Trip to the Marmot Dam

The marmot dam was a project to generate electricity built in 1908 to 1912, located in Sandy River, Portland. In 2007 this dam was removed.  Before the dam the Mount Hood Railway and Power Company did some logging in this area, taking the tree gravel to build the dam. The relive of the river is a psychological structure. The Western Rivers Conservancy buys this area to the Portland General Electricity (PGI), and then they sell it to the government.

 

Behind the dam was a huge amount of sediments, like rocks, sand and gravel that for many years it was stored. The scientist had lot questions, before the dam was removed, because they thought that after remove the dam it can cause damages to the entire ecosystem living in it, because never has this much sediments been realized, and it can pollute the river a long term. After the dam was removed the scientist was so impressed, because after a strong precipitation the river rapidly removes all the sediments away, and it didn’t produce too much damage. The good thing is that the scientist predicted that the river would need two or five years to remove a half of the sediments.   

In 2007 was an experiment to see what kind of vegetation can grow in this area. This area is a secondary succession, because the soil already exists.  This was a logging area, and they have a facility, and now they reforest this area.  They connect healthy part of the river, and make a corridor, with different patch for the wildlife, because the animals don’t stay in one patch, the fish can’t stay in one piece of the river, so they make this corridor. The person in charge of the area said, “we have to connect as many of the habitat as we can, in other words more connectivity you have it will help the environment” Some of the restoration was in 2010. This area is covered by conifer trees, and deciduous trees. 

Why the Dam was removed? 

The dam was a barrier for the wildlife, because the fish couldn't go back and forth, less genetic diversity, suffocate salmon and block tributaries downstream, and store the fish.  One of the benefits of this project is that the river now has free flow.  When the dam was removing, it wasn’t too much damage in the wildlife, because the process was so fast.  After the administrators of the project finish with the restoration in this area they are planning create a natural refuge for animals, and public recreation for people who likes to go in the forest, and camp.

When the river raises the channels changes. The river has free flow. In the reforested area they have to different types of forest. One that has a lot woody debris and the other one is younger and not too much woody debris. The soil is black red color, and it’s reach in nutrients. Around the river you can see some erosion, but it’s natural.

I had a great experience in this trip at the Sandy River. I learned so many things such as: if I want to reforest an area I have to do some studies, about if the soil is good to plant the trees, the history of the place, like if the area was logging before to see if the area is Primary or secondary succession, and also to know who was the owner of the area.  Those things will help me in futures projects, which I’m planning to do some reforestation, in my community after I finish with my principal project that is water quality in my return to Honduras.  These two projects are connected with the project at the Sandy River, because the people an charge of the project at the sandy river are conserving this area, and that is what I would like to do in my community.