Travis County Commissioners Court
May 13, 2008
Item 20
Item number 20.is to receive consultants stream bed assessment and water quality evaluation report on hamilton pool and receiving streams in Travis County with a portion of in hays county and take appropriate action this item may be taken into executive session this afternoon depending how the discussion goes.
>> sir, do you have another copy?
one for the clerk, if you have one.
>> next, we'll have item number 20.
technical difficulties?
>> length of time to start the computer.
I will start and introduce and he explain we've already provided a copy of our report for the clerk.
but good morning.
I'll start without my computer.
I'm with the the engineers with sb consultants in Austin, Texas and we're here today to present to you an assessment of hamilton pool and receiving watershed.
we have provided a detailed report and literature review of the assessment we've completed and the report has been turned in and we are having some technical difficulties.
if all else fails, I have provided with you copies of my hand outs, the presentation will not be here as sophisticated but we will go from there.
we'll start from the hand out fans it gets started we will catch up on the presentation.
>> okay.
>> as I've already said, michael and I are from sb consultants and we were hired in August of '07 so conduct an evaluation of the hamilton fool and receiving watershed.
I think we've count countered up to 10 unnamed tributaries that flow into that area.
so we did complete the assessment.
we have of hamilton pool itself, of all of the creeks and all of the unnamed tributaries.
we provided a copy of the report which details much of the data that is going to be presented today.
my hope is to provide you a presentation of 15 to 20 minutes of the result of the assessment and the recommendations for the restoration of the week.
about 8.7 miles square, I've already named off several creeks and unnamed tributaries.
the volume of hamilton pool is approximately 2 million gallons.
those facts will be important as we discuss the restoration later in a few minutes.
up from from hamilton pool is a ranch development, from this point forward we will call the ranches.
at this point in time, I need my pictures, but during spring of 2007, phase 2 of this development was under construction.
give me just one minute.
beginning in the spring of 2001 there was numerous things that occur with the springtime rain event.
we have several photos to show the significance and magnitude of the storm water damage that occurring at the ranches at this time.
the bottom line was the on-site control failed and there was severe amounts of sediment in a leaf the site via storm water flow.
and all is lost not having my great photos to show you.
as a result of the off-site discharge of storm water that contained with sediment silt, tceq, hays county and Travis County county all conducted investigation of those.
>> do we need to take 10-minute recess, let you all try to work that out?
>> I would appreciate that.
>> sure.
>> we will take a 10-minute recess and so we'll start back up at about 10:40.
okay.
>> I appreciate that, thank you.
>> no problem.
>> we are about to restart after a short recess to deal with some technical difficulties.
let's call this voting session back to order.
we do expect Commissioners Davis and eckhardt to rejoin us momentarily.
but let's proceed.
>> hi.
good morning again.
thank you very much for your patience as we get our technology back together.
we're going to fly through the first three or four slides because you already heard me discuss them.
but I guess do I need to tell anybody to put those up?
is that going to happen?
there we go, thank you.
we've already introduced ourselves, told thaw we were hired in December of '07.
we've completed our assessments and I've already given you the facts about hamilton pool.
we were at this screen when I wanted to be able to show you some picture of the construction that was underway in the spring of 2007.
what I have here is an aerial photograph that was taken by the county, and if you'll notice to the bottom left of your screen -- can you see my -- you can see my mouse.
just so you get an idea of what the construction activities that the ranches of hamilton pool are, I wanted to show thaw this big white line that goes through, if you will follow my mouse, is the road that then becomes grand summit boulevard tovment the bottom left you will see a culvert.
that is culvert g.
and then you will notice through the middle of this area there's smaller roads and those are considered hall roads and we'll talk about those as well.
then you will notice in the bottom there is the little black line are silt fences.
this is culvert f.
