While exploring opportunities in the groundwater-surface water nexus could provide solutions to many water supply issues, it faces some limitations that could slow progress. Many of the challenges are understandably regulatory, since surface and groundwater have historically been treated as separate realms and this enters largely unchartered territory.
“It’s not that these regulatory agencies are opposed to the nexus, but they are responsible for avoiding any adverse impacts that could emerge from this approach,” Maliva said. “For example, they need to ensure that groundwater withdrawals do not impact surface water systems that depend on that water source for their supply.”
Also, water management and protection rules and regulations have been playing catch-up to the science.
Maliva observed one instance in Florida where an aquifer recharge system using surface water was required to treat the water to remove coliform bacteria and other pathogens at the wellhead. But over the past decade or so, significant scientific data has been collected showing that these organisms naturally rapidly die off in the groundwater environment.
“The cost for unnecessary treatment renders some systems that would provide water resources benefits economically unviable,” he added.
Every region and system presents its own specific challenges, but there is an overall need to apply sound science and adjust rules, regulations and policies so that the use of water resources can be optimized, while ensuring that public health and the environment are protected.
It is also important that maximum value can be obtained from all water sources and to increase the resiliency of water supply systems.
“It makes good sense to anthropogenically recharge excess surface water or reclaimed water that would otherwise not be beneficially used to increase the amount of groundwater available during high demand periods or droughts,” Maliva said. “This reduces discharges to surface water that may contain high levels of nutrients or other pollutants.”