Full Momentum Episode 30: Nature Like Fishways and N Values

[Music] all right welcome to full momentum in HC Raz podcast I am your host Ben KY uh joining me today we have Chris gell as always um and we also have a couple really really awesome guests on the show to talk about uh a special topic that we all really enjoy um getting into and working on and that is uh the the projects um that are called nature-like fishways or ruin channels so to discuss that particular topic today we have our own Tyler krider who's a senior engineer out in Pennsylvania and then we have uh Mike love who's a managing principal of Michael love and Associates in California so welcome Mike and Tyler to the podcast welcome guys thank you for having us yeah glad to be here yeah good to have you on yeah so this is a really exciting topic and is one that Chris and I can can contribute on the modeling side of things but we wanted to bring in two experts because this kind of gets out of our area of expertise um as we kind of get into the nitty-gritty of nature like fishways and there's also been a lot of really cool developments and research that's been that's been done on this particular topic and so we're going to cover some of that today um before we get into that though I do want to provide an opportunity for you two to introduce yourself to the audience here talk a little bit about yourself um so Tyler if you wanna if you want to start that'd be great sure thanks Ben yeah Tyler crer um grew up in uh Pennsylvania never thought I'd continue to work in the state but here I am um I've played in streams as a kid and I'm still trying to do that for my work and try to get paid on the best days um and so I got an engineering degree um environmental resource engineering specifically from Sunni ESF in Upstate New York Syracuse New York um that sort of launched me into the this interesting field of environmental resource engineering um then finished up with a bachelor or sorry a master's degree at Virginia Tech in biological systems engineering uh focused a little bit more on sediment transport and some stream processes work there um and then jumped into a career at Ken Schmid and have worked on a variety of projects spanning Dam removals habitat restoration and um more more recent years nature like fishways um so yeah I'm located near the susanah river in Pennsylvania um that's where a lot of my work has occurred and across the Mid-Atlantic and that's sort of where I come to it I'm not a heavy hecz user I know some of the basics and use a lot of that in um undergrad and a little bit through my career um I often turn to the Ben and his team and others for some of the detailed work and and work with them on the outputs overall so awesome for having a on today Tyler is that the susqu Hanah behind you uh that is yep the most recent fish way I've completed U there on the susqu Han it's about a half mile wide at that point just to give people a sense of scale for those that haven't stood on One bank and looked across it yeah very cool awesome welcome Tyler and uh Mike I'll throw it to you next okay um yeah Mike love um I went to school at humble State University uh similarly I went through the engineering um Department there um environmental resource engineering and um now it's called Cal Poly humbl they just renamed it for into a Cali to a poly Technic um and that's up in the northwest corner of California up in the Redwoods very different than what most people think of Califor it um and right on the coast um kind of grew up playing on in streams and and uh especially at the beach kind of manipulating streams as they float into the ocean so really uh was excited when I learned about opportunities to work actually moving real streams around and doing restoration um so after college I did a maricor with the US Forest Service oh very cool and that uh are they threw me right out the first like month I was there there in October which wasn't the great time of year up into the Pacific Northwest the 96 floods that just happened which was like 100 to a 500-year flood event depending where you were and I was sent out with my uh field partner to do Culvert autopsies we call them where we would figure out how a covert failed we dig out the inlet and find the stick that caused it to fail and compare the cul size to the stream size to the stick that caused the entire Road or highway to blow out um very fun learned a lot um and then as part of that I after that started uh working uh with forest service and maricor actually writing the fish Crossing software with um Mike furnace led the project and Susan fire we wrote The Fish Crossing software which is a 1D hydraulic model for covert Hydraulics that routed fish through it um and so that that was kind of how I jumped into fish passage and then was working with h Dr Margaret Lang we did some research with students um and no off Fisheries trying to look at um fish passage back in the late 90s and helped to develop those guidelines as uh salmon were being listed as endangered uh we needed Road stream Crossing guidelines um and so kind of everything kind of came from there and just started a small company Michael Len Associates MLA and we've got a small crew very interdisciplinary we um I you know I did the 1D RZ thing but I've kind of passed it on to most my staff that do the 2D RZ um we do everything we do the surveying the modeling the plans the specs the construction management so kind of get to dive into all that for fish passage and and restoration projects in General on the streams and estuaries so very cool very cool well thanks for that intro Mike and welcome to the podcast I think that's the first time I've ever heard the two words covert and autopsy together this is really cool makes me think maybe you've got a television show coming up uh like another CSI could be like cul Culver scene investigation maybe I don't know I don't know how what the audience would be for that it might just be the four of us tuning in though probably no it probably be everybody that happens to listen to this podcast is at least at least for the pilot episode maybe I don't know very cool um and my understanding is that Tyler you and Mike know each other right you guys have met at some some conferences or some uh some technical workshops or whatnot how did how did you guys meet yeah so the American Fisheries Society biological engineering section had a grant to expand the science of nature Lake fishways um and so Mike and I and several others collaborated on a nature Lake fishway Workshop hosted by the SED restoration Federation um in California in late March um and so that's where we first met each other um we may have seen each other in passing the prior conference but uh so we really got a chance to collaborate and we did it again as a one-day workshop at fish passage 2024 I guess just last week um so yeah very very cool well I'm glad you guys met and I'm uh even are glad that you were willing to come on and and share some airtime with us today talking about this topic before we get into the primary topic for today I do want to go into a couple listener questions that we received um since our last episode release um and before I do that I also want to recognize and thank everybody who tunes into the show uh we just crossed the 150,000 uh viewer mark on our uh vodcast so this is episode 30 gotten on average about 5,000 views per per episode and so anytime we cross cross a milestone uh like 150,000 views you want to recognize that because it's pretty cool we started this four years ago and uh have had that much reach um both nationally and internationally so it's a and when you get to 150k too you know it's not just you and me Ben watching there's got to be more people than just the two of us so that's right yeah I have I have parents watching the channel on Loop that can only count for so many views so yeah that's right um all right so first question that we had uh that we wanted to get into today this one's an easy one Chris I'll let you share your screen um because I think that's the best way to answer this um and this was uh based on some of the comments and conversations that we had around the um shallow water equations um that you need to choose between using the full shallow water equations or the simplified diffusion wave of approximation and somebody had asked how do you know if you're using the full momentum or the diffusion wave set of equations how can you verify what your model's using yeah well the easiest way to know is just check under options and go to comp