Irrigation Guidelines for Site Supervisors

Irrigating Efficiently: Best Management Practices

Objectives

Apply correct amount of water to maintain your landscape with an attractive appearance. Save money and limit water waste from runoff, overspray, ponding and deep percolation. Avoid damage from irrigation water to buildings, paving and other assets.

If using recycled water…
Prevent cross-connections between recycled water system and drinking water system.

Management

• Develop a list, by controller, of all irrigation control valves (stations) including the type of sprinkler or equipment, plant material irrigated and normal-weather-year irrigation schedules.
• Locate points of connection to municipal water pipelines (meters), controllers, isolation valves and control valve service areas on a schematic map. Use one 8.5 by 11 inch sheet per controller.
• Deliver electronic and paper copies of lists, maps and schedules, to the landscaper, management company, and other interested parties. Store a copy of all documents in the controller enclosure.
• Inspect the system frequently by operating each station and observing every sprinkler while in operation. Document inspections to allow tracking and analysis of results.
• Create a water budget using local weather data and measured area of turf and other landscaping. Read your water meters on a regular basis (weekly to monthly). Compare your budget to the meter readings.

Irrigation Scheduling

• Irrigate only between 9:00 pm and 6:00 am.
• Test sample sprinkler stations to develop representative precipitation rates and uniformity for your system. If required, seek expert help. Use these data to develop accurate schedules for your system. An irrigation cycle should just fill the plant rootzones and no more.
• Fully use controller scheduling capabilities and features. Separate turf and ground cover/shrub/tree schedules by using different programs. To limit runoff, use as many multiple program start times as possible and practical. Employ percent-adjust feature as a convenient way to change station runtimes.
• Operate turf stations no more than five times per week and ground cover/shrub stations no more than twice per week in normal summer weather. In extremely warm weather, add an irrigation day to the program or use percent-adjust.
• Schedule irrigation start times as close as possible to the lowest wind period at dawn. Operate systems during the day only for system checks and when applying water with drip or bubbler programs.
• Change programs to reflect weather through the year (monthly in spring, summer and fall). After rainfall of 1/2 inch or greater, shut down the controller. Shorten program runtimes rapidly through the fall to maximize water savings.
• Accurately calibrate drip and bubbler irrigation runtimes to avoid deep percolation.
• Sample soil moisture to check schedules only on the afternoon before an irrigation cycle. Movement of water in the soil requires saturation; therefore the rootzone is wet immediately after irrigation.

Field Equipment

• Use radio remote controllers to facilitate frequent system checks (this may require installation of connection jacks).
• Repair leaks and breaks immediately based on systematic inspections. A malfunctioning sprinkler can spread problems to other heads. Leaks and misalignment cause runoff and ponding, introducing wet conditions that can allow damage to other sprinklers from mowers.
• Stations should only operate sprinklers of the same type (spray with spray and rotor with rotor). Spray type sprinklers apply water at about three times the rate of rotor sprinklers.
• Ensure each sprinkler operates with the optimum nozzle. Eliminate overspray by using limited range nozzles in narrow plantings. Achieve higher water application uniformity in turf stations with matched precipitation nozzles where possible.
• Set stations to the proper pressure. High pressure causes premature failures, overspray and/or misting. Use the flow control on the control valve to reduce pressure. A low-pressure problem is more difficult to solve, seek expert help.
• Avoid overspray in outdoor eating areas, particularly near drinking fountains.
• Orient sprinklers vertically (except on slopes) while adjusting arc and range to limit overspray onto other plant material, hardscape or buildings.
• Install check-valves where elevation changes causes draindown after valve operation.
• Make sure bubblers have basins of sufficient size to avoid runoff. Operate bubbler stations only long enough to fill the basins.
• Do not add sprinklers to an existing station without expert help.

Plant Material

• Maintain turf with less than 1/3 inch of thatch. This often requires thatch removal on an annual basis. Aerate as frequently as possible.
• Mow turf only after several days without irrigation so that the soil is dry as practical. After mowing, extended popup sprinklers must clear the turf by
• 1-1/2 inches. Carefully trim or edge to avoid damage to sprinklers.
• Trim ground cover and shrubs to allow uninterrupted spray from sprinkler nozzles to avoid puddles and overflow.
• Maintain segregation of plant material by water requirements. Don’t allow drought tolerant and water needy plants to mix on the same station or valve.

Recycled Water Users

• Monitor the site routinely and submit inspection reports to the City as required by the recycled water Customer Agreement.
• Continuously educate all maintenance personnel on the use of recycled water and remind them that it is not approved for drinking, washing or cooking.
• Keep all pertinent records and references complete, up to date and accessible.
• Keep others informed of all activities involving the recycled water system.
• Ensure that all valves, valve boxes, controllers and other appurtenances are identified for the use of recycled water and replace as necessary.
• Advisory signs must be placed at facility entrances informing the public that recycled water is in use (replace as necessary).
• A recycled water irrigation system must not use hose bibs. Quick coupling valves must have purple locking caps.