Wet Weather Planning

Good morning, and welcome to the wet weather planning webinar. I'm glad you've all joined us for this discussion. Let's jump right in. Dori Saba is a seasoned engineer and project manager with more than twenty years of experience working on a variety of municipal water resources and transportation projects for the public and private sectors. His technical expertise includes hydraulic and hydrologic modeling, natural systems protection and restoration, watershed management master plans, stormwater infrastructure design, and dam engineering. His background also includes extensive work with project development, planning, scoping, and budgeting, QA, QC, and construction services. His expertise in client and staff management is beneficial to our recent stormwater professionals and our municipal and private customers. He is also a certified GIS professional and erosion and sediment control designer. Ken Ory is also with Withers Chevenell, and he's with their practice area lead for utilities. He has more than twenty six years of extensive experience in water and waste management wastewater treatment, design and construction, water conveyance, including pump stations and ground and elevated storage, sewer conveyance, including pump stations, force mains, and large diameter outfalls, wet weather facility design and planning, water distribution and sewer conveyance optimization, and operational analysis. In addition to the traditional water resource engineering above, Kenya has completed projects in greenway design, transportation, roadway design, including forest, asphalt, land development, public works, facility design public works facility designs, stormwater design, including stream restoration, and low impact development techniques, and resilience design for buildings. We are very pleased to have them both with us today to share their extensive knowledge and experience around wet water wet weather management, which I think we all today understand is a critically important piece of of every municipality's responsibility. So I will go ahead and turn it over to you now, Dorey. Thank you very much. Hey. Perfect. Well, thank you, everyone, and I'm glad to be here along with Ken to present. And, we'll we'll be talking about the wet weather planning. It's predicting the rain and the runoff from it, as well as building the ark. We'll get here in a minute as to why the verse is in here. And I'll go to the our famous Warren Buffett, and Ken loves this, quote, predicting the rain doesn't count, building the ark does, and that's why he we want to talk about both, when why predicting the rain actually does count because we do not have any way of knowing when to get to the arc if we're not going to predict that rain. And that's why we'd, we will be talking about both of them, not versus, and, why we need them. And I'm really glad that we are starting holistic approach. Both, you saw, Ken is leading our utilities and the one on the store motor, and we need to think of a one water approach if we want to be successful with all this. Also, another word buffet quote in here, and, this applies actually to me. I don't own my yacht. I just use cans in here, but but that's I'm going to put him on the spot now throughout the presentation. And if you need a yacht tour tour, just contact Ken. That's his Yeah. So let's start with the big picture. Why to worry about it? I mean, we see that nice pictures or some, clouds coming in and the satellite imagery. But what this really means I mean, we start to think of it that it's flooding the areas. With time, it starts to become a memorial. We'll just stack things which hurricane topped to each other or which storm topped the others. It does not have to be only a hurricane. In terms of flooding and stormwater, actually, we need to think more of the impact and the flooding that it causes rather than the category of the hurricane. But, really, once we start to go into this other slide is whenever it's flooding, not everyone has in their mind other than us in the profession what is going to happen, those oceans, treatment plant, the critical facilities, and the operators will have to struggle and deal with it. What happens during these events? I mean, the title says it there's a lot of water and how to handle it, whether it is during the peak of storm or how long it takes, how how are we going to route it, where it's going from. And then the bigger question is what we're going to do. Do we just keep increasing pipe sizes? So make the sanitary sewer much bigger to account for the inflow from the these big events. They are designed for a certain volume of water that's coming from homes. Once we start to have inundation from flooding, they will get overwhelmed. And is it realistic? Do we keep raising taxes? We will increase the rates for treating the sewage water. And same thing for stormwater. Like, how in addition to just how to manage it, but also how are we deriving these flows? What kind of data are we using? We have data that is being used, and there are multiple conflicting interests between various stakeholders that are impacted from it, whether, municipalities, water management districts in certain, jurisdictions or developers, and how are we going to really be able to answer the questions with the that relies really on accurate data, up to date data, and more data than