computation options and tolerances you'll get to your um options and tolerances window go to the 2D tab right here and on uh row number six it tells you what equation set you're using for every single 2D area you have in your model so um a lot of people get confused about this what is this default column uh the default column is just what Ras will adopt for any new 2D area you put into your model but for the what's being used for a specific 2D area is under the column header of that particular 2D area so in this case we only have one 2D area it's called Reservoir and you can see that we're using diffusion wave and so if you want to change it you would just click here and um select the other equation set from the drop down um um whether it'swe I don't know why it's not letting me pick that over there let me reopen it could it be because of the size of your window maybe I don't know if that's yeah maybe I messed that up okay there we there we go okay um so you've got diffusion wave you got um thewe um The Listener calls it full momentum which was the original name for swe LM but then they started having these kind of offshoot or like variations of it so they change it towe which stands for shallow water equation and then Elm em and liia are three variants of the shallow water equation that we could talk another hour about but normally I would say 95% of the time Ben wouldn't you agree we use the elm for for most of our yeah so double check on that um in this opt options and tolerances um not sure that maybe the question was well what about looking at output How would how would I know and one quick way to know is look look in your output in Ras mapper look for areas where you have significant contraction and expansion of flow so here we can see we've got this model example this is actually our Workshop from our class so if you uh if you want to learn about this in a little more detail sign up for our class but um here you can see we've got these obstructions in the middle of in this case it's a reservoir but it could be a river and it causes a contraction and a sudden expansion of flow whenever you have a sudden expansion and even contractions you tend to get flow separation but one of the big differences between diffusion wave and the full momentum or the shallow water equations is that diffusion wave does not account for rotational flow so you get this kind of idealized pattern which doesn't look very realistic especially if you've been out to Rivers right right Tyler and Mike you guys seen enough Rivers right you would go well this doesn't look right I don't see water making 180° turns around an obstruction like this there's going to be some separation and Y and some Eddy patterns right and so that's what you get with diffusion wave you get this idealized flow without rotational flow so um this tells me right away hey this is most likely to Fusion wave so when we switch over to the swe full momentum now you can see we've got our rotational flow so this would be another kind of visual way to tell in your results whether you've got diffusion wave or the full momentum swe equation very good thanks Chris that was a great answer and I forgot to plug this is a good opportunity since you brought it up our uh next classes that we're offering um we have our six week online class that's starting October 9th that'll run through November 13th um that's a 1D 2D class um so that's open for registration at this point if you're interested going go to kinmit uh clmg group.com and you can find a link there to sign up for the online class and then the in-person class uh we're going to be teaching uh in Atlanta Georgia September 10th through the 12th that's a Tuesday Thursday yeah be hot it's gonna be warm the class will not be outside I got got confirmation it's not goingon to be outside can we teach this in shorts I wonder um is that frowned upon I think we can teach in shorts but we should have plenty of air conditioning so I don't think that'll be necessary maybe shorts and our uh and our um our t-shirts with the Run man on them yeah yeah and uh in addition to that imperson class in Atlanta in September uh that will also be connected to our annual um HC Raz Pub and Grub um so we're going to have that I believe on Thursday evening so if you're attending the class or if you're in the area and just want to join us for a night of Raz presentations and and beers uh look for more announcements on that particular event coming up next question uh from listeners here um this is an interesting conversation I don't know necessarily if we have a good answer but it's a good conversation to have so this person is is running a very large model with a few hundred thousand cells they have 17 different boundary condition uh input hydrographs so a lot of different inputs um probably a very flat system um a lot of different flow and a lot of flow quantity and they're trying to run this over the course of a 12 Day simulation uh with a half second time step and when they when they go to run this model the program the the quotation here is the the program does not simulate so it doesn't complete the simulation um the solution they found is to divide the model into four 3-day simulations instead of 11 12-day simulation and that seems to work um and they're wondering Chris what what could possibly be going on here uh any anything jump off the page to you well the first thing that jumps off is 110,000 cells is not particularly large I mean I would call that maybe a medium size um I try to keep my sell count below 100,000 if possible but if I go over I'm not too freaked out about it and it certainly is not the kind of thing that would cause your model Mount to run um I mean we've had models of over a million cells before and they run it just takes a while for them to go right so it's likely the 12-day simulation side of things it's the length of the um simulation that you're trying to run that's playing a part in this um breaking it up into four different models is an interesting um idea and kind of adds to me anyway adds a little more of my confusion as to why this would not work because um I don't I don't want to say it's not a memory issue but the fact that you got it to run with four separate models means you probably have uh enough hard drive space but maybe there is a ram issue um on the memory side of things it could be some of your scratch files are getting too big um and so I would check to make sure your resources on your computer are um sufficient enough you've got lots of hard drive space you've got plenty of RAM and um and as we always say Don't run it off your network either that's just a especially with a big model uh your network drive run it off right off of your local Drive um if you can uh or if you've got a remote computer we've got a nice remote computer with we can um we can dial into that um works really well too but running it off a network you're asking for trouble and that could very well be the the problem here too yeah it's Poss you lose connection at some point during that simulation the first thing that comes off to me is this is kind of an issue that we run into a lot of times with with questions from from listeners and that is not given a lot of information in terms of what exactly is happening at the end of the model so the description here is that the model does not simulate um that could mean a lot of different things you know does the model crash does the model restart so when you open it it's closed uh does the model run but it doesn't post-process the results a lot of different potential outcomes here and so uh this doesn't necessarily answer the question but I do think it's a good reminder for everybody who's listening and that is if you're looking at the results of a model simulation uh understanding how the model doesn't finish can be really helpful for diagnosing what actually what the problem is um because again if the model crashes due to instability that will lead you down One Direction of troubleshooting if the model just B on just closes out and and restarts um that will lead you down another path uh if there's a memory issue oftentimes you'll actually get some output that that uh specifically calls out that the the model or the computer space is running out of memory and so really pay attention to how the model is not completing and that can help you not only ask better questions but also to potentially self diagnose a little bit better what's going on yeah I mean look at the the compute messages um now this one is a nice stable model and in fact it's so