Travis County Commssioners Court
July 29, 2003
The Closed Caption log for this Commissioners Court agenda item is provided by Travis County Internet Services. Since this file is derived from the Closed Captions created during live cablecasts, there are occasional spelling and grammatical errors. This Closed Caption log is not an official record the Commissioners Court Meeting and cannot be relied on for official purposes. For official records please contact the County Clerk at (512) 854-4722.
Item 35
Is lcra here also? Okay, then let's call up item number 35, consider and take appropriate action on the u.s. Army corps of engineers study showing the 100-year flood plain elevation on Lake Travis as 722 feet above mean sea level.
>> judge, Commissioners, this is -- what's on your agenda today is a result of a study that was done by the core at the request of lcra, and the result is that this study, which we have now been presented with. We have in our possession an engineering study that we have reviewed and commented on, and that study shows that there is a very high degree of potential for the base blood elevation for the 100-year event in Lake Travis to go from 716, which would currently regulate to one foot above that, to 722. That's a significant rise. And rather than mess up the details myself, the [inaudible] and john mccloud from lcra, and elston is from u.s. Army corps of engineers, is going to walk us through how we got to where we are and what it all means and what is going to fall out of the continuing study on this. The study is basically at that point where looking at elements to mitigate that effect, to do something about that six-foot rise is underway. And with that, elston.
>> thank you. We do have a presentation to put together. If you will give us a few moments, I believe we need to still hook that up. But in the meantime, I will take the opportunity to introduce myself. I'm elston [inaudible] with the army corps of engineers out of the fort worth district. We've undertaken this study, started approximately three years ago, and I think what I'm going to go ahead and do is the first part of this is really kind of like it feeds us into the study. So therefore I will kind of start with that. About three years ago, we epl embarked on this study, and it was at that time it became apparent that the meteorology in the state of Texas is very unique. There were -- if you bring up a map, which we have, as we start this, you will see that all throughout the central Texas area, where rainfall amounts throughout the 20th century that were some of them in excess of 50 inches in the very short span of time. That is a very unique situation, and it became apparent to lcra that this needed to be investigated on a further basis. We now have the -- the posz pweults are almost endless with today's technology and never before has there been something put together that would look at the entire basin as a whole and be able to analyze it not just in Travis County, but we started this study north of buchanan dam and went all the way to the gulf. Over 350 river miles. Which we developed frequency profiles in terms of how high the flood waters would get at a certain risk. And this was done on a very comprehensive matter. Give us just a few more moments. Do you have the handouts in front of you?
>> [inaudible].
>> we'll just go with the handouts.
>> we're about ready.
>> all right. The second slide you have in front of you shows an interesting map, and it has the point rainfall over -- some of them that occurred during the last recent history. And of particular note such as the one that happened this last year down near comfort where -- I don't remember the exact amount, but it was supposed to be --
>> is that -- maybe it's supposed to have a presentation.
>> well, they have it here. He doesn't --
>> we're trying to get the --
>> there it is.
>> thank you.
>> [inaudible].
>> this way the millions of residents who watch this show will be able to go right along with us.
>> okay. Here we are. We are ready to go now. What I wanted to pay particular note to was that in July of 2002, only a few miles to the south of the lower colorado basin, we had a total of 45 inches of rain in just a short period of time, and you all might recall how much of that was in the media about a year ago with canyon dam going over the spill way for if first time in its history. Another interesting note here is that while some of these areas were in the colorado basin, they haven't been critically centered yet in the colorado basin and for the most part most of the very large floods have. However, it is coincidence have missed the basin. But yet we all took this into light, and it's just a matter of time before the risk catches up to us. And so we took it on -- the lcra took it upon themselves as is pointed out in their charter from the state that it is their responsibility to aid in the prevention of damage to persons or properties. And with that they decided to partner with u.s. Army corps of engineers to undertake a feasibility study. This happened approximately three years ago. In addition to that, they also started a coalition or what this is is they banded together all their local governments and the counties within their basin with the common goal of flood plain management. Travis County is a member of the Texas colorado flood plain coalition. The accomplishments of our study to date where, first of all, it was a very extensive amount of work we had to do. Because we started with essentially nothing. We didn't even have the appropriate mapping to start with. And just to put the mapping in place took approximately a year and a half. With the mapping finally in place, the next step we went to modeling to develop a more complete flood level information flout the basin extending from upstream of lake buchanan all the way to the gulf. This was then integrated in with elevations we've taken from all the structures within the flood plain. And we now have an understanding of the number of structures we have that are at risk to flooding within the basin. Finally we took a preliminary look at all the alternatives and we estimated the cost of the possible flood stkapblgs that -- damages that could happen within the basin should that significant flood event occur. That doesn't go to say that we are completing through with all our work. We still have a lot to go. We have to develop alternatives, possible reduction or resolution of some of the problems that we have identified. We also have the mission to identify and develop possible ecosystem restoration opportunities. All of these things I'm talking about now are still to come as part of our second phase, which will get underway in this next fiscal year starting in October.