what was used initially to derive to derive what we are using now in our formulas. And, really, it's time to start to think of it from a performance measure. Like, where do we want to get to, and what are our level of services? What that's the thing that we want to set from the beginning, and then we start to design accordingly. We're not chasing the next storm that comes in, and then we'll go back in circles and redesign things now that they failed. And we'll talk about each ones in details in the coming slides in here, but that's the big picture. So the presentation in here, really, it covers both predicting the rain and building the ark, like I said. We'll talk about, in terms of the rain. It's not only forecasting rain. It's also, like, what happens to the rain, the storm, and the flows that they will generate, how do we plan for, flooding, and how do we plan the wastewater system around it, and talking about level of service in a little bit. So for predicting the rain, like, really, the first thing that comes to mind is, okay. We know it's going to rain. We're going to forecast it. But what are the regulations in place? Like, what what is driving our design? Is it just the regulation, and is it regulation on the stormwater side or wastewater side? And we'll touch base on both of them. And then, typically, whenever we're talking about the big storm, every the mindset is directly going to flooding and how to protect the, some structures from flooding. But sometimes the water quality impacts are overlooked, and, when you're doing small, small storm events, that's where we designed to improve the stormwater quality. But we get one big event that will offset all the good work that was done during the small events if we are not planning correctly. So it's time to start to consider both. We'll talk a little bit about the public perception and whether it's reliable to just rely on it that the public would go and push to for higher design standards or not. And then realistically, what storm are we going to design for? How much can we invest and not something that's the realistic concerns in here? Regulatory drivers, we mentioned it, like and here we have few of these things that, we're going through also. But, really, for the wastewater itself, there isn't a set of regulation that tells you, like, okay. We're we're going to design for this storm level of service or not. And having that holistic approach of looking at both, we can rely some and these are the sanitary sewer work. We could rely on some of the stormwater regulations to do the work, but these are too localized. Sometimes some areas have some level of protection for a hundred year event. Some, have it for the five hundred year event. But all of them are based on floodplain areas, so it's effective floodplain, regulatory floodplains. We know that floodings are extending way beyond this, and there are areas that are map not met that are not effective. So there are plenty of deficiencies in the regulatory environment that would allow us or not allow us to really design for the appropriate storms and be prepared and know what is our level of service and know what is our level of preparedness, where are our vulnerabilities in case of a event. Water quality impacts, I think the pictures speak to themselves, but, yes, that's as nasty as it sounds. I mean, like, going off big waste, they are overflowing out and going all over the place. That's because of that level of service. Like, they are designed for the operational considerations, but what happens from the outside, outside and it does not have to be just during a hurricane, anything during major storms. We have tons of septic systems, houses that are on septic, and we'll have that combination. Just last month here in County, they had about one point five million gallons during tropical storm, Debbie of treated and untreated wastewater go and mixed, into the water bodies. So there is substantial impacts to water quality that, is at stake in here, and it is long overdue that we start to consider all these into our design and, operations. This one is about public perception in here. Some nice pictures. I mean, people will get upset about flooding or enjoy it depending on your personality or not. But I don't think outside of our practices and people who work with it, we are not thinking as much of how are we operating our plans. It might come on the news like the like we saw on the previous slide that we have some breaking news of overflows that happened. But in terms of operation, this we cannot rely that this will become a public push that we need to improve the environment, the regulatory environment and what we design for. It's it's on us as an industry to start to make these improvements. And here, it will just be another alert in for you, whether it's a hurricane or or need to check something or your Pokemon thing. Here, we'll dig into a little bit of the some of the data. We're starting to dig into the data other than the concept as to what we are seeing. So, a lot of folks are familiar with either intensity duration frequency curve or or, or volume curves, but these were designed based on a certain set of data. And then we say the return interval is one hundred year or two hundred years. This is in one year. We have three storm events here right next to each other that, above the two hundred. Just, two