Spokane tackles toxic fire runoff with wattle bags and drain filters

SPOKANE, Wash. — As rain continues in the forecast, Spokane city officials are taking action to prevent toxic runoff from fire-damaged properties from contaminating the city’s storm drain system and groundwater.

The city is deploying two primary methods to manage storm water runoff: wattle bags filled with hay or compost, and cloth filters placed over storm drain openings.

Wattle bags serve as barriers to catch debris and toxic materials before they flow down driveways into roads and storm drains. The bags also slow water movement, reducing the risk of mudslides in affected neighborhoods.

“We want to make sure that those harmful chemicals don’t get into our stormwater system and impact our aquifer, which is our drinking source and then secondly our infrastructure. It’s, you know it takes a lot of resources to maintain that,” said Kirstin Davis, Spokane’s city communications manager.

The city prioritized neighborhoods situated on inclines, where stronger water streams are more likely to carry contaminants downhill. To date, approximately 600 wattle bags have been installed in driveways throughout Spokane.

When ash and water combine, they create a cement-like material that can clog pipes and damage infrastructure, leading to costly maintenance issues.

“If we have additional ash that gets in there and causes clogs and is difficult to clean, that adds a lot of maintenance time to those different pipes and is just, you know, it’s an extra cost that we have to build in,” Davis said.

The second mitigation strategy involves placing cloth filters between storm drain lids and the drain openings themselves. These filters trap large debris and toxic particles, preventing them from entering the underground drainage system.

City crews are actively monitoring the filters they’ve installed and will replace them once they become saturated with debris. Residents who have storm drains near their properties and need filters installed or replaced can contact the city by calling 311, and a crew will assist with the installation.