On the Front Lines of Dam Safety - podcast episode cover

On the Front Lines of Dam Safety

Jun 28, 202142 minSeason 4Ep. 22
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Episode description

Each of the 90,000 dams in the U.S. plays a critical role in the community it serves — from preventing floods, to generating hydroelectric power, to providing a water supply for drinking water, irrigation and recreation. On this podcast, meet the professional rope access technicians whose jobs involve preserving the structural integrity of each dam — by providing a rarely seen perspective of some of the largest infrastructure in the world. Collectively, our team of more than 40 certified by the Society of Professional Rope Access Technicians has logged approximately 50,000 hours suspended from ropes, getting an up-close view of dams, bridges, tunnels and other hydraulic infrastructure.

Transcript

I'm John Torek. And I'm Danny Sullivan. And you're listening to Speaking of Design. Bringing you the stories of the engineers and architects who are transforming the world one project at a time. Help Wanted. Seeking a thrill seeking applicant with specialized training who wants to protect thousands of lives. Today, we'll meet professional rope access technicians whose jobs put them on the front lines of infrastructure safety every day.

So we find ourselves on the top of a dam, and sometimes we gotta make our way down through the gates. You have to step over the railing and lower yourself onto the rope and the harness. That's Mike Fuga, a senior geologist in HDR's Berkeley office and a member of the rope access inspection team. And for some reason, that just doesn't seem natural in my head. So that first step is a doozy, trying to get over the railing there, and my heart's usually pumping. His colleague, Kenny Desange, knows

that feeling. When you're going over the railing, you're not really taught on your rope yet. You have to sit into it. And so just that feeling of I need to lean over this this hundred foot drop and sit into my rope definitely had me what I call depth gripping the handrail to make sure when I sit into this, I'm not going anywhere. Kenny lives in Sacramento and is the hydraulic structures practice lead for

the company. He and Mike are among 44 inspectors and technicians at HDR, certified by the Society of Professional Rope Access Technicians or SPRAT. Collectively, the team has logged approximately fifty thousand hours suspended from ropes, getting an up close view of dams, bridges, tunnels, and other hydraulic infrastructure.

Those hands on inspections have given team members a rarely seen perspective of some of the largest infrastructure in the world, including California's Oroville Dam, the iconic Golden Gate Bridge, New York's Bayonne Bridge, and Idaho's Dvorak Dam, the third largest dam in The US. Like Kenny and Mike, most inspectors enter this career of adventure without any rope experience with merely a degree in civil engineering or geology as the first qualification.

But occasionally, someone enters the field with more of a thrill seeking background. Growing up near Yosemite, doing a little bit of rock climbing was sort of like a prerequisite. I wanted to graduate eighth grade, I think. And then going to HDR, I didn't know I would be involved in the rope access program. That's Travis Ford, a hydraulic structures lead based in Denver. He began his career with more typical structural engineering work, which led to the opportunity to

join the rope access inspection team. Whether it was spillways and, you know, big infrastructure or fish ladders, it sounded pretty neat for a young structural engineer. So I I did that and joined and started working on some levee projects and some hydraulic structures, and then sort of started following Kenny around on inspections and showed interest in that. In spite of his rock climbing background, Travis still remembers the intensity

of one of his first dam inspections. I went straight to Detroit Dam in Oregon, and that one happens to be about 470 feet high. And the access to it, we had to climb up over the skin plate of this big hydraulic gate. So we had to climb, like, under the bridge and over the skin plate and then get over the top, and and there's no, like, foothold. But you go over this edge, and we put little rope protection on and

set the rope over the top. But I did a little peek with my hands over the top of the gate and looked down, and and I'm like, okay. And so everything just got very methodical. It was a similar career path for Jarlene Nineveh, a structural EIT who works with Travis. She moved to Denver after graduating from the University of Buffalo in 02/2018. I actually didn't know anything about the rope access industry prior to HDR.

