Reservoir Water Filtration to Protect Irrigation Meters and Equipment, USA
Country
USA
Application
Protect Irrigation Systems
Water source
Reservoir
Filtration solution
3 x 16” Mega EBS (130 micron)
Background
The city of Spanish Fork supplies irrigation water to its citizens from seven wells located in the city’s vicinity. As the population has grown, the supply of water has become inadequate during peak irrigation hours in the summer months. In order to alleviate the shortfall that occurs during specific hours of the day, the city authorized building a storage reservoir that serves as both a buffer for supplementing peak period water usage and as a recreational facility. The 70 acre-foot reservoir is cement-lined with a portion of the perimeter designated as a swimming area. Beach sand was imported and lines part of the reservoir bed for the enjoyment of the swimmers. The bottom of the reservoir has an additional layer of gravel and tree stumps to provide habitat for fish that will be added to the reservoir at a later date. According to the city planners, the dual use of the reservoir (recreation and irrigation water supply) justified the capital expense for the project. A filtration system was included in the system design to remove debris from the reservoir water to protect the irrigation meters and equipment.
Challenge
When customer water flow demand exceeds the capacity of the city’s well system, the pressure at the filtration pump house drops below a set point. This triggers the reservoir control valves to open, allowing water from the reservoir to flow through the Amiad Mega EBS filters into the city’s water supply, supplementing the water from the well system. The reservoir is located at an elevation about 450 feet above the filtration pump house. Depending upon the water level in the reservoir, the gravitational pressure is 190 – 205 psi. The design parameters of the filter system allow a flow rate of up to 5000 gpm per Mega EBS. Three 20” pressure reducing valves (PRV) maintain 90 psi feeding the filter system. The level of water in the reservoir is sensed by the SCADA system as a function of pressure at the filtration pump house. When customer water flow demand is less than the capacity of the city’s well system, the pressure at the filtration pump house rises above a set point and a signal is sent to close the PRVs that feed the filters. If the level of the water in the reservoir falls below the minimum level, VFD pumps turn on in order to send water from the well system to replenish the reservoir. A single 36” pipe line of ½ mile in length is used to move water both to and from the reservoir. If the reservoir reaches maximum capacity and the irrigation demand remains low, the city’s wells begin to shut down in a manner determined by the SCADA system and water is provided from the reservoir.
Solution
• 3 x 16” Mega EBS filters • 80 micron screens • Up to 15000 gpm (3407 m3/h) • 90 psi
Results
The Amiad filters were selected for this project, and were the basis of design, based on the extensive quantity of Amiad filter installations on irrigation and water meter protection applications in the state of Utah. The engineering firm was very familiar with Amiad’s quality product line and their existing customers were happy with the performance of the previous installations and the limited maintenance requirements of the filter systems.
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