City of Laredo, Texas Citizens Environmental Advisory Committee, 13 Apr 2022

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From YouTube: Citizens' Environmental Advisory Committee Meeting 041322

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Citizens' Environmental Advisory Committee Meeting 041322

A

Sure happy to is everyone ready.

B

A

Okay, uh good afternoon, everyone, my name, is russell jordan, a member of this uh of this committee. Today's date is april, 13th 2022.. It is uh 1, 20 uh p.m, and I'd like to call the meeting to order and uh the first item, I guess- would be a roll call of members.

C

Okay, I will take care of that from this. uh Mr jim jones,.

B

C

Russell jordan.

A

C

Richard on sundays,.

B

We fired all our citizens.

A

Well then, and uh item number five, then I guess, is the meat of the meeting would be discussion, presentation of a floodplain study of sakate and manalas creeks.

D

um Mr chairman of john porter,.

A

D

Thank you. Thank you, everybody for being able to make it, so we recently got a grant from texas water development board and uh from the water development board. We we have anita with us and then the consultant that's going to be doing. The work is, um is eric and he'll he'll be going over. The he's got a presentation, and then uh he can answer questions uh but yeah.

D

This will will explain to the committee and also allows the public to to learn more about this um floodplain setting that we're going to conduct for minatas and zagate.

A

D

Eric, if you want to, if you want to introduce yourself and uh and and and the floor, is yours.

E

Okay, great yes, so thank you, everybody. My name is eric scheiby with shopee consulting. We were able to help the city with this grant application and ultimately were selected by the city to assist with this very interesting project. I'm going to turn my camera off. I wanted you all to all see me, but I'm on my phone and my battery's going down. So if I turn my camera off, then it'll save my battery and anyways I'm going to transition over to a powerpoint slide.

E

So let me do that right now,.

C

E

Okay, so this uh project is a flood control. You know basically a drainage plant of pinatas and zagate creek watershed I was visiting with john porter and other folks at the city several years back about some of the drainage issues that have plagued the city for uh quite a long time, and with the recent water development board, flood infrastructure fund money, it looked like a great opportunity to do a nice cost share.

E

We were able to get 90 funding for this project by the texas water development board and all that came about from the 86 legislature, which host hurricane harvey. uh The legislature allocated approximately 750 million dollars to drainage projects and they broke this funding into four categories.

E

Category one projects are planning studies, category two or design and construction. I don't really remember what three and four are, but it's something like flood warning and and other activities of that nature.

E

This map here illustrates the different projects throughout the state that were approved through this infrastructure fund. um Anita with the texas floor development board is on this call and she'd be able to answer. You know any other questions pertaining to this overall program.

E

About what the water development board is wanting to do is anywhere where there isn't an existing drainage master plan, they wanted to initially fund those, that's why they call them category one and then they're moving once the drainage master plans are finalized and projects construction projects are identified, then those would then roll into a future category 2 application.

E

So this is kind of a long term program. This is all also being built into the regional flood, plain effort which some of you may be aware of, and that's along the little rio grande regional flood planning group- and I know laredo- is that part participating in that? I believe, there's some members of the city that are on that board and it it spans the lower colorado. I mean the lower uh rio grande from you know, basically, midway up the texas. uh You know border of mexico down to the gulf of mexico.

E

uh Previous studies done on the zagate, creek and monada's creek are back in 2010.

E

It was a texas, water, development, board, blood protection planning, study, uh dated 2010 and it focused on a portion of the zagate watershed, but it did not focus on the entire zagate creek watershed which this this project will focus on all the tributaries, etc and I'll go into a little more detail on that.

E

Then the monado's creek, the last time it was studied, was in 2004, and that was a fema effort. So some of this, as you can see, is somewhat dated anywhere from 10 to almost 20 years old.

E

The something to keep in mind is the level of development. You know 20 years ago is significantly different in laredo than it is now, and that obviously adds to additional runoff additional flood risk et cetera.

E

This is a map that illustrates the general the the meat of the project area. So the primary focus of this project is on the monado since it got to the creek, but we're also going to be doing a community outreach for everything for the various watersheds that are within a a certain hub boundary, which that's just a fancy word for a larger watershed.

E

Boundary that's been established by the us geological survey and that essentially and I'll show you a map of that of what those limits are, but it it expands out into wet county this map here, zakate creek is the watershed boundary in red and the watershed boundary in orange is monadas creek.

E

This shows the current effective fema floodplain maps uh based upon the best available information that we have, and that's the 2010, that's that this is actually studies prior to that 2010, even in sacate country.

E

um This is a map. This next figure is a the study results of the 100 year, estimated flood risk from the zagate creek watershed. So I'm going to flip back between these two, but one thing you should look at is the flooding extents so again, this area in purple versus the area in blue on the cottage creek and you can see, there's a quite a bit difference in some areas of the estimated flood risk.

E

The methods used in this 2010 study are dated the engineering methods and there's some better tools available, called two-dimensional modeling that will allow us to better estimate flood risk once it leaves the channel and goes blood flooding through the streets and the storm sewer systems, etc.

