As the Port Townsend City Council unanimously approved the 2019 stormwater management plan April 1, city officials speculated on the impact of climate change on the city’s water supply.

After no members of the public took part in the evening’s public hearing to discuss the stormwater management plan, council member Bob Gray observed spring rainfall levels for the city are among “the driest I’ve ever seen,” and wondered aloud whether anyone had any data on that.

City Engineer Dave Peterson, who had summed up the stormwater management plan’s aims as “preventing flooding” and enabling “stewardship of the environment,” had nothing to add.

But Public Works Director Greg Lanning said snowpack levels are “less than normal” compared to the past “20 or 30 years.”

Lanning further cited findings from the National Oceanic and Atmospheric Administration showing that temperatures for the coming three months are expected to be warmer than normal as well.

“So not only do we have less snowpack, but it’s coming off earlier than before,” Lanning said.

While Lanning expects rainfall levels in the autumn to make up for this enough for the city to “get through, he noted the need for the city and the Port Townsend Paper Mill to expand their water storage and conservation options.

According to Peterson, it’s not the amount but the intensity of rain that is a key factor.

Peterson welcomed more data on how such action interacted with similar phenomena, such as rising sea levels.

When Lanning repeated comments from reservoir staff, regarding how dry they’d found last fall, council member David Faber asked, “Are they saying it’s worse than the summer of 2015?” referring to the year Washington declared a drought emergency after a record-hot July.

“They’re comparing it to that, let’s put it that way,” Lanning said.

City Manager David Timmons offered the additional observation that a factor deserving of more study is the “duff” levels of decaying vegetation on forest floors.

“The duff arguably counts as another form of a reservoir, because it absorbs water and then re-releases it gradually,” Timmons said. “One of the things they found, in the wake of the (Olympic Peninsula) fires, was that the duff had dried out.”

The stormwater management plan update is intended to plot a course for the system’s future.

The update to the plan includes updated performance standards, which recommend policy and regulatory updates in anticipation of stormwater practices and regulations continuing to evolve.

The city plans to use the stormwater management plan for day-to-day development reviews, operations and long-term planning, whose objectives include:

• Updating and defining drainage connectivity and mapping.

• Preparing updated policies for protecting the natural and built drainage system.

• Describing approaches to protect and improve the existing roadway drainage system.

• Preparing standard designs for future road drainage infrastructure.

• Assessing the existing impacts and potential changes due to new development.

• Preparing concept designs for capital projects to address existing stormwater problem areas.

• Preparing site development information and reviewing materials, including low impact development measures.