- Beavers have begun to reconstruct a dam on Merestone Pond along 121st Avenue in Tigard. The city removed the dam earlier this year to keep debris out of a nearby culvert.
Remember how upset the residents of Tigard, OR were when the city ripped out a beaver dam and ruined the beautiful pond in their backyards? Well guess who’s back? I’ll give you a hint. They have a flat tail and they’re good at driving public works crazy.
“The beavers are back in there doing their work,” said Brian Rager, assistant public works director for the city. “We can confirm that there are beavers building a dam. It’s not as big as it was, but they are in there working.”
Now the story of residents outrage was such a dramatic example of beaver appreciation that it made it all the way to the state of New York’s Beavers: Wetlands & Wildlife newsletter. I found out about this new development when a local wrote me a heads up. I had to send a letter about this, which I’ve been told will be printed this week.
City might move dam upstream
The beavers have returned to the same place they built the original dam, Rager said, directly in front of the 121st Avenue culvert. “Where the beavers are building now is not the best location,” Rager said. “It’s still next to a culvert and next to a sewer manhole.” If the dam were moved only a few yards upstream it would solve the city’s problems, Rager said, but that would require state permits, which Rager said will take until next summer to acquire.
Did you catch that? If the dam were moved upstream their problems would be solved! Ingenious! I’m sure all you need to do is invite the head beaver to the next city planning meeting and explain what you need.That should take care of it!
Sadly the paper didn’t accept graphics, so I had to content myself with a letter.
I was happy to read about the returning wetlands at Merestone pond, but still confused as to the potential problem the city feels is posed by the beaver dam. The article makes it sound as if they aren’t blocking any culvert now, but the fear is that if the dam washes out in the future the debris would head downstream and it might plug the culvert then. Tigrad wouldn’t be the only city to “REINFORCE” a beaver dam to keep it in place if that’s the issue, or build a debris fence. This video would show you how its done in arid, flash areas to preserve dams.
The idea of “Moving” the dam mystifies me. I assure you that no beaver expert anywhere knows of any guaranteed way to lure a beaver dam to a better location, even if city staff does the labor themselves the beavers may still prefer the dam where it is. Usually they have a good reason for putting it there in the first place – maybe the width of the channel, the curvature of the pond floor, some natural feature, or proximity to materials – sometimes it makes to them and not to us. I have never heard or read about them moving because a better location was recommended by public works.
As for the trickling of water over the rock being an instigator of building behavior, yes that is basically true. Water running IN PLACES THEY ARE BUILDING OR MAINTAINING triggers them to keep working. Water running in places they have no interest in doesn’t provoke them in the slightest. If a human built rock wall really did trigger them to rebuild it was because it was in the exact same place they had already maintained for years. (Beavers build with rocks too, so I’m not convinced it wasn’t entirely their work)
In the mean time, Tigrad should familiarize itself with real tools for managing beaver dams, available here. There are plenty of experts in the Oregon area who could help train your staff, but let me know if I can be of help connecting you with one.
The local who tipped me to the story sent a letter as well, and said I was welcome to publish it. He also noted that the area was blind to the salmon issue because that particular stream wasn’t listed as a “salmon run”. He wished his officials got wise like those forward-thining sages in Martinez!
(Words fail me.)
I’ll check in the Tigard Times to see if they posted Dr. Perryman’s comments. Thanks a lot. I am also sharing Dr. Perryman’s comments with my watershed council in the Milwaukie/Clackamas/Happy Valley/Oak Grove/Gladstone area southeast of Portland, OR, which includes a couple of key sanitary sewer/surface water management special districts and a parks district whose track records with beavers aren’t exactly supportive of beavers’ free engineering and habitat restoration.
For some reason, folks around here seem to be concerned about the flooding the “beaver dams” have been causing–or downstream flooding that might occur if the dams were washed out during high water storm events. Our public agencies here in Clackamas County, unfortunately, have let private lands and public lands become inundated with grading and structural improvments (along with utilties, roads, etc) within the 100 year floodplain over the years in our north urban area of the county. Hence, they have had to undertake remedial flood protection improvements, including a very expensive flood control dam and a levy in a 90 acre open space (known as “Three Creeks”). Because they figure they’ve solved the flooding with their engineered “solutions,” they don’t want the beavers messing around to change the hydrology.
We do have 3 significant (multi-million dollar) stream improvement projects in our area of No. Clackamas County urban area that are being supported financially by Metro’s “Nature in Neighborhood” capital grant program.
So beavers still have a ways to go to prove themselves in the urban area of the beaver state. And salmon are best to remain somewhere in the hinterland under forestry and agriculture because urbanites haven’t prioritized them in their lifestyle and urban fabric.Thanks for listening from one outpost of the Pacific Northwest in the great county of Clackamas. PS: the salmon planners still think the Clackamas is a trophy river and are “talking” about all the stops to pull to sustain them (or at least their hatchery cousins)–stops short of what the private property owners feel is the highest and best use of their property.
Pat Russel
Thanks Pat, just so you know Martinez didn’t do the right thing because they wanted to. They did the right thing because hundreds of folks and families just like you pressured them over and over again. I hope Tigrad keeps the pressure on, because this whole story could have a very happy ending.