I did that wrong.
this is culvert f, d and e.
and the property line runs here along -- you can see the tree line where they've been cleared to do the development.
so this is a picture, just an aerial picture of the construction activities that were occurring in the spring of 2007.
during rainfall events, there was large amounts of silt and sediment that washed and eroded away from the ranches.
like I said already, there was numerous investigations that were completed.
the on-site controls failed.
this is a silt fence that was at the bottom of one of the culverts that we saw in the last picture.
you'll notice here that the silt fence has been , water is running over the top and you will notice here to the bottom left the silt is coming out through the bottom as well, there's a thick cover of mud.
this is an aerial photo that shows where the on-site controls failed.
this is culvert c.
you'll notice there's silt fences that run parallel to some of the flow on either siefd this culvert, and the -- you'll notice that is -- there's a big disagreement.
this is Davis creek that feed intooz hamilton creek.
you will notice this creek is completely mudded over.
you will also notice in the bottom of the silt fence here where this silt fence has failed at this point where you can see the mud -- just a river of mud as it flows topographywise into the creek.
we also want to note that this here, we will talk about these in a little bit, there are natural depressions along the creek that feed into hamilton pool.
this area is about 10 to eight feet deep with a little grotto on the side.
it's a natural swimming pool that could be used.
but you will notice that this creek is completely mudded over.
this is post-rainfall event in spring 2007.
>> it looks like a road rather than a creek.
>> yes, it does.
and they drove through that creek at that point initially, but later on they moved that road.
they no longer drove across it.
as a result, there was non-compliant and very severe discharges of send.
laden storm water.
as you indicated, it looked like a road.
they used to drive here.
they had a pump placed here.
since then there were requested to put the pump on the other side to refrain from driving across the creek bed.
but this is the same photo of the same time frame just turned, but you will notice that the mud continually leaves this area and again if you will notice right where my mouse is, there is another hole there which is probably about eight to 10 feet deep as well.
it is completely full of water.
and it will fill up and as it fills up the water will leave this area through a shallower creek bed.
so what we saw when we did the assessments of the creek bed and all the tributaries that the silt source is the ranches.
there are a build up of silt in areas along the creek that go down several feet.
layers of this silt cake the majority of the creek and ha p hamilton pool itself has a shelf of about five to six feet of silt along its bottom.
so what you see here on this map is a very large map.
so without -- there's no detail to this.
what we did is we took this map and cut it into four to show you.
this is the bottom of the map.
like I demonstrate earlier, that grand summit boulevard that was under construction, you will see here from this cul-de-sac back around, this is grand summit boulevard as it was being constructed.
as shown in part of the pictures, culvert g, f, e, d, c, b and then a is on the next photo for reference purposes.
so what I wanted to show you at this particular map is some of the photos and some of the evidence that we found.
this is the same picture that we saw earlier, and I want to make sure that you realize that we're facing the north.
this aerial is looking north.
this is a second picture of some of the construction activities at one of the culverts where you see massive amounts of fill that's been brought in to cover the culverts that drainage the creek off to the side.
this is just for magnitude of the amount of fill and dirt that was used to cover these culverts.
and this roadway is level at this point in time.
at this point it's still a valley, but they brought in enough fill dirt to essentially make this roadway level.
going from the aerials and the perspective of what we showed you, this is culvert e.
this is grand summit boulevard, so this is an unnamed tributary that feeds off site, past the road into Davis creek, which feeds later on into hamilton creek.
this is a photo taken of the creek bed right downstream of culvert e.
and to be perfectly honest, my staff engineer got stuck in this and I could not pull him out.
I told him he was on his own to find a tree to pull himself out.
and this mud here is several feet thick.
it's very sticky and it almost feels like quicksand.
it will quickly sink you about 18 inches to two feet.
much taller than our boots that we had on at the time.
back to the picture, another one of the crisis that happens in this facility is you will notice these lighter colored roads are considered haul roads.
what I want to pay attention to right now is this area where I'm circling, this is a haul road that feeds from both sides and there's actually this haul road y.
so what we've determined during assessments is that this haul road, this is a picture of a rock gab onthat was put in at the bottom of this haul road.
you will notice this is completely caked up.
it's almost the same height as the rock gabion.
the silt that is washed down from the road and up top construction during rainfall events, it washes down.
this gabbion has failed.