stable I just tried to run it at a 1H hour time step and it worked so go figure right um I was hoping to get it to crash so I could show you some error messages here but when your model does crash or it doesn't run look through here the messages are not always that helpful especially when you start getting the red text you get these unknown kind of for looking computer code errors and uh that that doesn't help us out too much so um look though look in between that um look for keywords look for something that can kind of give you a clue um there's usually something in there that you can use to at least kind of steer you in the right direction as to figure out what's going on um so yeah and even if you can't understand the text at least you can include that text in a question if you're asking for technical support from somebody else yeah yep absolutely all right last question here before we dive into the primary topic for today um and that is that's a follow up on the river River restoration 1D versus 2D episode that we had last month um Robert shom who we had as a guest for that presentation was sharing uh an approach that they used for modeling River restoration sites with 1D models and for those sites they ended up using blocked obstructions uh to simulate some of those restoration features and the effects that those would have on upstream cross-sections and the followup question here is um would an ineffective area be more appropriate instead of blocked obstruction for doing ond restoration modeling um and what would kind of the pros and cons of each be so Chris do you want to give kind of a 10,000 foot overview on on what that would look like yeah so first of all if you have a 2d model you don't have to worry about ineffective flow which is one of the great things about 2D models but we're still doing 1D modeling and they still have their place for sure and when you've got a 1D model how do we take into account water that's not moving in the Downstream Direction in other words two-dimensional effects right so you get water moving laterally or in the case of an Eddy pattern you might actually have water moving in the Upstream Direction well any water that's not effectively moving in the downstream Direction has to be treated as ineffective flow in Raz but we also have this thing called a blocked obstruction and they they're kind of entered in the same way in Raz um they look similar in how they're represented just the colors different the blocked obstruction is black and the ineffective are is kind of a green hatched color um so they are sort of similar in a lot of respects now the big difference is an ineffective area allows water to be inside of it it just doesn't treat that water as conveyance so it's not actively moving Downstream uh what it is treating it though as is storage so when you have an ineffective flow that water in there is part of the storage term in the the full momentum equation okay now a blocked obstruction is exactly that it's just completely blocked area out so there's no water in there so it's neither storage nor conveyance now when you have a steady flow model there is no um ineffective other than taking away from your your uh flow area there's really nothing done with the ineffective it doesn't deal with storage at all storage is only a part of an unsteady flow analysis and so if you're doing a steady flow model or quasi steady an ineffective area and a blocked obstruction are almost the exact same thing now the only difference between them is how they treat wetted perimeter an ineffective area does not count the wetted perimeter or does not count the perimeter under that ineffective area as wetted perimeter whereas a blocked obstruction does count that as wetted perimeter so that can change your answer slightly but if you're doing a steady flow model and you go all right I'm doing this as in effective an ineffective area over here let me switch it to a blocked obstruction and see what the differences are it probably be a very slight difference but not much but when you get into an unsteady flow simulation then they're going to have a very big different effect on the attenuation of the flood wave through that area blocked obstruction does not store water so has no effect on attenuation whereas an ineffective area does it is counted as storage and so it will attenuate your flood wave more yeah so you'll end up with a slightly or you'll end up with a higher water surface elevation if you use blocked obstructions than if you use yeah so that was sorry about the long discussion but the question here is actually which would be more appropriate um I'm assuming for River restoration and so hopefully having that understanding of the differences can answer that question for you but I see a blocked obstruction as being a more conservative way to represent say something like a log Jam because you're blocking the whole thing out right uh especially in a steady flow type of model you're blocking it out you're going to have more flow getting pushed around it so you're going to have higher velocities around the perimeter of that structure higher sheer stresses you're going to have more head loss Upstream as well um as a result so might be a more um conservative but maybe not quite as accurate because these log jams will have some water inside it will have some storage and and so that's how I think of it y good yeah no that's a good answer I don't think that there's like as with most things with hydraulic modeling there's not a clean answer just a matter of kind of understanding the limitations between the two things and and that's a really good point Ben it's like I I almost put more value in in answering this question in the description of the two different features because that arms you with the knowledge needed to make that decision yourself because every model is different everything's going to have its own kind of of unique situation and circumstances and so understanding the differences will help you make that decision um instead of ask you know instead of us just giving you a blanket result for which is better or more appropriate yeah yeah yeah and that's a great transition into the nature like fishway rough and channel discussion because there are quite a few parameters and decisions you have to make as a modeling user with how you're representing certain features within nature like fishway and um there's not necessarily a right way or a wrong way to do that important to understand what the impacts would be on your model so that you can you know quantify the uncertainty um and you know what what the results of those assumptions might be so and we'll get into that a lot more here in a second um before we transition into the main topic for today I'm just going to do a quick little ad read here um so we are grateful to be sponsored by our firm clench Associates who is known throughout the industry as a firm that provides practical solutions to complex problems affecting energy water and the environment M you can learn more at kinmit group.com you can also sign up for our 1D 2D HC Raz classes at kinmit group.com and you can see some really cool nature like fishway project examples on our website as well I know we got some some cool visuals and descriptions of of some of those projects up on the website so a lot to learn there if you're interested uh in doing so let's go ahead and and transition so again a reminder our main topic for today is kind of everything around nature-like fishways and roughing channels including the the name difference between those two things which we're going to get into here in a second but I thought it'd be helpful maybe Tyler if we could start um with a brief overview on kind of the history of nature like fish ways where these came from how we got to the point where we're at today in the industry of of using these um for you know fish passage Solutions at different projects sure yeah so the some of the slides be Sharon here uh we're from our two-day nature Lake fishway Workshop presentation those slides are uh published on the line and so we can include a link in that um with the vodcast but I'll just go over very briefly um a small portion of that and um talk through that so just want to acknowledge that since pre-colonial times in North America people have been modifying river systems more for the harvesting of fish um as you can see here in these Graphics there's such thing as an eel we that's found in the susqu Han River for out migrating eels to funnel them into a basket so people can Harvest those at low