Governor signs Dye's tree bill to cool urban heat-emitting coastal cities

OLYMPIA–On the warmest days in the summer, Seattle and other coastal cities can be as much as 17 degrees warmer than surrounding rural areas. The hotter temperatures not only affect the atmosphere, but create warm stormwater and sewage drainage that flows into Puget Sound, resulting in algae and risking fish populations.

A bill authored by Rep. Mary Dye seeks to address the problem by incentivizing the strategic planting of trees in urban coastal areas in Washington state. House Bill 1114 was signed into law Wednesday by Gov. Jay Inslee.

"Larger coastline cities retain heat from rooftops, pavement and other heat-absorbing materials, creating what is known as 'urban heat islands.' Seattle is ranked 10th in the nation for its urban heat island effect. These human-made canyons absorb heat, which not only drives up the costs for residents who use air conditioning, but the warmer stormwater runoff is detrimental to our environment," said Dye, R-Pomeroy.

House Bill 1114 establishes a program involving municipal electric utilities, PUDs or investor-owned utilities that engage in tree-planting activities. It also allows the utilities to solicit and use voluntary donations from customers to fund tree-planting programs. In addition, it would authorize the Utilities and Transportation Commission to adopt a policy to incentivize investor-owned utilities' tree-planting programs and cool roof programs that improve the efficiency of energy use.

"The bill is modeled after a successful tree planting and cool-roof program implemented in 1991 by the Sacramento Municipal Utility District in California. More than 600,000 trees have been planted in the Sacramento area since the program took effect, and the utility estimates that customers are saving as much as 40 percent on their cooling costs in the summer," said Dye. "This bill will reduce the negative effects of urban heat islands in our coastal Washington cities, and will improve the environment and quality of life."

The measure encourages municipal electric utilities and public utility districts to assist customers in the acquisition and installation of materials that would help reduce outdoor heat absorption and provide energy conservation. This would include tree plantings, as well as materials and equipment installed as part of a utility cool roof program.

"The Sacramento program provides a utility incentive in which customers can get rebates by participating and they save a lot on their power bills. Strategic planting of trees will create a cooler environment and reduce energy use, creating calmer, cooler cities," noted Dye.

The 9th District lawmaker says the bill is part of a longer-term plan she has to create "salmon-safe communities" by using trees, permeable building materials and other efforts to improve salmon habitat and reduce toxic runoff.

The measure takes effect July 24, 2021.

–John Sattgast