Sequim officials say groundwater monitoring reveals model gaps; city outlines deep‑well, reuse and rate changes

Sequim public‑works leaders told the Dungeness River Management Team that the city’s most recent water‑system review shows the utility is prepared for expected growth but has found inconsistencies between field data and the regional groundwater model.

“ We have 1,850 acre feet of certificated water rights,” said Paul Busich, Sequim’s public works director, as he summarized the city’s water‑rights portfolio and the recent review of the 2022 water‑system plan. City engineers said that a Port Williams supplemental allocation, Silverhorn wellfield production and the rainy collector well together support that figure, but Ecology has questioned earlier interpretations of how supplemental rights were counted in the 2022 plan.

Nick Dosti, Sequim’s utility engineer, reviewed system assets — three active well sites, roughly 3 million gallons of storage across three reservoirs, about 3,100 service connections and a reclaimed‑water network of roughly 4.75 miles of purple‑pipe distribution. “Our average daily production across the whole water system is about 1,080,000 gallons,” Dosti said, noting production and population growth have tracked closely over the last decade.

Sequim reported completing a deep test well in April 2024 at roughly 575 feet that targeted the third aquifer and modeled production near 800 gallons per minute. But monitoring during pumping showed previously unmodeled responses in upper aquifers and nearby monitoring wells. “Our data shows that those bathtubs, in fact, have holes in them,” Dosti told the group, describing the aquifers as more ‘leaky’ than the model assumes. City staff said that difference could mean the model underestimates impacts on connected surface water.

Sequim outlined three response options: accept the current model, perform a localized calibration for the city’s deep well, or invest in a full regional model update — a multi‑year, expensive undertaking. The presenters said they have discussed a phased approach with Ecology and Department of Health and that limited drawing from the deep well could proceed via a showing‑of‑compliance while broader modeling work is planned.

The city also flagged operational steps to reduce unaccounted water: following an AMI (automatic meter infrastructure) rollout, Sequim said it is changing irrigation‑meter procedures and billing practices to discourage misuse and reduce apparent losses. “We will no longer turn your meter on and turn your meter off,” Busich said, describing a new practice that shifts onus to meter owners to winterize and to monitor irrigation systems for leaks.

Sequim staff closed by noting capital priorities that feed the long‑range plan — a new reservoir, expansion to serve growing pressure zones and a booster station (design funded at $555,000) that would open service to roughly 3,300 ERUs — and asked partners to help fund and participate in any model‑update effort.

The DRMT scheduled Q&A and follow‑up; staff asked for coordinated participation from neighboring utilities and state agencies if a regional model update moves forward.