And working under Travis, I think the first time we did a few seat out inspections, and then I've seen the monrope. And then we all went to a warehouse where we kind of got to practice, and that's where I got introduced to the rope access. And it looked like cool thing to do. Getting out of the office, seeing breathtaking views, actually experiencing

the structures you study on screen. If you have the stomach for hanging 500 feet in the air with the wind whipping in your face, There's a lot to like about a career in rope access inspection, although that doesn't mean your family and friends will agree. And and all my friends don't understand why I do it. But I always explain the same thing, you know, the two system robot. I don't think my mom hears any of that. She just sees these pictures that I showed her, and

she doesn't like it at all. My mom still does the same thing, so it doesn't it never goes away. My dad won't go out there. Like, he's had the opportunity to go, you know, that we had a dam right near where I grew up, and he just stayed at the abutment. He won't go out there. If you're listening, mom and dad, there's a lot of training required before any team member ever steps into a harness. On this port set here, which is the same line that I'm ascending up.

My backup is on So there's three different certification levels, one, two, and three. And really at the one, that's essentially a worker level. So you're going in without any any type of rope access experience. You learn various maneuvers to make sure you're comfortable on rope along with a couple of rescue sprat certified level one technicians,

meaning they've completed that first training course. It's four days, and then the fifth day is kind of the the written test and the oral test, and then all the maneuvers you have to go through to get the certification. So it's basically going through all of the basic things like ascending, descending, knowing all of your gear, a few of the maneuvers like rope to rope transfers and stuff like that, and then you have to show all of that you learned on the last day. Kenny's now a level three, but

he also came in with no experience. Honestly, I had zero background with any type of rock climbing or rope climbing or anything like that. I just remembered day one at the training center trying to put on the harness, and I was like a tangled mess, essentially. So I really didn't have a lot of experience going into it. After you pass level one and reach five hundred hours of experience, you can pursue level two certification. Once again,

you go in. It's another four day course where you're learning more advanced maneuvers and also really focusing on rescue techniques there. Travis and Kenny have reached level three, which requires more than 1,000 on the ropes. Similarly, level three certification involves a four day training with a fifth day of written tests and independent reviews of

your maneuvers. The level three duties are to be the supervisors of the job to be able to supervise multiple people underneath you who are working on that job and also confidently put together job hazard analysis, safety plans, inspection procedures. So you're you are in charge of that job, so making sure you're comfortable with those duties. For Mike, the biggest takeaway was simply to always be mindful of safety once you're

in the air. So in terms of safety, you know, it's really taken the time to think about what you're doing because you do have to transfer between ropes. You've got your gear and everything. And so it's just been real mindful of yourself, your surroundings, and what you're doing with the ropes just to make sure you don't find yourself on one point or on no points, especially since you're suspended up to the air. And sometimes it's six feet off the ground, sometimes

it's a few hundred. And even with no prior experience, that preparation calmed his nerves for his first inspection. I got this weird thing where if there's, like, a system in place, I like, my fear gauge. I I have, like, a switch. I can kinda, like, turn off fear almost. So shark cages are an example. The system here, right, you got, like, a two rope system. So it's like, alright. We got our main line and our backup. So as long as I don't do anything stupid,

everything should be just fine. Even if something does go wrong in the air, Kenny explained that the redundant rope system provides extra security. So let's just say someone was to freak out and just kinda lose it on rope. If they just let go of everything, they're actually just gonna stay in place. It's not like they're going to to drop down to the end of the line or anything like that. And so it's a even if you load items up backwards or put it on the rope backwards,

you'll just stay in place. And so it's a really good feature of our equipment to where if you were if something was to go wrong with either user error or even a functionality, you'll just end up staying in place and not going anywhere. It's not like you're gonna go down the road. The training helps each team member become familiar with the long list of equipment needed for an inspection.

So, basically, we plan out how much rope we're gonna take out into the field, The stuff we're gonna use for anchors, so it could be wire sling, soft sling. We have Ropel, which basically protects all the soft goods or soft materials. We have carabiners that blocks everything and helps build the anchors. Then on top of your personal protective equipment like your helmet, boots, and gloves, as well as rescue kits and first aid kits, you still have the tools needed for

the job. Those include rock hammers, clamps, calipers, headlamps, cameras, iPads, batteries, special rain paper notebooks that can be used when they're damp, and Motorola radios with a specific FCC approved channel for communication. That's a lot to hang on to while you're suspended from a rope. We never drop anything. That I don't think I've ever seen that happen before. So, you know, it's it's definitely %. One hundred % tie off. Right? I'm being totally sarcastic when I say we

