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Replenishing our parched aquifers

Tom Farkas, PG | 05 Aug 2015 | Comments

The CBS News Program 60 Minutes developed an interesting segment titled “Depleting the water” which chronicled the depletion of groundwater supplies in several drought stricken agricultural areas throughout the world. Water levels are quickly falling as a result of little to no natural replenishment (recharge) through rainfall, coupled with increased groundwater use to sustain agriculture. In the US and California specifically, aquifer water levels have dropped in excess of 200 feet just in the last few years from the most recent drought. My colleague Mike Woolgar also recently commented on distressed aquifers, highlighting the issue of lack of control and regulation on how much water is being drawn from these reserves. As both the US and world’s population continues to grow, the demand for food will undoubtedly increase, putting further stresses on water supplies—especially groundwater supply.

It’s an important issue that we can’t afford to ignore and steps to replenish these valuable assets are currently being made through water reuse. The Orange County Water District in California (also highlighted in the 60 Minutes piece) is now taking steps to replenish or recharge its aquifers, implementing a 96 million gallon per day recharge program using highly treated wastewater from its sanitation plant. And in my work at Atkins, I’ve been busy supporting our client’s aquifer recharge programs—especially in Florida where reclaimed water recycling has been practiced for more than 30 years.

I recently led an Aquifer Storage and Recovery (ASR) project, assisting the City of Palmetto, Florida in enhancing the citywide reclaimed water system that services both residential and commercial customers. In the past, The City of Palmetto had to periodically discharge a portion of its reclaimed water into Tampa Bay because they lacked enough storage to capture it all during the rainy season.

The City looked at various storage alternatives to avoid water shortages during the dry season, and ultimately decided that utilizing aquifers made the most sense. We then designed and constructed a well to recharge, store, and recover excess reclaimed water in the Upper Floridian Aquifer. During the rainy season, approximately 2 million gallons per day of reclaimed water, from the Palmetto wastewater treatment facility, is pumped down to depths between 400 and 600 feet below the surface for storage and later recovery. The aquifer will hold upwards of 100 million gallons of Palmetto’s excess reclaimed water annually with an expected recovery volume of 50 million gallons (during the dry season), allowing Palmetto to meet its growing water needs.

To make the best use of our water resources, we must take note and plan early. The startup of this ASR system in March 2015 was the culmination of a 5-year project period that began with design, permitting, construction and hydrogeologic testing. And operational testing will take place over the next few years.

It’s critical that we not only plan for our current water needs, but we must factor in future population growth and climate change to find smart solutions that will work many decades into the future. No matter your role—engineer, planner, city manager, or a general water user—it’s everyone’s responsibility to be a good steward of our precious water resources. Through conservation, reuse, and smart infrastructure decisions, we can all make a difference.

City of Palmetto, Florida Aquifer Storage and Recovery Project
City of Palmetto, Florida Aquifer Storage and Recovery Project