3.5.1 Irrigation Systems

Controller-based irrigation systems are recommended to protect both the monetary investment in the project and to insure healthy landscape development. The design and extent of the system should be appropriate to the plant material and the location. Design and installation must meet all state and local rules and requirements related to the public water supply.
  • System Design
    • Irrigation components within the system should be selected for longevity and durability and should be secure from vandalism. Controllers and backflow preventers should be enclosed within lockable enclosures. All valve covers should be lockable as well. All valves and nozzles should be plastic. Typical system components are:
      • Controllers may be electric, solar, two wire, and/or battery-operated;
      • Rain sensors & water budgets required by state code;
      • Soil moisture sensors; and
      • Bubblers & drip irrigation, including laser tubing & emitters.
    • If adding new irrigation to an existing system, always ensure that the components of the new system are compatible with existing equipment; controller stations, valve decoders, etc., should all work together.
    • Within median and groundcover areas, drip irrigation is the best option to comply with TCEQ requirements and to avoid overspray onto pavement areas. When combined with bubblers for trees, these two components form an effective and efficient system and aid in water conservation.
    • Under limited circumstances, TxDOT may consider turf irrigation within the ROW, notably in those situations where responsibility for the maintenance and operation is assumed by local governments or other TxDOT approved entities. In this case, drip irrigation is the preferred method of application.
  • Inspection and Maintenance
    • Main system components should be easily accessible and away from traffic lanes.
    • All irrigation systems will require routine inspection and maintenance.
    • In most situations, roadside landscape irrigation systems that are three to five years old will not be repaired if damaged.
    • The system design should also allow for scaling back to manual operation during maintenance (when required) or during times of severe drought.