CSU Northridge Campus-wide Irrigation Efficiency Project
Facility managers at CSU Northridge have worked to successfully meet university, state and local water conservation goals for many years. Completed projects included turf removal, irrigation shutdowns, and low flow plumbing fixtures. Building on these initiatives, in 2016 they completed a series of resource management strategies with a campus-wide irrigation efficiency project as its centerpiece.
A multi-pronged water conservation initiative made cost-effective, smart irrigation controls the centerpiece, developed by taking advantage of campus resources and student talent.
An initial study showed that the cost of a full irrigation retrofit would be in the range of $400K, an amount that was not feasible due to budget constraints. Instead the team opted to modify and update the campus’ existing system, leveraging in-house resources such as student and staff expertise. The benefits of the project were four-fold: utility cost savings, water savings, labor savings, and student learning opportunities. It was estimated that out of the 55-million gallons of water saved by the program overall, 39-million gallons were due to the irrigation system upgrades. Ultimately this project allowed the campus to save $150,000 in annual water costs, and to surpass local conservation goals by six percent.
Irrigation technician replaces a broken sprinkler. The new system will save water by helping staff locate problems.
In order to transform the dated irrigation control system into a “smart” system, 62 individual controllers were upgraded with bi-directional communication, weather station connectivity, flow sensors, and master valve operation. The bi-directional communication capability allows the field controllers to constantly communicate with a centralized irrigation control system. An irrigation dashboard, located in the Grounds Shop, was designed to provide an easy-to-use tool, showing real-time system information. The system helps the staff to pinpoint any problems based on location, sending alarms until the issue is resolved.
Flow sensors installed at each controller allow the central control system to monitor water consumption, and to ‘teach’ each field controller how much water should flow through the pipes at a given time. The flow sensors ‘learn’ how much water should flow through a station at any given time, and once the maximum flow of water is determined, the volume is programed into the control system and used to detect leaks and unscheduled flows.
Irrigation system display in the grounds shop.
Each controller was additionally fitted with a master valve. These are operated by zone controllers commanded by the central control system, and work in conjunction with the flow sensors. If the control system detects a leak, unscheduled flow, or other irregularity, it automatically commands the master valve to shut, reducing potential leakage until the problem is resolved. Finally, by adding weather station connectivity to each controller, the system is better equipped to account for evapotranspiration, and respond to changing weather needs by adjusting the irrigation schedule.
Drought-tolerant landscaping on campus.
Rather than hiring design consultants and outside contractors, the project team took advantage of in-house resources to reduce costs. The project was a collaborative effort with staff from CSUN’s Sustainability Group, Grounds Department, Management Information Systems (MIS) and students. By retaining the development in-house, the project also provided experiential learning opportunities for the MIS students, who were enlisted to develop the irrigation display screen. As the involved students graduate, the head of MIS will be charged with hiring new students to ensure that the project remains a collaborative initiative.
With this initial stage of the project completed, the team is now looking to transition from hand-drawn maps to digital maps by using geographic information system (GIS) software. By virtualizing the maps, they may become more comprehensive, showing locations of flow sensors, master valves, nozzle types and surrounding plant types. The display will also provide a means to compare water use over time, using visual interfaces such as heat maps. Digitizing the maps may offer the additional benefit of increased labor productivity, as problem zones will be detected immediately, and staff will spend less time pinpointing the location of problematic areas.
Images copyright CSU Northridge.