved by the City Engineer, all drainage piping of 12 inches diameter and greater shall be constructed of reinforced concrete pipe class adequate for proposed street loading. Open drainage inlet pipes or culverts with any opening dimension in excess of 18 inches shall be equipped with debris grates having an exposed area at least seven times the pipe opening area to avoid backwater accumulations from trash buildup and unsafe stream velocities and a maximum opening size of six inches. Drainage piping outfalls with any opening dimension in excess of 36 inches shall be protected from unauthorized entry by fencing, partial or total submergence of the outlet, debris grates or other methods approved by the City Engineer unless in such a location as to render routine maintenance operations impossible. Outfalls and their channels shall be protected from damages due to scour and erosion to the satisfaction of the City Engineer.

(2) Agricultural drain tiles which are disturbed during construction shall be restored, reconnected or connected to public storm drainage facilities.

M. Open channel systems.

(1) Where open channels are utilized in either the minor or major drainage system, they shall be designed so as to minimize maintenance requirements and maximize safety. Drainage easements (in lieu of dedications) shall be utilized to accommodate open channels and adequate access shall be provided by the City for maintenance of drainage capacity. Side slopes shall not exceed a four-to-one slope. Drainageways with grades of 0.75% or less, or where subject to high groundwater, continuous flows, or other conditions as determined by the City Engineer that would hamper maintenance operations due to consistently wet conditions, shall have a paved concrete invert of not less than eight feet wide and side slopes to a point one foot above the channel invert.[1]

[1] Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II).

(2) In areas where invert paving is not required, the drainageway bottom shall be grass. If the drainageway has a bare soil bottom or the natural grasses in the drainageway are disturbed due to development operations, the drainageway bottom shall be sodded and securely staked to one foot above the elevation of inundation resulting from a pre-development ten-year, twenty-four-hour storm event. Other disturbed areas shall be seeded and prepared in accordance with the City's erosion control requirements. Velocities for grass-lined channels shall not exceed those presented in the City's surface water management study, if one is adopted.

N. Standards for on-site detention storage. The subdivider shall employ on-site detention to control erosion and sedimentation, reduce the post-development peak runoff rate or temporarily store stormwater runoff due to inadequate downstream drainage facilities. The detention (storage) facilities shall be subject to regulation in accordance with the following standards:

(1) Where on-site detention is temporarily employed for erosion and sedimentation control, the detention facilities shall safely contain the pre-development runoff from a twenty-five-year storm event of twenty-four-hour duration within the limits of the facility.

(2) Where on-site detention is permanently employed to reduce the post-development peak runoff, the detention facility shall safety contain the post-development runoff from a twenty-five-year storm event of twenty-four-hour duration within the limits of the facility.

(3) Detention facility peak discharge rates for the maximum storm required to be contained shall not exceed the pre-development peak discharge rate from a ten-year storm event of twenty-four-hour duration or the capacity of the downstream drainage facilities, whichever is less.

(4) All temporary detention facilities shall safety contain or pass the runoff from any storm of any duration which exceeds the maximum storm required to be contained up to the one-hundred-year storm event of twenty-four-hour duration.

(5) All permanent detention facilities shall safely contain or pass the runoff from any storm of any duration which exceeds the maximum storm required to be contained up to the one-hundred-year storm event of twenty-four-hour duration on both public and, if necessary, private properties without inundating any building at the ground elevation, the travel lanes of any arterial street, the center 10 feet of any collector street or the top of the curb on any local street.

(6) Determination of on-site detention volumes shall be computed by procedures established by the United States Natural Resources Conservation Service in the most current edition of its technical publication entitled "Urban Hydrology for Small Watersheds, TR-55," and as accepted and approved by the City Engineer.

(7) The storage of stormwater runoff shall not encroach on any public park (except parks designed with detention facilities) or any private lands outside the land division unless an easement providing for such storage has been approved and recorded for said lands.

(8) All detention facilities shall be designed with the safety of the general public and any considerations for ease of maintenance as top proprieties.

(9) Any wet detention facilities shall include riprap to not less than two feet above the normal pool elevation for protection from wave action.

(10) The sides of all detention facilities shall have a maximum slope ratio of four to one (horizontal to vertical), with flatter slopes being required where determined practical by the City Engineer.

(11) The Common Council, upon recommendation by the City Engineer, may require the installation of fencing or other such security measures in detention facilities with excessively long down times or permanent water features or other features requiring additional security for safety reasons.

