Groundwater supply declining, study says

Islanders may want to keep a closer tab on their taps.

A city-commissioned study indicates that the island’s finite water supply is declining in some areas.

The island’s deepest groundwater supplier, the Fletcher Bay aquifer, showed some of study’s steepest declines, especially in the Eagledale and Sands Road areas. Linked in recent years to high-capacity wells, the aquifer meets about 30 percent of the growing population’s water needs. Another large portion of the island’s water supply is generated by several small wells linked to a sea level aquifer, which in recent years has had instances of saltwater intrusion due to over-pumping.

Bainbridge’s water supply has become a top concern for residents, dominating community priority surveys and City Council campaigns.  Despite widespread public interest, the island has lacked a comprehensive analysis of whether it can satisfy its increasing thirst.

“There’s a lot of concern on the part of Bainbridge citizens about the state of their aquifers and what they can do about it,” said Joseph Lubischer, an engineer who helped lead the study for Bainbridge-based Aspect Consulting.

While the study’s limited scope prevents it from offering definitive answers, it does indicate that the concerns were well-founded.

“The last 20 years have seen some big, deep wells go in,” Lubischer said. “So, we’ve seen some changes recently, and we have a limited amount (of water).”

Of particular interest is Island Utilities Well 1, which supplies much of the Eagledale neighborhood on Eagle Harbor’s south shore. The high-capacity well registered the study’s steepest drop, declining from about 40 feet in 1988 to 25 feet last year.

“The Eagledale area is a concern and bears further investigation,” said Erick Miller, the study’s lead hydrologist.

Some new wells appear to be draining the supply of older wells. The Meigs Farm Well experienced a substantial water level drop when two Sands Road wells began pumping in 1994, according to the study.

The Sands Road wells showed declines in recent years, indicating use was outpacing recharge. Although lower than in previous years, the Sands Road wells appear to have stabilized in 2005.

The study also indicated that saltwater has seeped into a handful of sea level wells, making for unpalatable tap water. Increased pumping of near-shore wells sucks out freshwater and draws Puget Sound in.

The scope of the saltwater problem is unclear, said Lubischer, and requires further study.

“We’ve seen this problem on Whidbey Island and Marisone Island,” he said. “So far, Bainbridge appears to have ducked the bullet, but the data’s not as tight as we’d like.”

The study relied on data provided by utilities and other sources. The quality and quantity of the information was inconsistent, limiting the scope of the study.

The study’s limitations highlight the need for better data collection and communication between the city, well operators and other government agencies, said city water resources specialist Jalyn Cummings.

The study’s chief recommendations include taking a closer look at water use in the Fletcher Bay aquifer and evaluating saltwater levels in wells within a quarter mile of the shoreline.

In areas where pumping is outpacing aquifer recharge, the study outlined several potential fixes, including water metering, voluntary water conservation, limitations on well drilling and other regulatory solutions.

3 thoughts on “Groundwater supply declining, study says

  1. It’s past time for Bainbridge Island to have applied for “sole source aquifer” status with the State. Public Works had an application ready 3 years ago, but it was never sent in & has since been lost.
    How close to the edge do we want to live? The bottom line for the island is that we’ve maxed out on population and must take steps to put a ceiling on growth first. Then, of course, lots of conservation options should follow.

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