flow um from that then um moved into just acknowledging the 17th Cent Century in France uh they were working on some sort of a salmon ladder um trying to support that population getting Upstream heading into the 18th century back in the US uh the Plymouth colonies passed a law prohibiting Weir across Rivers because they realized the rivers were important to fish and so that um was on the books initially I think industry took over and the dams were built anyway in some cases uh but they did at least recognize that these seasonal migrations happened um and then we come into the sort of the 1800s early 1800s in the Cod ladders um again this is for fish harvesting not necessarily for passage but you can see how the fish may have swam up this modified bypass system and they would be people with Nets in each one of these pools harvesting fish uh for consumption um it was primarily about eating the fish instead of saving the fish um in this period of time um in about the 20th century um Gustave denil published a paper and some information relative to denil fishway which is what we think of as a technical fishway um and that really expanded throughout the 20th century uh with some of Milo Bell's work related to these Technical fishways and we think of technical is ones that have a lot more concrete and steel as the basis although some of us would argue that a nature-like fishway still is a technical fish way just a little more nature like um so then in the 20th century a lot of it was about sort of the concrete and steel ice Harbors vertical slot fishways fish lifts where you put the fish in a hopper and raise them up 80 feet above the dam and dump them above the dam um but then there's more recently uh been a turn back to some of the nature-like fishways where you're actually mimicking the natural system but it's still a hydraulically designed structure to provide suitable depth velocity and uh characteristics that the target species can pass through so that's a little bit of the history of nature-like fishways um and maybe how they orally used for harvesting fish and modifying rivers to to where we are today we're trying to often bypass a dam um or a road crossing or some sort of a barrier um could be a perched cver you just need to reconnect the stream and provide passage at so so and as I asked this next question T I don't know if you can pull up an image to show the audience what a nature-like fishway looks like compared to maybe one of these more kind of hard infrastructure fishs Mike my question for you is you know the transition between more of the hard infrastructure fish passage solution to more of this nature likee fishway rough and channel solution is was that made because of uh actual efficiencies in or effectiveness of those more nature-like fishways um in terms of actually passing populations or is it more of a visual thing like what's the driver behind kind of going in that direction well there's definitely the visual ual thing for for us humans but I I think it was our understanding that um these natural steep streams that we we were seeing very small fish of all different species migrate up in nature um these streams were doing better passage than our Technical fishways and they were passing many different species um in life stages so it's that complex Hydraulics uh that that the nature-like fishway creates the micro Hydraulics the the you know the uh substrate of the bottom making very low velocity zones that small fish can move through versus these Concrete fishways where it's it's fairly uniform vertically what the what the velocity distribution is so trying to create those nooks and crannies for all the different fish is where I think why we move to Nature likee fishways besides the Aesthetics for us humans so sure yeah now if if we have if we recognize that they're they're better looking and maybe they're more efficient at passing multi species why not just do these at every single project what's the big setback there or what's the big limitation in terms of their limitation yeah no there's definitely one uh the slope that they work at um so so you know at the upper limits I mean people push it and and you know fish can go you know salmon do go up like 10% slopes for a while such but generally we're limiting our our our slopes on our nature like fishways to four to 5% and it really depends your context if you're in a big river like Tyler in it's that those those slopes are crazy we're like one and a half percent so you need a lot of real estate yeah so it's just about real State and and and you know now do I have a big switch back and I have to have this channel go s turning around and looks kind of out of context with what you're building and you don't have the real estate so and the cost go way so a lot of things to think about um technical fishways definitely have their place it's kind of a toolbox and get right the right tool for the right project so I I love modeling nature likee fishways roughing channels that was one of the first things I did when I came to Klein Schmidt and I worked with Tyler uh the York Haven site and one of the the first questions that that came up in our early on discussions was hey can we model this in in hecz and how do we do that and uh I had never done anything like that in hecz in a in a 2d model uh but I thought you know based on my experience I think we can do it and so we went through it was it was a challenge which is why I liked it so much and we got some really good results but so you know what what goes into the analysis side of things I mean HEC Raz is just one piece of it but um you know how do we know that this thing's going to stay in place maybe Chris before I jump to that a little bit I'll just share a graphic of sort of what a constructed fishway looks like um and then a little bit of the Raz side as well to orient the viewers um so this is a fishway here that we um completed last year um and at first glance you could say oh this just looks like a rip WRA Channel um but this was actually all Upland um in most cases portions of it were connected to the river before so just gives you a sense of what sort of a naturalized system can look like this one is just being opened up that's why some of the water is so turbid but you got all these Boulder protrusions um this one was more of a a rough and channel style so you got sort of a quiescent pool area with a riffle at about two and a half percent slope um and so that's sort of what we're looking at when we're talking about the actual constructed side of a nature-like fishway if we think about sort of the why I'm going to switch to an Arial image here on that yor Caven project that you mentioned Chris um and so this was a dam water's flowing from the head Pond here towards the tail water and there's no fish passage on this Dam currently and so we said hey we need to create something that um allows water to flow around it and hence the fish to swim upstream so what we did is we came in this is the existing terrain pretty high system set up there um and we' cut into that a fishway now this fishway is a little more of a pool and wear system so you've got water flowing in from the head Pond coming over the first Weir enters a large pool and then comes down a series of wears and this one actually switched to a bit of a hybrid system with a roughing Channel and some zones of Passage to the downstream end um but that's a little bit what a bypass fishway can look like sometimes you've got where your whole road is crossing your River and you just need to put your fish way the whole way across the river in this case this is a susqu Hann it's a relatively large river went with a bypass that bypass is still 120 ft wide um you can put a nature-like fishway on a small stream something that's 10 foot wide can get a nature-like fishway to connect back a Calvert or something that's perched and provide that aquatic organism passage so that gives a little bit of the context of um of what type of fishway um a fishway natur like fishway could look like both once it's built and in the the modeling scenario so yeah that's great and I think that that picture in particular highlighted the point that Mike made in terms of you know that's a pretty flat slope right between upstream and downstream compared to you know some of these higher head dams right where there's quite a bit of difference in elevation and you'd have to have a amazing amount of of uh area and length to be able to have those slopes be passable for for fish so Chris do you want to Reas your question um you had asked