waiwai e-newsletter
Wednesday, May 18, 2022 | Issue 06

Every Day is a Delicate Balancing Act

Reliably providing water to O‘ahu homes and businesses is no easy feat. It requires continuously balancing supply and demand to provide 145 million gallons of water every day.

The Board of Water Supply’s goal is to make sure water supply meets summer max day demand. The BWS has a complex water system to help in this effort. The BWS water system is composed of five shafts, 194 groundwater well and pumps, 13 treatment facilities, 13 tunnels, 192 booster pumps, 172 potable water reservoirs and 2,100 miles of pipeline that service 21,000 fire hydrants and 170,000 customers islandwide.

Many BWS customers may not realize what takes place behind the scenes. Decisive, quick actions ensure a steady, uninterrupted supply of water. For example, when the Halawa Shaft and the Aiea and Halawa Wells were shut down as a result of the Red Hill water contamination crisis, the BWS team was able to maintain a steady supply of water by redirecting water from the Waipio, Pearl City and Honolulu pumping stations. The BWS team is also completing repairs to the Kalihi pump station and Kalauao Wells so that they can be brought back into operation to increase water capacity. It’s all seamless to customers!


WaterWisdom Wednesday


Bryan Andaya, Chair of the Board of Water Supply’s board of directors, shares more details about the work of the BWS team on a recent WaterWisdom Wednesday on Hawaii News Now.


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Defining a "Alert" Water Shortage Condition

An “alert” water shortage condition is a serious situation. It means the BWS pumps have to operate longer to meet max day water demand. It means water conservation, even if it’s voluntary, must be taken seriously.

What triggers an “alert” water shortage condition? Every pump within the BWS water system is capable of pumping different amounts of water. Some have large capacities; others have smaller capacities. Standby pumps are available to ensure dependable water service should pumps suddenly fail or require preventative maintenance. When the Halawa and Aiea pumping stations had to be shut down, it placed a greater burden on the remaining pumps and there are water quality and regulatory limits that cannot be exceeded. The remaining available pump capacity has been significantly reduced below standards.   

Ideally, these pumps operate for 16 hours a day or less. When the pumps have to be kept in operation for longer periods — 20 hours a day to keep up with water demand, an “Alert” water shortage condition, — this is a telltale sign that conservation is necessary to reduce water use. When a pump is used for 22 hours a day or more, our water supply has reached a “critical” water shortage stage, and progressively restrictive conservation measures are required to avoid low water pressures and disruptions of water service.


Preparing for Summer

Before the Red Hill water contamination crisis, the Board of Water Supply was able to successfully balance water supply and demand. Even during the hot, dry summer months, when water use typically goes up, everyone’s water conservation efforts has helped to maintain that delicate balance.

This year, water conservation is especially critical. It’s vitally important for everyone to conserve water now — before we head into the summer months — to avoid a water shortage. In addition to the fallout from the Red Hill water contamination crisis that has resulted in less available water, Oahu is experiencing half as much rainfall as in previous years. For example, in February 2022, O‘ahu experienced 51% of normal rainfall, in March 2022, 46% of normal rainfall and in April 71% of normal rainfall.


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Posted: 05/18/2022