don't drop anything. We we drop things all the time. I think the high value ones were I think someone dropped their car keys or a rental car key before. I I've dropped my notes. I've been lucky enough to where they floated on top of the water, so I've been able to get them in. But, you know, radios, I know a camera went in in Alaska. And when that happens, it doesn't get ignored by the

team. Yeah. Not we have a yearly award for who drops the most expensive item, and, you know, we're trying not to get on that list, but it's it's pretty funny to bring it up. With nearly three thousand hours of experience on the ropes, Travis has two such awards to his name. The first involved a friction device called a GriGri that helps you descend in a controlled manner. However, when you change ropes, you have to

detach it. I decided to just take mine and and set it nicely on the spillway slab, but, you know, I'm I'm secured, but the the spillway is actually at an angle. So I think Kenny describes it. He just said, Travis, just set it down and and just watched it roll down the spillway. So, anyway, that's that's that's the first one. Travis received his second award shortly after he got a new TUF phone. And they were, like, you know, the newest, coolest TUF phones. So I decided to keep that in my

pocket. And, you know, the harness tends to work its way a little bit, so I was climbing up. I don't know. But it slipped out of my pocket, and it landed. It went down about 70 feet or so, hit the top strut of a radio gate, blew apart. You know? It was it was only so tough. And then it rolled down into the Stilling Basin, and, of course, we couldn't go down there because they were they're spilling from the powerhouse or something. So, anyway, we we tried

to call it and look at that. I swore it lit up in the Stilling Basin for a split second and rang. Although the team has a sense of humor, they take their safety seriously. Rope access is a two rope system. I carry that through a lot of my gear, actually. I actually have a backup line on my camera in case, you know, that were to go sailing. We have tied off, in my case, maybe twice, heavy

tools, hammers, things like that. When we're over any kind of, like, public traffic, that kind of thing, we'll close that area, typically, just in the case that something were to fall or somebody drops a water bottle or debris from the structure, that kind of thing. So, yeah, on the safety side, we're well aware of the the hazards there and and mitigate that.

In addition to Sprat technicians who inspect bridges and tunnels, the team has experience analyzing, designing, and inspecting all kinds of hydraulic structures. This includes concrete dams, arch dams, spillways, hydraulic gates of all kinds, canals, penstocks, energy dissipation structures, walls, platforms at hydraulic projects, and intake and outlet works.

Each of the 90,000 dams in The US plays a critical role in the community it serves, from preventing floods to generating hydroelectric power to providing a water supply for drinking water, irrigation, and recreation. That's why the rope access team plays such a critical role, giving dam owners the detailed information needed for third party inspections, stability analysis, security analysis, design modifications, regulatory compliance, construction reports, and long term planning.

It's all about dam safety through routine surveillance, monitoring, and maintenance to preserve the structural integrity of each dam. The work begins long before anyone is strapped into a harness. Typically, in the office, we will scratch and claw to get plans, and that's important. Sometimes on dam projects, especially, it's like either there was a a fire in the powerhouse and all the plans are gone, or there was a flood and all the plans are gone, or it changed hands enough and, you know,

there's there's no plans. So we have to see if we can get those plans so then we can figure out, okay, this this high and, you know, it's this material type, and these are the details that could be problematic. I'd say that's important both from an access standpoint as well as figuring out what to look for. Charlene said they also review previous inspection reports so they can look for previous findings such as cracks

and see how they've changed over time. Just so I could have a mental note of if there's anything I need to specifically focus on. And, you know, we wanna make sure that we document everything that was previously documented. For example, if it's a spa just to see if the spa got bigger or if there was an exposed rebar before, there's exposed rebar now. Basically, there's bookkeeping of all the previous notes and expanding on those and any new findings.

