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§ 155.121 SURFACE WATER DRAINAGE.
   (A)   All subdivisions shall be developed with adequate surface drainage. Surface water drainage improvements shall consist of storm sewers and/or open channels, inlets, catch basins and manholes designed and constructed to conform with standards established by the village’s consulting engineer and shall adequately drain the area being developed, including drainage from other areas which naturally drain through the areas being developed. Inlets and/or catch basins shall be spaced so that water will not flow overland more than 500 feet and shall be located so that, in no case, will water be required to flow across a street. Water shall not be retained outside the center ten feet of drainage utility easement. Inlets covered by a metal grate shall have a grate of a type that will not be hazardous to a bicyclist.
   (B)   If, as the result of subdivision development, surface water is deposited in existing roadside ditches in quantities exceeding their capacity, the developer shall improve the ditches and replace culverts as needed to handle the flow.
   (C)   Unless engineering evidence is presented to the village’s consulting engineer warranting exceptions, storm sewers which will drain 20 acres or less for residential development shall be designed and constructed to meet the following criteria:
      (1)   Major and minor arterials: ten-year storm frequency; and
      (2)   All other areas: five-year storm frequency.
   (D)   (1)   It shall be the responsibility of the subdivider to provide grade control for rear lot drainage to each lot owner. Swales are not public works which shall be dedicated to and accepted by the village; nevertheless, no construction surety shall be fully released until the village’s consulting engineer has approved the swales in the subdivision. The village’s consulting engineer will not approve any swale until adequate turf and/or grass has been established at the elevations set forth in the construction plans. Upon approval by the village’s consulting engineer, it shall be the lot owner’s responsibility to maintain the drainage course and to keep it free from features that restrict natural drainage. All swales less than 1% in grade shall have either of the following:
         (a)   An eight-inch minimum underdrain pipe that allows water seepage as indicated on the drawing entitled “Detail of Yard Underdrain” set out at Appendix A at the end of this chapter; or
         (b)   A portland cement concrete swale, five inches thick, as indicated on the drawing entitled “Paved Ditch Detail” set out at Appendix B at the end of this chapter.
      (2)   End sections shall employ a grated cover to keep animals or children from trying to enter the system.
   (E)   The controlled release and storage of excess storm water runoff shall be required in combination for all of the areas indicated on the preliminary plan.
      (1)   The controlled release of storm water runoff shall not exceed the release or discharge rate which existed at the site prior to development. This rate shall be known as the predeveloped discharge rate. In the case of multiple discharge locations, no location shall discharge at a rate higher than the predeveloped discharge rate for that location under any set of conditions. The controlled release rate in any case shall not exceed the rated capacity of the existing natural downstream outlet channel or storm sewer system as determined by the village’s consulting engineer. The rate at which storm water runoff is transported into a designated storage area may be as determined by the design engineer and is unrestricted.
      (2)   A natural or surface channel system shall be designed with adequate capacity to convey the storm water runoff from all tributary upstream areas through the development. This bypass channel shall be designed to carry the peak rate of runoff from a 50-year storm assuming all storm sewers are blocked and that the upstream areas are fully developed and have been saturated with antecedent rainfall. No habitable structures shall be constructed within this channel, however, streets and parking or playground areas and utility easements shall be considered compatible primary uses.
      (3)   (a)   Storm water runoff capacity of detention facilities and discharge rates from such facilities shall be calculated by analyzing volume and rate of runoff during pre- and post-development conditions for the ten-year and the 100-year recurrence intervals.
         (b)   Storage capacity and discharge rates shall be based on the maximum calculated volume and peak flow of storm waters, respectively.
         (c)   Storage facilities shall be designed using the soil conservation service (SCS) method of calculating runoff discharge rate and total volume of storage. The rational method of calculating runoff may be used for subdivisions less than 20 acres.
         (d)   The storage volume shall be provided for the fully developed watershed that is tributary to the area designated for detention purposes. The control structure for discharge shall maintain the release rate at or below the rate established in division (E)(1) above for all rainfall events of 100 years or less frequency.
      (4)   (a)   Detention reservoirs or any bottom storm water storage areas shall be designed to serve a secondary purpose for recreation, open space or other types of uses that will not be adversely affected by occasional or intermittent flooding. A method of carrying the low flow through these areas shall be provided in addition to a system of drains, and both shall be provided with a positive gravity outlet to a natural channel or other storm sewer facility with adequate capacity. The combination of storage of the water from a 100-year storm and the design release rate shall not result in a storage duration in excess of 72 hours. Maximum depths of planned storm water storage shall not exceed four feet unless the existing natural ground contours and other conditions lend themselves to greater storage depth, which shall be approved by the village’s consulting engineer. Minimum grades for turf areas shall be 0.6% and maximum slopes shall be 10%. Storage area side slopes shall be kept as close to the natural land contours as practical and a 10% slope or less shall be used whenever possible. If slopes greater than 10% are necessary to meet storage requirements or area restrictions, approval shall be obtained from the village’s consulting engineer, and suitable erosion control shall be provided in addition to the protection required to ensure public health and safety.
