Bainbridge Island is an EPA-certified “sole source aquifer,” obtaining all its water from aquifers that are “recharged” almost entirely (∼95%) by rainfall.  For that reason, the entire Island is designated as a “Critical Aquifer Recharge Area.”  Development, by creating impervious surfaces, increases rainwater “run-off” and reduces aquifer “recharge,” while also increasing water extraction.

See City of Bainbridge Island (COBI) Groundwater Fact Sheet: https://www.bainbridgewa.gov/DocumentCenter/View/15376/Groundwater-Fact-Sheet?bidId=

Well Monitoring Data (reflecting effects of past water extraction) already show Significant Aquifer Depletion, based on our existing population (∼25,000 people).  Water levels have been declining in COBI’s major production wells, and in at least one of KPUD’s major wells.  Table 1 shows declines in the deep Fletcher Bay Aquifer (FBA), which provides about one-third of the Island’s water.

The declining water level in this critically important deep aquifer (FBA) means that extraction is happening at a faster rate than its ability to recharge, even at our current population level.  There is also evidence of decline in the Island’s other, shallower aquifers, which provide water for most private wells and for surface streams that support wildlife and sensitive wetlands.  A clear sign of unsustainable stress on the shallow aquifers is the order from Washington State Dept. of Ecology closing portions of the Fletcher Bay and Murden Cove watersheds to new wells due to alarming reductions in surface streamflow. (Ironically, while COBI plans for growth that will further diminish aquifer levels and streamflow, the State spends millions to install larger culverts in the hope of restoring salmon runs!)

Depletion of Island aquifers is further evidenced by the following:

• 2015: COBI’s Commodore well was over-pumped by the City and essentially “mined out”;
• 2016: KPUD drilling for SB #9 in Lynwood failed, producing only a small amount of water;
• 2023: KPUD drilling for SB #11 at Gazzam Lake failed to find water; that effort was abandoned;
• KPUD’s failed efforts for major production wells at SB #9 and #11 cost the utility ∼$500,000;
• 2025: drilling by Wing Point Country Club for new production well failed; another dry hole.

Similarly, Groundwater Modeling (reflecting effects of expected future growth and climate change) by COBI’s own water consultants (EA Engineering, Science, and Technology, Inc.) projects Continued Unsustainable Aquifer Depletion.  An EA presentation to City Council in February 2025 showed the following expected drops in the Sea Level Aquifer, and EA’s April 2025 Technical Memo showed the following expected drops in the FBA, under EA’s “Low-Mid Impact” and “Mid-Impact” scenarios:

Expected Declines in Sea Level Aquifer Under Low-Mid Impact Scenario

Expected Declines in Fletcher Bay Aquifer Under Mid-Impact Scenario

While these declines were described by the City’s Public Works Director as “sustainable outcomes” at the February 11, 2025, City Council meeting, in reality they are evidence of unsustainable and irresponsible “aquifer mining.”

In July 2025, EA provided this Summary of its Groundwater Modeling Findings:

COBI Draft Groundwater Management Plan and Summary available on City website at: https://cityofbainbridgeisland.civilspace.io/en/projects/groundwater-management-plan

Note that under the Mid-Impact Scenario, the FBA may decline an additional 16 feet in the 0-20 year timeframe.  In the 20-50 year timeframe, a possible 37-foot drop puts the mean groundwater level of the aquifer below sea level (resulting in sea water intrusion), with central and south end production wells experiencing 60-foot decreases.  These declines are based on the EA Model assuming a population growth of 8,380 new residents over the next 20-year period (419 new residents per year; see Summary page 7), with a similar trajectory thereafter.  But the COBI Planning Commission is advancing zoning changes for even greater population growth over the next 20 years, beyond 8,380, and well beyond the 4,524 target set by the Washington State Growth Management Act, upzoning the Ferry and High School Road districts to accommodate ∼10,000 new residents Island-wide (those two districts + existing capacity on the rest of the Island).  Moreover, in June 2025 COBI City Council directed the Planning Commission to continue to upzone additional districts of Winslow, which if adopted would further increase population growth and result in even greater depletion of the Island’s aquifers and greater reduction of surface streamflow.

In addition to the water supply issue, which is of primary importance, the infrastructure costs of supporting such growth will create extraordinary burdens for Island residents, with serious displacement effects.  Water rates for residents have already gone up significantly in 2025, with additional rate increases scheduled for the next several years, and plans for additional wells and water-related infrastructure will impose substantial new costs on Island taxpayers.  Island residents should not be expected to subsidize growth they do not want, at levels that exhaust the Island’s aquifers and other resources, degrade the natural environment, choke the roads with congestion, and destroy the small-town quality of life that Island residents have made clear they wish to preserve.  But even if all these other adverse consequences of COBI’s irresponsible growth strategy are disregarded, the sustainable management of the Island’s aquifers – the source of its most precious natural resource, water – must take priority over all other planning goals.