AustinPSD
Active Member
This weekend I worked on something new, building an earthen dam.
We had severe flooding here in the Central Texas and Upper Guadalupe River area the overnight hours of April 15th / 16th. The river went twelve feet above flood stage in the span of about six hours, and inundated about 60-acres of development work I've been doing in the flood plain for a park.
One 15-acre section is on an island in the middle of the Guadalupe, where I've been working our D3G in tandem with a guy running a forestry mulcher. We'd just finished the selective clearing, and I'd run the finished grade on this section to completion. The flood hit the next day.
The river pushed through a new channel on the upstream point of the island, and cut through the northern edge of the island, cutting through the new access road, washing out the low-water crossing, and generally tearing things all to hell.
I don't have the "before" picture, only an "after" of the temporary earthen dam I pushed up to divert the river back into its original channel.
After visually surveying what needed to be done, I harvested several dozen large rocks in the three to five ton range, selecting boulders that were as large, or as close to the size of the D3G blade as I could find.
The first challenge was pushing up these rocks from the harvesting area, and rolling them/pushing them about a quarter mile from where I quarried them to the dam site.
The first boulders I pushed were mostly flat, "saucer" shaped so that I could push them out into the river to use as more solid/known footing than what might be there. I was afraid that it would be sediment, or clay that I might sink the dozer into.
The flat boulders were far easier in general to push and place than the more rounded/oblong counterparts. The biggest challenge in moving them over distance was avoiding plowing the leading edge into my trail. I wanted to minimize the damage I would need to clean up after the fact, as well to avoid totally wrecking my main trail between the harvest site and the dam site.
After I got the flat boulders placed, I pushed over larger, more oblong/rounded boulders on the upstream side of the flat ones to give the river solid stone to hit.
Pushing the rounded boulders over distance was a bit more of a challenge, as my right hand stayed pretty busy on the VPAT control handle maintaining blade height and steering angle, while my left hand was busy on the steering stick and throttle buttons to maintain a decent (but slow) travel speed. All this was made a little more difficult by the ground conditions - just shy of to wet and muddy to work, along with the wreck of terrain created by the flood waters.
Once the boulders were in place in a U-shape in the river channel, I pushed lots of gravel and larger stone from the surrounding area into the deep section near the downstream dam face, to provide known footing for the dozer and reduce the water depth (originally about four feet, up to the running boards).
From there, I worked up a U-shaped gravel/stone wall on the downstream side of the boulder foundation, up to the height of the D3G's blade, section by section, until I was able to stop the flow of water and complete the basic dam.
From there, I pushed additional gravel and stone on top of the boulders and behind the top of the downstream face, until I was able to form a solid "road" on top of the dam that I could take the dozer over to compact the structure.
Last, I cut a few shallow blade-width channels to help drain out the area on the downstream side of the damn.
So far, three days later and the dam is holding, water-tight. The area behind the dam on the downstream side is mostly dry, with a two-foot deep pool remaining (but shrinking) immediately on the downstream side of the dam face. I'm going to push in more material over the next couple of days to reinforce the dam face on the downstream side.
Once that's done, I'll start again to recover the flood damaged area, this time by pushing up rock and gravel berms on the entire upstream shores of the island, and then recovering the grade on the interior, including the roads and trails.
Here's the end result of my little dam project:
We had severe flooding here in the Central Texas and Upper Guadalupe River area the overnight hours of April 15th / 16th. The river went twelve feet above flood stage in the span of about six hours, and inundated about 60-acres of development work I've been doing in the flood plain for a park.
One 15-acre section is on an island in the middle of the Guadalupe, where I've been working our D3G in tandem with a guy running a forestry mulcher. We'd just finished the selective clearing, and I'd run the finished grade on this section to completion. The flood hit the next day.
The river pushed through a new channel on the upstream point of the island, and cut through the northern edge of the island, cutting through the new access road, washing out the low-water crossing, and generally tearing things all to hell.
I don't have the "before" picture, only an "after" of the temporary earthen dam I pushed up to divert the river back into its original channel.
After visually surveying what needed to be done, I harvested several dozen large rocks in the three to five ton range, selecting boulders that were as large, or as close to the size of the D3G blade as I could find.
The first challenge was pushing up these rocks from the harvesting area, and rolling them/pushing them about a quarter mile from where I quarried them to the dam site.
The first boulders I pushed were mostly flat, "saucer" shaped so that I could push them out into the river to use as more solid/known footing than what might be there. I was afraid that it would be sediment, or clay that I might sink the dozer into.
The flat boulders were far easier in general to push and place than the more rounded/oblong counterparts. The biggest challenge in moving them over distance was avoiding plowing the leading edge into my trail. I wanted to minimize the damage I would need to clean up after the fact, as well to avoid totally wrecking my main trail between the harvest site and the dam site.
After I got the flat boulders placed, I pushed over larger, more oblong/rounded boulders on the upstream side of the flat ones to give the river solid stone to hit.
Pushing the rounded boulders over distance was a bit more of a challenge, as my right hand stayed pretty busy on the VPAT control handle maintaining blade height and steering angle, while my left hand was busy on the steering stick and throttle buttons to maintain a decent (but slow) travel speed. All this was made a little more difficult by the ground conditions - just shy of to wet and muddy to work, along with the wreck of terrain created by the flood waters.
Once the boulders were in place in a U-shape in the river channel, I pushed lots of gravel and larger stone from the surrounding area into the deep section near the downstream dam face, to provide known footing for the dozer and reduce the water depth (originally about four feet, up to the running boards).
From there, I worked up a U-shaped gravel/stone wall on the downstream side of the boulder foundation, up to the height of the D3G's blade, section by section, until I was able to stop the flow of water and complete the basic dam.
From there, I pushed additional gravel and stone on top of the boulders and behind the top of the downstream face, until I was able to form a solid "road" on top of the dam that I could take the dozer over to compact the structure.
Last, I cut a few shallow blade-width channels to help drain out the area on the downstream side of the damn.
So far, three days later and the dam is holding, water-tight. The area behind the dam on the downstream side is mostly dry, with a two-foot deep pool remaining (but shrinking) immediately on the downstream side of the dam face. I'm going to push in more material over the next couple of days to reinforce the dam face on the downstream side.
Once that's done, I'll start again to recover the flood damaged area, this time by pushing up rock and gravel berms on the entire upstream shores of the island, and then recovering the grade on the interior, including the roads and trails.
Here's the end result of my little dam project:
