Hearing examiner told under‑building parking is infeasible at Silverdale site because of shallow artesian aquifer, cost and building-code impacts

Kitsap County’s hearing examiner heard testimony June 2 that under‑building (subgrade) parking is not feasible for the Silverview multi‑family project in Silverdale because of a shallow artesian aquifer on the site, substantial added construction cost and code requirements that would change the building form.

The applicant’s hydrogeologist, Michael Pialski of TerraPhase Engineering, told the examiner that borings on the property encountered artesian conditions at roughly 23 feet and 28 feet below grade and that deeper or wider excavation would increase the risk of an uncontrolled artesian breach. “I don’t recommend digging any deeper,” Pialski testified. He said his remand analysis evaluated an additional 6‑foot excavation scenario provided by the project’s structural engineer and concluded the deeper cut would create “an unacceptable risk” because the glacial till cap over the aquifer would be substantially reduced.

Why it matters: the county remanded the project to clarify feasibility of subgrade parking and the extent of wetlands. If under‑building parking were required, the project team said the site’s geology and building‑code constraints would force design changes that significantly raise costs and alter the planned garden‑style apartments.

Most important facts

- Hydrogeology: Pialski testified borings B-5 and B-6 (drilled for the project) encountered water at about 23 feet and 28 feet below grade; he said artesian pressure and limited depth to the aquifer make deeper excavation and wider foundations risky because the till cap can be breached and an uncontrolled flow may follow. He used a conservative 6‑foot extra excavation in his remand calculations and advised against any deeper work.

- Structural and code effects: Architect and design consultant Mike Miller and architect Paul McCormick said putting two levels of structured parking under the four‑story garden‑style buildings would force a fundamentally different building: wider and taller, with internal corridors and elevators to meet travel‑distance and life‑safety code. Miller said that switching to double‑loaded corridor buildings with elevators converts a 39‑foot‑wide garden building into something nearer 65 feet wide, with transfer beams and additional foundations that complicate structure and excavation.

- Elevator and technical constraints: Witnesses said typical commercial elevators require a pit (commonly about 4 feet) and that “pitless” commercial elevators are not available for this building type; elevator pits and under‑garage clearance add several feet of required depth. Accessible (van) stalls require higher clearances (98 inches at entries). Miller and others said these requirements mean two levels of subgrade parking would add about 6 feet (structure and services) plus another roughly 4+ feet for elevator pits and related equipment — a material increase in excavation depth.

- Cost and market feasibility: Architect Miller and firm principals cited industry cost estimates that structured parking under a building in this region typically adds roughly $60,000–$70,000 per stall (contractor estimates and cost‑estimator inputs), while the appellant’s expert had cited a lower, national figure near $30,000 per stall based on a different set of caveats. Miller and Paul McCormick said the applicant’s market analysis (included in the record) shows the additional construction cost would push required rents above what the Silverdale market can support and would make the current, garden‑style, “missing middle” housing concept infeasible.

- Alternative designs: The applicant’s witnesses examined several alternatives (offset podiums, partial parking under a podium, two levels of parking, partial ramps), but testified that offsets or podium solutions carry large structural transfer costs and ventilation/lighting impacts (exposed parking screens and headlights), and still would not avoid deeper excavation near the aquifer. The applicant offered to present experts and evidence to show the under‑building options are infeasible; the examiner allowed the evidence presentations on remand.

Quotes

- “I don’t recommend digging any deeper,” Michael Pialski said about excavation below the conservative 6‑foot increase his team evaluated.

- “It would not be feasible. It would cost too much,” architect Mike Miller said when asked whether the project could absorb the cost and design changes needed for structured parking.

- “The project we have proposed is perfect for this region,” Paul McCormick (Innova Architects) said, arguing the garden‑style design meets Silverdale design goals without requiring subgrade parking.

What was not decided

No final land‑use decision was made at the hearing. The hearing on remand is fact‑finding; the examiner will take evidence and later issue findings and a written decision. The county and other parties may submit additional materials as ordered by the examiner.

Background and context

The Silverdale design standards encourage under‑building parking where feasible, but the project team and county staff told the examiner that “feasible” must be interpreted in context: geology, code, design standards and local market economics. Witnesses also noted recent state policy debates and legislation intended to reduce mandatory parking minimums because subgrade parking raises housing costs — a factor the applicant cited in arguing for the garden‑style approach.

Looking ahead

The remand hearing continues on wetland questions and other outstanding issues. The examiner and parties said additional filings or a short record‑closing period may be allowed so opposing experts can respond to new evidence produced during the remand hearing.