And I try to take as neat note as possible just because following the inspection comes the inspection report. It's better to get everything out in the field rather than getting back to the office and trying to figure out, like, where this picture was taken. Because each dam is designed to collaborate or at least coexist with nature, there's not a one size fits all approach to design. There's a lot of different designs. Somehow, we didn't, like, just design one, you know, radial gate and apply

it all over the country. A lot of different designs out there where having some inspection sheets is really helpful. It's sort of a three d structure, and when you're in there, just doing two d notes on a page, if they're not planned out well, can turn into a mess pretty quick. So I like to get everything planned out either on inspection

sheets or sometimes an iPad. Before heading out in the field, the team plans out the gear they'll need and prepares a job hazard analysis with a rescue plan in case of emergency. They also consider what technology they'll need, starting with how they're handling documentation. We have folks who take iPads out. We'll, you know, take photos and actually make their notes directly on the photo, which is pretty cool seeing it back in the office. Pretty time consuming in the field, so

there's a give and take there. You know, pen and paper, obviously, writing the rain paper specifically with cameras. And then also just with some of the NDE technology, a lot of that goes to an external memory device where you're able to save it and upload it and and store it on the actual device that's doing the readings. On smaller structures, it may be a team of three that heads into the field for an inspection. A larger project may involve more than a dozen inspectors.

For steel structures, team members inspect every seam and rivet to look for corrosion, cracks, loose fasteners, deformations, or any potential issues that could impact the structure's integrity or affect operation. They take measurements using calipers, ultrasonic thickness meters, and a magnetic particle kits to determine how much of the structure's material is left, whether crack is present, and whether it's expanding.

On concrete structures, they investigate for cracks, exposed rebar, seepage, or voids beneath the concrete. They look for delamination when the concrete begins to fracture into layers beneath the surface, as well as spalls, which are flakes of concrete that begin to chip off. Team members measure the joint offsets and gaps and also evaluate the concrete slab for uplift or cavitation when empty pockets form beneath the surface.

We actually have a number of certified nondestructive testing engineers who could come out to the site and do, say, mad particle testing, phased array ultrasonic testing, also just ultrasonic thickness testing. So we have some NDE, which is nondestructive evaluation technicians who are who are able to to come out into the field and basically try to find cracks and welds, even get some better measurements on section loss

for steel members. For spillways, we've had some ND folks come out to do ground penetrating radar, pulse echo technology to try to figure out if there's any voids beneath concrete slabs. Travis said that often the job calls for some combination of evolving technology

with some old school hands on inspection. So whether it's using the ground penetrating radar or impact echo or one of those other items or even, doing some destructive testing like coring and patching, the core so we can get concrete strengths and things. We're we're always looking for a new tool. So on that note, our our drone teams are able to get, like, a broad spectrum of, like, a lot of do the digital twin and do the even image recognition and

finding changes, things like that. At this point, they can't chip away at a a weld and then, like, a fracture critical detail in the gate that could be cracked or even look into that weld. But it is getting better, and we're always looking for, yeah, the best tools that we can apply to the project to really improve our probability of detection. You know, whether that's just using a wire brush and scraper or, like, scanning the thing somehow, even with

LIDAR or other tool. For geologists like Mike, inspection is less about the built structure itself. We're more concerned with the foundation materials, so what the concrete's poured on and where the dam is sort of using as a buttress for stability. And so we're after just sort of the rock mass structure. We're looking at a lot of the discontinuities in the rock and, like, Travis had alluded to, you know, weathered materials or broken up sections. And so we'll focus on those areas to

try and quantify those. And, ultimately, it feeds into some of its similar, some finite element type stuff in terms of, you know, dam stability. Understanding the impact of changing weather patterns and erosion analysis have also become an emphasis for geologists. When I go out there and I'm looking at the rock mass or some of the soils that could be out there, it's telling me a story. So there's, like, the geologic story, which I always find fascinating. There's sometimes

pretty cool features in the rocks. Particularly out here in California, there's a pretty active seismic sort of component. So lots of folding and faulting. So you get to see some pretty cool rock formations. These rocks are kind of fractured and kind of beat up. So those are the areas that we're looking out for. And in terms of trying to identify areas that might be susceptible to scour and erosion, we would anticipate to see some scour occurring during large flood

events. And if they're passing water over the spillways and and trying to identify trouble areas or if there could be a potential progression that would undermine the stability of either the spillway or the dam itself. Kenny explained how the information gathered in the field supports the technical analysis of the structure. In the office, we do a lot of structural analysis, finite element modeling for spillway gates and even spillways.

