As soon as the fall rains began, the intermittent headwater streams that were dry all summer flowed downstream into creeks, rivers, lakes and Puget Sound. Adult salmon that had been milling around in the sound have received the scent of their natal streams and are migrating from saltwater to fresh to spawn new generations.

In order for that remarkable process to be successful, wide riparian zones — vegetation next to streams — need to be covered with tall trees to provide shade that helps keep water cool for salmon.

Leaves and twigs falling from the tall trees and shorter understory vegetation provide organic nutrients for microorganisms that, in turn, become food for aquatic insects that fish and wildlife feed on. Trees and branches that fall into streams also create hiding places for adult salmon migrating upstream and, later on, their offspring as they migrate downstream to Puget Sound.

Riparian zones, function like sponges that help moderate stream flows and reduce floods, bank erosion and scouring of gravel salmon spawning beds. Root systems also absorb nutrients from surrounding watersheds and bind soil together.

Sadly, in rapidly growing urban and suburban areas around Puget Sound, upland forests, wetlands and riparian zones have been altered so much by development that they have lost much of their natural function.

As more of the watersheds that surround salmon streams are transformed into rooftops, parking lots, roads, shopping centers and housing developments, the volume of water in our streams increases very rapidly during rainstorms causing stream bank erosion and property damage.

Urban flooding is now a common occurrence, and many small streams have been encased in culverts.

When rainstorms arrive after long dry spells, roads and highways become slick with oil and other pollutants from our cars. Excess fertilizers, pesticides and herbicides from manicured lawns flush downhill. Pollutants from stormwater runoff have rendered many streams in Snohomish County streams unsuitable for kids to swim and play.

Except in north Everett where storm drains connect to the sewage treatment plant, every parking lot or roadside storm drain in Snohomish County leads directly or indirectly to a creek, stream, river, lake or Puget Sound.

And, during long duration high-intensity rainstorm events, some of Everett’s 13 sewer outfalls spew raw sewage along with stormwater runoff into Puget Sound. One way Everett is tackling this problem is to encourage north Everett property owners to reduce stormwater runoff into the sewer system by supporting rain gardens through its Let It Rain Program.

The cumulative effects of urbanization on micro-organisms and underwater insects that are the primary source of food for juvenile salmon has been devastating in urban and suburban streams.

The amazing silver salmon runs that used to be thick in Quilceda and Allen creeks between Arlington and Marysville are now just hanging on. Bear, Little Bear, North, Swamp, Lyon and McAleer Creeks that flow into Lake Washington from southwest Snohomish County are closed to salmon fishing because of depressed stocks. No fishing is legal in any of the numerous coastal streams between Everett and Edmonds. And pollution makes most of these stream unsuitable for contact recreation.

Replacing lost riparian zones is very challenging to say the least. However, it can happen. Snohomish Estuary restoration projects that are several hundred acres in size are underway thanks to a large collaboration between the Tulalip Tribes, local, county, state and federal agencies, as well as private individuals and organizations.

On a much smaller scale at the Northwest Stream Center in McCollum Park, the Adopt A Stream Foundation and Snohomish County Parks and Recreation restored three acres of wetlands from a parking lot that had been constructed on top of wetlands. Lost fish and wildlife habitat can be brought back!

We can also protect remaining upland forests and riparian zones in urban and suburban areas with improved development regulations, creative transfers of development rights and property acquisitions. And, with much less complex actions, we can mimic forest and riparian zone functions.

New development can be constructed using low-impact design techniques. A great commercial example is the Snoqualamie Ice Cream factory in Maltby. It is surrounded by a porous parking lot with an under-drain system and rain gardens that collect rooftop water runoff that infiltrates into the ground. There is no stormwater runoff flowing from that site.

On the residential side of the equation the Clearwater Commons is a unique housing development with homes surrounded by native plant landscapes and rain gardens that store and slowly infiltrate rainfall into the ground. Houses are constructed on concrete piers without the need to grade underlying native soils. No fertilizers, pesticides or herbicides or auto related pollutants drain into nearby North Creek from this housing development that has kept the creek’s riparian zone fully functioning. There, residents delight in watching salmon spawning in the fall.

Another positive note: Snohomish County is in the process of revamping its land use regulations to require low-impact designs on new development as early as 2015. All local governments will have to follow suit by the end of 2016 per directions from the state Department of Ecology. That’s a good signal for salmon.

Is there anything that we can do to reduce the negative affects of stormwater runoff from the large expanses of already developed property? What can we do to mimic the lost watershed functions? I recommend that Snohomish County establish a Salmon and Trout Relief Fund that provides owners of developed property small grants and technical assistance to reduce their stormwater runoff.

This concept is not new. In King County and Seattle (Rainworks), Lake Forest Park (Environmental Mini Grants), and Shoreline (Soak It Up), grants and technical assistance are available now to owners of developed land interested in reducing stormwater runoff and restoring fish and wildlife habitat.

There, property owners receive support to convert lawns into conservation landscapes. Imagine: no need for fertilizers, pesticides or herbicides and no mowing required! Rooftop downspouts drain into rain gardens where rainwater percolates into the ground instead of storm drains. Riparian zones next to creeks are being restored one lot at a time. It can happen in Snohomish County too.

With $6 million in revenues from an existing Urban Growth Surcharge Fund already collected from stormwater management fees, Snohomish County could provide the same services as our neighbors to the south without any new financial burden.

Want to send a good signal to salmon? Call 425- 388-3494 or email your County Council representative and request the establishment of a Salmon and Trout Relief Fund to reduce stormwater runoff from existing development and let your representative know that you support the establishment low-impact designs requirements on new development.

Imagine: streams suitable for both salmon and people. It can happen. Low-impact designs on new development and a Salmon and Trout Relief Fund that helps owners of developed property to mimic natural watershed functions lost are very good signals for both salmon and people.

Tom Murdoch is executive director of the Adopt A Stream Foundation, www.streamkeeper.org.