         (b)   Outlet control structures shall be designed as simply as possible and shall require little or no maintenance and/or attention for proper operation. Each storm water storage area shall be provided with a method of emergency overflow in the event that a storm in excess of the 100-year return frequency storm occurs. The emergency overflow facility shall be designed to function without maintenance and/or attention and shall become part of the natural or surface channel system described in division (E)(2) above. Hydraulic calculations shall be submitted to substantiate all design features. Both outlet control structures and emergency overflow facilities shall be designed and constructed to fully protect the public health and safety. Storm water runoff velocities shall be kept to a minimum and turbulent conditions at an outfall control structure will not be permitted without complete protection for the public safety. The use of restrictive fences shall be kept to a minimum and shall be used only as a last resort when no other method is feasible.
      (5)   Retention reservoir or wet bottom storm water storage areas shall be designed with all of the items required for detention reservoir storage areas; except that, a low flow conduit and a system of drains with a positive gravity outlet shall not be required. However, the following additional conditions shall be complied with.
         (a)   Water surface area shall not exceed one-tenth of the tributary drainage area.
         (b)   Shoreline protection shall be provided to prevent erosion from wave action.
         (c)   Minimum normal water depth shall be four feet. If fish are to be used to keep the pond clean, a minimum of one-fourth of the pond area shall be a minimum of ten feet deep.
         (d)   Facilities shall be available, if possible, to allow the pond level to be lowered by gravity flow for cleaning purposes and shoreline maintenance.
         (e)   Control structures for storm water release shall be designed to operate at full capacity with only a minor increase in the water surface water level. Hydraulic calculations shall be submitted to substantiate all design features.
         (f)   Aeration facilities to prevent pond stagnation shall be provided, if necessary. Design calculations to substantiate the effectiveness of these aeration facilities shall be submitted with construction plans. Agreement for the perpetual operation and maintenance of aeration facilities shall be prepared to the satisfaction of the village’s consulting engineer and Planning Commission.
      (6)   Where developments form only a portion of the watershed or contain portions of several watersheds, the requirements for providing storage shall be based upon that proportion of the area being developed as compared to the total watershed tributary to the storage area. Compensating storage will be acceptable whenever it is justified and feasible. As a watershed is developed with a series of storm water storage facilities, due consideration will be given for calculations of the allowable release rate and capacity of the natural or surface channel system as described in division (E)(2) above.
      (7)   Where development of a property presents the threat of flooding or damage by flash flood runoff to downstream residents, the facilities for storm water runoff control shall be constructed prior to any earthmoving or drainage construction on the project site.
      (8)   The construction of the storm water control systems shall be accomplished as part of the cost of land development. If the amount of storage capacity can be increased to provide certain benefits to the surrounding properties, negotiations for public participation in the cost of such development may be feasible.
      (9)   The ability to retain and maximize the ground water recharge capacity of the area being developed is encouraged. Design of the storm water runoff control system as provided in division (E)(4) above shall give due consideration to providing ground water recharge to compensate for the reduction in the percolation that occurs when the ground surface is paved and/or roofed over. The use of natural gravel deposits for the lower portions of storm runoff storage areas, the flattening of drainage slopes and the retention of existing topography are samples of possible recharge methods.
      (10)   During the construction phase of land development, facilities shall be provided by appropriate stockpile design, to prevent the erosion and washing away of the earth. Silting of downstream areas shall be prevented through the strategic use of silting basins, sodding of runoff channels and by limiting the period of time during which the earth is stripped of vegetation.
      (11)   Final engineering plans shall show complete details for all items covered in this section. Plans, specifications and all calculations for storm water runoff control and storm sewers shall be submitted for review and approval as part of the construction plan submittal or as part of the site plan submittal for large scale developments.
(Prior Code, § 150.045) (Ord. 96-006, passed 2-5-1996)
§ 155.122 BACKFILL OVER UNDERGROUND UTILITIES.
   (A)   Where an underground utility is to be placed in an area which has a permanent type street or sidewalk surface, or upon which such a surface is to be constructed within a period of one year, the backfill above the utility or in case of sewers, above the top of the granular cradle, to the level of the bottom of the permanent type pavement shall be made. This material will be in all areas where utility trenches cross the pavement subgrade, except in areas which will be lime treated or areas where rock will be used to stabilize the subgrade. The backfill shall be IDOT CA-6 or CA-7 crushed stone. Boiler slag will not be permitted.
   (B)   As an alternate, the use of “flowable fill” will be permitted. This mix shall consist of a lean concrete mix with no less than 50 pounds of cement per cubic yard, 200 to 600 pounds of fly ash, 2,000 to 3,000 pounds of fine aggregate and 35 to 65 gallons of water. Minimum 28-day compressive strength shall not be less than 150 psi.
   (C)   In areas not now subject to vehicular traffic, nor in the opinion of the village’s consulting engineer likely to be within a period of one year, backfill may be made with selected excavation material which is free from clods and stones; provided, such trench backfill is adequately jetted from the bottom up completely filling the trench immediately after backfilling.
