City of Bayfield, WI Design Standards

Commercial and industrial. Alleys shall be provided in all commercial and industrial districts, except that the Common Council, upon the Plan Commission's recommendation, may waive this requirement where other definite and assured provision is made for service access, such as off-street loading and parking, consistent with and adequate for the uses proposed. 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.

Dead end. Dead-end alleys are prohibited except under very unusual circumstances, and crooked and "T" alleys shall be discouraged. Where dead-end alleys are unavoidable, they shall be provided with adequate turnaround facilities at the dead end.

Cul-de-sac streets. Cul-de-sac streets designed to have one end permanently closed shall not exceed 700 feet in length and shall terminate with a turnaround of not less than 120 feet in diameter and a roadway turnaround of 96 feet in diameter.

Continuation. Streets shall be laid out to provide for possible continuation wherever topographic and other physical conditions permit. Provision 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. Dead-end streets not over 500 feet in length will be approved when necessitated by the topography.

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

Frontage roads. Where a subdivision abuts or contains an existing or proposed arterial highway, the Common Council may require a frontage road, nonaccess reservation along the rear of the property contiguous to such highway or such other treatment as may be necessary to ensure safe, efficient traffic flow and adequate protection of residential properties.

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.

Horizontal curves. A minimum sight distance with clear visibility, measured along the center line, shall be provided of at least 300 feet on major thoroughfares, 200 feet on collector streets, and 100 feet on all other streets.

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

Street grades. The grade of major thoroughfares and collector streets shall not exceed 6% unless necessitated by exceptional topography and approved by the Plan Commission. Grades of local streets shall not exceed 10%. The minimum grade of all streets shall be 0.4%.

Vertical curves. All changes in street grades shall be connected by vertical curves of a minimum length, in feet, equivalent to 15 times the algebraic difference in the rate of grade for major thoroughfares, and 1/2 this minimum length for all other streets.

Half-streets. Where an existing dedicated or platted half-street is adjacent to the subdivision, the other half-street shall be dedicated by the subdivider. The platting of half-streets should be avoided where possible.

Intersections.

Property lines. Property lines at street intersections of major thoroughfares shall be rounded with a radius of 15 feet or of a greater radius where the Public Works Director considers it necessary.

Angle of intersect. Streets shall intersect each other at as nearly right angles as topography and other limiting factors of good design permit.

Number of streets converging. The number of streets converging at one intersection shall be reduced to a minimum, preferably not more than two. Cross-type intersections on local streets shall be avoided whenever possible in favor of T-type intersections. Intersections of local streets shall be at least 125 feet from each other.

Number of intersections. 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 1,000 feet.

Property lines at street intersections. Property lines at street intersections shall be rounded with a minimum radius of 15 feet or of a greater radius when required by the Plan Commission or shall be terminated by a straight line through the points of tangency of an arc having a radius of 15 feet.

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 300 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.

Additional sight easements. At any intersection determined by the Public Works Director, 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 30 feet from the intersection point.

Street names.

New street names shall not duplicate the names of existing streets, but streets that are continuations of others already in existence and named shall bear the names of the existing streets. Street names shall be subject to approval by the Common Council, as recommended by the Plan Commission.

All streets shall be named in conformity with the street naming plan of the City or with adjoining streets. In the case of diverging streets, the name shall be repeated. New street names shall not duplicate the names of existing streets, provided, however, that streets that are obviously in alignment with others already existing and names shall bear the names of the existing streets. Long or continuous thoroughfares running north and south shall be named avenues; those running east and west shall be named streets; diagonal thoroughfares shall be named roads; and curving thoroughfares shall be named drives. Short or discontinuous thoroughfares running north and south shall be named courts; those running east and west shall be named places; diagonal thoroughfares shall be named ways; and curving thoroughfares shall be named lanes.

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:

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."

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.

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.

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.

§ 474-40 Specifications for preparation, construction and dedication of streets and roads.

General requirements.

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 § 474-39 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 Public Works Director. Combination concrete curb and gutter is required on all streets. (Refer to § 474-26, describing requirements for curbs and gutters.) A copy of all design assumptions and computations on which the proposed design is based shall be submitted to the Public Works Director.

