Orange County Branch Newsletter

February 2018

ASCE OC Younger Members Forum

GWRS & Anaheim Recharge Basins Technical Tour

By Josue Candelario

One of the biggest questions for Orange County today is how will we meet our water demand tomorrow? The Orange County Water District (OCWD) is the public agency tasked with tackling this problem and has looked at OC’s existing groundwater basins as part of the solution. This public agency is the leading water authority for the OC Groundwater Basin, the Santa Ana River, and the Groundwater Replenishment System (GWRS). Through a partnership with the Orange County Sanitation District (OCSD), OCWD has developed a dependable water supply that would otherwise be left untapped.

On Friday, December 8th ASCE OC YMF toured the GWRS facility and the Anaheim Recharge Basins. The tour began at the GWRS facility with Benjamin Smith, P.E., giving a presentation on Orange County’s water supply and its water reuse system. In short, he explained how water flows down from the Santa Ana River where it is diverted to the Anaheim Recharge Basins. Water infiltrates into the ground at the basins where it is filtered naturally. The water is then pumped from underground, treated, and distributed to different cities and agencies within Orange County.

Ben Smith Presenting on Orange County’s Water System

To supplement the existing water supply, OCWD built the GWRS facility which provides 100 million gallons of additional water. This facility makes use of a water source that would otherwise be left unused. The process begins at the OCSD where wastewater is treated and sent to the GWRS facility to receive advanced purification. The different processes for purifying the water are microfiltration, reverse osmosis, and UV disinfection. When the process is done the water is mineral deficient making it highly “unstable”, which means the water will strip any minerals it comes in contact with; hence consuming only highly purified water will strip your body of its essential minerals and make you sick.

Ben Showing the Filter Used During Microfiltration

From the GWRS facility the group traveled to the Anaheim Recharge Basins where we were given a more in depth look at the ponds. The main purpose of the ponds is to serve as an infiltration medium for water to replenish the ground aquifer. In addition, one of the ponds is used for recreational fishing for the added benefit to Anaheim residents. Since the creation of the ponds several bird species, some of which are endangered, have decided to take permanent residence at the basins. For this reason, the Anaheim facility must always be aware to not disturb any of the wildlife during maintenance of the ponds.

During seasonal maintenance, the water is transferred from pond to pond allowing for heavy machinery to remove vegetation and sediment. As a preventative measure to keep sediment from reaching the ponds, diversion berms are placed inside the Santa Ana River in a snake like pattern. This allows for water to travel a longer distance before reaching the ponds and therefore increasing the settling time. Further upstream, a rubber dam is located to control the water level and regulate the flow. By restricting flow the water level rises high enough for water to pass through a trash grate which is cleaned by an automated claw. This prevents trash and debris from entering the ponds downstream.

Rubber Dam in Santa Ana River

Automated Trash Grate

It was great to meet the faces behind the scenes and see how this great example of water reuse works. On behalf of ASCE OC YMF, we would like to thank everyone at the GWRS and the Anaheim Recharge Basin facilities for showing us around.

Group Picture Inside of the Reverse Osmosis Membrane Facility

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