days ago, Monday or Tuesday, we're in stormwater conference ironically on the coast, and we had an eighteen initial frame during half a day on the East Coast with Carolina Beach in here. That's over a one thousand year event, and that can occur a couple times a year now. So we have we are using data that is not really reflective of what's going on. Not only we are seeing extreme more extreme events and more frequent event of that nature, but also the amount of data that was available and the quality of the data that was available and used to derive these plans might not have been, the best. On the good side, we're starting to see some improvement overall as an industry. We're starting to look more at this data. But, again, there are multiple competing interests and, multiple stakeholders that need to be accounted for, and these are all considerations that we need into our planning. This is actually during these storm events, and that's what, we have when we see something like this. Other things is we're starting to look a lot at forecasting. So that's predicting terrain. Let's begin to predicting terrain. So we're not just looking at the back, backward and what happened in terms of data and assigning it to a hundred year. We need to start to look at it. Instead of just having forecast for the rain, we need to forecast flooding conditions. So what is going to happen once that rain hits the floor? We're starting to see some, plenty of it on some, rivers. Some of them don't have it available. But once we start to increase that level of forecasting, we can start to be ready for it. We maybe we might not be able to design for just the biggest storm ever. That that's the practical consideration. But we know how to be ready for it. We know what's coming, and we can forecast between once this rain happens. We we have done really good in terms of weather forecasting. It has a lot of variability, but that's really common. Now we're starting to become more in tune with flood forecasting rather than just doing them as static plans. And we talked about the data. We really have much more data than before. We have a variety of satellites, whether it's a doppler or other, more stations that we can pull from. And we need to consider the various aspect of the rains. So now we've just talked about what happened couple days ago, eighteen inches of rain in half a day. But couple, before that, we'll have a five days duration storm, and that's a whole different way to handle it than we handle the short burst. So we need to account for long duration, high volume, high intensity, or low volume. So we need all that combination to be factored in into our design. And, actually, going from the forecast of the rain, we're going to see it, how is it spread out, the temporal distribution of the rain, and convert that into the predicting the flooding and what's going to happen for us in here. Rain data, USGS sites in here are very common. They are used, and then if you go to the USGS site, you can pull them with an overlay of a spatial imagery of the National Weather Service in North Carolina. And here, we have hundred sixty six site. But now data has becoming more available, much more, dampest. And here, we have over two thousand sites, and it will provide us a much better distribution, especially with the, rainfall amount. I mean, we are way past the time where we can say this station and that station, we're going to do the seasons polygon or that there's a a lot of spatial distribution other than temporal in the in the rainfall amount and geography and physiography that we need to be able to pull more data, have a denser network to be able to derive, to make our decision and build decision making. The good news, this is starting to become industry wide, and that's what we're advocating in here really to push for better use of more data. We have universities and the university here and their, DEQ and the regulations, they are working on it to try to really revise these curves that we showed earlier, the dense the duration and the frequency of the storm. We're trying to look at the design storms, how to apply them with this information in here. And in here, it's not that we're saying that the work that was done before is not I mean, we still need to do the master planning like we used to do it. We analyze the storms and see where there are vulnerabilities and improvements, but we can capitalize on this. The work has been done. We've been doing master planning for a lot of municipalities and developing these stormwater models. We can use these models to start to use them in prediction. So we are going to move from looking backward to looking forward. How can we forecast the flow? How can we forecast the floods that are going to happen and to do it live? All this data now is available. It's connected to the Internet. We have APIs. We have others such that the computational power allows us to go and predict what flows are what areas are flood prone during what storm live and start to guide our responses accordingly. So that's a great way to and here we have an example from the town of Morrisville that we did, but we can leverage a lot of the existing effort and that has been done. The studies that were completed, these are calibrated models, so they have gone through the test of validation and then use them in order to do our predictions. This