And this kinda helps us identify stress concentrations for specific gates for looking at normal loading conditions, which ones are overstressed. And that can give us a a target to really do a focused in-depth inspection on those members since they're fracture critical. Or if we're seeing signs in the field of deformations relating it back to the stress analysis and trying to figure out why that's happening.

If there's a deformation in a flange, did something hit it, or is the the water service elevation too high and and overloading the the strut? With the added benefit of having the same people working on the analysis. The engineers and the EITs who are out in the field doing the inspection are actually the ones performing the analysis back in the office. So there's a transfer of information there that isn't lost because it's a one to one individual, you know, doing it

in the field or the office. Our folks are doing multipurpose type projects where, you know, they're functioning as the inspectors and the engineers doing the analysis, and that's just a huge benefit. Travis noted it also heightens the inspection team's awareness of what to look for when they're covering such a massive structure. Sometimes our inspections kinda

need to evaluate on the fly. So having really qualified folks out there that have some background in the dam safety realm to understand the consequences of when there are things going wrong and what to look for. It's kept us from missing things, I would say, and it's always a risk that we don't find something. But keeping your eyes open out there is really, part of the job and and can change the course of the whole project.

Even with all the the preparation and the critical work to do, there's still a sense of adventure once a young engineer gets up on her first inspection. Charlene recalls the feeling she had on her first big dam, the nearly 100 foot high Williamson Dam in Cisco, Texas. Williamson Dam was really tall. So I had that moment where I'm like, okay, I'm actually doing this, and this is

really different from the training center. And it was pretty much the first time I got to inspect one of the dams that we do analysis and so, like, the building analysis, and then we work on so much. So that was, like, the first time I was out there, and I got to actually, like, feel the size of the dam and this huge structure. Depending on the type of job, you can be up on the ropes for a long time, which requires some planning to stay fueled. Definitely some Clif bars. I try not to

drink. It's like a a battle of staying hydrated and not drinking too much because using the bathroom for me is a little more work. So Gatorade for sure. I somehow always manage to get some oranges. I sneak in some cookies in there too. It's usually really hot. And a lot when you're moving around a lot, it's just a matter of when you're getting tired. Typically, technicians spend a lot longer time in the air on a bridge project as Kenny experienced on an inspection of the Golden Gate Bridge.

On the bridge side, it could be pretty difficult, you know, going back to the Golden Gate. We're only allowed to enter on one side and exit on one side. And so just doing a floor beam takes, I don't know, two to three hours, and then coming back doing another floor beam takes two to three hours. And so that's why on the bridge side, you're usually taking food with you. So you could be suspended twelve hours. And so my lunch at Golden Gate consisted of a a pack of raisins

and a cliff bar. It's usually a slightly different story on a dam where you're in a remote location away from the public and descending down from the deck level. Travis is quick to point out the perks. Our lunches are definitely better on the on dams. That's ridiculous. Yeah. You know, on on a bridge, you sort of get out there. You get traffic control. It takes a while to get up on the structure, and you're sort of there quite a bit of the day.

With dams, you know, we rappel down, and then we we can hike back up to the deck. And we can just, you know, pull a cooler right out there under the deck, and we typically like to get some, you know, get the deli meat going, maybe some fancy cheeses, and get get, get parked out there on the dam. Besides, it's it's a beautiful area typically that we're in, some, you know, canyon or something.

Sometimes they do even better than that. My lunch at Lake Matthews consisted of DoorDash where we got Mediterranean food one day, Thai food the other day. And, it's always a running joke within the rope access program that the bridge guys kind of, you know, nudged at us a little bit on how good our our lunches are. But that doesn't stop Travis from being creative on a bridge job. I seem to remember one day we ordered pizza at a bridge, and we had to get

it sent up from a boat. And the guy operating the boat threw the pizza, like, in a bag and then just, like, hoisted the bag to the rope. There was no preparation on delivery method there on on his part, unfortunately. And so we got the pizza at the top of the bridge. It's just a pile of pizza. In addition to the fun stories about what they bring to lunch, Mike has one involving what he brought to dinner. Once again, being a geologist, we're kinda

out tromping around. So some of these spillways have little, you know, drainages on the side. And since I'm after the foundation conditions, I gotta go poke my head around on the outside of the concrete, and sometimes that entails walking through some vegetation and picking up some travelers. There's that one time we were doing a a job down on the coast here, and there was a nice little stream, some vegetation. I had sprayed myself with, like, the bug

spray and everything. So I was like, alright. I'm feeling pretty good here. No snakes. You know? Always gotta watch out for snakes. And then we get to dinner later that night, and I got a tick crawling right on my arm. And I remember we're sharing a table with, like, a couple. This was pre COVID. And they noticed it, like, crawling down my arm and onto the table, and I think I ended up pulling, like, three of them off before I think I got all of them.