it's not intended to essentially stop the silt, but to stop the flow.
the silt will come out, but there is evidence all way around both sides of this where this has been overwhelmed and there are silt cakes down here of several inches.
this haul road, if you notice in the top, this little unnamed tribtory flows on and off the ranch's property into other folks' property to the right of my mouse, and it flows back into the tributary that feeds culvert d.
and these are photos.
what I was just showing you that tributary fed in right up here at the top.
this is a picture of the haul road that feeds culvert d.
what I want is very important to notice here is there is no culvert.
so the flow that comes from upstream that feeds this tributary feeds over the road.
and you'll notice here that the silt fence is no longer present.
all of this is cake silt from the haul roads being washed out.
and the second picture that's pretty evident, this is also a silt fence that is on that same haul road that feeds from the southside and you can see at any given amount of time this has already failed.
there's already silt on the other side of the silt fence neighborhood more rain it is over the fence.
this is an absolute failure of the silt fence.
further down -- these roads feed into the tributary that feed culvert d.
this is of picture of when I got stuck in the mud and michael was able to pull me out, but left my boot behind.
we sank for 18 inches to two feet in this area too.
it is a pool that has been completely caked over by the silt that was fed from the haul roads.
so when you leave culvert d and again this is grand summit boulevard, we hiked down through all the creeks, and this -- I lost my picture.
hold on I lost my picture.
this is downstream of d.
this is actually Davis creek.
you'll notice that this is caked over too.
there's several inches of silt along the bottom.
you will also notice there's lots of animal tracks along with of course our tracks.
so then when we leave culvert d as it merges with Davis creek, this is culvert c.
this was a gabbion that was put in after the construction started.
what's important here is that it has slowed the flow, but the silt has built up on the back side and the next picture is important to notice that michael is standing on the gabbion and you can see that the silt is only an inch or two away from his foot.
so the silt has filled up this to the top of that.
and we tried to take a stick to estimate the amount of silt that was behind that gabbion and we pushed it as far as the stick until it started to break.
but that's a decent representation of the mud that's behind this rock gabbion at the end of culvert c.
so then flowing from culvert c, we go off to the next picture.
so then you'll notice here is again for perspective, it is grand summit boulevard and this is culvert a.
what I want you to notice at this point is that this is the county lane.
we were in hays county.
this is Travis County.
another picture along the creek where I showed you in the last picture where we're walking along in the mud, we noticed a smell as we started to walk.
and michael was behind me and noticed that as I would step, he could see the black layer developing on the bottom of the creek, which means it's essentially void of oxygen.
so it was essentially a rotting smell that you could smell underneath.
and what this indicates here is that there are layers and layers of silt here.
this is not a one-time event.
this would rain, the silt would settle in these low depressions, it would rain again, the silt would settle on top of it.
there's layers and layers of silt.
so as you walked the mud is sticking to the bottom of our shoes and it would uncover a very an oxic layer on the bottom of the creek.
it definitely smelled like rotten eggs.
it's a rotting layer.
>> so is that to say it's basically choking the creek?
>> absolutely.
>> anything living, whether it's plant life or --
>> yes.
there's also consequences associated with that.
when you take it away from its natural characteristics and you have opportunityistic vegetation and bugs and animals and so forth, it changes the whole ek eco logical look out for the creek, especially in these low areas.
as we followed the creek from here, this is the property line that we leave rarchgz and we go into the Davis' property.
and therein lies the discussion about this is hamilton creek that flows through culvert a and this is Davis creek.
for purposes of our sanity, we named this one Davis and that one hamilton so that we could keep up with them simply because this ran through the majority of the Davis property and they like it being called Davis creek.
so when we leave the property, what's interesting about this picture, they did have a haul road that ran through the edge of that property.
what is important to note is that this here is the surface of the road and this is the surface of the road, and they actually had to come and physically pull this culvert back.
the road washed out such that this culvert became free.
so this culvert actually moved past the fence line and had to be physically pulled back.
so this was a washed out culvert at the edge of the property indicating the amount of wash that was coming down.
so we leave the ranch's property and we do enter the Davis' property.
and the Davis have on their property the same pools that you saw upstream, but they have an absolutely beautiful area that is -- that they have said going on the information based on the Davis, this pool is 20, 30 feet deep.
as it stands now it's three to five feet deep.
and this right here I have to point out is the crazy dog.
he's crazy.
he runs in that water all the time.
everybody knows the crazy dog, so now you guys know the crazy dog.
this is the Davis' property, and they use it for their own purposes.
they do clean it out every once in awhile.