>> russell, could you give us the number where you said the number of structures affected by the floods?
>> yes, sir. We're going to get to that.
>> are we?
>> our first step was to develop the mapping throughout the entire basin. The amount of definition of this is it's entirely digital and we are -- it's called a two-foot contour mapping, which we believe that at any point in location it's plus or minus one foot. That's pretty good detail for this region especially. There are some rural areas we just went to plus or minus two feet. But the more populated areas we went to plus or minus a foot. And then finally down in the lower part, of course, a foot makes a lot of difference. While it sounds like it's very tight, in the coastal areas a foot can make a lot of difference. Again, this is all hypothetically modeled and this is just an example of the type of rainfall that we are talking about. Remember that we showed some points there in the first slide about 45 inches in a very short time frame. This is what we ended up as choosing as our hypothetical flood event for a flood that would happen on approximately once every 100 years. And that point that you see there, the very mid-point of that bullet, that's a 10-inch rainfall. So we're not showing you that these things are beyond reason. These things do in fact happen. One of the things that may be slightly different is that, for instance, a six- and seven-inch rainfall is over a rather extensive area, and yes, it must be critically centered, which hasn't happened yet over this basin. A critical center as we see it for the purposes of hydrologic modeling is somewhere in mason county. So it's way out west. And it's on the llano river within mason county. So this is key as we go into investigating alternatives is that it's not just the main stem of the colorado river that has a problem, but the llano river is a major tributary and a major factor. After we did the hydrologic aspects of this, we developed what we consider profiles. These are hydraulic profiles all the way along the main stem of the river. For the most part, our findings were relative -- relatively close to what we had with our earlier mapping. And with what we had shown on fema mapping, which has been in place since the late '70s. However, there's one area in particular within Travis County that has come to light that there is an extensive difference. And that is on Lake Travis itself. Why is that so much different? It's simply because Lake Travis is a storage reservoir. It is not just a run up river type situation where if you are off 10% on peak discharges you might have a foot of difference. Instead it's a volumetric controlled thing where if you are off 10% on amount of storage within the reservoir, that equates to an extensive novel sraeugs difference. So it is very sensitive to its storage versus elevation rather than discharge versus elevation. Then we come to the next part of this where we have estimated the amount of damages as a result of the flood profile. I'm showing these numbers in two persctives. Number one, we are showing if a 100-year flood event were to occur. Again that is correct is if a flood would occur on the average of once every 100 years. That doesn't go to say that if it happens next year, that we're safe for another 99 years. You have that 1% risk in any given year. But this is nonetheless a standard that our society typically has come to trust and to go by, and so we're showing those numbers in terms of a 100-year flood event. We're also showing them in terms of what you would expect annual. If you were to take all flood events over a long course of time and come up with an annual average, those are also shown on this slide. Also the number of structures that are at risk from a 100-year flood event are also showing. Will you see there that Lake Travis has the vast majority of structures that are at risk within Travis County. Lake Austin has a significant amount of damages on it as well as the lower part of Austin. However, those numbers are rather pale in comparison so what we have dealing with Lake Travis. The total expected annual damages within the county that we currently are estimating, and this is, again, just for structure and contents to those structures, approaches $12.7 million annually. [one moment, please, for change in captioners] .