So definitely the wildlife is something to keep an eye out for. In fact, Travis explained why a dam makes a perfect home for wildlife. My father was a wildlife biologist, so I have kind of an affinity for kriggers out there. That living in infrastructure, One of the first projects, Georgia Power, there was so much water that was coming over the spillway gates or through this, you know,

leaky's old side seals. And at these hydropower plants, they wanna keep the water as high as possible, right, so they can generate electricity. But it also means that there's lots of vegetation under there. So it can be like a jungle inside the girders. So we have some pretty spectacular documentation of vegetation within these these gates, huge ferns and different things. Meaning the team needs to be prepared for a lot more than ticks. Whether it's snakes. So water moccasins like to be in

that area in Georgia. So we got snakes on dams. And, I know we've run into some raccoons and different things in there. I went into one area and saw a ringtail cat in Texas. And then, I know we've had some, run ins with raptors as well. So often we if we find a big nest or something, we'll just avoid the area and try to come back when they're not nesting or something. But they can

get pretty ornery with us. They they're sort of territorial and can, you know, do a little bit of dive bombing, stuff like that. And then I I know the army corps had a picture of a a a black bear on one of the big radio gates on the Columbia River. It was just perched up there on the on the gate. The terrain itself around the dam can also add to the adventure as well as the hazards, especially for the geologists. I'll say those the structure guys have it easy. Everything is all concrete

and relatively flat. And, I won't say smooth, but everything's kind of a little more manageable. Once you get over the edge of the concrete and onto some of these online portions or the abutments, I mean, you're dealing with all sorts of overhangs and craggy rocks, loose

rocks. So it kinda it's not usually as steep, which ends up being a little trickier because you kinda it's all about, like, rope management and trying not to step on stuff or hooking on things, and it's a little easier when everything's just kind of up and down, and it all just falls to your side. When the water level at the dam is being kept high to provide hydropower, it can add additional excitement for the inspectors.

What happens when the water near the top of the gates is that sometimes there can be some wind, and what that causes is small waves. But when those small waves right up on the gate, they can be like

a wheelbarrow full of water. And if you're on the downstream side of the gate, given it was hot and it was kinda nice, you know, to get drenched every once in a while, but when you're in the middle of, like, writing a note and then get hit by, like, a wheelbarrow full of water, It can, kind of, shake you up a little bit. Kenny recalled a job where a new colleague started getting hit by the waves. I remember he found something, and so he was trying

to talk to me. And it was literally every five seconds, a bucket of water would land on him. And so he would say, hey, Kenny. He got he got hit with a wave. I found something down here, and then he would get hit with a wave again. And he literally just had to move 15 feet, so so he cannot get hit with a wave. But it it took him a couple of minutes to figure that one out. So it's it's pretty funny. But, yeah, like Travis said, if it's hot, it actually feels

pretty good. The actual work they're doing is interesting as well. In February 2017, the main spillway failed at California's Oroville Dam, the tallest dam in The United States. The dam provides drinking water, hydroelectric power, and flood control near Folsom, California. Now the integrity of a major dam in California comes under threat after days of historic rainfall.

