HAH Expansion/Second Supply Project

This field may be checked to activate Phase 1 of the Tacoma Second Supply Project. Phase I expands HAH capacity by 25,000 ac-ft to a storage of 50,400 ac-ft (approximate stage elevation of 1,167 ft). 20,000 ac-ft of the increased storage is allocated for municipal water supply and will be stored during the spring to be released during summer and fall. The remaining 5,000 ac-ft is allocated for low flow augmentation to benefit fish habitat. This option also activates Pipeline No. 5, which will distribute the additional water supply.

Note: The model will more accurately reflect the system if the Secondary Supply Project and Green River HCP are implemented together.

Green River HCP, Phase I

This option will implement a change in operating policies designed to improve Green River habitat. The flow requirements designated by the HCP will become binding at the end of 1999. Previously, the only binding requirements were the Corps baseline flows of 110 cfs.

Cedar River HCP

Activating the Cedar River HCP will instigate the Instream Flow Agreement, which creates binding instream flow requirements on the Cedar River, measured at Landsburg. The binding flow requirements designated by the HCP will become binding at the end of 1999. Previously, Seattle Public Utilities honors non-binding instream flow requirements are those designated by the Department of Ecology as part of the Instream Resources Protection Program (IRRP). .

1% Conservation Per Year

Selecting this option initiates a one percent per year demand reduction each year for 10 years. Seattle Public Utilities and their purveyors have agreed to begin this initiative during the spring of 2000.

Use Wells

This option should be activated.

Highline Well Capacity

This option should stay at its default value of 10 mgd. As of now, there are no plans to expand this.

Tolt Pipeline II

This option, which should be activated, is an additional pipeline from the Tolt water supply. This project will also include construction of a tieline between the new and older Tolt pipelines. This option implements the addition of the Tolt Pipeline II, which has a capacity of 120 mgd. The pipeline will be online late in the year 2000.

Elevation at 1710

Activating both of these options allows the user to incorporate the Tolt Filtration Plant (TFP) into the simulation. By reducing turbidity, this plant will increase the amount of potable water available from the Tolt Reservoir. Current plans allow dead storage to be reduced to 1710, but future plans include gaining additional water supplies by reducing the elevation to 1690. The plant will be online by late 2000.

Tolt Relies on Cedar

This option should be activated. With this option selected, flows in the Cedar and storage in Chester Morse Lake determine critical fish flows.

Section 1135

This option, which increases HAH reservoir storage is not activated. By implementing the HAH/Secondary Supply project, this option becomes displaced.

Expand Tideflat Groundwater

This option should be activated to increase Tideflat Groundwater pumping capacity by 5 mgd. This well is included in the group of In-Town Wellfields (including Gravity and Tideflat Wellfields) with a maximum capacity, without this option, of approximately 14 mgd.