Storing Water Underground for Future Use

What if you could save the water that falls in rainier seasons for use during times of drought? Scientists at Dow’s Terneuzen site in the Netherlands are working with farmers to do just that, and the solution may be found underground.

Dow Terneuzen and local farmers are working to implement underground water storage for drier seasons. The program is part of a wider effort to cut the site’s reliance on remotely sourced virgin freshwater to zero by 2025. Dow is currently sourcing freshwater to its Terneuzen site from the Biesbosch area to meet the site’s water needs.

To reach this ambitious target, Dow is actively working on water savings, recycling and reuse. Since the 1990s, the site has used treated municipal wastewater to generate steam for its manufacturing plants. Today, about 75% of the site’s water is from reused sources. To achieve 100% water circularity by 2025, the remaining freshwater will require investment in developing new technologies and strong partnerships on a regional level to balance the demand between the municipal, industrial and agriculture sectors from various water sources.

Finding alternative freshwater sources

That’s where Dow’s pilot project exploring underground freshwater storage capabilities comes in. In recent years, the Terneuzen coastal region has experienced long droughts during the summer months, while excess water falls in the winter and drains into the sea. As climate change intensifies, summers are expected to become drier and winters wetter.

Through a unique project supported by Freshwater Resources for Seas or Coastal Regions (FRESH4Cs), scientists from Dow Terneuzen are working to infiltrate rain water and store it in old creek ridges, where some farmers get their water. These creek ridges are in a higher-lying zone in a former tidal area. FRESH4Cs is a collaboration among 10 partners from the United Kingdom, the Netherlands and Belgium, with support from Intterreg2Zeeën and co-funded by the European Regional Development Fund.

“Potentially, those creek ridges can be supplemented with excess fresh surface water. In this way, we ensure that it doesn’t drain off to the adjacent sea but stays nearby for drier times,” said Niels Groot, an environmental specialist at Dow. “In the winter, we are going to infiltrate water into the subsoil. In other words, we are going to let the freshwater bubbles that are already there grow. If there is a dry period in May or June, then we can draw water from it.”

A technical study is looking at areas that would be suitable for underground freshwater storage based on a number of factors, including whether the soil and groundwater characteristics are suitable to infiltration and extraction without negatively affecting the surrounding area.

FRESH4C also is conducting field measurements to further select the best location for underground storage of water by sampling and analyzing subsoil and groundwater. In addition, a non-technical study is examining the required permits and the infrastructural needs to transport the water to end users. Based on these studies, a business case will be developed that defines the framework for managing the water system, such as pricing and ownership issues.

Farmers in the region have agreed to participate in a demonstration project, which ends in 2022. The success of the project will then be evaluated to determine next steps and whether the project can be deployed on a larger scale.

“We are looking for freshwater bubbles with subsoil that are suitable for filling, and the farmers are looking for ways and facilities to do this. With this cooperative approach, we spread the risk and share the benefits, if it turns out to be successful. If it succeeds, it creates a win-win situation,” Groot said.