I believe they said every 10 to 15 years.
and it is now refilled back up.
they've indicated that 20 to 30 feet is now down to three to five feet.
from this point forward I'll not differentiate between hamilton and Davis.
it's not hamilton creek.
we'll go off the page here into the next map inset.
so this is the Davis property here.
this is the creek.
and this is for your purposes of trying to figure out where you are, this is hamilton pool road.
so the creek comes close to hamilton pool, it leaves the Davis property, a little corner of the reimers property and then goes into the meyers' property.
and here it confluences with the cripple creek and that is known locally as cripple creek.
and so at the confluence of cripple creek, what's interesting to note here is you will look on to the left of the photo is cripple creek and to the right of the photo is hamilton creek.
what we did here several times is you can take a stick and you mix it here and you mix it here and try to time how long it takes for things to settle.
on this particular side it took less than a minute.
and on this particular time it took longer than I was willing to stand there and watch dirt settle.
several minutes.
it actually just went on downstream.
this is actually after several days of after a rainfall event, and you can still see the water is still very cloudy.
so when we leave the confluence with the cripple creek on the meyer's property, it actually feeds us into a low water crossing at hamilton pool road.
and hamilton pool road, this is facing from hamilton pool road towards hamilton pool.
what's important about this location and its importance from this point forward is that this is a low water crossing.
you can see right here where the road is.
you can see a slight indention where the water stops.
it also indicates the road flows up on both sides of this.
it used to be a low water crossing, until such time they came in and put in the bridge.
this is the same bridge, but looking upstream towards the meyers' property.
and along both sides of this have been man-made, concrete bags were placed or hard rock was placed.
so this is actually -- it's been manipulated to some degree and it is probably five to six feet deep normally.
it's completely caked over now, but at the time this photo was taken, what's important to realize here is that the low water crossing is acting like a sedimentation pond.
and it's a fairly long, large sedimentation pond as it was used as a low water crossing in the past.
this is a result of the same creek bed when dry.
this here is the creek where we saw the water in the previous photo.
and this is where the water has left the creek bed because of the low water crossing it seives as a detention pond.
and this is the cake and silt leftover.
this is several, several layers' thick, upwards of six to eight inches of silt thick that dries and makes a mud cake.
so then as we leave the hamilton pool road crossing, we do enter Travis County property and we end up at the hamilton pool itself.
this is the final inset of this large map where it feeds into hamilton pool.
and this portion of the creek is fairly significant is that it leads into the pedernales river.
you will notice that you can see the topography changes on both sides.
hamilton pool itself acts as the ultimate sedimentation basin.
the water comes in there, absolutely flows, it circles, flows, and the silt falls out, precisely why we have the five to six feet of silt shelf in the pool itself.
so as part of the assessment, we did complete a hike from this particular area and have not recommended any cleanup.
there is silt sustaining, there is some silt, but it's very eco logically sensitive, plus it's difficult to get into and it the magnitude is percentages of what we've seen upstream simply because hamilton pool has served to essentially protect it from a lot of the silt buildup we saw upstream.
so the next series of photos, it was taken on June 1st, 2007 and this is actually within hamilton pool and you will notice it's very muddy.
two weeks later this is hamilton pool that you can see it's still muddy, but it's got a green tint to it.
what's important, this is September 10th, 2007.
and why this picture is here is that we actually found a preimpact picture from a very similar perspective.
this was taken in 2009 about the same direction, I guess, as what the last picture was taken where you can see the water is fairly clear and you can definitely see the bottom.
so this was -- this is hamilton pool.
so then we'll move on from the map.
now that we finished up the assessment, we presented the following options for restoration.
of course, always one option is always going to be no action.
we don't have to do anything.
