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A. Underground Utilities – Location and Alignment.

1. For all crossings, the angles of crossing should be as near a right angle to the street centerline as practicable; however, lesser angles may be permitted based on economic consideration of the practical alternatives.

2. Crossings should avoid deep cuts, footings of bridges and retaining walls, wet or rocky terrain, or locations where highway drainage would be affected.

3. Where irregularly shaped portions of the right of way extend beyond the normal limits of the right of way, variances in the location of the utility lines will be allowed as necessary to maintain a reasonably uniform alignment.

B. Underground Utilities – Cover.

1. The minimum cover of underground utilities as measured from the actual surface point of the installation within the street right of way will be as follows:

a. 36 inches within the street prism, which may be reduced to 24 inches with approved casing or protective concrete slab, or to 12 inches in solid rock when backfilled with controlled density fill (CDF).

b. 30 inches outside the street prism, which may be reduced to 24 inches with approved casing or protective concrete slab, or to 12 inches in solid rock when backfilled with CDF.

c. Secondary electrical service lines and all communication, cable television, and other low voltage lines may be placed within the street prism at a depth of 18 inches if backfilled with CDF, except for principal and minor arterials, where these lines may be placed at a depth of 24 inches if backfilled with CDF.

The requirement for CDF backfill does not apply when the underground utility is constructed by means of pushing, boring, or bore-pulling as specified in subsection (F)(2) of this section.

2. Where less than the minimum cover is made necessary to avoid obstacles, the utility may be either rerouted or protected with a casing, concrete slab, or other method acceptable to the City.

3. Cover for utilities carrying transmittants that are flammable, corrosive, expansive, energized, or unstable may not be reduced below the safety limits specified in the appropriate industry standards and specifications.

4. For street and sidewalks constructed with permeable materials, in addition to item 11.50.060(B)(1), utilities shall maintain a minimum one (1) foot separation from the bottom of the permeable storage section.

C. Underground Utilities – Encasement.

1. Casings are required for street crossings where casing is required by appropriate industry code or where local features, embankment materials, construction methods, or other conditions indicate any possible damage to the protective coating during installation, or where the City determines the installation of casings will reduce or eliminate damage to the City right of way.

2. Casings may be required for the following conditions:

a. As an expediency in the insertion, removal, replacement, or maintenance of a carrier line crossing or other locations where it is necessary in order to avoid open trench construction.

b. As protection for carrier lines from external loads or shock either during or after construction of a street.

c. As a means of conveying leaking fluids or gases away from the area directly beneath the traveled way to a point of venting or drainage.

d. For jacked or bored installations of coated carrier lines, which must be contained within a casing unless assurance is provided to the City that there will be no damage to the protective coating.

3. Casing pipes must extend a minimum of 6 feet beyond the toe of fill slopes, back of street ditch, or outside of curb.

4. Other than for necessary vents and/or drains, casing pipes must be sealed at both ends.

5. Casing pipes must be designed to support the load of the street and superimposed loads thereon and, at a minimum, must equal the structural requirements for street drainage facilities. Casings must be composed of materials of sufficient durability to withstand any conditions to which they may normally be exposed.

D. Underground Utilities – Uncased Carriers.

1. The carrier pipe will conform to the material and design requirements of the appropriate utility industry and governmental codes and specifications.

2. The carrier pipe will be designed to support the load of the street plus superimposed loads thereon when the pipe is operated under all ranges of pressure from maximum internal to zero pressure.

3. Suitable bridging, concrete slabs, or other appropriate measures as approved by the City must be used to protect existing carriers which, by reason of shallow bury or location, are vulnerable to damage from street construction or maintenance operations.

4. Existing carriers may remain in place without further protective measures if they are of adequate depth and do not conflict with street construction or maintenance and provided that the utility and the City mutually agree that the lines are, and will remain, structurally sound and operationally safe.

E. Underground Utilities – Appurtenances.

1. Vents are required for casings, tunnels and galleries enclosing carriers of fuel where required by federal safety standards. Vent standpipes, as well as air release valves, locator stations, pressure cleanouts, and other appurtenances projecting above the ground and/or requiring periodic examination or maintenance, should be located and constructed so as to neither interfere with maintenance of the street nor to be concealed by vegetation; preferably, they should stand by a fence or on the right of way line.

2. Drains are required for casings, tunnels, or galleries enclosing carriers of liquid, liquefied air, or heavy gas. Drains for carriers of hazardous materials must be directed to natural or artificial holding areas that will prevent the potential for surface or groundwater contamination. Drains from which only water or other nonhazardous liquids will discharge may be directed into the street ditch or other natural watercourse at locations approved by the City. The drain outfall may not be used as a wasteway for routine purging of the carrier unless specifically authorized by the City.

3. Surface markings of underground utilities will be in accordance with applicable state and federal standards.

4. Automatic shutoff valves must be installed in line at or near ends of structures and near unusual hazards unless other sectionalization devices within a reasonable distance can isolate the hazardous segments.

5. Unless otherwise approved by the City, all aboveground appurtenances to underground installations proposed for location within the City right of way that may constitute a roadway obstacle for traffic using the street must be located as close as possible to the right of way line. If, due to narrow right of way or other conditions as may be determined by the City, an adjacent to the right of way appurtenance location still constitutes an unacceptable roadway obstacle, said obstacle must be:

a. relocated to another place within the right of way,

b. converted to a breakaway design,

c. crash-protected, or

d. relocated to another location off the street right of way.

Actions a, b, and c of this subsection must be approved by the City as a condition of permit approval.

6. All installations of nonmetallic materials that may contain hazardous or environmentally objectionable liquids or gases under pressure must have a metal locating wire or equivalent placed alongside the nonmetallic conduit. All subsurface installations, both active and inactive, must be locatable unless otherwise exempted.

F. Underground Utilities Installation. All utility installations shall ensure safety of traffic and preservation of the roadway structure.

1. Trenched installations must provide for backfill and restoration of the pavement, paved shoulders, curbs, and gutters in accordance with Section 11.80.100.

2. Untrenched construction (i.e., pushing, boring, or bore-pulling) will be required for all utilities 2 inches (2") and smaller in diameter crossing roads paved with asphaltic concrete or cement concrete and for roads paved with a bituminous surface treatment except when another method is approved for a specific location.

a. The length of untrenched construction must extend a minimum of 4 feet from edge of pavement or greater if specified by the Director, except that a 2-foot minimum may be permitted by the Director for service connections where conditions warrant.

b. Pipelines installed under a road without disturbing the surface shall be made using a technique approved by the City but in no case shall the size of the opening exceed the pipe diameter by more than 5% or 1 inch, whichever is greater, unless bentonite or an equivalent nonshrinking material is injected into the void. If, during the process of pushing, boring, or bore-pulling, the roadway or shoulder of the road is damaged or distorted in any manner, the utility must make immediate repairs to the satisfaction of the City.

c. Overbreaks, unused holes, or abandoned casings must be backfilled as directed by the City.

d. Jetting under roadways will not be permitted. This does not prohibit the use of boring or driving techniques which use water to only remove cuttings and does not permit the water to remove material outside the designed bore dimensions. In all cases where water is used, the discharge shall be captured and disposed of or otherwise controlled such as not to violate the City’s water quality regulations.

3. City utilities will comply with this section insofar as applicable to the type of utility and installations for City utilities. (Ord. M-4179 §5, 2016; Ord. M-4026 §9, 2012)