Beaver Threat
Some people have asked if a beaver dam might damage our rock wall. I have talked with a Claremont resident that states that a beaver dam might damage his home! He also feels that a beaver dam would trap toxins in our area. The notion that a beaver dam threatens our rock wall or our homes is absurd. Spreading this type of dis-information is not helpful.
In this section I will present information about Bronson Creek, why it is where it is and how it may change. To watch Bronson Creek change from a man-made drainage ditch into a functioning wetland is exciting.
Here is a topographical map showing Bronson Creek as it goes past Claremont Greens. The topographical lines are 10 feet apart. To this map I have added a brown line showing the lowest point in the wetlands. Normally, we would expect the creek to be at the lowest point in the valley. However, the creek was moved to the north side of the valley to make pasture land.
On the right is an old topographic map made before any Claremont development. It shows the same area as the above map. Bronson Creek is shown in its current position indicating that the creek was moved before this map was made.
In the upper right corner of this map, just left of the road, is the Hansen House. On the other side of Kaiser Road from this house is the Hansen Ridge Park that opened in 2014. In the park you can find a sign showing an early picture of that house. The house is still there.
West Union road is shown in the lower left corner of the map. 158th Ave runs to West Union and stops. There is no Bethany Blvd.
In 1995, the Claremont developers and others re-engineered the area where Bronson Creek meets Kaiser Road to make that area into a wetland. That area is shown on the above map as Claremont Open Space. A sign near Kaiser Road describing this project is shown below.
The above map is from Google and it shows Bronson Creek going past Claremont Greens. The field on the right is the area that was re-engineered into a wetland. The field at bottom-left borders our townhomes and has not been re-engineered to be a wetland.
There are some important differences between these two fields but they are hard to see at first glance. A couple differences are shown in the image on the right. There is a new lake that I have circled in blue. And there are multiple streams that were not there when that land was pasture land. These new streams wander rather than traveling in a straight line. Streams that people create tend to be straight but this is not natural.
The childish drawing on the right shows a cross section thru our rock wall and Bronson Creek. The rock wall is about 15 feet high. As you walk from the rock wall to the creek you go downhill. At the creek there is a bank. On the far side of the creek there is a berm. This berm was made from the dirt that was removed to make a new path for the creek. After you go over the berm the land continues to drop a small amount until you get to the center of the field.
The distance between the rock wall and the creek is always greater than 25 feet along our townhouses.
If the berm was not there the creek would move away from our townhouses and over to the field. I presume that, long ago, the creek was flowing thru the field, probably in many small streams. To turn that wetland into pasture land for domestic animals the creek was moved to the current course.
A beaver dam anywhere along Claremont will cause the creek to go over the berm and flow into the field long before the water will get near our wall. In fact, this is happening right now.
In the above image Bronson Creek is shown in cyan, flowing from right to left. Our neighbors with the weeping willow trees have re-routed part of Bronson Creek to flow thru their property, making a decorative lake. The berm that keeps the creek from flowing into the field is shown in light brown. If that berm were not there Bronson Creek would move over to the field. This spring there was enough rain to cause Bronson Creek to go over the berm at the right side of this diagram. This is shown by two blue arrows.
An existing beaver dam, shown with two red lines, has raised the lever of Bronson Creek so that it is going over the berm in the middle of this image. This is not the beaver dam that was removed. The beaver dam that was removed was near the word "Creek" in the upper-right. The new path of Bronson Creek is shown in purple. Even when there is little flow in Bronson Creek it continues to flow into the field near the beaver dam.
Our neighbors with the weeping willow trees have a very large estate and I suspect they do not like to have the water level in Bronson Creek any higher than it is because it does not work with their decorative lake. I have seen a gardening crew come from their property and remove the beaver dam.
Eventually, Bronson Creek will permanently breach the berm somewhere on the right side of the above map. This will allow Bronson Creek to flow thru the field in the summer rather than just during very rainy times.
As Bronson Creek moves into the field it will help store flood water, it will trap sediments and reduce erosion and it will provide a home for native plant and animal species. The beaver will play an important part in making this happen. It will reduce the water flow in the man-made creek while forcing water into the field. The new water paths in the field will have areas where the water flows slowly allowing sediment to settle out. We have already seen a change in the field vegetation with more native species and more habitat. These wetlands will provide us with a natural water feature that is more interesting and varied than a man made water feature.