(Prior Code, § 150.046) (Ord. 96-006, passed 2-5-1996)
§ 155.123 SIDEWALKS.
   Concrete sidewalks at least four feet wide and four inches thick shall be constructed on both sides of each street at least four and one-half feet from and at least four inches above the backs of the curbs. Sidewalks shall be located one foot inside the street right-of-way. Sidewalks shall be constructed along all streets bordering the subdivision. All sidewalks along arterials and minor arterials shall be five feet wide. All walks at corner lots shall be extended out to gutter(s) either by a common extension at the center or continue at right angles to the gutter.
(Prior Code, § 150.047) (Ord. 96-006, passed 2-5-1996)
§ 155.124 SEWAGE DISPOSAL.
   (A)   Sanitary sewers.
      (1)   When a subdivision is located within the service area of a public sanitary sewerage system, sanitary sewers shall be constructed throughout the entire subdivision in such a manner as to serve adequately each building lot.
         (a)   Public sanitary sewers shall be located in the north or west boulevard (between curb and sidewalk) within the street right-of-way or in a 15-foot easement behind the sidewalk within the house setback area. Parallel sewer lines along the street may be used. Sanitary sewers shall not be located in the rear yard.
         (b)   Under no circumstance shall the entrance of storm water or ground water to the sanitary sewers be permitted.
         (c)   All sanitary sewer collections and disposal systems shall comply with the ordinances of the village and the requirements of the Illinois Environmental Protection Agency.
      (2)   Acceptable sanitary pipe materials shall be acceptable to the village consulting engineer and shall consist of:
         (a)   PVC composite sewer pipe conforming to ASTM D 2680 with solvent weld or gasketed joints;
         (b)   Polyvinyl chloride (PVC) sewer pipe conforming to ASTM D 3034, type PSM for sizes four inches to 15 inches and ASTM F-679 for sizes 18 inches to 27 inches. Minimum acceptable SDR shall be 35; or
         (c)   PVC corrugated sewer pipe with a smooth interior. This pipe shall conform to the requirements of ASTM Standard F-794 and Uni-bell Uni-P-9. Pipe shall be made of PVC material having a cell classification of 124-54-B as defined in ASTM D 1784. Pipe stiffness at 5% deflection shall be 46 psi for all sizes (eight inches to 30 inches) when tested in accordance with ASTM 2412. PVC pipe meeting ASTM F-942 is not acceptable.
      (3)   All sanitary laterals will be marked by using a two-inch by four-inch (painted orange) board four feet above the ground to denote location of service lines.
   (B)   Private sewage disposal systems. Where no public sanitary sewerage system is available (see § 155.027(A)(1) of this chapter), individual sanitary disposal systems shall be installed to service individual dwelling units according to conditions set forth in § 155.027 of this chapter. These sanitary disposal systems shall be installed in accordance with the latest revised edition of the State Private Sewage Disposal Licensing Act and private sewage disposal code promulgated by the State Department of Public Health and the applicable ordinance of the village. Sufficient area shall be provided to accommodate two seepage fields.
(Prior Code, § 150.048) (Ord. 96-006, passed 2-5-1996)
§ 155.125 WATER SUPPLY.
   (A)   Public water supply.
      (1)   Water mains not less than six inches in diameter shall be constructed throughout the entire subdivision. Larger diameter pipes may be required by the village to provide for future transmission needs, in which case, the village shall pay any additional costs.
      (2)   Every water supply system shall be designed in such a manner as to provide an area fire flow meeting the requirements established by the village’s fire protection district. Water mains larger than six inches in diameter shall be installed at the subdivider’s expense if needed to provide the area fire flow required by the insurance services office guild for determination of required fire flow. A minimum of 1,000 gallons per minute with a residual pressure of 20 pounds per square inch shall be required. Fire hydrants with shut-off valves at each hydrant shall be installed throughout the entire system at maximum intervals of 400 feet or less. All fire hydrants shall be three nozzle hydrants with threads as specified by the village’s fire protection district and shall have flow characteristics similar to those of a five and one-fourth inch hydrant valve.
   (B)   Private water supply. When a public water supply is not feasible and the subdivision is outside the corporate limits of the village, a private well may be used. Wells shall be constructed according to the Illinois Water Well Pump Installation Code.
(Prior Code, § 150.049) (Ord. 96-006, passed 2-5-1996)
§ 155.126 ELECTRIC DISTRIBUTION.
   The underground electric distribution system shall be installed on utility easements along front lot lines. Transformers shall normally be placed on every other lot line with secondary conductors and distribution pedestals installed on the opposite side of the street. In some instances, transformers may be installed on both sides of the street. All primary and secondary cables shall be in conduit.
(Prior Code, § 150.050) (Ord. 96-006, passed 2-5-1996)
§ 155.127 STREET LIGHTING.
   Street lights shall be installed along public streets in the village by the subdivider.
(Prior Code, § 150.051) (Ord. 96-006, passed 2-5-1996)
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