Trip Field Report about:
"Succession" and "Marmot Dam Removal"
"Succession" and "Marmot Dam Removal"
Marmot Dam on Oregon’s Sandy River was removed. Portland General Electric in 2007 removed Marmot Dam, which was part of the Bull Run Hydroelectric Project. In November of 1999, PGE filed a notice not to look for a new license for the Bull Run project near the city of Sandy. PGE decided that it would not work for them to meet current standards for protection, mitigation and enhancement of the natural resources affected by the project especially salmon on the Sandy River.
The Bull Run project was located about 30 miles east of Portland on the western slopes of Mount Hood, and consisted of: • Marmot Dam, a 47-foot-high, 345-foot-long roller-compacted concrete dam that was built in 1989 to replace an earlier timber structure.
• Little Sandy Dam, a small concrete diversion dam on the Little Sandy River.
• A complex system of connecting canals.
Yards of sediment — silt, gravel, cobbles and boulders — had accumulated behind Marmot Dam during its lifetime.
Photos courtesy of Portland General Electric
Marmot Dam was a 345-foot-long concrete dam built in 1989 on the Sandy River.
Involving 23 governmental and nonprofit organizations and several years of effort, PGE committed to remove the dam extracting only as much sediment as was required for the demolition. The remaining sediment would be allowed to disperse with natural stream flow.
The dam was fractured by drilling, and then controlled blasting.
After the dam was removed forest is recovering slowly. There are Big leaf Maple and Red cedars also Sword Ferns grow on the ground. trees are around 200 years. While in the entrance side we can see that second succession have been taking place on the past years. When the dam was removed the sedimentation went a way just by nature. Then salmon can flow upstream. there were benefits that this process brought.
a bridge is left people is visiting that historical act. biking and hiking activities are been developed by Oregonian now days.
The view downstream after the dam was removed.
Here is a link to a video to see the removal process and detailed.
http://www.opb.org/programs/ofg/segment/marmot-dam-removed/
Hi Antonio,
ReplyDeleteGood job on your post/ lab 4. I like that you added pictures to illustrate the location of the field trip destination. Your grade is 7.5 out of 10. You missed 2.5 points because you did not use enough references to the ecology of the place.