Travis County Commissioners Court
Tuesday, August 9, 2011 (Agenda)
Item 12
>> and do we have a representative here on item 12?
cleanup of hamilton pool?
>> yes.
>> 12 is to receive briefing from espy consultants, inc.
on the completion of phase 2 of the cleanup of hamilton creek and hamilton pool.
>> good afternoon, judge Biscoe and members of the Commissioners court.
we'll get our folks assembled up here, but I will go ahead and lead off.
I'm here to sort of introduce a happy tale.
as you know we have been engaged in the cleanup of hamilton creek and hamilton pool over the last year or so after the big discharge that occurred back in may and June of 2007.
what we have here today, victoria harkins who is the lead for espey consulting who has been doing the work out there cleaning up, and give her a chance to stribt distribute these things and fire up her presentation, and I actually have a little sample of some of the stuff here that has been cleaned up.
but I think what I want to do as we're waiting for this to set up,, I'd really like to commend -- I'd really like to commend victoria and her folks for the outstanding work that they have done out there.
they really had to think outside the box to make some of this work.
you know, we've had some issues in terms of timing and --
>> can you see it?
>> no, there's still --
>> they're down there.
>> they've got it down below?
>> right here.
>> down below us.
okay.
very good.
so I think what I will do is I will turn it over to victoria and let her tell the story.
>> hi, thank you for having me.
we're going -- I'm going to present a fairly brief presentation of the completion of the project.
it's been -- it's been long.
we started in July of last year, and we finished phase 1 November of last year, and then we kicked off phase 2 in February of 2011 and we finished right before easter.
so what I want to present to you, a brief presentation.
on the slides that you he see now, this is a picture you've seen before.
this is hamilton pool prior and hamilton pool in 2007 after the contamination of silt from the development upstream.
a brief history, just to remind everybody kind of where we were.
in October 2007 there was a lawsuit filed against a developer and their engineer, and in March of 2009 as you-all are aware the Travis County Commissioners accepted a settlement agreement for 2.1 million to clean up both the creek and the pool.
in December 2009 Travis County extended a contract to espey consultants for phase I of the cleanup, and in December of 2010 Travis County extended a notice to proceed on phase 2.
it wasn't necessarily a contract because we already had the contract but notice to proceed on phase ii.
phase I started, like I said, in July of 2010, and the first part of the project was restoration of the creek itself.
of course it made sense to do the creek first before it flowed into hamilton pool.
we started that project in July, finished it right at thanksgiving, in November of '10.
we removed approximately 6500 cubic yards of silt and sediment from the creek.
I made a presentation to the court prior that gave you lots of details on that and I'm not going to go back over it today.
phase ii of the project, though, is what -- we haven't shown you many of the pictures from that be but we essentially focused on the cleanup of hamilton pool itself.
and what we did is we designed a filtration system so we actually used pumps and divers and a barge and booster pumps and we moved the water to a treatment plant that ran the water from shaker through some mixing tanks into a filter press and then moved all the water back to the creek.
I'll go into a little bit of -- and I have some pictures of that in a moment.
we subcontracted the commercial diving services and we also contracted with a sophisticated filtration unit system in order to filter the water.
some pictures that you see here, it's one of my favorite pictures, a picture down the cliff, about 50 feet to the surface of the water, we actually had a crane brought in and dropped the barge to the surface of the water and that's where the divers actually operated from.
in the top right hand picture of the treatment plant, I climbed up the hit to get kind of more of an overview shot, and I'll show you some pictures of that individually, but essentially it started with the divers.
we removed up to about 9 feet of silt and sediment off the bottom of hamilton pool.
we filtered the water column.
we had a process where the divers were in the water.
we would use them on the bottom of the pool and then there were times that we would leave the pumps and filtration unit unmanned and we would just filter the water column itself.
so you'll see a picture there, it's just a picture of one of the divers set up on the barge.
the other picture is just showing the bubbles.
we would use the bubbles in the pool to monitor where the divers were and we would keep them on a grid pattern for cleaning the bottom.
and then the far-out one is just a really cool picture.
>> [chuckle] so what we did is when the water would leave the pool via the barge and the divers which you saw, the water was pumped up to a booster pump and the booster pump we'll talk about in a minute, was necessary to move the water 3100 feet.
the water would then go through a shaker system, which essentially removed the larger material, gravel, sticks.
we also actually had a lot of -- the
>> [inaudible] type material leave, and sunglasses and goggles and flippers and toys and all sorts of stuff off the bottom of hamilton pool.
it would then go through a filter press.
would you believe the water -- and that would remove the silt and sediment from the water, and then the cleaned water was carried back to the creek.
it was imperative as part of the project to leave the water level in hamilton pool as undisturbed as possible.
there's a great ecological benefit to that.
there's the vegetative bench that we tried to keep wet.
what -- he could pass around is that's the filter take, where part of the process when we ran through the filter presses was to essentially remove the material in small micron filter presses and that's actually the cake that came out.
the outside of it is a chalk that we use to essentially precoat the materials and then the silt was removed on the inside.
so that was -- that was our -- we call it the filter cake.
we were -- we estimated about a thousand cubic yards of material was removed from the bottom of hamilton pool and also throughout the water column.
so this next picture is a graph.
during the project we monitored water quality throughout the entire time, monitoring to make sure there weren't any issues of dissolved oxygen, any issues of ph.
of course temperature changed with the season as we moved through, but the picture that you see here is a graph of seveny measurements.
sechy is a disk you drop into the water and measure the distance at which you can see it.
you'll see -- as we were working through the project when the divers were down and we would break through big areas and, you know, nine feet of silt, the water quality in the pond, the clarity would decrease.
it got pretty muddy.
but as we went and we continued to clean, the clarity improved.
and then since we've left the pool, the clarity has increased over 4 meters.
so the next picture is just a couple of photos I wanted to present.
