Overview

This project will retrofit the Sprinker Recreation Center Parking lot to address water quality and reduced in-stream flow in Spanaway Creek. The Sprinker Recreation Center Parking lot is approximately seven (7) acres of impervious surface. This project will enhance infiltration of rainfall and ground water recharge to improve base flows in Spanaway Creek, reduce peak flow discharge into Spanaway Creek, and reduce the pollutants associated with runoff from conventional asphalt parking areas. Stormwater from the parking lot is currently captured by a series of storm drains and pipes connected to a 30-inch conveyance system along Military Road. The 30-inch pipe discharges directly into Spanaway Creek, approximately 1,000 feet west of the parking lot.

Project Overview (pdf)

Project Objectives:

• Recharge groundwater and enhance in-stream base flows. This project will retain and infiltrate parking lot runoff and will reduce direct runoff discharge into Spanaway Creek.
• Improve water quality prior to infiltration with selected LID techniques such as porous pavement and bioretention facilities to treat the stormwater prior to infiltration.
• Demonstrate low impact development and stormwater retrofitting techniques.

Phase 1 / Pilot:
The Sprinker Low Impact Development (LID) Phase 1 project constructed a bioretention facility and repaved a portion of the parking lot using porous pavement. The project replaced 6,700 square feet of impervious pavement with porous pavement and replaced 3,700 square feet of impervious pavement with a bioretention facility. The improvements infiltrate runoff from approximately 1.7 acres of the parking lot into the well-drained Spanaway type soils underlying the site.

Low Impact Development (LID) in the Sprinker Parking Lot Brochure (pdf)

Phase 2:
This project will consist of retrofitting the remainder of the parking lot and construction of improvements including bioretention facilities and porous pavement. Results from the pilot project are being incorporated in the design of Phase 2 improvements. This project will be monitored for effectiveness.

Low Impact Development (LID) in the Sprinker Parking Lot Informational Sign (pdf)

Phase 1 Final Construction Plans (pdf)

• Cover Sheet
• Summary of Quantities
• Plan Sheet
• Bio-Retention Grading Plan
• Cross Sections and Details
• Planting Plan