>> what's the consequence of no action?
>> we're going to talk about it in just a second.
>> I can wait.
>> you can wait.
the second option is manual removal of the silt.
the second is the manual removal and a wash down.
and the fourth option is the silt removal from hamilton pool plus the filtration of the water.
so the no action alternative, it's intrue active that with subsequent rainfall event, there will be movement of this silt.
if upstream the haul roads and the ranches have been stabilized, then the silt introduced into the creek should cease.
that is a key that it should cease.
so as subsequent rainfall events occur, the silt will reentrain.
now, the issue is and what we've seen since spring 2007 is that numerous rainfall events are required because it will move the silt into the next low depression spot and then it will stop and then you need a little more water at first to fill up the depression and then to move the water to the next depression as it moves down and of course ultimately into hamilton pool.
so there's several issues involved with that.
floods will tend to scour the bottom of the creek and do some natural cleanup.
the ultimate issue is that I don't think that it's possible to have a flood event large enough to scour hamilton pool.
hamilton pool when the water hits hamilton pool, it goes through a high drollic jump.
the flow slows immediately.
even with large amounts of water, they call it short-circuiting where the water will hit the top, as soon as it slows the water will move out, leaving that bottom tub of water on the bottom of hamilton pool undisturbed.
it's a shock.
they use it in water quality ponds in that first body of water.
so the no action leaves silt in the creek and eventually, like I've said, the ultimate sedimentation will be in hamilton pool.
I'm not sure that no action is ever going to clean it out unless a food of -- I don't even know the magnitude.
I haven't even tried to determine that.
so with no action, what I have here and I hope it shows up -- I messed up.
I was doing so well.
all right.
what I have here is just a photo that I took, a small video showing this is upstream of culvert d.
this is a very small rainfall event.
but as the rain comes down the tributary the tributary that feeds culvert d, it piment up the silt and that's a small detention pond and it's completely mud.
that stays in that pond until there's enough water for it to reach the culvert height and then it will leave.
so this will stay silted up until there's a large enough rainfall event.
and of course assuming that you're upstreams have been stabilized.
so along with the second option presented was the manual removal where large amounts of the sediment can be removed from the culvert areas and natural depressions along the creek.
the sediment that's been deposited is very easily visually recognized.
this is a photo that's upstream of hamilton pool along the reimers property.
and you can see very easily where the silt is a much different color than the natural bottom.
so the next option and what we recommended is a combination of manual removal as well as the wash down.
the manual removal will be able to essentially remove the large pocket pockets and sediment, silt that's several feet thick.
then there's also areas on the creek that it's very difficult to get into, plus the bottom may be cobbled in an area.
so we recommended using a spray down with a high pressure wash in some areas.
in as much using the high pressure wash and spray down, we will use the natural depressions for temporary sedimentation pools so that they will reach the temporary sedimentation pools, dewater them and then we'll collect the silt.
what you've noticed, this is just a picture back up to the map of what we've seen before.
these little blue pools are where we have gps'd in the locations of temporary sedimentation ponds that can be used to essentially wash parts of the area down and use those as detention ponds to let the silt settle out, and then we'll remove them manually.
this is a picture of one that's on the Davis property.
the creek actually comes in from the left, takes an extreme 90-degree turn and then flows off down to -- this actually feed intooz her pool.
this pool is already -- it probably has five to six feet of silt in it.
this is a naturally occurring sedimentation pond where we have to do -- we don't have to do any aggression sieve movement or construction in the creek bed, trying to stay as natural as possible.
but using the natural pond.
and her private property road runs' right here for access, use that as a sedimentation pond, dewater it and pull the sedimentation out.
>> when you say dewater it, I'm not understanding the terminology.
you mean going in and sucking out the muddy water and then extracting the water out of it?
