The Army Corps of Engineers has installed a series of dams or levies creating small lakes (up to 60 acres) for flood control. They insist that no trees be allowed to grow on these dams. Every few years they will remove all volunteer woody plants of a couple inchs caliper or larger. Farmers often request that the trees remain, especially those near the water line as they improve the fish habitat. The "Corps" insist that the roots jeopardize the integrity of the dam. What do the Experts think? Are roots a Dam problem? Do you know of any published information substantiating or refuting this hypothesis? jlp

Reply to post by jlp, on March 07, 2000 at 16:17:56:

I heard Claus Matteck talk about dam trees.

One consideration was that with woody vegetation, burrowing animals are attracted. Woodchucks, rabbits,etc. Burrows weaken the dams and dikes.

You might thumb through some of his books to see if there are nay notes on dams and dikes.

Tom

Reply to post by jlp, on March 07, 2000 at 16:17:56:

just like the fedgov state something without explaining.

I asked an engineer (non-ACoE) about that a few years ago, thinking that the roots would add stability.

A dam or levee is a ramed earth construction. Roots will break that up and water will migrate along the roots readily, reducing coheasion further.

Reply to post by jlp, on March 07, 2000 at 16:17:56:

I am a student in the MSU-Bottineau on-line soils course. I have my BS Degree from NDSU in Fargo ND. I am currently working for the USDA Natural Resources Conservation Service. I previously worked for the US Fish & Wildlife Service in their Private Lands program. In that position I created and/or restored many wetlands with embankments or small dams. Generally I worked on dams of less than 12 acre feet. There was a general rule of thumb that planting trees on the dam would eventually cause it to leak and wash out. The tree roots would allow water to follow their path and form channels through the dams. This seemed like a reasonable explanation to me at the time. Now since enrolling in this course I have learned of how the root channels do facilitate water movement. Also the roots loosen the soil as they grow and attract other organisms which further loosens the soil. All of the these things could cause an earthen dam to fail.