He news in Northern California tonight, tens of thousands forced to evacuate tonight due to concerns the Oroville Dam's emergency spillway could fail. Good evening, everybody. The water was spilling over into this emergency or auxiliary spillway. About 03:00, this afternoon, engineers who had been monitoring the situation there noticed that there was some sort

of erosion on that emergency spillway. With water thundering out of Oroville Dam, Officials are in a race to fix the damaged spillway and lower the lake level, which is at near capacity. At one point, officials said if that emergency spillway breached, a 30 foot wall of water could cascade into communities downstream. Now this is Kenny remembers the moment a colleague told him the news. He came to my office, and he said, hey, Kenny. Something's going

on at the spillway. Can you grab some tools and meet me out there? And, you know, I I I had a bunch of questions, and he is pretty much like, that that's all the information I have, so bring whatever you think is necessary. And so I I grabbed some tools from what I thought it was and drove out to the site. And as soon as I got there, I I said, yeah. Everything I brought is gonna

be useless. Rainfall had raised the water level on the lake, and the heavy flow began to erode away the main spillway that controls flows downstream. It eventually created a 300 foot crater. After the California Department of Water Resources closed the spillway, the high water level overtop the emergency spillway, which also began to erode. Concerned for a potential dam failure and catastrophic flood, the state evacuated a 88,000

people from their homes. I was ultimately the first person that went down into the hole, and that was something that a lot of people will probably never get the opportunity to do again. And, you know, knock on wood, I'm not gonna be able to do it

again. But it was just fascinating at the amount of engineers who really took pride and wanted to develop plans to fix the spillway, you know, emergency action plans that were being developed real time and just working with a a great number of folks here at HDR, at DWR, and a number of other consultants that were out there. You you know, just really showed that the community, the engineering community came

together. More than 50 HDR staff mobilized and began working alternating twelve hour shifts, seven days a week, to monitor and report on the condition of the spillway to help DWR form an emergency response. Travis was also among the first responders. Just walking the spillway in the middle of the night with a radio and a flashlight, And then the next day, not knowing if they need us to go climb gates again.

There was a dam downstream that we needed to go look at as well to make sure that was okay and just kinda being at the ready all the time. And Kenny and I were monitoring leads out there. So we have a team, a crew during a shift, and it was pretty pretty wild dynamic situation. The emergency response, temporary repairs, and reconstruction of the spillway eventually cost more than $1,000,000,000.

A greater catastrophe was averted, but it further highlights the importance of inspecting and maintaining infrastructure. Some small offset like in a spillway with high velocity flow can be catastrophic when it comes to, you know, the integrity of the structure. Oroville was an example of that. We don't know what kinda joint offset or anything it may have had, but one small defect

became an unraveling there. I would say that, you know, during the inspection, sometimes we're there, and I had an old slab and buttress dam and, know, look at some rock fall issues and things. We started looking at the underlying buttresses of this Amerson stop, all dam. And they had some pattern cracking, some, like,

sheer type cracks. And and then we also saw some issues with the outlet works where there were separated flow flanges in the in the piping at high head situations and, yeah, just kinda unraveled some additional findings at the dam. We're like, you know what? This needs a this needs a bigger look. So we recommend, you know, a follow-up and then ultimately, you know, some interim risk assessment stuff as they plan to either, retrofit significantly

or replace the dam. The Oroville Dam incident also caused dam owners and regulatory agencies to reassess their aging infrastructure. Where are spillway dams that are high risk? And some of the dams that are over highly populated areas, we took a little more time with and did rope access inspections along with some ground penetrating radar, and we used some pipe inspection methods to look at the drain systems underneath these spillways. So we really overlaid, like, a lot of

different methods to try to find defects. Travis and Mike shared an example that they worked on in Southern California. I led a team doing rope access inspections of everything, and we got essentially with arms reach of all the component. So the the spillway itself, you know, the gate structure, the the walls on the sides, and we rig ropes, like, horizontally to traverse and to get those. So we had to install some concrete anchors to do that. And then down at the flip bucket, we looked

at that. At phase two was the destructive testing or drilling, that we did. And so there's a big drilling program out on the emergency spillway, but, also, I think we ended up doing 20 some odd holes, 26 holes maybe in the service spillway. And these were targeting areas that were identified on the GPR results that as anomalies or areas that might the slab might be a little thinner than design or maybe some delaminations

or cracking. Kenny mentioned an inspection in the Pacific Northwest, another job that helped avert more serious consequences. And, basically, we're inspecting the gates, and we saw some what Sam Plank actually said was one of the one of the worst deformations he'd seen on a on a strut arm. And so if one of those were to fail or become overly distorted, there could be a failure of your gate and a uncontrolled release of your reservoir so you'd be losing a

lot of water. And so we were awarded an emergency analysis contract where we did the finite element analysis of the gate, and the core actually went in and did an emergency retrofit of those gates just because of the items that we saw in the field and how

concerning they were. So it was it was really rewarding in the sense that, you know, our inspection findings led to a major finding that could have been disastrous and being able to be part of the team that developed the the retrofit plans and specifications and ultimately got it constructed.