>> you let it settle and you suck the water off the top very carefully until it reaches the top.
it is a mud, it's a pretty good mud, but you do try to get the water off the top after allowing it to settle.
and it is a vacuum the size of it truck.
>> is that a pretty expensive process?
>> I have presented cost estimates.
I believe you've been provided a copy of the cost estimate.
and that includes using the vacuum trucks.
>> okay.
>> and like I said earlier, when we're looking at the photos, the low water crossing at hamilton pool and hamilton pool road is a very large -- it's not a naturally occurring sedimentation pond because the low water crossing was put into place and they accented both sides of the wall.
but that would be our last temporary sedimentation basin to use.
it's prior to the pool in an effort to protect the pool from any further silttation.
did I go back the wrong way?
here?
so then that leads to once we recommend the cleaning of the creek, then there's always taking care of hamilton pool itself.
so we have the recommendation of use of dives and high pressure filters.
we have a vacuum pump that we've used and lifts the sediment from the hole to a holding taj and the water is run through a filter press.
the filter press removes a very high percentage of silt.
the resulting water is less than five microns.
it's very, very clean.
it's better than the filters you will have on the bottom of your sing for your drinking water.
the effluent would be placed back upstream past the waterfall.
this is a picture of the cleanup that we did of a very similar natural icon in the area where we used the filter pump and the pipes, and you will see this is a pipe that goes above the surface, and it feeds into a holding tank.
these are two holding tanks.
and then it feeds into a filter press application.
and that's my husband.
and I made him stand up there for perspective to see how big the facilities are.
these are two filter presses running side by side with a slurry tank mix.
the water is pressed through.
it's filtered and then the cakes on the filter presses are dried and they actually run in series.
it's built on high drollic pressure.
when the first one or the second one meets its pressure are, it's turned off and brought offline.
the other three continue to work.
it's shaked, shaken, the filter cake runs through a conveyor belt and off into a rolloff box for disposal.
so when we put together, we did provide you with a cocht estimate to do both the restoration and the restoration of hamilton pool for an estimated time of six months, a conservative time.
we hope to finish far before six months and an estimation of 45 days of running continuously filtration equipment on hamilton pool itself for a total cost for 2.3 million.
and I'm open for questions.
thank you.
>> so this is for the Travis County part or travis and hays county?
>> it's for the entire hamilton pool and its watershed.
no differentiation is made between hays or travis.
>> so it would cover both?
>> absolutely.
questions?
>> very good.
>> what is the eco logical ramification of no action?
>> we have recommended to the county the use of bio west, which are eco logical and biological experts.
I can give you my estimation that the creek bed will be choked out and there will be eco logical effects to vegetation and so fort.
I will have oh honestly say I'm not an expert in that field and will have to defer to the ramifications of such to people who know more than I do.
>> if we were to do nothing, what would be the effects on the quality of the water in hamilton pool and for how long?
>> I believe that it will be a very long-term effect on hamilton pool.
I believe that the silt shelf will stay there.
I think it will stay cloud and stay muddy, and especially during high use that actual individuals will actually create a muddy hole from individual use, from people coming to swim.
you can see it even when we're down here an walk along the bottom.
you can always tell where you've been because there's always a cloud following you.
I will tell you on the other projects we did in a similar fashion, the clarity of the pool was less than half a meter, and using this process we achieved greater than four meters.
and that was to a disircht set of objectives.
we actually feel like we could do much better than that.
we met our goal and exceeded it on that particular project, using very similar filltation setup.
>> so for Travis County residents who want to see this, if they were to go to hamilton pool today, what would they see?
>> they will see in my opinion a green, very cloudy pool.
you cannot see further than probably three to five feet.
does that make sense, see down through the water three to five feet?
>> and before the event?
>> I've been told -- I can honestly say I've not been to hamilton pool prior to being asked to assess the creeks.
and the pool itself, I've been told you could see the bottom, 20 to 30 feet.
>> how many?
>> 20 to 30 feet.
apparently there's some brush at the bottom that would naturally wash in, and you can see the tops of the trees and turtles and various animals swimming around, and now you can't see any of that.