E

That was not able to be captured even in this 2010 study.

E

This is ultimately the study limits, uh as you guys have seen this last or not last slide. But this next slide you can see the boundary in red again is zacate freak. The boundary in orange is monado's creek and then there's this boundary this black boundary, and that is the hub10 watershed.

E

This is the area where we're going to be doing some public outreach out in webb county to solicit feedback on any flood risk issues that may exist well outside of these primary focus points so that this information can be gathered, disseminated to the water development board and then possibly future grant money may be available to webb, county or the city and other watersheds, such as chicone, creek or or some of the others.

E

The the main focus of this project again is a drainage master plan, and by that we mean identifying flood control solutions, that's channel improvement projects, levees regional detention, ponds, flood warning improvements such as additional gauge river gauge locations, maybe even real-time flood mapping that could be displayed on a website so that people can see the real-time flood risk as as a rain event is occurring.

E

This is just a little schematic of a typical, uh typical cross-section of a channel, as you have uh you know, fill and improvements that are done, such as this little house. That's shown on the left side that impacts the floodplain and you know in order to protect structures or to reduce that flood risk. You know, channel, widening or levies or different type of projects is, is ultimately going to be what's required to manage that flood risk long term.

E

I know there's a lot of there's a lot of communities and I know laredo probably does it as well uh detention. You know onsite detention improvements, but something to keep in mind with on-site detention is that it does mitigate blood risk immediately downstream of those detention ponds. But it does not manage flood volume, and so it focuses primarily on managing peak flow and one of the risks that communities will always run into is, as development occurs, there's added impervious cover via pavement or building rooftops and there's less of water.

E

That's able to infiltrate the soil, so there's an increase in volume and there's very rarely do communities manage volume. um They almost always focus on peak flow and when you don't manage volume, uh you're going to always have an increase in flood risk along the floodplain.

E

So one of the ways that we're going to help address that is not only look at an existing conditions, estimate of flood risk, but we're also going to estimate a future conditions. Now, that's not so much of an issue. I'm going to go back a couple of slides, that's not so much an issue on zacate creek, because it's pretty well fully built out, except for maybe at the very upper head water, but on monado's, creek, there's still portions of the watershed that remain undeveloped.

E

That would be that we could estimate what those uh additional impervious cover may be and then come up with a future conditions. Flood risk.

E

The overall scope of this project, again, is you know: we're trying to reach out to the community, identify existing flood risk in the outer area. We're also trying to identify flood risk within monadas. It's up, cicada, creek, using engineering methods and calculations uh determine you know, are the are the fema flood maps accurate?

E

I think we already know in zakate, creek they're, not uh probably they're, going to it's going to be shown that the ones in monadas and menatas creek are not accurate as well, and then, where can we do future flood control improvements and that gets challenging in urban areas because you have limited right-of-way?

E

Sometimes the best thing you can do is just concrete line the channel, something to keep in mind when we look at alternatives for this project, we're not necessarily going to come up with solutions that will eliminate flood risk, but the goal will be to come up with cost-effective solutions that reduce flood risk.

E

So we'll be looking at okay, how many buildings get pulled out of the flood plain or uh how many buildings get pulled out of a 25-year flood plane? And then what does that construction cost? And then come up with projects that have a positive benefit cost, primarily because it that is the best way to achieve grant funding, both federal through fema, as well as through the corps of engineers or even the state fif program, category 2 funds.

E

This is the project schedule that we have right now. The goal is to have this project complete by september 2023. So we kicked off this project about a week ago or a month and a half ago our firm was selected through our due process. I think back in november december time frame, and then we signed a contract in january february and uh we're soon going to be starting.

E

Our field survey data collection, where we survey the various bridge structures and colbert crossings throughout the city, and then we're going to be starting our hydrologic analysis, that's where we come up with our uh detailed watershed, boundary in sub-watersheds and ultimately come up with the peak flows for the 100-year event, 500-year event and then we'll move into the hydraulic modeling.

E

That's the two-dimensional modeling, where we can simulate the flow not only what's going down the main channels of these various watersheds, but once it overtops the banks and floods through the streets and winds its way in between buildings. Where does that water go that'll, be followed by alternative analysis and benefit cost analysis and then draft report?

E

We have three public meetings. This is the first of the three we'll have two more.

E

The next public meeting will likely be coincide with the completion of the the new h, h, modeling, which ultimately is the new floodplain maps and flood risk areas that we are estimating from our models, uh something to also keep in mind we're going to be calibrating all of our results to historic flood events, so we'll be at some point, looking to visit with the city, the county, the local community, about any high water marks that are available from past flood events that we can make sure our model is recreating those storm events accurately before we start looking at alternatives.

E

The last public meeting will focus on it'll, be you know, around september of 2023 or or august that last public meeting will be presenting the results of our study, which is the meat of it all being the alternatives that we identify. The rough cost estimates for them. The benefit cost ratios and then identifying projects that that the city could likely apply for future category 2 fif branches.

E

And that is the sorry.

C

E

So that's the conclusion of my presentation. Is there any questions.