>> but what's happened over the course of time is that the larger homes and the ones that are more expensive homes and the ones that are newer, built within the last 25 years, they were not allowed to build in anything less than the elevation 717, one foot above that 100 year. So while it's only about a 550-structure difference in the number of structures, it's that area where you get all your expensive homes at. So all of a sudden we're putting a lot of expensive homes at risk. It's always been there, but now we are estimating that they will be at risk for a 100 year storm event. What we do now, the next thing we have to do, we develop alternatives for reducing it. And while we have an information paper that's going to be published next month, this information paper contains the exist is information for existing conditions I just put out. But we thought it wasn't right to put it out to the public and not have any possible reasonable option, so in addition to that we decided to take -- before we released that information paper, we took a preliminary look at some of the alternatives. And that's what we're going to talk about just briefly. Number one, we could take no action, go blindly along our way. Number two, this ties into what we're talking about today, to adopt the raised floodplain levels and make the insurance available. Now, the insurance is already available, but we would be updating the maps and putting out the floodplain procedures we have in place and utilizing to the best of our abilities? Item number 3, we could buy and remove the structures that are at risk. Now, this could be a very expensive proposition. I've provided a number here that shows you our estimated value of the structures that are there. Just to the structures and contents, the value approaches 277 million. Now, if we were to actually try to have to buy those structures and remove them, then, of course, you also have the property to deal with, so that number would be somewhat greater than that. That's a very expensive way to go. Another alternative is to modify the operating rules on mansfield dam. And we're going to talk a little bit more about that. The costs involved, rather insignificant. It's just adoption of different operating rules. But there are trade-offs, which we're going to talk about. We could take a look at new reservoirs upstream, possibly on the llano or the means dam, or we could combine any of these alternatives. How do we decide what to do? Well, we've decided that at this point that we would not look at the first three options, we're going to do that more in-depth and in detail next fiscal year, but we did want to take a closer look at options 4 and 5 because they seem to be some alternatives that could possibly work. And as a result we've decided to go forward with some preliminary engineering investigations. And again, the feasibilities only from an engineering standpoint and not from an economic standpoint. Again, we looked at modification of the mansfield dam operating rules as well as possible new reservoir sites on the llano river as well as the mean dams upstream of lake buchanan. Again, the two reservoir sites that we selected, they were rather -- while they weren't at ran don, they were very generic and the sites that we're going to be looking at for further investigations are both in llano and mason counties as well as upstream of lake buchanan.
>> nelson, what are the roughly costs and and obviously the size of it, but how long does it take to really do a reservoir? If you were to start tomorrow, is that a 20-year project?
>> yes, sir. Without a doubt something of that magnitude could easily go into a 15 to 20-year category. So it is not a fix overnight, it is a fix that would be very long-term, and certainly something that we can't rule out at this point, but it's something that you have to keep in mind is long-term. And that comes into play with some of the things that you might be talking about a little later about floodplain management. So anyway, yes, it is a long-term situation.
>> why does it take so long?
>> oh, gosh, why does it take so long? Anything from land acquisition issues, extensive study, everything has to be taken into account.
>> coming up with the money to pay for it?
>> yes, that's another thing, coming up with a sponsorship and the money to pay for something of that extensive. We're talking about a reservoir in this modern day, and it would be in terms of hundreds of millions of dollars. It is no small feat, even given that we're talking about areas at are not extensively populated, it's still a very expensive proposition. Is there a presumption that this would be a u.s. Army corps of engineers project, or would that revert to the lcra or both?
>> if we were to look at this -- and when we go into our second phase of this and other extensive phases, if reservoirs prove to look economically favorable, they would be considered in the report as a corps of engineers reservoir with local sponsorship. We don't do them on our own any more. There has to be local partners and local sponsorship. And they would be shown in that perspective, but only if our investigations proved it would be economically justified. If our initial investigation showed that -- well, if it's feasible, they're not economically justified and then it kind of goes away at that point as a viable al learn active.
>> which means you would be dealing with congressional appropriations. I know that congressman pickle spent almost 15 years getting monies for the boggy creek improvements in east Austin.
>> no doubt. We are already with those issues just to get this study going and underway. So we deal with this on an annual basis.
