The Mowers Arrive

Good Morning Jane,

Many congratulations to you on your identification of three juvenile MEW GULLS and their record-setting early arrival. Your brave venture into the dangerous terrain of juvenile gull identification really paid off in this case.

I was very glad to hear that you have become a staunch advocate for the wispy little native wild rose that we discovered on our walk several weeks ago! What a survivor that small being is. I am hoping it will  flourish with your fierce protection.

Well, the related news from my end of the river is that the City mowing crews began their  annual flood control operations yesterday, August 9th. I was down by the Highway 1 Bridge yesterday morning as the crew chief, Randy Clayton, gave instructions to his workers. As I listened, I realized that Randy didn’t have the new information about the adjusted width of vegetation to be protected along the riverbank. We called Siobhan O’Neill from Public Works who came down immediately. She talked with Randy and made sure that the crew would leave  15 feet along both edges of the river , 10 feet more on both sides than the 5 feet protected in previous years! The City has made this adjustment to bring the mowing into compliance with government documents.

Workers begin to cut vegetation just below the Highway 1 Bridge  (looking south). They seem to be  leaving the required 15 feet edge of vegetation along river edge.
Same area as above after the mowing.  Although there is severe cutting, the 15 foot edge has been protected, offering  much more habitat than last year.

For readers who are interested in seeing the governing document, go to our ‘Links’ page, then scroll down to Lower San Lorenzo River and Lagoon Management Plan, p. 4-3.  There you can see the exact specifications for each reach of the river.

In the meeting that Bruce and I had with Public Works several weeks ago, it was also agreed that there was a typo in the document governing the mowing in the estuarine reach.  The document said that any willow  over ½ inch diameter needed to be cut down!  (In the other reaches it is 3 to 6 inches.)  Siobhan O’Neill had already checked with one of the authors of the document. She was told that it was probably a typo and should be corrected to read at least  3 inches. Can you imagine – all that habitat lost over all these years because of a typo! Hopefully this means that no willows on the estuarine reach will be cut this year.  But we should stay watchful.

As I was watching the operation get started, I was reassured to see Gary Kittleson, the City biologist, turn up with his binoculars. The California Department of Fish and Wildlife requires that a qualified biologist check out streambed areas for possible bird nests in any area to be mowed. As I was talking to Kittleson, he saw a juvenile COOPER’S HAWK fly into a tree in the area just downstream from the mowers.

Juvenile Cooper’s Hawk (google image)

Let’s hope the diameter of the tree was less than 6 inches or it will not be there when the hawk returns. All alders, sycamores, cottonwoods and box elders fall beneath the chainsaws once they reach 6 inches. It breaks my heart every year. The rationale is that once they reach that girth, they could contribute to log jams during a flood event. I wonder. If they were carefully spaced, would it be a problem?  It’s a complicated topic.  How do we argue these technical matters with the Army Corps of Engineers.  Thankfully, our City tried and often succeeded over the years, keeping our river from being trapped in a concrete channel.

Did you know that Pasatiempo Creek drains into the San Lorenzo River on the east bank of the riverine reach – right where that pump station is? The station even has a gate that can be opened and shut, just like Jessie St. Marsh. I was very surprised, but now understand why there is that rich wetland area with braided channels and a wide sandbar in that area.

Confluence of Pasatiempo Creek and San Lorenzo.



Umbrella Sedge, a native wetland plant,  in the confluence between Pasatiempo Creek and the San Lorenzo River.






Apparently the drainage sets up a hydrological problem since the tributary is lower than the river itself (due to aggradation) and doesn’t work by gravity the way it should. As a result a lot of trash collects at the confluence and creates a big clean-up problem for the city. It’s not just the homeless who trash the river. Lots happens upstream as well as near the Boardwalk – as you well know!

This is a cross channel south of the Pasatiempo confluence that runs west to east, connecting the channel on the west side of the river with the east side.  These channels change every year depending on a variety of conditions.  This winding back and forth between channels is called braiding.  It is an area surprisingly rich in native wetland plants.  That is fennel in the foreground, not a native but as you once  pointed out to me, a plant that provides both food and nesting material for birds.  

It’s always hard for me to believe how much beauty there is tucked out of sight on this river.  And I’m always surprised how many native plants have kept coming back year after year, in spite of the mowing.

Soon we will be faced with another onslaught – the Paddling Project.   A journalist interviewed me last week  for an upcoming article she has been commissioned to write about this situation for the local magazine, Adventure Sports.  She said she hopes to give a balanced report. The article was proposed by Greg Pepping.  Never a dull moment on this river.

Happy gulling to you,






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