§ 510-44 Nonresidential subdivisions.

A. General.

(1) If a proposed subdivision includes land that is zoned for commercial or industrial purposes, the layout of the subdivision with respect to such land shall make such provisions as the City may require.

(2) A nonresidential subdivision shall also be subject to all the requirements of site plan approval set forth in the City Building Code.[1] A nonresidential subdivision shall be subject to all the requirements of this chapter, as well as such additional standards required by the City, and shall conform to the proposed land use standards established by the City Comprehensive Master Plan or Official Map and the City Zoning Code.[2]

[1] Editor's Note: See Ch. 259, Building Construction.

[2] Editor's Note: See Ch. 635, Zoning.

B. Standards. In addition to the principles and standards in this chapter, which are appropriate to the planning of all subdivisions, the applicant shall demonstrate to the satisfaction of the Common Council that the street, parcel and block pattern proposed is specifically adapted to the uses anticipated and takes into account other uses in the vicinity. The following principles and standards shall be observed:

(1) Proposed industrial parcels shall be suitable in area and dimensions to the types of industrial development anticipated.

(2) Street rights-of-way and pavement shall be adequate to accommodate the type and volume of traffic anticipated to be generated thereupon.

(3) Special requirements may be imposed by the Common Council, upon the recommendation of the City Engineer, with respect to street, curb, gutter and sidewalk design and construction.

(4) Special requirements may be imposed by the Common Council, upon the recommendation of the City Engineer, with respect to the installation of public utilities, including water, sewer and stormwater drainage.

(5) Every effort shall be made to protect adjacent residential areas from potential nuisance from a proposed commercial or industrial subdivision, including the provision of extra depth in parcels backing up on existing or potential residential development and provisions for permanently landscaped buffer strips when necessary.

(6) Streets carrying nonresidential traffic, especially truck traffic, shall not normally be extended to the boundaries of adjacent existing or potential residential areas.

§ 510-45 Grading.

The subdivider shall grade each land division in order to establish street, block and lot grades in proper relation to each other and to topography as follows:

A. Master site grading plan.

(1) A master site grading plan shall be prepared by the subdivider for all new subdivisions. This plan shall be prepared in accordance with the requirements and standards of the City.

(2) The master site grading plan shall show existing and proposed elevations of all lot corners, control points and building locations. The plan shall also indicate all overland storm drainage in and adjacent to the subdivision. The cost of the preparation of such a plan shall be paid for by the subdivider.

(3) After approval or modification of these plans by the City Engineer, the full width of the right-of-way of the proposed streets within the subdivision and the entire subdivision lot area shall be graded in accordance with the master site grading plan. The owners of the subdivision lots shall adhere to those plans.

(4) Upon completion of all street and subdivision grading, the grades shall be checked and inspected by the Building Inspector to determine that the completed grading work is in accordance with the master site grading plan. All grades shall be within 0.4 of a foot of the elevations shown on the master site grading plan.

(5) The cost of all required grading work, supervision, certification, inspection and engineering fees shall be paid for by the subdivider.

B. Right-of-way grading. The subdivider shall grade the full width of the right-of-way of all proposed streets in accordance with the approved plans, including the grading of site triangles at each intersection.

C. Block grading. Block grading shall be completed by one or more of the following methods prior to the installation of utilities:

(1) Regrading along the side or rear lot lines which provides for drainage to the public drainage facilities.

(2) Parts of all lots may be graded to provide for drainage to a ditch or to a swale, provided that any ditches or swales are in public drainage easements.

(3) Draining across rear or side lot lines may be permitted, provided that the course of drainage is within a public drainage easement and is toward public drainage facilities.

D. Miscellaneous grading requirements.

(1) Lot grading shall be completed so that water drains away from each building site toward public drainage facilities at a minimum grade of 1%, and provisions shall be made to prevent drainage onto properties adjacent to the land division unless to a public drainage facility.

(2) Grading activities shall not result in slopes greater than three to one on public lands or lands subject to public access.

(3) The topsoil stripped for grading shall not be removed from the site unless identified in the erosion control plan approved by the City Engineer as not being necessary for erosion control or site landscaping purposes. Topsoil shall be uniformly returned to the lots when rough grading is finished. Topsoil piles shall be leveled and seeded for erosion control prior to the City releasing the one-year guarantee provision on public improvements in the streets adjacent to the lots on which the topsoil is stockpiled.

(4) Such grading shall not result in detriment to any existing developed lands, either within or outside of the corporate limits.