Now that the rains have returned are you seeing stormwater causing any problems for you and your property?

The problems can include:

• Downspouts that pour water on the ground next to the foundation of your home or business
• Downspouts and stormwater flow that create muddy messes
• Plugged stormwater drains
• Large flows of stormwater, creating erosion
• Excess stormwater flowing onto steep slopes, contributing to landslides

One option for controlling downspouts pouring stormwater on the ground, next to your building, is to install properly sized rainwater cisterns at downspouts. Those cisterns can store the downspout water and avoid the initial muddy mess sometimes made by downspouts pouring water on the ground.

They can protect the foundation of your building from water damage. Depending on the space and your interests, that rainwater can be used to irrigate part of your landscape. The Seattle Conservation Service is a good local source for 200-gallon rainwater cisterns: tinyurl.com/ms2bnm8p.

Another option for controlling and using downspout water or other flows causing problems is to direct it into a professionally-designed rain garden. A rain garden is a lower section of your garden that includes plants well adapted to the varying water conditions provided by downspout water.

Professionally designing one requires a number of steps that you can learn more about from the Western Washington Rain Garden Handbook — available free at tinyurl.com/bddw3fh2.

Most plugged storm drains can be unplugged easily, and then a wattle can be installed around the drain to protect it from being plugged again. Wattles are just tubes of straw that can be anchored in place around a storm drain to prevent blockage and filter the stormwater.

You can learn more about wattles here.

There are also hidden or less obvious problems with stormwater:

• It can pick up tire particles off roadways and deposit those particles in island streams where they can be harmful to salmon and other wildlife.
• Stormwater can pick up other pollutants including a class of pollutants called PFAS, and deposit them in island streams, and eventually, the Salish Sea — where they also can be harmful to salmon and other wildlife.

For many years, scientists have known or suspected that something in streams and rivers was harming salmon besides just the silt that can smother their eggs. The chemical in the tire particles that can be picked up by stormwater, and cause harm to salmon, is called 6PPD.

A team of researchers from the University of Washington and Washington State University studied many chemicals and eventually determined that the harmful culprit was the 6PPD chemical in tire particles. Find out more here.

Now that we know this, it makes the case much stronger for installing systems to filter out those tire particles before the stormwater containing them reaches salmon-bearing streams or before it exits into the Salish Sea.

Thankfully, we now have a lot of working examples of filtering and diverting systems that can perform that task. Those systems include rain gardens, green roofs, vegetated swales, permeable pavement, porous concrete, and more.

Another pollutant that scientists have learned a lot more about lately is the class of pollutants referred to as PFAS or “forever chemicals.”

They are called forever chemicals because they do not break down quickly or easily. Unfortunately, a growing body of science has determined they can be harmful to wildlife and humans — and they are widespread in many of the products that most of us use, and usually not eliminated by wastewater treatment plants.

But running stormwater through one of those filtering systems mentioned above, or even simply good soil with a lot of organic content, provides a way to stop those chemicals from getting into the water where they could usually create more harm. Of course, the downside of running the PFAS-contaminated water through one of these filtering systems is that after doing so, that soil should not be used for growing food. And if that soil does not hold onto the chemicals, it could allow them to transfer to the groundwater and to the drinking water supply.

So the best long-term solution is to learn which products have PFAS chemicals and look for alternative products that do not contain them.

The following website of Washington State University has some good ideas on addressing stormwater also: ruralstormwater.wsu.edu.

Rainscapes is a King County program that sometimes funds stormwater projects, depending on what you plan to do and the availability of funds. Find out more here.

If your property is connected to the Vashon Sewer District or located in the Shinglemill Creek watershed of downtown Vashon, I can provide free consulting help for you on your stormwater and your landscape. My help will be customized to your interests and your property. You can contact me at mlaurie@mindspring.com.

Michael Laurie is a sustainability consultant who has lived on Vashon since 1998.