>> a little bit about the preliminary analysis. First of all, changing in the operating rules. Again, you have to remember the answers -- we were trying to find out is there some engineering solutions out there. And the results indicated that yes, there are. There are indeed some engineering solutions out there that could solve the problem, both in terms of operating changes as well as the new reservoirs. And this side kind of gives you perspective that if we were to increase releases or even release earlier from Lake Travis, we could already help the situation by several feet. While increasing the discharge to 120,000, where in terms we are now limiting that discharge to 90,000, we could draw it down to almost the point that it was originally, down to near 716. If we utilize the entire spillway on Lake Travis and open up the gates as early as we can when we do understand that there is a flood of this magnitude coming, we could bring it down to elevation 16. So yes, this is an option. New reservoirs -- both new reservoirs that we looked at, both the llano river and the colorado river showed that engineeringly we could bring the elevations down and down rather significantly, being there's also possibilities of a combination of these two that would bring it down even more. But here's the bad terms poablghts that are certainly possible, there is an extensive trade-off involved. You have a classic downstream, upstream relationship here, where while we're currently on lake Austin, showing 88 structures that get water in their homes with the release of 90,000 cfs, this would increase by approximately an additional 133 homes or more than double if we were to increase that release by only 33%. So you can see it's perfectly sensitive and can be set up for a classic battle of upstream versus downstream. You can only keep in mind that lake was put into place to protect the citizens located in Austin and downstream of the lake. And downstream an entire basin. So this must be kept in mind. What's next for us again, we're going to issue that first information paper. They should be out public on the streets next month. Has undergone an extensive review and it has all the engineering that's associated with it. And the county and has already seen the numbers that are in that release. We are going to evaluate the alternatives there shown here in much more detail. We continue to form partnerships and we're always looking for more and more partners and agencies. The lower colorado river authority floodplain coalition is kind of our baseline for developing this and they're very interested in what we're doing and keep a handle and abreast on this study at all times. Finally, we're going to develop and hopefully in the future try to implement something that would a r. Assist in rereceiving some of these issues that you see here today. And with that i'd like to conclude the presentation and entertain any more questions that you may have.
>> so to the Travis County resident who has a home on Lake Travis today at 717, --
>> I would tell that citizen, first of all, don't panic. That's something that we're very concerned with as we release this information to the public. You're not settling in the floodplain. We are, -- we believe we have a more accurate assessment of the flood at risk, that you nowr at risk somewhat. We believe the accuracy of our risk assessment is that you are more at risk than you originally thought, but please don't panic. The best approach immediately is to use explain measures and tell that citizen, by all means, get floodplain insurance get insurance to protect you from any possible flooding in the future so that if it does happen, at least you're insured for that. And then on top of that you must assure that citizen that we're looking at alternatives and not just floodplain management.
>> have you noticed when you go and tell a resident that -- what you need to do is take floodplain insurance, it doesn't -- doesn't someone already have the floodplain insurance even if they're at the 717 or not necessarily?
>> if they're above 717 on Lake Travis, they are not required to have it. In fact, with the way things are drawn up, if they're only that zone above the 100-year floodplain, they can actually get the floodplain -- the flood insurance at a cheaper rate because they're in that zone. So they can still get it and it's even at a cheaper rate.
>> well, that's the gripe we're going to hear, especially the Commissioner of precinct 3 concerning Lake Travis. We'll have a number of people call and say what does this mean? Can I not get insurance? Yeah, you can get insurance, but at what cost? And I guess you have run some numbers.
>> the current insurance rates are based on the fema maps, which shows the floodplain at 716. The proposed recommendation in front of you guys today is to let folks know when they come in for a building permit that this study is out there. That's all staff is recommending at this time because the study is ongoing. They may find a solution in two, three years when this study is up, and we don't want to adopt something radical such as the 722 if in three years the study finds that it's back down to 716. But flood insurance is available to all citizens of Travis County because we participate in the nfip through our floodplain regulation.
>> Commissioner, having been here, done this in terms of -- I know judge Biscoe has even more in terms of what happened out in the graveyard point area. What's really difficult is if we have this fiduciary responsibility related to the administration of the floodplain and yet people come in with absolutely tragic stories in terms of damage who want, no matter how crazy it might be, to rebuild, even not having floodplain insurance. They want to take the risk and rebuild. They do not want to give up their homestead. And I i don't understand that, but those are the difficult things, not how you may have to get flood insurance, it's to deal with some very difficult stories about people who have sunk their lovely hood into there and have tried to come up with some pretty darn creative ways to get around it, carlos and charlie's one of them in terms of the floating structure. But most of the folks don't have the opportunity to do a floating thing and they've got to figure out ways to elevate their property or get their property out from the flooding area. That's what people don't understand. It's like Lake Travis is meant to be an inundation area. It doesn't mean it might. It is that it will. And everything below there is constant level lakes. And it flushes out of mansfield dam and it's got to go someplace. And those folks below should not have the expectations they would flood. That's what travis was built for is to hold it all until it can be logically released, but some of the most difficult stories I ever to do do in 18 years in television had to do with flooding and the incredible amount of damage that it can do to lives and property. The lives lost are just --
>> bottom line, who is -- what is the gospel here? Is it the corps? Is it lcra? It certainly isn't Travis County. But when push comes to shove, if you have this outrage of people saying, you know what, I did build mine at 719. Now all of a sudden I have an insurance policy -- because you're right, the homes, a lot of these homes are not lean-to's. They are multi-million-dollar homes. Some flood insurance on that is going to be something that you're going to have some squirming about, I'm sure.