yeah so you know I my interest of course no surprise is how do we model this right um you know to me it's it's not a 1D model there's there's really no chance of that unless you're doing something really really basic right um and a 2d model seems more appropriate but maybe not even tells the full picture because you can imagine in something like you showed Tyler there's a lot of vertical acceleration of flow you're not going to get in a 2d model the 2D hackr model um so I'm interested in you know what is the the process how how do you go about designing this so we can make sure not only is it going to pass fish but is it going to stay in place um for a long enough period of time uh for its design life uh what's the process there and while you're telling that I want to just show a video real quick of some of our earlier modeling in hecz 2D of the York Haven um just to give people a flavor of of what that looked like but um yeah what do you guys think yeah so I think it starts out with some of the just the design criteria what's what's your design case some individuals are okay with a little bit of movement in their fishway if it's not protecting critical infrastructure you can acknowledge that some of the Rocks may move and that's okay you may have a set sediment Supply that's suitable and you can just let that sort of replenish some of your rocks as it comes downstreams in other cases you need that thing to be bulletproof up to the 100e flood and Beyond um so I think that's some of setting of The Design criteria um I think coming from a world where I've dealt mostly in 1D models in my under graduate work I'm just even having the ability to do a 2d model was awesome and it gives you so much more visibility into the the variability of flows and depths um across the crosssection um and I think that's where a lot of the guidance right now is at for fish passage at least is related to sort of your depths and velocities for Target species um and so that's often what we pull in as part of our design criteria um system there and yeah I Mike any thoughts you have I think and you've got that one graphic of kind of that design process Tyler but you know really I emphasize with everyone I work with here is don't don't start with a complex model but really start with a A you know you're you're at a cross-section analysis um and then we have these empirical equations for Mannings roughness coefficients um and so run run different shapes of cross-sections for your roughing Channel and and then you know use the Manning's uh empirical equations to estimate what that roughness could be size your Boulders um here let got this I can jump to that graphic um but yeah I mean just here's like the standard equation from the core um this is often where we start with our sizing our Rock and then we have some relationships because our our rock mix is going to be much wider gradation than what the core uses for a standard rip wrap so yeah our d84 is going to be in this case one and a half times what the core equation gives us and we make a gradation then that goes into that Mannings roughness uh equations that use grain size and then that goes into getting us a Mannings in that goes into our single cross-section analysis and we kind of iterate on that scale because it's fast you can do it in an hour and then then we can start to now we got to start grading in in CAD and make a surface um so so that's why we really want to work it out in that single cross-section analysis the the the first few steps yeah it it almost seems like it's a real balance it's it's almost you have like you know your your standard like scour protection calculations right where you're coming up with the size of of rip wrap that you need to stabilize a bank or to protect to bridge abutment and then on the other side of things you have like a a stage zero restoration project where it's all about just you know putting in certain features to return a system to its natural uh kind of uh physical uh processes but you're not super worried about you know things changing or moving that's kind of part of the whole deal nature like fishway almost seems like it's it's kind of bridging both of those options where you you have hard engineering as ects where you need certain things to stay uh or certain things that are sized to to protect but at the same time you kind of have to or want to have some of those natural processes occurring within your design is that is that right yeah and I I think from my perspective is like so this is step one but then the art of it and using nature to and the simulating nature piece of it is the next step which is now I gotta I know the rock size I need for stability and for roughness now I got to start making an arrangement um and that that's where um that's where the the fun part is is like how am I going to arrange my big boulders I call them structure or frame Rock Boulders um to give the flow patterns I want for the type of slope and size of the and flows I'm working with in the size of the channel and kind of figure out am I a kind of a shoots or Rapids and pools I'm doing like a step pool system what is it that I'm building here sure Tyler do you want to go ahead and share that figure um goes through the nature like fish fish W process so people can kind of get a better understanding of what that looks like at a high level think if that's coming through yeah it's a good reminder Mike of that uh sort of sequence of what a natur like fishway design can look like that we presented at the one-day Workshop here uh so we start out with this uh system that's got a problem um what is that problem it's generally fish passage and so we think about that and we say okay let's develop some design criteria what are we going to do um what are requirements to get fish past this barrier We Gather some data that's sort of an iterative process thinking about risks and what you might need for permitting once you got some data then you can start thinking about Alternatives there okay is a fishway the best option are there other non-f fishway Solutions Dynamite might be involved you might just get rid of the dam you might truck the fish up and around it truck and transport is a thing where people harvest not Harvest but collect the fish and move them up stream above the dam um and it maybe thousand net a thousand miles 100 miles or so Upstream might just be literally just around the dam of butman and that's cheaper than building a fishway but if a non-fish way solution doesn't work then you think about okay what type of fishway works again considering risks and cost maybe you need to go back and gather some more data um considering the type of fishway it might be there's a non-n like fishway solution this is those technical fishways we talked about a little more concrete and steel um certain situations those are very appropriate um particularly High head um but if you conclude that a nature-like fish weighs the correct one um Mike as you acknowledge then you start thinking a little bit more about the local geomorphology is a step pull system a little more appropriate is more of a roughen Channel with a large riffle and then a larger pool below it appropriate and you take that into sort of this initial pick a slope pick a cross-section and run it and this 1D not even 1D an Excel calculation almost where you're really just trying to understand what's going on preliminarily and get your your ballpark width and slope set you might have a constraint you say I can't go more than 500 linear feet on this fishway and so is my slope even suitable for this species do how many borders do I have to think about putting in there what roughness do I need um take that slope and cross-section then and uh throw that and sometimes you might pick a slope and it may say hey we need to go back and gather more data you got to go back to the drawing board um maybe you can go ahead and go on to hydraulic modeling um and do that first sort of best case scenario you take that into your hydraulic model you develop a reasonable hydraulic model check if that meets your criteria for your given species check your costs as with any good project keep an eye on cost throughout it um and that may require you to do a stability check at that stage as well Mike as you said checking your rock size can we get that big of rock locally um what sort of gradations are we talking about and you sort of iterate in that slope cross-section hydraulic modeling criteria check stability check for a while um and sometimes that may require you to go back and pick