Grand Ridge Water System Modifications

Owner: Grand Ridge 18, LLC | Port Blakely

Client: Robert Fitzmaurice, P.L.S., Project Manager

The Issaquah Highlands Community Association (IHCA), as the owner of the Grand Ridge Water System, desired to improve system reliability and transfer ownership of the system to the City of Issaquah. The City and IHCA developed a memorandum of agreement governing the conditions of transfer which included addition of redundant storage tanks and revisions to the existing booster pump station.

CHS provided analysis of the system’s historic domestic and irrigation water use and forecast build-out demands. That analysis served as the basis for sizing two new storage reservoirs and replacement booster pumps. The design included replacement booster pumps and related station improvements, tank additions, piping revisions to facilitate station isolation and temporary bypass, electrical, telemetry and SCADA, reservoir site layout including 600 foot access road at 20% grade and vehicle turnaround on a constrained site, site fencing and security, pervious pavement design, reservoir site piping and valve and vault design for tank fill, discharge, draining and overflow.

CHS provided coordination with multiple agencies to facilitate transfer of ownership. City of Issaquah standards were utilized and City utility permits were obtained. King County clearing and grading and building permits were obtained and the project report was approved by the Department of Health. CHS also coordinated a geotechnical engineer’s analysis of the tank site, electrical and telemetry design by electrical sub-consultants, tank design by a tank manufacturer and surveying which included topographic and boundary survey, boundary line adjustment, easement creation and construction staking. Additionally, CHS provided project cost estimates and scheduling prior to construction.

Project Cost: Approximately $2,000,000  |  Funding: Homeowner’s Association & Private Developer

2012 – Current (2014)
CHS Staff:
Evan Henke, P.E., Principal
Eli Zehner, P.E., Project Manager
Nadine Firestine, P.E. Project Engineer
Josh Korakis, CAD Technician

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