>> but flood insurance will not be required for a property at 7, not unless it's already required presently by where they are as far as the floodplain maps go. In fact, without with this new -- even with this new information, the flood insurance is relatively cheap compared to a home that is in the floodplain now. So we would encourage all citizens of Travis County that fall between that 716 and 722 to go ahead and purchase it now. A policy is in place if maps do change, the rates will not be increased under current fema regulations.
>> so what is fema doing with the new projections?
>> fema currently has this study under review as to the corps and lcra and everybody else out there. Tomorrow staff is meeting with fema on a scoping study to remap Travis County. In all likelihood, this core study will be a part of that remapping effort. It is likely we won't see the 722 on a map for four on five years, but the scoping effort is just underway, so we will have to come back and update you on exactly when fema expects to update our map.
>> and so is the real answer to why all of a sudden have you decided, even though you've said we've had a study, is it the sophistication, is that really what we've got down to? Because it's not like more runoff from -- it's not like some of the areas where we have water -- what the real answer to it is with the sophistication of what we are able to do today and to determine, you know, with all of the meteorolgy and everything factored into the thing, we're telling you that this is the newest and best information we can give you today?
>> yes, sir. The technology that was available the last time this is really studied in-depth was the late sfets '70's. And we dent have the tools at that time do the analysis that we did now. It is quite different.
>> how long has it been 716.
>> 1978.
>> '78? Okay.
>> how far from Lake Travis do you need to be for this to be irrelevant to your life?
>> staff is recommending 723.
>> that's the highest --
>> it varies.
>> how far from the lake? Say I'm three miles from the lake. Is this irrelevant to me in my life? Do you see what I'm saying?
>> in all likelihood it is. There hasn't been an evaluation on how much extra land has been in the floodplain. That's phase 2 of this study. In some places it won't make a difference because it's cliff side. Other places it could be acres and acres of more land in the floodplain.
>> you don't want to be three miles south of mansfield dam. [ laughter ] if something were to happen to the dam.
>> that's correct.
>> but as a general rule, if you are within what distance of Lake Travis, you probably ought to be concerned because it impacts you more than others. Is there like a rough distance that we can use?
>> sir, it's really more dependent on vertical depth than it is distance, and I think that's what she was trying to say, is in some areas where the scope of the -- in terms of an economic impact, I think there is an economic impact further out and how it can affect communities and how they deal with it, all the communities along the lake. It will certain have an impact to the community.
>> is it safe to say that if you've got a lot that fronts on the lake, you're definitely affected? Lakefront lot?
>> yes, sir, that's a safe bet.
>> can I ask one other question? This study, is it based on existing conditions or does it factor in future development --
>> that's one point I should make. This is a large -- the largest basin in the state in terms of square miles. And urbanization -- this is not a result of urbanization in the colorado watershed. That's just -- I could probably get a computer model to tweak slightly different by putting some urbanization in there in terms of -- in terms of relative difference, it's very slight.
>> so it's based on existing, but you're saying the urbanization wouldn't make that much of a difference if you factored it in?
>> that is correct. I mean, there are things in terms of land use changes as a result of farming practices that probably have a bigger impact than urbanization itself had within the basin.
>> so it's not like this study is going to be outdated as of tomorrow and --
>> also the counter to that is a sister project here where we're dealing with the onion creek watershed that has urbanization over it during the next 50 years. That's the flip sewedside of that point.
>> that one is affected by new development?
>> yes, sir.
>> how do you -- in sharing this information with those many lake side community, I'm thinking of lago vista, point venture, Lakeway, how are they learning what we have just learned today?
>> I think we brought this initially to them back in April, isn't that correct?
>> so they have been aware of it and are aware of this study that's coming up.
>> so if a resident who sees this program later after not panicking, as you recommend, who should they call for more information, the county staff or lcra? Who?
>> we have a website on board right now that they can start, and it has all the points of contact with Travis County, lcra, myself and the city of Austin. They're all on there.
>> and what's that website?
>> the website is www.fdep.org. Flood damage evaluation project.
>> we might see about getting a link on our website so that somebody could just punch it up in terms of floodplain information and would get a link and people won't have to figure it out.
>> our call stacy. Stacy is very much informed.
>> we appreciate your visit. Anything further on this item?
>> thank you very much.
>> appreciate the hard work.
Last Modified:
Wednesday, July 30, 2003 12:31 PM