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IRRIGATION AND WATER MANAGEMENT 18 April 2016 Landscape and Irrigation www.landscapeirrigation.com Many systems will have specialized equipment, such as water treatment systems that will have their own requirements. Winterization The pressures and stresses arising from the freezing of water are readily capable of fracturing pipes and breaking fittings. Removal of all of the water from irrigation systems is an important precaution in freezing climate areas. Expulsion of water by air or draining of water from the system is a preventative maintenance program. Details on the procedures for winterization are provided by irrigation companies. SPRINKLER HEAD CONDITION ASSESSMENT The operation and condition of each sprinkler/rotor should be regularly checked. The following are fault categories that can be identified. (1) Rotation — Not rotating to desired degree (continuous 360 degrees for full-circle sprinkler); slow rotation; no rotation (2) Damaged — Wiper seal damaged/broken; turret seals leaking; rubber top damaged/removed; riser stem damaged/broken; nozzle damaged/broken (3) Vertical alignment — Riser stem "tilt" or angle affecting performance of sprinkler (4) Clearance — Riser stem not clearing surrounding ground/turf, due to sprinkler too low in ground (5) Grass obstruction — Grass/turf interfering with nozzle stream (clearance would be good if grass height was maintained) (6) Arc adjustment — Part-circle sprinklers over-spraying outside of target area DRIP SYSTEM MAINTENANCE The risk of malfunction of drip systems is well recognized, and preventative maintenance programs are strongly promoted. These programs are mainly designed to prevent blockages of emitters. They include a) flushing of the system, b) chemical injection, and c) scheduling of irrigation. Flushing Over time, debris can lodge in the drip system pipe and valve network and, in some cases, organic material can grow within the pipes. Deposits and growth can build up on the walls of the pipes. Flushing of the complete network at velocities greater than the system design velocity facilitates removal of these contaminants. Chemical injection The chemicals that may be injected into a drip system include fertilizers, disinfectants, pH modifiers and chemicals to protect the drip system through dissolving particles. Chemical injection requires precision hydraulic management. Preparation and adjustment of correct concentrations is a fundamental part of achieving effective control and outcomes that are safe for humans and the environment. Scheduling One of the risks associated with drip systems, particularly where the emitters are buried, is the intrusion of roots into the emitter and pipe. Also, there is the risk of soil particles being drawn back (sucked back) into the pipes. The risk of root intrusion occurring can be mitigated through the management of the irrigation application. Operating the irrigation so that the plants/crop are not excessively stressed will reduce the likelihood of root build-up close to the emitters. Monitoring of soil moisture, using sensors, will also provide information about the appropriate/threshold set point value to Low rotor heads disrupt the water stream. This is a common problem, contributing to poor performance. Planned, systematic checking is required. This tilting rotor head is functioning hydraulically, but water application is poor. Checking and rectifying should be part of a preventative maintenance program.