§ 151.05  DESIGN STANDARDS.
   (A)   Blocks.
      (1)   General. Block length and width of acreage within bounding roads shall be so as to accommodate the size of residential lots required in the area by Chapter 152 of this code and to provide for convenient access, circulation control and safety of street traffic. Blocks intended for commercial, institutional and industrial use must be designated as so.
      (2)   Block length. In general, intersecting streets, determining block lengths, shall be provided at intervals so as to serve cross-traffic adequately and to meet existing streets. Where no existing plats control, the blocks in a residential subdivision should not exceed 1,320 feet in length, except where topography or other conditions justify a departure from this maximum. In blocks longer than 800 feet, pedestrian ways and/or easements through the block may be required near the center of the block. Blocks for business or industrial use should normally not exceed 1,320 feet in length.
      (3)   Block width. The width of the block should be sufficient to allow 2 tiers of lots of appropriate depth. Blocks intended for business or industrial use shall be of a width so as to be considered most suitable for their respective use, including adequate space for off-street parking and deliveries.
   (B)   Lots.
      (1)   The minimum lot area, width and depth shall not be less than that established by Chapter 152 of this code in effect at the time of adoption of the final plat, except for cul-de-sac lots which may have a front lot width of not less than 75 feet.
      (2)   Side lot lines shall be approximately at right angles to street lines of radial to curved street lines.
      (3)   Every lot must have its full frontage abutting on a city approved street other than an alley.
      (4)   Setback or building lines shall be shown on all lots and shall not be less than the setback required by Chapter 152 of this code.
      (5)   Lots abutting upon a water course, drainage way, channel or stream shall have an additional depth and/or width as required to assure house sites are not subject to flooding.
      (6)   In the subdividing of any land, due regard shall be shown for all natural features, such as tree growth, water courses, historic spots or similar conditions which if preserved will add attractiveness and stability to the proposed development
      (7)   All remnants of lots below minimum size left over after subdividing of a larger tract must be added to adjacent lots, rather than allowed to remain as unusable parcels.
      (8)   No plat shall extend over a political boundary or school district line.
      (9)   Double-frontage, or lots with frontage on 2 parallel streets, shall not be permitted except: where lots back on arterial streets or highways, or where topographic or other conditions render subdividing otherwise unreasonable. These double-frontage lots shall have an additional depth of at least 20 feet in order to allow space for screen planting along the back lot line.
   (C)   Streets and alleys.
      (1)   Except for cul-de-sacs, streets shall connect with streets already dedicated in adjoining or adjacent subdivisions, or provide for future connections to adjoining unsubdivided tracts, or shall be a reasonable projection of streets in the nearest subdivided tracts. The arrangement of arterials and collector streets shall be considered in their relation to the reasonable circulation of traffic, to topographic conditions, to run-off of storm water, to public convenience and safety, and in their appropriate relation to the proposed uses of the area to be served.
      (2)   Minor streets should be so planned as to discourage their use by non-local traffic. Dead end streets are prohibited, but cul-de-sacs shall be permitted where topography or other physical conditions justify their use. Cul-de-sacs shall not be longer than 500 feet, including a terminal turnaround which shall be provided at the closed end, with an outside curb radius of at least 50 feet and a right-of-way radius of not less than 66 feet.
      (3)   Where the plat to be submitted includes only part of the tract owned or intended-for development by the subdivider, a tentative plan of a proposed future street system for the unsubdivided portion shall be prepared and submitted by the subdivider.
      (4)   When a tract is subdivided into larger than normal building lots or parcels, the lots or parcels shall be so arranged as to permit the logical location and openings of future streets and appropriate resubdivision, with provision for adequate utilities, connections for the re-subdivision.
      (5)   Under normal conditions, streets shall be laid out so as to intersect as nearly as possible at right angles, except where topography or other conditions justify variations. Under normal conditions, the minimum angle of intersection of streets shall be 80 degrees. Street intersection jogs with an offset of less than 125 feet shall be avoided.
      (6)   Wherever the proposed subdivision contains or is adjacent to the right-of-way of a United States or state highway, arterial or railroad, provision may be made for a marginal access street approximately parallel and adjacent to the boundary of the right-of-way, or for a street at a distance suitable for the appropriate use of land between the street and right-of-way. The distance shall be determined with due consideration of the minimum distance required for approach connections to future grade separations, or for lot depths.
      (7)   Alleys shall be provided in commercial and industrial districts, except that this requirement may be waived where other definite and assured provisions are made for service access, such as off-street loading, unloading and parking consistent with and adequate for the uses proposed. Except where justified by special conditions, such as the continuation of an existing alley in the same block or where necessitated by the lack of alternative adequate off-street loading space. Deadend alleys shall be avoided wherever possible, but if unavoidable, the deadend alleys may be approved if adequate turnaround facilities are provided at the closed end.