September 2007 your top left-hand corner, that's the picture you saw prior.
January 2008, you know, there's a picture of the pool itself.
you can still see the water is very green colored and then there's a bunch of sediment along the bottom.
and then the two pictures on the right, and I hope you can see them to some degree to give it justice, is once we started cleaning, you can start to see the definition along the bottom of the pool and also the picture on the bottom -- the two pictures on the bottom are from the same angle, to see the difference in the cloudiness of the water, and it really was a very successful filtration.
where did all the silt and sediment go?
from both phase I and phase ii we moved the silt to what was an old qory that had been used to construct hamilton pool road.
we filled it up with like I said be 6500 cubics yards and another thousand cubic yards plus the cheero we used to precoat the facility ermings rvetioners, plus all
>> [inaudible] we pulled off the bottom of the pool.
we smoothed it and shaped it so it would hold no water on the top.
we didn't want this going anywhere else.
we covered it with the 4-inch topsoil lung kind of a closure and then we receded it.
and those are pictures you can see and that's been finalized.
the landowner was very happy when we were done.
I want to do present a few challenges along the way.
we addressed pretty effectively the golden cheek warbler, the habitat in the bal con he's preserve includes the pool so part of the initial startup is we were going to interfere with the golden cheek warbler habitat.
we moved our treatment things 2400 feet away from the pool and that presented its own challenges.
we had a sound contained booster pump brought in to essentially push the water to 3100 feet and then we had issues that we dealt with engineering-wise to keep the material from settling out in the pipe, and then inherent with that much slurry and that distance, we did have some equipment issues that had to be addressed.
and then of course communication became an issue.
if you've been out to hamilton pool cell phones don't work, so we ended up with a pretty -- we actually figured out kind of a kindergarten walkie-talkie staging place.
when people were on the bottom of the pool they'd radio to the top and the top would radio off.
after we got the kinks moved out it was pretty smooth.
I would like to briefly mention when we had to move the treatment plan from -- in phase ii from the pool itself over to the private property some distance away, I made a request to move some of the contingency funds.
there was quite a bit left over from phase I into phase ii.
we used those funds to address all the costs necessary for the 31-foot of pipe, the booster pump.
we actually need the another pump to move the clean water up over.
we didn't have gravity in favor of us there.
but anyway, the county worked really well with respect to moving the money around, and at the end of the day we ended up about 100,000 less than our overall budget.
>> so did we buy those pumps or lease them?
>> we rented those pumps, and came with maintenance plans to go with it.
we never went for more than six to eight hours down.
I had them on the money with respect to, you'd better get out here and fix it.
>> I thought maybe we were proud owners of collection pumps.
>> I don't know that you'd want these big-ol' things.
>> [laughter] I do want to say, that my counterpart for Travis County was keith, and we even mesh today.
there was never a moment that I could not pick up a phone call that he didn't do it or find someone else to do it.
the county has an amazing number of resources down to putting up a sign through heavy equipment operator, and it was really, really nice to get to know some of the folks that worked for the county.
very, very nice.
I do want to tell you that since then keith and I have presented this project at some elementary schools, the middle schools and stem prosecution, where we both -- programs, where we both want to take this as a public education opportunity to teach kids about erosion and cleaning up water.
and then thinking outside the box and we've done that and we've actually been invited to go back.
in addition we've already been publishing one paper that has to do with some dredging, and I've also presented -- I've also prepared a paper that I hope to present at numerous conferences and so forth, but that is something that of course I can keep involved in as we go along, but that's the future of it, as I wanted to use it as an opportunity to maybe teach some kids to watch out for some of the stuff they do in the future with respect to erosion and watershed planning and that kinds of thing.
>> when are swimmers allowed to go back?
>> we never kept them out of the pool.
they were allowed to swim.
we buoyed off a section of the pool.
we had about a thousand gpm running through those pumps, so they could hurt somebody, and so we did buoy off and kept them away from the divers themselves.
>> I'm getting a terrible image like a swimmer being sucked up -- willy wonka.
>> I think some of the kids -- we had problems with kids diving down with their goggles on wanting to see what was going on.
we did put a safety grate on the front so we didn't have teenagers -- but we did keep them away and honestly we had no issues whatsoever.
we were more of the 20,000 leagues under the sea kind of a, you know, scenic point.
>> questions, comments?
thank you very much.
good job.
>> good job.
really amazing.
>> look real good.
>> oh, good.
>> I think in closing I'd just like to mention that in addition to the work that keith did, the folks from parks were invaluable in this.
charlesberg, in particular, was active with this all the time and mike brewster and dan chapman and folks like that.
so it was a good team effort.
I think victoria gave fairly short shrift to some of the very clever things they did out there and some of the things she did included sort of twisting the arms of the company to provide us brand-new equipment that had never been used before, so that we would victim cleanest possible -- so so that we would have the cleanest possible containment for the water as possible.
thank you very much.
>> thank you.
appreciate it.
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