one, that's another example. That's the same area in here. We used it to validate it, know what, areas we have of concerns, where the water is going. That same model can be run instead of using those design storms and saying that's what will happen. We will say during the next twenty four hours, that's what we're going to see. This is the the forecast of the rain, and therefore, here's our forecast of flooding. And if we have a critical facility in the area, if we have a treatment plant or others, we can plan accordingly. And with this, I think we can move to the waste portion. Can Yes. Thank you, Dory. And so what Dory was was really kind of summarizing is that we have a lot of different data methods. We have a lot of different sources coming in, and now we can actually predict on a micro level. So no longer are we getting surprise phone calls, from residents on on certain streets because we've modeled it. We understand what the improvements are, and we with the prediction levels, we can start to help notifications and such. As it pertains on the wastewater side, hydraulic modeling is is nothing new. We've been doing it for decades. I started back when you had punch cards. I'm not sure if if many of the, people on here remember those days. But, again, as an example, what we're talking about is this is an example in Kannapolis, which is an area just north of Charlotte. You can see for relative size. I've I've seen some of the larger cities in the attendee list. So this this can be on as a big of a scale as you would like. In this case, there's seven sewer sheds. I do I do notice sewer shed is two words. The word always tells me to separate it. I've always seen it as one word. But I didn't want a presentation with the red with the red scribbling under sewer sheds. But so we can start predicting flows in a positive way. And so, so when we're looking at the different components of planning. Right? So in this point, we're still predicting the rain. We're still we're still predicting the rain. We're not quite building the ark yet. So North Carolina is exploding from an economic development standpoint. So we're being put we're being made to answer a lot of questions. One is what do you do when you have eighteen inches of rain? Actually, one of my staff was on Oak Island. I think they got twenty three inches of rain. But we're having to answer not only that question, but also what about development? How do you handle the homes? How do you handle the master planning? And so as part of that, we're actually going through and projecting in conjunction with the land use plans, where that development is gonna go. Again, so this is this is Kannapolis. We just had to kinda work with their land use plan. You can see the, the source at the bottom. And so we're saying that their their dry weather flow, not a drop of rain on the ground, their dry weather flow is actually going to almost double, which isn't uncommon. We have we have some small towns like Troutman, which is also in this area, that their population in the past five years has gone from two thousand to six thousand. And so we're we're we're trying to struggle in in in how do we deal and balance with the growth as well as the wet weather. So one of the ways we do this is that we look at the dry conditions. So in twenty twenty two in dry conditions, right, which is when economic development this is when they're asking, do you have capacity? Can you handle this shopping center? Can you handle this data center? And so the answer is sure. Great. Everything's fine. It's sunny. It's cloudy. We can we can we can take this flow all day long. Well, then the summer rolls through and we have these summer thunderstorms. And so there's a so the next thing you know, you have a ten year storm. So, if you're asking that capacity question between a rainfall and a dry weather, how do you answer that question? And so then we look in the future and say, okay. Even without rain, if we just add all this development in two thousand and thirty, what does our system look like? How does that perform? And then of course, if we take that ten year storm and add it in two thousand and thirty. So, when you're asking these questions of your system and your councils and your boards, you know, and you're having these opportunities come up, everybody wants to say yes, but it's really under what condition and how do you evaluate that. And so just for example, a ten year storm outside of Charlotte is about four point nine eight inches or or five inches. And so when we're talking about this level of prediction, okay, and we're talking about predicting the rain and predicting these, with these sanitary sewer models and with these stormwater models, the capability is there now to actually be running these models real time in the background using different data sources. So the town of Cary is an incredibly innovative, they they they actually won awards for for some of the stuff they were doing during COVID. But on the stormwater side, they have this prediction level down so that they can notify residents and notify through through alert systems, about flooding certain flooding items in certain areas certain areas to avoid. And so when we're talking about predicting the future and when to get on this arc, this is just another toolbox. These tools exist on a micro scale across the nation. But