Project costs. All roadway surveys, dedications, plans and specifications and construction will be at the expense of the applicant or applicants. This includes any expense incurred by the City in the preparation of plans and review and inspection of plans and construction.

Preliminary consultation. Prior to the design, preparation and construction of any roadway to be dedicated to the City of Bayfield, the applicant shall notify the Public Works Director. An on-site meeting will then be arranged to be attended by the Public Works Director and the applicant. Plans must be provided in order for the Public Works Director to check the design and the drainage.

Material slips. Copies of material slips for all materials furnished for the road construction projects shall be delivered to the City before the City approves the final construction.

Required inspections.

Prior to the commencement of any street construction, the subdivider shall notify the Public Works Director, at least one workday in advance, as to the nature of the work being done. The Public Works Director shall be contacted for required inspections after the following phases of construction:

[1]

Subbase grading;

[2]

Crushed aggregate base course;

[3]

Bituminous surface course; and

[4]

Shouldering.

Any deficiencies found by the Public Works Director shall be corrected before proceeding to the next phase of construction.

Tests of materials. The City reserves the right to obtain a sample of the roadway base material prior to placement on the roadway for purposes of determining whether the material meets gradation and soundness requirements.

Pavement samples. Samples of bituminous concrete will be taken by the City during pavement construction operations for purposes of determining that the material meets specifications.

Construction standards. All streets and highways constructed in the City or to be dedicated to the City shall fully comply with the following construction standards:

Street rights-of-way.

Type of Street	R.O.W. Width To Be Reserved (feet)	R.O.W. Width To Be Dedicated (feet)	Pavement Width (Face of Curb to Face of Curb) (feet)
Arterial streets	80	60	30
Collector streets	60	60	30
Minor streets and culs-de-sac	60	60	36

Roadway ditches. Where curb and gutter is not required by the City for rural cross-section streets, the minimum ditch slope shall be 0.50%.

Roadway base thickness.

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.

Residential streets shall have a minimum roadway base thickness of six inches of compacted in-place crushed aggregate base course of gradation No. 2 in the top layer and gradations No. 1 and No. 2 in the lower level.

(c)

On commercial, arterial or other heavy-use streets, as determined by the Public Works Director, a base course of eight inches compacted shall be constructed upon an inspected and approved subgrade, either well-graded crushed gravel from a state-approved pit with a maximum stone of 1 1/2 inches and no greater than 10% by weight passing a No. 200 sieve or No. 3 crushed rock approximately six inches in depth and one or more layers of fine aggregate, either three-fourths-inch crushed gravel, well-graded with no greater than 10% passing a No. 200 sieve, or three-fourths-inch traffic-bound crushed rock.

(d)

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

(e)

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

(f)

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.

(g)

The subdivider shall furnish drawings which indicate the proposed grades of streets shown on the plat and, after approval of those grades by the Public Works Director 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.

Roadway base 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.

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 Public Works Director.

Pavement thickness. When building permits have been issued for 50% or more of the subdivision and/or a block in a subdivision, the street(s) within said subdivision or block shall be paved with three inch plant mix bituminous concrete at adjacent landowner expense. In the case of commercial, arterial or other heavy-use roads, the Common Council may, in the alternative to the above standards, have the Public Works Director provide specifications for paving such roads after researching the site(s) and conducting a soil analysis. In any case, the Common Council shall have the sole discretion in determining the use and construction classification to be adhered to.

Roadway culverts and bridges. Roadway culverts and bridges shall be constructed as directed by the Public Works Director 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.

(8)

Driveway culverts. Driveway culverts shall be sized by the Public Works Director (if appropriate). The culverts shall be placed in the ditch line at elevations that will assure proper drainage, and they shall be provided with concrete, metal or landscape timber endwalls.

(9)

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 slope of 2.5% shall be protected by erosion control materials such as hay bales, sod, erosion control mats, etc.

(10)

Drainage improvements. In the case of all new roads and streets, the Public Works Director may require that stormwater retention areas and storm sewers be constructed in order to provide for proper drainage.

(11)

Continuity and transitions.

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.

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 the event a transition in pavement width cannot safety occur at an intersection, it shall not occur closer than 250 feet to the intersection of right-of-way lines. In width transitions, the ratio of the transition length to width shall not be less than 15:1 unless the Public Works Director determines that special circumstances prevent use of such ratio, in which case the minimum transition ratio shall be 10:1.