a different type of fishway if you can't get a solution to work out just like if that model doesn't um converge at the end of your run you know something's wrong and you need to go back and see which parameters you need to T tune sometimes you got to go back and even ask is the fish way the right type um and sometimes you go the whole way back to your design criteria and say maybe this design criteria just needs to change we had one fish way that required us to have a narrow Notch for low flows and it was just causing us headaches and we went back and said we're just going to strike that we talked to our partners and acknowledge that's what we needed to do to make this function but once you get out of that once you check all those boxes on cost criteria hydraulic models good stability good only then do we think about sort of the design drawings um and then to follow on the detailed costing and risk assessment and then get into permitting but that's sort of the the life cycle but there's a lot of iteration there in that slope hydraulic modeling I mean I don't know how many York Caven runs we did I mean it was probably 30 40 runs of like detailed 2D hydraulic models um that we were running and that when we did have a pretty good idea what we wanted to do but it was hey tweak this modify this let's see um so getting that first start as good as you can is really helpful um as Mike acknowledged there start just a simple Excel equation for a weir equation how much flow can I get across this flow control structure um what does that look like yeah so you can see this is a great figure and and kind of thanks for stepping through that with us uh Tyler um it obviously this is a a very complex process requires a lot of iterations um a lot of probably multidisciplinary input from from different team members um and and just thinking about and seeing some of the the hydraulic modeling that's done for these types of things you know one question that pops to my mind is you know can we get what we need from a 2d model to answer these types of questions you know particularly because as we all know the 2D output is a depth averaged output so basically you have a single velocity throughout your water column that's the Assumption that's made within 2D modeling um these are very three-dimensional uh cases in in in many situations and so Mike I guess throw it to you first do you feel like 2D modeling is adequate in many of these cases is there a need to do 3D modeling or is that kind of the direction things will go as computational resources become you know more available well I'm sure it'll go that way once we have those resources but at this time I I don't think we have those resources for the size of the projects that we're modeling um and I'm not sure if we know even with more information what we're lacking I think is really the information on the Fisheries the biology side A lot of times um you know turbulence we can go into L that for for a whole day um and and what you know disorienting the fish and and all that also when we start talking about fish that are that are you know a quarter of the size of your cells in your model um you know how accurate is it going to be no matter what um so I think it really for larger fish when you're modeling in a 2d I think it gives you a fairly good answer and and also thinking a lot of these nature-like fishways I think as as we saw the earlier example um the fish passage flows that we're analyzing they're they're typically below the top of the big boulders so so it's we're not having like streaming flow over the top of the boulders and a flow separation vertically but rather we're having more of a contraction expansion Jet and wake flow and maybe the the 2D model is pretty good for that um you know some of the validation uh modeling and field measurements we've done I think it shows that it is does to uh do quite well with that type of flow so is it is it common to take this or are you aware of any uh um projects where it's gone to physical modeling yeah um yeah we've done a couple physical models with Northwest Hydraulics up in the Pacific Northwest they built it for us and we're working with them on the designs um here I could share like one example um and and and I learned probably more in physical modeling and playing at the beach with streams and stuff than I did with with any type of numerical model um because you really feel it um you know this this is an example a rock layout this is actually for the physical model um for one of the sites this is on TBO Creek in Orange County California where they still actually have a large steel head seun uh rainbow trout um and so this shows the kind of the large structure rocks ABCs their layouts and pools and basically shoots and pools um and this is kind of the physical model of it it's a one to six scale we did um they it and then myself Ed Wallace with NHC we moved the boulders around turn back the water on do it again and again and again we really rearranged the whole layout after playing with this um and and try to make one of the shoulders the edges higher than the other so when one would we found that when water would start to go over the top of the biggest Boulders it would start to stream um it probably wasn't good conditions anymore for large uh steel head to go through so we really wanted to uh always have areas that had big boulders sticking out all the way up to our high fish passage flow so here's kind of you know some of the runs um so what what was the what was the trigger that actually made or allowed you all to to do a physical model because that's not a small undertaking so kind how did that how did that come up um it's a a large scale project um and there was a lot of different uh entities and owners that that had a lot of questions so um and as well as we had a a another physical model in the same lab of the entire project so this one was really focused on the ruffing channel but the the bigger one you know was full the entire project area that really gave a visual you know Hands-On for those that really need to approve the project as well so it served both Hydraulics as well as a little bit of public relationships uh building building trust in the that it's going to work are those wears that you have in the middle there uh it looks like they're made out of wood is that um a permanent feature in the final design and is that a common thing to do for these um it is it was in this case it was these uh we concrete wears that were going to be in between to uh be able to control very low flows so kind of similar Tyler mentioned like we we were you know had to pass fish at three CFS so it was yeah and then you got to get that concentrated 50 CFS on the upper end so it's a huge range and then here's another one we did I'll just real quick just this is a similar s a different lab by NHC but uh same river system another fishway so different flow so um this one was done during covid we couldn't go to the lab it was kind of not nearly as uh informative because I wasn't there to be hands off and move Boulders around Mike did you invite any those holders into the the first example when you could go to the lab you could actually invite them in and say hey this is what it'll look like do they appreciate that yes and we actually as part of the you know project we actually flew them up to the lab and and walked them through did you know did move things around for him put debris into it yeah it was very Hands-On and then this one we did kind of a video kind of live stream with them um yeah that's something I think us Engineers sort of forget about sometimes is the public relations piece and how much valuable that how valuable that can be to sell a project or convince somebody this is going to work when they see it physically modeled a 2d model is good we understand that and can read it but some people just need to see that flowing water um yeah well you guys have seen those sand tables right at conferences it's like a giant sand table and they all get to play in it so how fun is that right yeah that's very very very cool um thank you for sharing that Mike yeah that's a a great kind of of uh another option right as you're trying to Wade through the different um design criterias and the way to sell these types of projects the physical modeling could be a really interesting component um and I lik your your thoughts on the kind of the 2D 3D comparison and how where we're at right now 2D is probably adequate in many many cases um I'm going to turn it over to you Tyler for a follow-up question