really, it's about bringing this to the forefront. You know, I still joke with some of my staff that we predict you know, we we gather sewer flow data in fifteen minute intervals only because back in the day, that's the only amount of data that that you could fit on a a floppy disk. But we're still doing it that way. So here we are having these capabilities, but we're still using some of the older methods of prediction. And so the question is how do we get there? What is that next step? So this is where we get to building the arc. Right? So now that we can predict this flow and we can predict these things, it's about determining what that level of service is. Is it to stop the one person who shows up at council meetings every month? Is it to stop that occurrence? Or is it to stop sanitary sewer overflows? And when? Like, what what event? You can see when homes are underwater and some of these different things. When when is that when are you gonna draw that line? Because there's always gonna be a bigger batter storm. It's about breaks and force mains because your velocities are changing. Is it overall volume, storage tank? Is it is it a poor customer service perception? Is it because you don't wanna increase rates? And lastly, of course, because stressed councils and boards are having to answer for this. So determining your level of service is not only about sitting behind a desk and running calculations. It's also understanding with the stakeholders what the goal is. And when you're determining that goal, you have to look at all the different data sources. So, obviously, we have to pull in the GIS information. Historical rainfall. So when you're determining your level of service I know when I was in when I was in Pittsburgh, we had Ivan, and then we had another hurricane even back to back. I know we don't really think of Pittsburgh as hurricanes. But we had two hurricanes back to back about three days three days apart. And so that kinda became a standard for which we were determining our level of service and understanding what the capital was going to be required. And of course, designing we're engineers. We'll happily design it. But there's not enough money out there to actually build it. And so when you're looking at different rainfalls and how you want your system to perform, it doesn't have to be a design storm. When you're defining your level of service, it can simply be a storm that created havoc across town. And and and maybe it's to take the amount of people flooded from from dozens down down to one, and that allows you to better focus your efforts. And, of course, land use plans. Thinking back to that slide from Kannapolis, maybe this helps focus where you push development in your community. Because I've seen a lot of land use plans that push development out to areas where land was cheap but there was no utilities. So bringing that and making that part of the wet weather discussion allows you to to expand the scope of of your land use plans. And, of course, there's field data. You have flow monitoring. You have CCTV. So you have the cantering. You have smoke testing. You have dye testing. You have all these different data sources that can feed into this and help you understand complaints, breakages, and all these different factors that can help you evaluate this. And, of course, there's projected sewer flows, dry wet weather, gravity sewer capacity analysis. In my opinion, I have to I have to put quotes around that, we should not be using Manning's equation anymore. We have the importance. Manning's does not take into account momentum and a lot of other things such that it's it's kinda like using the model t back in the day. It was there for a reason. It has a lot of scientific basis. But we have a lot of data and a lot of sources now that so if we're using an old gravity sewer capacity analysis, we should be mainly using it for inverts and and other basis. Of course, we have flood plain mapping, stormwater system mapping. All of these different data sources have to come in to help facilitate the discussion of what is our level of service. Do we want it to be one of these storms? Right? So what storm is gonna generate surface flooding? So one of the reasons that I've that I kinda hammer this and and I'm happy to work with Doreen in some of these is is that we need to understand what storm is gonna generate surface flooding. If you have homes that are going underwater during a design storm, say a ten year storm, that river or or creek or pond has now become one with your sanitary sewer system. So at what point are you going to effectively take a river that's flowing right through homes in a six inch lateral into an eight inch pipe down to a pump station. So what storm what realistic storm? If you have incredibly large amounts of surface flooding and then and from what I saw on the attendee list, there there are several of you that have localized flooding occasionally. You need to think about what what the impact of that flooding is. And, of course, what's the time of year? Around here in North Carolina, the summer thunderstorms, they hit they hit pretty hard, and then we kinda roll right into hurricane season. In the spring, things are very wet, but we don't get a lot of the hard and intense rainfalls. So we have to make a conscious decision because of the dollar amounts associated with that. And so