§ 474-41 Block design standards.

Length; arrangement. The lengths, widths and shapes of blocks shall be appropriate for the topography and the type of development contemplated, but block length in residential areas shall not exceed 1,500 feet nor have less than sufficient width to provide for two tiers of lots of appropriate depth between street lines. As a general rule, blocks shall not be less than 600 feet in length. Blocks 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.

Pedestrian pathways. Pedestrian pathway easements not less than 10 feet wide may be required by the Common Council and/or 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.

§ 474-42 Lot design standards.

Size.

The size, shape and orientation of lots shall be appropriate for the location of topography of the subdivision, the type of sewerage or septic system to be utilized, 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 Chapter 500, Zoning, of the Code of the City of Bayfield.

Lot dimensions, shape and size shall provide for conformance to the requirements of Chapter 500, Zoning, for the permitted land use(s) without the need for the granting of Chapter 500, Zoning, variances by the Zoning Board of Appeals, but in no case shall have a frontage of less than 80 feet at the building line or a depth of less than 100 feet. Excessive depth in relation to width shall be avoided. A proportion of approximately 2 1/2:1 shall be considered as a desirable maximum for lot widths of 80 feet or more.

Commercial 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 Chapter 500, Zoning.

Lots abutting major highway. Residential lots adjacent to major and minor arterial streets and highways and/or railroads shall be platted with an extra 15 feet of lot and an extra 15 feet of minimum yard setback and shall otherwise be designed to alleviate the adverse effects on residential adjacent lots platted to the major street, highway, railroad or other such features.

Corner lots. Corner lots for residential use shall have extra width to permit full building setback of at least 30 feet from both streets, or as required by applicable zoning regulations.

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

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

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.

Natural features. In the subdividing 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.

Land remnants. All remnants of lots below minimum size left over after subdividing 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.

Large lots. In case a tract is divided and results in parcels of more than twice the minimum lot size provided for by Chapter 500, Zoning, of the Code of the City of Bayfield 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 Chapter 500, Zoning.

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 (ref.: Ch. Trans 233, Wis. Adm. Code). The subdivider may appeal this requirement to the Public Works Director. Upon written request of the Public Works Director, 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.

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

§ 474-43 Drainage system.

Drainage system required.

As required by § 474-30, a drainage system shall be designed and constructed by the subdivider to provide for the proper drainage of the surface water of the subdivision 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 by the Common Council, upon the recommendations of the Plan Commission and Public Works Director.

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.

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, no further allowance shall be made for flow beyond that point, and basins shall be used to intercept flow at that point.

Drainage system plans.

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:

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

Quantities of flow at each inlet or culvert.

(c)

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

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

The design criteria for storm drainage systems shall be based upon information provided by the Public Works Director.

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

Drainage system requirements. The subdivider shall install all the storm drainage facilities indicated on the plans required in Subsection A of this section.

Street drainage. All streets shall be provided with an adequate storm drainage system. The street storm system shall serve as the primary drainage system and shall be designed to carry street, adjacent land and building stormwater drainage. No stormwater shall be permitted to be run into the sanitary sewer system within the proposed subdivision.

Off-street drainage. The design of the off-street drainage system shall include the watershed affecting the subdivision 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 of the City to provide for the future maintenance of said system.

Protection of drainage systems. The subdivider shall adequately protect all ditches to the satisfaction of the Public Works Director. 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.)

Drainage easements. Where a land division is traversed by a watercourse, drainageway, channel or stream:

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

The watercourse, drainageway, channel or stream 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

Wherever possible, drainage shall be maintained in an easement by an open channel with landscaped banks and adequate width for maximum potential volume flow. In all cases, such easements shall be of a minimum width established at the high water mark or, in the absence of such specification, not less than 30 feet.

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 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.

Dedication/preservation of stormwater management facilities. 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 Public Works Director. Whenever a proposed stormwater management facility (e.g., detention or retention basin) shown on the Comprehensive Stormwater Management Plan, Comprehensive 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 Plan and/or Official Map. Storage areas necessary to serve areas outside the land division shall be held in reserve for a period of five years from the date of final plat approval for future acquisition by the City or other appropriate agency having the authority to purchase said property. The subdivider and City shall enter into an agreement with the City to provide for the purchase of the lands held in reserve prior to the conclusion of the five-year reserve period.