C

um Did you say that uh you were going to consider a high marks for flooding natural flooding or not uh not natural place like like that's what we had? um She opened the gates of the.

E

Yeah, so it could be both uh you know. If we all we need to know, is you know if it's an un, we'll call an unnatural flooding where you know there was a release along the rio grande and it backed water up uh that could be. If we had are able to get some flow information for those releases, then we could see how that affects things.

E

But something to keep in mind is if it's not a rainstorm, you know the rio grande will only back up so much, but our focus of this project is not the rio grande. It's the monado zakate creek, so that rio grande effect, would only you know likely affect monado since I've got the creek near their outfalls.

E

So primarily the focus is going to be on rainfall events and we're going to try to get you know any historic rainfall or flood events on those watersheds. We want to get high water marks for, and you know, any kind of records of what flooded, what buildings flooded, how deep and then, when we simulate our, we can actually recreate those storm events if they were within the last 20 25 years because of nexrad radar data for those storm events that the national oceanic and atmospheric administration has catalogued.

E

So we can take those and we can recreate those storm events in our computer model and make sure that our model is replicating reality because we we always recognize. Models are never perfect, but we want to make them useful and the best way to do that is to calibrate them to real storm events.

E

Anita is there anything that you wanted to chime in on? Are you were you able to get your audio to work.

F

Yes, y'all hear me: I had to call in.

E

F

Yeah, no, I don't have anything particular to hat um to this. I think it was a great presentation. Does anyone have any questions about twd or anything on our side.

C

Yeah so there's a question.

B

Sorry uh for the flood predictions of abletons and paving it where it would be like five to ten feet more than they expected. You are using the modern oceanic radar uh instead of just having it for the start that we know of. Since we know that our atmosphere, uh pressure and everything is changing due to climate change. You might want to have it where it could be 10 5 to 10 feet more flats than the current rate, because our current rate is before we have more catastrophic climate change.

E

Right, you know the topic of climate change is very complex and historically flood risk analysis and drainage. Studies of this nature that fema have done or the corps of engineers have always been standing where we are and looking into the past and saying, okay, what happened in the past is that you know let's get some statistics for rainfall in the past for flood risk in the past and then say you know we'll project that into the future.

E

It gets very challenging to have a good handle on how much the climate will change and how quickly you know, will it uh will there be an additional?

E

You know one inch of rainfall statistically you know every month, or will it be much more severe and I have yet to be able to find good literature or scientific studies that can well predict that so what four of engine years many times a year we've got some echo. What.

F

F

E

Okay, so uh what the corps of engineers has recommended in other federal agencies is that we, whenever we design flood reduction solutions, we add free board. So, for example, if we design a detention pond for 80, acre feet of storage- hey, let's add an additional 10 or 15 percent to that to account for future flood risk or climactic changes. Or if we build a levee- and we say it needs to be 10 feet tall. Maybe we make it 12 feet tall.

E

Unfortunately, that's been the limited recommendations that I've been able to find by the federal government in order to handle that, but that is how we would handle. It is not necessarily in the modeling, but in the final recommendations that we give for flood reduction solution.

F

uh Sorry all I had got disconnected. Can I hear what the original question was.

C

C

About uh if the natural flooding events like the release of water, probably understand.

B

Could be raised by five to ten feet to account for climate change that could.

E

Be their current.

B

Event, since our temperature is of the current climate, but we still you're averaging out for 25 and a hundred years, we might want to average up more of footage that would be needed because of the climate and how it's constantly changing.

C

That was the second or the second question. Yes, but the first one was about release of water from the amistad living.

F

Can you all hear me yeah? We can hear you yeah. I think um when it comes to specifics, like that er answering the question earlier was more fitted.

F

And I honestly think, like eric mentioned earlier in his presentation uh learning what the region, I believe, is region 15 for uh laredo what they're doing as well when it comes to climate change and historic rainfall data would be useful and beneficial to tap into their meetings every month as well. Eric, I'm not sure. If you have spoken to anyone over there or thought about attending the meeting that I would definitely recommend it.

E

Okay, yeah. That sounds good. I will.

F

If you need a contact or if you want me to send you any like upcoming information about one of the greetings, I can do that.

E

Yes, please do.

A

Does anyone else have any other questions for mr sheeb.

C

There's another question:.

B

So sarah sorry about that, I have for me if we do a quick google search, I'm just wondering uh for the short term right now before the project is able to be fully developed uh for the short term. Are they able to get a like uh inflatable directive barriers for flooding? There are a lot of them that they have on youtube and there's even some plastic ones that are made, so they could direct um flooding, flood water on the streets, away from houses and directed towards the river there's.

B

Also other areas like using barriers such as, if I'm not mistaken, in india they're using care as a barrier where we use hay since hair is more permeable and water is able to pass through.

B

E

Yeah so and you were cutting out a little bit, but it sounds like you were asking about some immediate solutions to flooding risk and I think I'll defer to john or someone at the city on that one, because our focus is on this master plan.

C

We usually uh review development and projects and blueprints, and we ask them to include best management practices such as the one that you described. Thank you for individual projects and developments.