sorry. One of my one of my favorite pictures is is the diver on the toilet. Just because of the fact it just that's effectively what we have from a hydraulic standpoint. It is the same thing if you have surface flooding and you're and and and you're trying to send. So Dory had that picture earlier of the gentleman in the boat. He was actually headed out to to turn off a pump station. So the question is when you have a when you when you have a public works staff taking a boat out to turn a pump a pump station off, really what is your level of service? And so an example oh, I kind of scooted right past that. There we go. So that one is already on a timer. Alright. So in in traditional wet weather planning, what we do is and and engineers love to do this. We get a call from a council that says fix this. So we run out. We say, okay. We need a bigger pipe. We put in flow metering. We figure it out. We say we do some dye testing. We do some CCTV. We do a lot of different things. We we rehab it, and then we go to construction. We fix it. We settle back. Likely, we retire because the project stayed so long. Then the next thing you know, a bigger, badder storm comes, and we are right back answering in front of a council as to why that project didn't work. Most engineers are gonna say, well, it was a bigger storm. It had a higher intensity, and we just didn't design for this. And so the way I like to to answer these questions to councils is that, look, we did our manhole inspections, our CCTV, our flow metering. We modeled all kinds of different events. We modeled the small storm in the spring when the ground was wet. We modeled the the the frog choker, as somebody used to say, in the summer. And we performed our activities. And so we understand exactly what percent of rainfall is getting into the sanitary sewer system and the impact that that has. So then we did our different activities to more, dye testing and such to understand what we may be able to fix. And lastly, we come up with an alternative analysis that says, if you want to fix this basin for this storm, then you are then then this is what it's gonna cost. And then you present that to your boards, to your councils, to to the customers because all of our solutions have have resulting impacts whether it's on tax structures, whether it's on on rate structures. But we have to be able to make an informed decision. And then we memorialize that in a in a capital improvement plan. And so I I kinda like this slide because I joke, we can circle the solution and just throw money at it, and we all always knowing there's gonna be a bigger storm and then, you know, and we kinda weather the storm with with with the public in the in in the public meetings, or we can really point to a solution that that we can defend as part of this. And so the other part of of the solutions within North Carolina, this is again these are the four seasons we have to deal with here in North Carolina. And as part of these and as part of these seasons, we have to be able and be ready to answer questions. No. We cannot always answer the questions on the football performance. But, really, between summer hurricane and football, we have a lot to answer for. During pollen season, all we do is wash our cars in North Carolina. But during the rest of the seasons, we are actively engaged in this wet weather planning. And so we're helping our communities. We're helping the industry move forward in in making these decisions. So I guess this is where I turn it back over to the the Brightly staff to help facilitate any of these in in the q and a if there happens to be any, which is what I'm used to doing. Yep. Thanks, Ken. So, great presentation and great information. We don't currently show any, questions. I do remember that I forgot to tell people to add questions as as you were presenting, so I'm sorry about that. We do have a few moments. If you guys, if those who are attending have some questions, please put it in the Q and A box at the bottom left corner of your screen and we can we can address that. We also are going to add a question in a follow-up email you'll get next week to see if there'd be interest in having kind of a a special Q and A session with Ken and Dory to dig deeper into this these topics. We know it's a lot of information that's just been presented to you. It's kind of hard to, to to consume and formulate your questions on the fly with such a needy subject. But if you are interested in having kind of just an open Q and A session with these, knowledgeable gentlemen, we are happy to arrange that. So look for the email that'll come out next week. Tomorrow, you'll get one that just shows the recording. And, please do go ahead and and rewatch if you want to or forward to your colleagues. That'll be, good information that you can rewatch this entire recording. And then next week, a week from today, we'll, we'll send you an email that show that asks you if you are interested in attending a live Q and A session where we can just explore these topics. So look for that. Let us know if that would be helpful for you. And I I'm not seeing any questions currently, at this time. So I think we'll go ahead and close. Thank you so very much, Ken and Dory. This was really good information. And thank you to everyone who attended today. Have a great rest of your day. Thank you, everyone. Thank you, everyone.