Choosing an Option for Design

The project design team developed a limited engineering evaluation for each option. This evaluation took a high-level look at a variety of factors including cost, community impacts, tree impacts, feasibility, constructability, benefits, and long-term operations and maintenance. SPU assessed the information and our subject matter experts on urban streams and habitat provided additional thoughts on how SPU would implement some of the design ideas. Additionally, our subject matter experts weighed in on the expected maintenance activities with the resources and skills of our office and field teams in mind.

To decide on an option, SPU used a Multi-Objective Decision Analysis (MODA) Tool. The SPU MODA Tool includes developing project-specific criteria that quantify performance metrics and qualitative values, called the Performance Criteria.

Stakeholder community values are reflected in the Performance Criteria based on engagement and outreach. Together the criteria define the project problem and can be used to evaluate the project options. Non-differentiating criteria are not included.

 

SPU and SPR met several times to discuss the preliminary options and the expected performance of each option. The parameters for each preliminary alternative were compared to form a basis of understanding of each option’s performance against the criteria. These parameters included, for example:

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• Construction cost

• Construction risk

• Operations & Maintenance activities

• Operations & Maintenance cost

• Feet of restored creek

• Tree impacts

• Wetland impacts

• Construction Duration

• Other impacts (such as Lakeridge Playfield closures)

Following these discussions, the options were scored. City of Seattle staff from both Seattle Parks & Recreation and SPU developed the criteria to score the options and then scored each option through a survey. The results of the scoring, reported as the Value Percent are plotted against each option’s total project cost in the below graph.