Many people talk about drip irrigation and its high efficiency but what does this mean in terms of water savings? A recent retrofit at the Riverside County Waste Management Department (RCWMD) facility in Riverside, California is one example of how a properly designed, installed and maintained drip irrigation system can save water, money and maintenance, as well as enhance the overall site.

Project Challenges:

The Riverside facility was constructed in September, 2002 and the landscape plan included traditional overhead spray heads throughout. However, much of the landscape is designed with sparse plantings next to buildings and sidewalks. The use of spray heads in this application was not the best solution for a number or reasons:
• Irrigation water exceeded the monthly budget set by the local water district by over 40%, leading to substantial fines.
• At the current rate of water usage, the site would use its total water allocation before the end of the year and not be able to irrigate at all.
• Overspray was damaging the sidewalks and buildings and leaving water spots on the windows
• Weeds were growing between the plants, fed by water from the spray heads.

In addition, the maintenance crew was using a trial-and-error method of scheduling, and their experimentation often caused over-watering.

Then, Dave Matthews, Refuse Control Coordinator for the RCWMD attended a Xerigation class taught by Dave Palumbo, a Rain Bird representative, focusing on low-volume irrigation principles. Armed with this information and the knowledge that other municipal sites within the county used drip irrigation, Matthews recommended to his management that the site convert their conventional spray system to drip irrigation in the sparse planting areas. “The water district fines were exorbitant,” says Matthews. “We realized that the irrigation system needed to be changed or we would run through our water allocation quickly.” He was able to convince his management that they had to do something to reduce water consumption, avoid water fines and reduce his maintenance.

Solution:

Following the class, Matthews contacted Rain Bird to discuss switching spray heads to drip irrigation for the sparse planting areas to help control both water use and unintended irrigation. Matthews and the facilities management team decided to convert a zone that contained shrubs to drip irrigation. If the new installation resulted in lower water bills and less maintenance, Matthews planned to convert the rest of the sparse planting zones to drip irrigation.

The existing spray heads on the site were capped off using Xeri-Caps™ for Spray Heads, and the zone was retrofitted with 12” Polyflex Riser/Adapter Assemblies and 2 GPH Xeri-Bug Emitters on each riser. The polyflex risers were placed next to the shrubs, cut to the correct length and then the Xeri-Bug emitters were screwed onto the risers. Trees got their own drip systems, as well: 7 GPH Pressure-Compensating Modules for small trees and 10 GPH emitters for larger trees. To provide filtration and pressure regulation for this zone, the XCZ-100 control zone kit was used .Also, since Matthews wanted a robust, rodent-proof and vandal-resistant system, he used PVC for the entire zone.

Results:

Low-volume irrigation directly at the plant site had two benefits — it eliminated over-watering and reduced weed growth. “It was so easy to convert the existing spray zone into drip,” says Matthews. “The Landscape Drip team helped us with the retrofit installation which allowed us to install a robust, water-conserving system.”

The building maintenance staff also appreciated the absence of water spots and excess water on walkways from over-watering.

The realized savings from the retrofit included:
• EMWD fines stopped, and the facility’s water usage is well below the budgeted allotment
• The one zone used 4,620-gallon of water less per month (55,000 gallons per year savings). Estimated water savings for the entire facility are 1.1 MM gallons of water yearly.
• The facility maintenance crew also saved time and money with reduced weed growth and water cleanup.

Today, the waste management department manages its own water waste, and the facility saves costs as well as a substantial amount of water. The new drip system is robust, vandal-resistant, and water-efficient, and the facility’s water usage is well below their budgeted allotment.