Storm drainage facilities.

The subdivider, at his cost, shall install all drainage facilities identified in the Erosion Control Plan (Building Code), if applicable, or determined by the Public Works Director 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.

The subdivider shall submit to the Public Works Director 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:

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

Quantities of flow at each inlet or culvert.

(c)

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

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

The design criteria for storm drainage systems shall be reviewed by the Public Works Director and approved or modified.

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 Public Works Director.

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 postdevelopment runoff resulting from a two-year, twenty-four-hour rainfall (ten-year, twenty-four-hour rainfall for commercial zoning district) event as determined in the most current edition of the Soils 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 such accumulations do not encroach on any traffic lane of any collector or arterial street, nor on the center 24 feet of any local street, except on cul-de-sac or permanently dead-end streets serving less 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 except on cul-de-sac or permanent dead-end streets serving less than 10 dwelling units and where the minimum grade in the valley gutter and street gutter between the valley gutter and the next downstream drainage inlet is not less than 1.00%.

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 postdevelopment runoff in excess of that accommodated by minor system components resulting from twenty-four-hour rainfall events for storms with return frequencies greater than two 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.

Drainage piping systems.

Unless otherwise approved by the Public Works Director, all drainage piping of 12 inches diameter and greater in street rights-of-way shall be constructed of Class Three reinforced concrete pipe. Piping materials outside of rights-of-way shall be subject to approval of the Public Works Director. 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 Public Works Director 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 Public Works Director.

When, on the basis of the soils information, the Public Works Director determines that the ground water elevation is less than nine feet below the proposed street center line elevation and the adjacent lots have access to a storm drainage piping system, the subdivider shall be required to provide approved sump pump laterals from the storm sewer piping system to the property line of each lot for connection to by the property owner.

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

Open channel systems.

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 provided adequate access by the City for maintenance of drainage capacity. Side slopes shall not exceed a 4:1 slope. Drainageways with grades of 0.75% or less, or where subject to high ground water, continuous flows, or other conditions as determined by the Public Works Director 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.

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 predevelopment five-year, twenty-four-hour storm event. Other disturbed areas shall be seeded and prepared in accordance with the City's erosion control requirements.[1] Velocities for grass-lined channels shall not exceed those presented in the City's Surface Water Management Study, if one is adopted.

[1]

Editor's Note: See Ch. 190, Construction Site Erosion Control.

Standards for on-site detention storage. The subdivider may employ on-site detention to control erosion and sedimentation, reduce the postdevelopment 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:

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

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

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

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.

All permanent detention facilities shall safety contain the runoff from 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.

Determination of on-site detention volumes shall be computed by procedures established by the United States Soil 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 Public Works Director.

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 4:1 (horizontal to vertical), with flatter slopes being required where determined practical by the Public Works Director.

(11)

The Common Council, upon recommendation by the Public Works Director, 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.

§ 474-44 Nonresidential subdivisions.

General.

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.

A nonresidential subdivision shall also be subject to all the requirements of site plan approval set forth in the City Building Code,[1] if applicable. 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 any City Comprehensive Plan or Official Map and Chapter 500, Zoning, of the Code of the City of Bayfield.

[1]

Editor's Note: See Ch. 152, Building Construction.

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:

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

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

Special requirements may be imposed by the Common Council, upon the recommendation of the Public Works Director, with respect to street, curb, gutter and sidewalk design and construction.

Special requirements may be imposed by the Common Council, upon the recommendation of the Public Works Director, with respect to the installation of public utilities, including water, sewer and stormwater drainage.

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.

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

§ 474-45 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 shall be prepared for all new subdivisions. This plan shall be prepared in accordance with the requirements and standards of the City.

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.

After approval of these plans by the Common Council, or its designee, 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.

Upon completion of all street and subdivision grading, the grades shall be checked and certified by the Public Works Director to determine that the completed grading work is in accordance with the master site-grading plan.

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

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 sight triangles at each intersection.

Block grading shall be completed by one or more of the following methods:

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

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