As the demand for available water resources increases in the future, proper and efficient water management practices will become even more crucial for all of us. At the same time, the environmental, recreational, aesthetic, and economic benefits of beautiful well-managed landscape, turf and garden areas will grow in importance.
- Ideally, we should be using drip irrigation (low volume) for all ornamental and landscape plant material; pressure regulated spray heads; and automatic rain sensing devices that shut down irrigation systems during a rain event.
Along with these mechanical devices, it is important to have a properly designed irrigation system from a reputable contractor. In all states, contractors may also have a Certified Irrigation Designer (CID) or Certified Irrigation Contractor (CIC) designation through the Irrigation Association of America.
1. The Spring Start-Up:
An underground irrigation system is like any other mechanical device and should have a tune-up every spring. A proper maintenance program will insure that your system will operate for years without any major problems.
- A proper spring tune-up will include an inspection of each individual zone and controller setting. The trained service technician will also check the nozzle and arc adjustment as well as any leaks and or weeping valves.
- A spring tune-up is also a good opportunity to check backflow prevention devices that protect our drinking water supply. These devices can only be tested by a grade 6 water operator; ask your service company if they qualify.
2. Irrigation Audit:
Another beneficial service your qualified irrigation contractor can provide for you is an irrigation audit. This procedure can also be performed by the homeowner. The goal is to eliminate waste and run-off by determining the precipitation rate of each individual zone for a specific run time to ensure the correct amount of water is being applied.
- By determining the precipitation rate (PR) of each individual zone, you can calculate the inches per hour. In our area of the state, the soil is clay or clay loam and will absorb about .32 inches of water per hour. Any more fills the pores in the clay and becomes run-off.
- Setting up an audit field differs for each type of sprinkler being tested as well as how they are spaced. The three major types of sprinkler heads are spray heads, rotary/impact and stream sprays (finger spray) and the three major spacings are single row, triangular and square.
- Various parts of your landscape require different patterns.
3. Measuring Application Amount:
Supplies needed to set up an audit field are catch cans (a minimum of 16) or ground staked rain gauges and flags to mark the individual heads.
- Run the zone for 15 minutes. Then, using a larger rain gauge, pour the water from all catch devices into that measuring device and divide by the number of catch devices used. This will give an average of precipitation for that zone. Then multiply by four to determine how many inches per hour that zone is delivering.
NOTE: To measure your specific irrigation installation patterns, work directly with your irrigation contractor.
Run-Off Prevention:
After each zone has been calculated, determine the run times for each zone where the precipitation rate does not exceed .32 inch per hour. It is better to apply the water in two .16- to .17-inch applications so the first application has time to absorb into the top layer of soil and pass into the root zone, which encourages deep root growth.
- For hand watering, you may want to take your measurements in 30-minute increments, and place your catch cans in a 10-foot by 10-foot grid. After you have established your run times, it is a good idea to use battery-operated timers on the faucet or a baking timer to prevent overwatering.
- Once the audit is complete, locate your irrigation controller, and program each individual zone with the information from the audit. When setting up your controller, take into account the turf type to be watered.
4. Controller Programming Tips:
- Water turf during the cool part of the day.
- Never water during the heat of the day.
- Water plants and vegetable gardens after the heat of the day to replenish transpiration losses.
- Be sure to use the A/B program on the controller to separate start time for turf and landscapes.
5. Upgrading Irrigation Systems
- Newly planted and landscape beds should be irrigated with drip irrigation (low volume). A professionally designed drip zone will be tailored to give each plant, shrub and ornamental the exact amount of water needed. It also prevents the over-watering of some plants and the under-watering of others and uses far less water to perform the same duty as an aerial system. Drip systems should be run about twice a week in the spring and the fall and three times a week in the summer. Drip systems emit water on an hourly basis and if designed correctly, the entire zone should be able to run for one hour.
- Pressure regulated spray heads are designed for high pressure areas with a static water pressure of 60 to 100 psi, reducing evaporation losses and wind drift and ensuring that a larger water droplet reaches the ground. Pressure regulated spray heads can save between 50,000 and 120,000 gallons of water per year, per residence and even more at commercial sites.
- The automatic rain sensor is adjustable for one-eighth inch to 1 inch of rainfall. A recommended setting for our area is .25 to .5 inches.