on that and that's about you know something that we run into a lot of times which is people using 2D modeling by default just because it produces results that are more visually appealing but in reality in many cases doesn't necessarily actually give us better results than just a typical 1D model would so in your opinion I don't know if you've actually done nature like fishway modeling in a 1D model setting but do you feel like uh you know the 2D modeling and and the results that we get from that are we're almost tricking ourselves in terms of like the amount of detail that we're getting um from a modeling solution like that when in reality so much of the work that goes into the natur like fish way process like you mentioned is just kind of simple spreadsheets right and just Computing kind of some of these high level design estimates or Boulder sizing and then just taking that out and and and making it happen do do you feel like 2D is is still necessary piece of that puzzle or do you think we can probably do more with less so I think there's been a lot of things that have been designed based on Weir equations and onedimensional Analysis for many decades and I would say that that is still very valid um I think where 2D has its strength is as we start to think about indiv idual fish species and is this fish going to swim in the center of the channel or in the edges um and really selling that to the the stakeholders that care about that fish it shows a spot for that fish on a map you can literally plot on a map this depth and velocity is suitable for this River Herring to go the whole way from the the tail water up to the head pond on a map where 1D you're left with a cross-sectional average and yes it should work based on experience but it you can literally plot it on a map and we've got enough biological data now that I think we know depth and velocity for most of our Target species that we care about um or some surrogate can be picked that you can sort of understand by logically where that fish may swim or best we know um so I think 2D does offer a valid use in a nature-like fish way um but I still think that initial Weir equation and Excel calculations is where you start and hopefully take out a lot of your runs because if you start with a 2d model right off the bat unless you got a really good CAD person and somebody who's really good at hecr you're spending a lot of time and effort iterating early on when you should just be on a weir equation basis and just just go yeah and I know you've got some good examples of routing fish this is just another one like that so this is what a lot of our our reviewers want to see is um this is like um hydraulic a run at a fish passage flow for salmon uh through a CT in a roughing Channel and you know just a Trace determined route there in the dash line of where the fish could swim that gives it good depth and velocity uh conditions and then we plot those depths and velocities along that pathway that path um so they can see yeah maybe we're not meeting criteria every little spot but you know you can kind of get the sense okay there's a little you know peak in velocity somewhere well I people that know that fish yeah they'll make it right through that spot so I thinkt go ahead Chris yeah I was just wondering how wide that Culver is uh 14 feet for scale okay oh cool okay it's a Bo so I think this discussion on like utilizing the results from 2D which I agree are very visually appealing but also like important in terms of like telling the story of how this is going to work for fish that are experiencing the the NRA fishway Ren channel the of course the followup question is how do we know that those results and the the figures that are being generated are representative and real once this thing gets bit gets built so I want to transition to validation and calibration um because I think that's that's a natural connection here so Tyler I'll start with you in your experience um how have you gone through the process of validating or calibrating those modeling results that you're using to tell a story of how this thing's going to function yeah let see if I can find a slide here while I'm talking um but often times you you do all the mod you do the pre-work the data Gathering to get your head Pond and tail water um come up with that and try to understand what what's going on in the system um and then use that to build your model and of course we all think the model is absolutely right until we prove it's not by doing the actual construction and show that it doesn't uh behave like we thought it did and that's why going back out and doing that validation is so important um let me see here if I can kick off a slide set and get back to share this oops not that one um no no rush and let's see here if I can get down to that just talk about this a little bit um here that should be coming through um yeah that hydraulic verification piece is critical because if you're knowing that that fish can swim at a depth and velocity yes that might be the general average but your fish in your region might be smaller they might be larger um there might be certain things that just you don't recognize and so you either do well you do two things I'll say the first is this hydraulic verification where you actually go out with an adcp or Marsh MC Bernie or pygmy meter and take some spot measurements take a GPS point take a spot velocity and depth and see if it matches up well um this is the fishway that we did on the susqu the one that was constructed last year and this is all the spot measurements we took at depth and velocity adcps can be challenging um especially if you get a little bit of turbulence um some of these systems don't do well on that but you get the best data you can uh for that system and then you come in um and run all that uh through there and get these sort of comparisons on the top here we've got a design case with green being passable for River Herring that's what we thought we were going to get then we've got the asilt condition a little bit less green but still identified those passage zones um and work through some of that so yeah it's a it's definitely worth doing um and if you build it everything sounds great in the model um and you as we I indicated earlier everything sounds perfect until you actually think about actually constructing this and where do your rip wrap tips actually stop relative to your smooth surface that you're modeling um do you put the boulders in the terrain or not I know Mike's got some experience with that on the back side but I'll just close with this the second portion there is you can also just test the fish you can literally go in and tag the fish and see if they swim up through the system or not you can there's mechanisms to insert a tag in a fish and then see if it swims through the fishway and you can detect it Upstream so that's sort of the other way of verifying that it it meets your needs um Beyond just the Hydraulics comparing that Tyler what was the key takeaway here in terms of Lessons Learned between the design and the asil condition because as you noted you know it looks like based on the data collected that you went out and and got uh that there is less pass area than um you know what was origin orally modeled um what were the key takeways was it was it underestimation of of roughness like what was the what was the the key change there bring this photo back in and so the key takeaway here was in your as built it's it's really important to get the contractor to understand where your grade is and also for the hecz modeler to understand where your grade line is because your rip wrap is going to vary up and down by 6 in low 6 in high you want your design grade at the bottom of that at the lowest point or do you want it at the tips of the rip wrap or somewhere in between when we did the asilt survey on this one they used the Drone to get it which was great we got great coverage and could see all the boulders but it did mute out some of the low points that were missed by the Drone and so our surface was slightly higher than we had designed it as so you'll see in this case here this green that we had on that Fringe we thought we were going to get a lot more shallow habitat for this species that sort of creeped in a little bit because our terrain was shot a little High um so a big lesson learned for me on this one was making sure that your contractor and your hydraulic modeler and your construction staff that are supporting it in the field building it understand where that design grade is and make