With aging infrastructure, limited funding, and outside forces like climate change and increasing water demands, dam owners face mounting pressure to not only meet community needs, but to prevent a catastrophic failure. I think the realization is that a lot of our infrastructure is 50 to a hundred years old, if not greater. So just understanding that all of these structures have a set lifespan, you can't expect things to last forever.

And so keeping up on proper maintenance or retrofits to at least extend the life, but ultimately, at some point, starting to think replacement, I think that's going to be one of the, the big items that will come up here in the future. Climate change specifically is changing the equation for which infrastructure was originally designed. We are updating potential maximum precipitation

analysis. So, essentially, how much is a big storm going to generate and then potential maximum flood routing, how much is this storm, what type of flood is it going to make? And is that going to jeopardize the dam? And how do we size for that? Those are all related to climate change and then also related to sea level rise. Mike said the convergence of many factors means the industry can't be

comfortable with the status quo. There's definitely an intersection there between the age of our infrastructure and then some of these sort of larger forces at play, the climate change and whatnot. We could definitely stand a little more investment on that front, I think. And while fixing things and and sort of maintaining what we've got is is good as we move

forward too. You you have to take into account some of these other forces like climate change so that you don't find yourself in a worse position than when you started. And so there's gonna be some pretty large implications. Travis cited a local project example. We've seen locally here in Colorado small watersheds that are for show five times the potential flow than they did, you know, pre fire. So we could get all kinds of debris, and and

it becomes a potential dam safety concern. I think one area, it said the hydraulics on it said, one over 70,000 chance of overtopping pre fire. Post fire, it's about one over 500. So it it can, you know, jump up pretty fast there in the, you know, how how resilient these structures are when affected by a natural disaster. Kenny said all the work contributes to a bigger picture. There's a number of other analyses that go into this. There's potential failure modes. There's level two risk analyses.

And so, really, a lot of the information that we're gathering out in the field are help feeding these other types of analyses. And I've said this to multiple clients and just even family members. The ultimate endgame here is that we want the structure to be safe because it's protecting anywhere from one person to hundreds of thousands of people behind it. We're here to make sure that the the structure is in adequate condition so those people feel safe. And so it always plays a role

when we're out in the field. If something takes an extra two hours, let's get it done. If it's gonna give us some answers or just make us feel more confident on the behavior of the structure. Mike offers an even more philosophical perspective. When it comes to the geology, usually, we're talking time scales of several thousands of years to millions of years. Right? And so how do you make that relevant to present day and and some of

these structures and the work we're doing? And so that's where I kind of also find some of the meaning and just acknowledging that the rocks are there to tell you a story, but we've engineered around it to provide these reservoirs for drinking water irrigation and all the folks downstream. So it kinda helps bring it full circle to to why we do this kinda work and making sure that we've got safe and competent infrastructure.

That role puts the rope access inspection team on the front line of dam safety every day. I guess the rope access team is sort of a infrastructure first response when it comes to imaged components. Being that trusted responder for clients when they need help has paid dividends across the board, not only in more inspection work and stuff, but helping them respond to it in a

long term. Jarlene recognizes the significance of that role every time she's on the job and discovers a crack, corrosion, or seepage that might tell a larger story. Like, always inspecting with the thought of when you find a defect, like, was this something that happened during construction, or is this something that's happening because something's wrong with the structure? And if it is something wrong with the structure, what's causing it? Is it gonna get worse

over time? Like, you just always go in there with the mindset of trying to figure out the issue and how to fix the issue and any potential risk that could happen. I think that's always in the back of my mind. For more information, visit hdrinc.com/speakingofdesign. You'll find pictures, bios of our guests, and links to related articles. And be sure to subscribe and drop us a review on your favorite podcast app. Thanks for listening.

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