The $1.9 million project repaired and replaced substandard electrical ducts, aged water lines and other deficient utilities beneath Sid Snyder Avenue, the primary entry point to the historic Capitol Campus. The project began in August 2014 and was completed in December 2014.

A jumble of utility lines removed from beneath Sid Snyder Avenue. The long pipe in the foreground is an original cast iron irrigation line with a connection to a modern PVC pipe.

Accomplishments

• Upgraded failing, substandard potable water, sewer, high-voltage electrical and irrigation lines to meet current standards and codes.
• Installed a state-of-the-art stormwater management system to reduce the amount of polluted surface water runoff that washes into Capitol Lake and Puget Sound.
• Added 33 trees of various species and nearly 3,300 native plants along the street edge to frame views of the Capitol Building and filter polluted runoff through the new stormwater system.

Challenges

• Sid Snyder Avenue is one of the oldest streets on the Capitol Campus. The water lines were nearly 80 years old. Some of the utilities, including primary power lines, were at high risk of failure.
• Over the past decades, modifications were cobbled together resulting in a mix of dissimilar utility lines.
• Opening up the ground beneath the road exposed many failing and substandard utility lines. It also revealed many 'must-do' but unanticipated repairs.
• The unforeseen conditions caused delays made worse by bad weather including above normal rainfall in October and November. These conditions interfered with pouring concrete for the new road surface.

Stormwater management system

Among the most visible parts of the project was the construction of a new, cutting-edge stormwater management system that will reduce the amount of polluted surface water runoff that washes into Capitol Lake and Puget Sound. The new stormwater system consists of seven small bioretention cells that appear as shallow depressions along the north side of Sid Snyder Avenue.

More than 3,000 native shrubs and small trees were planted in the cells to help filter and clean surface runoff during rain events before the water reaches Capitol Lake and eventually Puget Sound. After a few years growth, the planted cells will become a subtle feature of the west campus.

When it rains, the surface water that flows across urban yards and parking lots, streets and driveways often picks up and carries toxic chemicals and other pollutants. The contaminated runoff then washes, mostly untreated, into nearby lakes, rivers or coastal waters where it can harm plants, wildlife and habitat areas.

In addition to the plantings in the stormwater management system, the project added 16 Autumn Blaze maple trees along each side of the avenue. Over time, the trees will form a leafy gateway to the Capitol. Autumn Blaze is a fast-growing hybrid tree adaptable to a wide range of climate and soil conditions, according to Washington State University Extension. The leaves turn bright orange-red in the fall.

The landscaping is consistent with the original Olmsted Brothers plans from the 1920s but incorporates mostly native plants and modern disease-resistant and drought tolerant species.