Crystal Mountain Resort Drainfield Expansion

(Crystal Mountain, WA)  Crystal Mountain Resort built a $2.5 million comprehensive wastewater treatment facility as part of planned major expansions and site improvements. The new facility, which includes one of the largest drainfields in Washington State, replaces a 1965 treatment plant and improves water quality by meeting current water quality standards for ground waters of the State of Washington for tertiary treated water effluent discharged to drainfields. Landau Associates provided hydrogeologic and geotechnical characterization services to support design and permitting of the subsurface disposal component of the treatment facility.

The primary project objectives were twofold: to develop a working hydrogeological conceptual model of the narrow alpine alluvial aquifer that would provide a reasonable basis for final design, and to address provisions of the Washington State Ground Water Quality Standards permitting guidelines, all known and reasonable technology (AKART), numeric standards, and anti-degradation standards.

Landau Associates conducted a field exploration program to develop a detailed site conceptual hydrogeologic model, which was the basis of analytical groundwater quality modeling.  The conceptual and water quality models provided a basis for a final conceptual design that would comply with state Ground Water Quality Standards. Specifically, the design addressed maximum allowable effluent loading rates and groundwater anti-degradation provisions associated with nitrate loading. The site conceptual model was used in conjunction with field data to estimate the impact of subsurface disposal at six different locations in the upper valley. Landau Associates also assessed stability of steep valley walls at the proposed treatment plant location. 

The new wastewater treatment facility paves the way for additional planned development, including expansion plans for a new hotel, while still meeting the resort’s environmental stewardship goals.