>> is this week -- are there certain times of year you would want to do this kind of work or is any time as good as any other?
>> we have investigated that to some degree and there is a small portion -- hamilton pool is part of the -- forgive me if I say this long, balcones canyon preserve land.
and they do have the home of the golden cheeked warbler and there is a time in August that we would not need to be doing heavy equipment or loud equipment during that time frame.
I do think that most of the area, most of the creek is outside of that canyon land preserve land, but we are sense sieve to that as well.
sensitive to that as well.
>> okay.
any other questions?
and we do have a copy of the full report.
>> you have a copy and also the color copies of the summary report without all the extensive attachments.
>> okay.
I beg your pardon?
>>
>> [inaudible - no mic].
>> absolutely.
we continually check on-site to make sure -- now, of course since then the roadway has been completed.
it is now asphalt.
they have their txdot rail sides.
they have concreted numerous sections of the creek bed.
I will say and continue to say the haul road that feeds into culvert d is an imminent re-- I'm not sure the appropriate word.
it's going to happen again in culvert d.
the other remaining culverts do appear to be somewhat stabilized.
do I think it's the optimum?
absolutely not, but they do appear to be somewhat stabilized and I don't think the crisis will recur.
it will recur at d.
it's imminent.
>> one other question.
you talked about the effluent would be filtered out and dumped back upstream.
I didn't understand.
>> it's very clean water.
>> the silt won't be put back in.
>> no, it's very clean water.
the reason we chose to do that on the last project is a very sensitive vegetative bench that exists around there.
it's beautiful ferns.
all sorts of different cat tails and so forth.
so it's very important not to disturb that vegetative bench.
and there's -- there's a volume of water measured in inches that you need to keep wet essentially.
even though it seems counter intuitive, we are diluting, we do plan on rotating the volume of the pool three times.
yes, there is clean water coming in from the top, but we concentrate our divers along the bottom so the clean water is coming in on the top.
there is some dilution, there is some repetition of that water being filtered more than once, but nrd to maintain the eco logical habitat there, we need to keep the vegetative bench wet.
>> that was my question.
thanks.
>> [inaudible - no mic].
fshes.
>> any other questions?
>> where does the silt go?
when you take it out, where does it go?
>> we have -- we do have disposal of the silt, and to be honest, we're trying to find a much better alternative than putting it into the landfill.
there are some old quarries out there that we have been investigating to possibly use.
of course, doing appropriate -- maybe a clay liner on the top and then topsoil and revegetating, but this is still an outstanding solution.
we have provided costs or at least an estimate of cost to take it to the landfill, and that's kind of our last --
>> last resort?
>> yes.
not something we want to do, but so that we do have an option to go forward.
>> we will probably try not to go to the landfill if possible.
>> I agree.
>> any other questions?
comments?
thank you very much.
>>
>> [inaudible - no mic].
>> that's a good question and I don't know that we have the answer today.
we certainly want to respect the bcp, so I guess we could do what we could before that.
and after the nesting season, complete it.
or wait until after the nesting season.
>> wait until the fall.
>> I believe it's an option to do a lot of the creek cleanup prior to and just staying away from that particular area.
there is an issue with the longer -- what we're seeing now is that the silt cake in the creek bed is acting as a substrate right now.
it's actually a soil.
and we're starting to see the development of some nuisance vegetation.
so as we go through life cycles, as we go through numerous summer, spring, fall cycles, we are starting it to see the introduction of unwanted kind of more of a nuisance vegetation.
>> it may take a little time to amass $2.3 million.
so far heavy praying by the county judge hasn't helped a whole lot, but we'll keep working on that.
but we will make that decision very soon.
the source of funding, try to chat with those who are partners and those who should be partners and try to figure out a way to fix it.
so we would expedite it to the extent possible, mindful of bcp ramifications.
did I do a good job of avoiding that question?
>> [ laughter ] that it?
thank you very much.
>> thank you.
>> insightful, informative.
helpful.
>> thank you.
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Last Modified:
Wednesday, May 14, 2008 8:51 PM