8.10.110 Bingham Junction South—Water management.
The shallow aquifer beneath a portion of the Bingham Junction property is contaminated, primarily with arsenic, as well as other substances. The source area as depicted in Figure L attached to the ordinance codified in this chapter contains significant amounts of arsenic that impacts groundwater. Water management on portions of the Bingham Junction property will also focus on preventing new sources of water from affecting the extent, direction, and flow of the arsenic plume within the source and plume areas.
A. Source and Plume Area Definition—Subdivision. The source and plume areas depicted in Figures L and J attached to the ordinance codified in this chapter are merely illustrative. At the time that subdivision (as defined by the Midvale City Code) occurs on any property within a source or plume area, the boundaries of these areas will be specifically noted by the developer on the small scale master plan, subdivision plat, and/or other permanent record maintained by Midvale City for purposes of compliance.
B. Unlined Storm Water Detention Basins. Unlined storm water detention basins are prohibited within the boundaries of or within one hundred feet of a source or plume area. Liners of detention basins must be impervious as determined and approved by the city (detention basins will be shown on construction plans relative to source area boundaries and will be included in site plan applications).
C. Wet Utilities and Irrigated Areas.
1. Slag Bedding Prohibited. Wet utilities may not be bedded in slag material. However, slag material may be used as backfill for wet utilities, above the pipe zone, as per APWA standards.
2. Flowfill or Equivalent Bedding. All wet utilities traversing a source or plume area must be bedded with flowable concrete (flowfill), “welded” HDPE pipe, or equivalent engineering solution acceptable to the city. (Wet utility locations must be shown on construction plans relative to source area boundaries and will be included in site plan applications.)
3. Collars or Equivalent. Low-permeability collars (or equivalent engineering controls acceptable to the city) will be required for all wet utilities within one hundred feet of the source area or plume area and that traverse a source area or plume area somewhere along the utility alignment. If used, collars will be installed at fifty-foot intervals. Collar designs or other equivalent engineering control design will be submitted with the construction permit and site plan application.
4. Surface Irrigation Restrictions. Within source areas, developers must provide a mechanism to limit infiltration of irrigation water. Minimum measures for source areas may include installing a buried impermeable barrier with drain system conveying excess water to the storm drain system beneath irrigated areas (or alternative with equivalent performance as accepted by the city). Large shrubs or trees may be placed in sealed planter boxes (the location of irrigated areas and piping will be shown on construction plans relative to source areas and will be included in site plan applications).
5. Irrigation Plans. For nonresidential development within source areas, all building permit applicants will be required to submit to the city an irrigation plan in order to implement the requirements in subsection (C)(4) of this section. The city will have the responsibility of approving and overseeing the implementation of the irrigation plan.
6. POAs. For residential development within source areas, property owners’ associations will have the responsibility of reviewing, approving, and overseeing the implementation of irrigation plans.
D. Concrete Rubble. Concrete rubble may not be used as fill material below the historic high water table within one hundred feet of a source or plume area.
E. Construction Dewatering. Disposal of contaminated construction wastewater must be done in accordance with applicable environmental regulations (to be included in site plan application). (Ord. 6/26/2007O-8 § 1 (Exh. A (part)))