Engineering Guidelines

The following guidance is subject to change as site conditions warrant. This guidance is presented to aid in the design and decision making process of the applicant. Each proposed crossing will be subject to review by the Ditch Company. Applicants are encouraged to consult with the Ditch Company early in the design process to review special crossing requirements. 

General 
  • Provide a construction schedule for approval by the Ditch Company prior to commencing activities. 
  • Provide quality control testing during construction. 
  • Include the appropriate Ditch Company contact information on the plan set. 
  • Provide the Ditch Company as-built drawings and quality control testing information at the completion of the project. 
  • Provide adequate structural setbacks, both horizontal and vertical, so that no portion of the proposed site work interferes with ditch activities. 
  • Any work done within the ditch must be completed during the non-irrigation season, generally November 1-March 15.

Maintenance and Access Road
  • The ditch side access road needs to remain open during the construction period at all times unless specifically approved by the Ditch Company. 
  • Resurfacing of all disturbed areas of roadway will require at least 4-inches of compacted driving surface to repair the travel way. Asphalt millings, recycle concrete, CDOT Class 6 and crushed aggregates are all acceptable surfacing materials. 
  • The access road is to have a minimum 16-foot wide travel surface with 1 foot of soil shoulder on each side. 
  • All gates are to remain closed during the construction process. 
  • All construction debris, including earth spoils, is to be removed from the site. 
  • No ornamental plantings or irrigation equipment is to be placed on the access. 
  • The access road should slope to drain away from the canal at 2%. 
  • Guardrail, fencing, posts, vertical curbs, signage and other obstructions to access the easement are to be avoided. 
  • Unsafe and unstable conditions created by the construction process will not be allowed. 

Easement Criteria 
  • The generally accepted easement width for open sections is the canal width plus 20 feet from the top of bank on both sides. 
  • The generally accepted easement width for enclosed sections is the outside dimension of the structure in feet plus 20 feet on both sides. 
  • Where the ditch is relocated or enclosed in a structure a formal easement delineated with survey metes and bounds are required for the crossing agreement. The new easement is to be recorded in the appropriate county or city office. 

Crossing Exhibit 

  • An exhibit depicting the proposed crossing(s) should be prepared to accompany the legal agreement. This is in addition to and separate from the construction drawings. 
  • The exhibit should be either 8.5” by 11” or 8.5” by 14“. 
  • The exhibit should identify adjacent property ownership and have the pertinent public land survey information (township, range, section, etc.). 
  • Survey property line metes and bounds information should be shown on the exhibit. 
  • If a new easement is proposed, ties to the parent property and the metes and bounds of the easement should be clearly shown. 
  • All crossings, including wet and dry utility relocations should be included. 
  • The canal and any nearby public street should be clearly identified on the exhibit. 
  • A north arrow and a bar scale should be included on the exhibit. 
  • The preparer's address and phone number should be on the exhibit.

Stormwater and Drainage
  • The Ditch Company does not accept stormwater or project drainage.

Crossing Type

Open Cut Crossings

    • Maintain clearance of the pipeline or dry utility to be at least 4-feet below the invert of the ditch. 
    • Low permeability material is preferred to granular bedding under pipelines. 
    • Place a trench cut off wall on both ends of the utility at least 15 feet back from the top of bank. 
    • Place a Karsonite marker or fence post with a sign on both sides of the canal at the edge of the easement to identify the location of the utility. 
    • Utility lines crossing the ditch should be placed in a steel casing pipe under the ditch. 
    • Storm sewer should be fitted with gaskets to provide a watertight crossing. 
    • The open cut portion of the ditch should be backfilled with a minimum of two feet thick compacted clay material with at least a PI of 12 and 35% passing the #200 screen. 
    • Compaction of all backfill and canal banks is to meet or exceed 95% maximum dry density, +/-2% of optimum moisture content (ASTM D 698).
Bored Crossings (Under Open Channel)
    • Maintain clearance of the pipeline or dry utility to be at least 4-feet below the invert of the ditch. 
    • Place a trench cut off wall on both ends of the utility at least 15 feet back from the top of bank. 
    • Place a Karsonite marker or fence post with a sign on both sides of the canal just outside the easement to identify the location of the utility. 
    • Utility lines crossing the ditch should be placed in a steel casing pipe under the ditch. 
    • The boring pit should be placed outside the canal easement. 
    • If the ditch side access road is utilized, all disturbed portions will require at least 4-inches of compacted driving surface to repair the travel way. Asphalt millings, recycle concrete, CDOT Class 6 and crushed aggregates are all acceptable surfacing materials. 
    • Compaction of all backfill and canal banks is to meet or exceed 95% maximum dry density, +/-2% of optimum moisture content (ASTM D 698).
Bored Crossings (Under Piped Section)
    • Maintain clearance of the pipeline or dry utility to be at least 4-feet below the invert of the ditch. 
    • Utility lines crossing the ditch should be placed in a steel casing pipe under the ditch. 
    • The boring pit should be placed outside the canal easement. 
    • Compaction of all backfill and canal banks is to meet or exceed 95% maximum dry density, +/-2% of optimum moisture content (ASTM D 698).


 Design Criteria

Structures

    • Flow criteria for the Colorado Agricultural Ditch is 83 cfs. 
    • Minimum free board is 2 feet above the design flow. 
    • Maximum side slope is 2:1 (H:V). 
    • All riprap is to be grouted in place. At least 10 feet of riprap is needed both upstream and downstream of any proposed canal structure. Additional revetments may be required due to specific hydraulic conditions. 
    • A geotechnical investigation and report to establish the foundation conditions is needed for all proposed box culvert, bridge, and retaining wall installations. 
    • Standard plans and specifications by CDOT are generally accepted for canal work. 
    • Tubular steel handrail is required for all wing walls and headwalls. 
    • Ditch Company standard lateral and check structure drawings should be utilized in design these types of structures. 
    • Only reinforced concrete pipe should be used in new structures.

 Relocated Open Ditch Sections

    • Flow criteria for the Colorado Agricultural Ditch is 83 cfs. 
    • Minimum free board is 2 feet above the design flow. 
    • Maximum side slope is 2:1 (H: V). 
    • The bottom and sides to the free board line should be two feet thick of compacted clay material with at least a PI of 12 and 35% passing the #200 screen. 
    • Bends in the ditch alignment of greater than 15 degrees should receive riprap protection.
Pipe Installations
    • Unless specifically approved in advance, all piping should be Class III (or higher) reinforced concrete pipe. 
    • Prefabricated, steel reinforced concrete flared sections with prefabricated sloping steel trash grates are required on each end of the piped section if freeboard is not attained. 
    • It is preferred to utilize screened native soil instead of granular bedding for pipe projects. 
    • Access manholes are to be installed at 100-foot intervals. “Tee” sections with special cast iron ring and lid are acceptable. 
    • A minimum of 2 feet of freeboard is required in all pipe sections. 
    • Scour protection consisting of 18-inches thick layer of grouted Type “L” (d50=9”) riprap is required on the ends of all pipe segments. 
    • Pipe slope is to be at least 0.3%. 
    • In porous soils, cutoff walls are to be installed 10 feet inward from both ends of the pipe. 
    • Only gasketed pipe is acceptable. 
    • Side slopes are not to be steeper than 2.5:1 or flatter than 4:1. 
    • All disturbed areas are to be revegetated with a weed free streamside acceptable mix. 
    • Plans are to include detailed design of the proposed system complete with a water surface profile through the structure.