      (8)   Half streets shall be prohibited, except where essential to the reasonable development of the subdivision in conformity with the other requirements of these regulations; and where the City Council finds it will be practical to require the dedication of the other half when the adjoining property is subdivided.
      (9)   (a)   For all public ways hereafter dedicated and/or accepted, the minimum right-of-way and paved width for streets, alleys or pedestrian ways included in any subdivision shall not be less than the minimum dimensions for each classification as follows:
 
Street
Right-of-Way
Paved
Arterial street
100 feet
52 feet
Collector street
70 feet
42 feet
Minor street
60 feet
36 feet
Cul-de-sac or marginal access service streets
60 feet
36 feet
Alleys
20 feet
20 feet
 
         (b)   Where the existing or anticipated traffic on streets warrants greater widths of rights-of-way or paved surface, these shall be required.
      (10)   Except when, under the recommendation of the City Zoning  Administrator that the topography warrants a greater maximum, the grades in all streets, arterials, collector streets, minor streets and alleys in any subdivision shall not be greater than 8%. In addition, there shall be a minimum grade on all streets and thoroughfares of not less that 0.5%.
      (11)   Tangents of at least 50 feet in length shall be introduced between reverse curves on collector streets.
      (12)   Reserve strips controlling access to streets shall be prohibited except under conditions accepted by the City Council.
      (13)   Private streets shall not be approved nor shall public improvements be approved for any private street.
      (14)   When connecting street lines deflect from each other at any 1 point by more than 10 degrees, they shall be connected by a curve with a radius adequate to ensure a sight distance of not less than 300 feet for minor and collector streets, and of a greater radius as the City Council shall determine for special cases.
      (15)   Different connecting street gradients shall be connected with vertical parabolic curves. Minimum length, in feet, of these curves, shall be 100 feet.
   (D)   Easements.
      (1)   Provision for utilities. Easements at least 10 feet wide, centered on rear and other lot lines, shall be provided for utilities, where necessary. They shall have continuity of alignment from block to block, and at deflection points, easements for pole-line anchors shall be provided where necessary.
      (2)   Provisions for drainage. Easements shall be provided along each side of the center line of any water course or drainage channel, to a width sufficient in the judgement of the City Council to provide proper maintenance and protection and to provide for storm water runoff and installation and maintenance of storm sewers, and they shall be dedicated to the city by appropriate language in the owner’s certificate.
   (E)   Erosion and sediment control.
      (1)   The development shall conform to the natural limitations presented by topography and soil so as to create at least potential for soil erosion.
      (2)   Erosion and siltation control measures shall be coordinated with the different stages of construction. Appropriate control measures shall be installed prior to development when necessary to control erosion.
      (3)   Land shall be developed in increments of workable size so that adequate erosion and siltation controls can be provided as construction progresses. The smallest practical area of land shall be exposed at any 1 period of time.
      (4)   When soil is exposed, the exposure shall be for the shortest feasible period of time.
      (5)   Where the topsoil is removed, sufficient arable soil shall be set aside for re-spreading over the developed area. The soil shall be restored to a depth of 4 inches and shall be of a quality at least equal to the soil quality prior to development.
   (F)   Drainage.
      (1)   Where municipal storm sewer systems do not exist, or the introduction of the system is deemed inappropriate by the City Council, storm water drainage shall be discharged to marshlands, swamps, retention basins or other treatment facilities.
      (2)   Diversion of storm water to marshlands or swamps shall be considered for existing or planned surface drainage. Marshlands and swamps used for storm water shall provide for natural or artificial water level control.
      (3)   No existing ditch, stream, drain, pond or drainage canal shall be deepened, widened, rerouted or filled without written permission from the City Council.
      (4)   Where artificial channels must be constructed to augment the natural drainage system, the channels as well as the natural drainage ways may be planned as part of a recreation system.
      (5)   The drainage system shall be constructed and operational during the initial phases of construction.
   (G)   Protected areas.
      (1)   Where land proposed for subdivision contains drainage ways, water courses, floodable areas, wetlands or steep slopes and thus may be unsuitable for development, the platting of those areas shall be consistent with limitations presented by the conditions.
      (2)   Subdivisions shall be designed so that not more than 25% of the minimum lot area contains wetland soil types, water bodies, water courses, drainage ways or flood ways areas, or is unusable due to steep slopes (over 18%). Also, no construction or grading will be conducted on slopes steeper than 18% in grade.
(Prior Code, § 19.105)