sure your as built can capture that accurately as well very very cool Mike do you have any additional thoughts on other validation or calibration methods that you've maybe used on on H fishway roughing Channel projects in the past yeah I mean we've just kind of started to do um you know validation or I'd say post post project evaluations um you a lot of our modeling in up till very recently has been you know just a a graded CAD surface and then putting a big manans in so you're not getting that flow diversity in your Model results and everything else you're getting checking the depth and kind of the C really just an average of velocities you're not really getting what the fish is really going to experience um so we're starting to put in the boulders into our surface like um Tyler has um it's a lot of work we tried using cylinders and Raz those work to some degree when they're sticking above the water but then at the same time you can't put them together and make that little you know Notch that Boulders when they touch make um really tricky we're really trying to find a a a faster way of putting Boulders into our surface that protrude like we usually want them to protrude about a third of their diameter above the surface so um you know those that have tricks for that I'd love to hear um we're trying different things um terms of validating and we were trying to understand how much the boulders in the in the surface matter which we know they matter a lot but how much they matter and how much they influence our Mannings um we kind of did some validation here's one of the sites this is the one I was just showing that box CT 14 feet wide fun building this uh rough and channel pools and shoots inside a box C wow yeah yeah glad we can put the top on as you're building it so still um and then so see I Advance it here so we what we find is they they you know initially the asilt conditions there's a they haven't gotten any flow on them yet and so there's um the surface hasn't really evolved to what it's going to be the fines haven't washed out and shadowed and everything so we this Creek was this stream was lucky enough that it goes dry in the summer I guess that's unlucky but lucky we could go scan it the next summer so this is a we scanned it um and got basically a liar you know groundbased liar scan made a surface of it um and there's our surface of it here we compared it to our design graded crosssections which was pretty close you can see all the lumpiness of those Boulders um we pretty good there um and then we had a high couple high flow events this was one of them um where we um went out there and we took velocity the in depth and water surface shots all over the place we also did lspiv which is with video tracking bubbles on the surface to look at surface velocities as well um but here's kind of that those are all the points where we took velocities um in the water uh you know two-thirds of the way of the water column and um and we have water surfaces and then we um put a model together and tried to calibrate the Mannings to that um and we you know here we had 06 8.1 this is the residual err between the observed and the um the model and so you know it's not bad but still I mean we're off by 04 feet here plus or minus but you know generally 02 plus or minus but the ends didn't matter all that much because now we had that surface roughness kind of in the model was a lot less sensitive to what end we used we found yeah I think that's a really really important thing that you just brought up Mike uh for the the listeners and Watchers of this podcast to understand that those end values you have posted there um they are highly dependent on not only the flow rate we're looking at depth of flow you know fish passage Flow versus flood flow but also how you're treating The Boulders and the other rough elements in your model are they part of the model geometry or are you lumping them into the end value cuz can make a big difference on what the end value you actually calibrate towards is correct do you guys agree with that or okay yeah Mike you had done some study on that as far as the form versus Mannings and form govern but you want to say a little bit more about that you know I I don't think we have enough to really say a hard number but I I know there's some other work on that as well I mean it's the form is definitely a huge proportion of that you know energy loss that's Mannings is trying to represent present so yeah I'd like to see a lot more work on that for sure yeah I think in reviewing some of the documents you sent us before this podcast Mike I think what what the the high level conclusions were were for flood flows the Mannings roughness um coefficient becomes quite a bit more important in terms of what you're what you're selecting there but for lower flows the form really drives a lot of yeah what's going on it didn't M it doesn't matter that much so which is nice I mean that's a really good thing is you know if you're not as reliant on picking the right end for your fish passage analysis yeah because models if if you got those Boulders in it the model's going to do a pretty good job um resolving that energy loss yeah we have a a project that we're doing right now um where we're looking at a natural Channel um and the fish passibility of it under different flows up in Alaska uh and uh the analysis that we did um we're spanning from 20,000 CFS all the way down to about th000 CFS so huge range of flows and what we did sensitivity analysis on all of our model conditions and what we found was agrees with what you're saying Mike at those higher flow levels the models more sensitive to adjustments than Manning andan at the lower flow levels even at a th000 CFS which for this system is pretty low flow still quite a bit of flow obviously overall um the the adjustments that we made to Manning and and turbulence were were very very very resulted in very small differences in water surface elevation velocity so um we we've observed the same conclusion that you just described and that's with that was with having these roughness elements actually worked into part of the terrain right yeah that is with having a high high high quality bimetric surface that's a very big distinction because when you don't have those roughness elements as part of your terrain or part of your cross-section your n will Skyrock it at low flows um to account for that missing roughness right yeah um that's part of the form so it's really it gets really tricky right because you know how much do you work into your model how much of those Boulders are part of your model and how much is part of the end value and and then that we haven't even talked about turbulence right so how does that play into the whole thing here so it gets really complicated yeah and just like you're saying Chris like yeah here's your Manning and if you this was back calculating if you don't have the form roughness in there is like go this is one foot depth in the channel and it's just go Skyhigh 0 five you know Mannings yeah yeah never learned I mean you see that yeah and you see that with Jarrett's equation too right when when you're um um when you use Jarrett's equation in a steep Mountain type stream it's I mean it inherently based on how it was developed in incorporates the that roughness those Boulders into the N value not into the shape of the channel so right yeah it's like n is now serving as like instead of a weir equation or a vertical slot you know it's an orifice or flow is going through these very narrow gaps and expanding and cont you're trying to somehow push that into a Mannings equation yeah yeah let's transition to the turbulence discussion Chris because you brought that up um we talked a little bit about man you're good that's a that's a good good transition um so obviously when you look at some of the um physical modeling that you just showed Mike as well as I think what a lot of the listeners might kind of view a natur like fish way to look like the Assumption here is that you know turbulence could have a pretty big impact on the results of your hydraulic modeling here but that's just an assumption so I guess from your experience Mike and Tyler is using turbulence when modeling these types of projects important should we be using it what value should we use what are your thoughts on that Tyler you want to go yeah this comes down to the what's your endgame um so I would say and I'm I'll admit I'm not a detailed uh knob Turner I don't love all the knobs that are actually in hecz I like to stick to the basics and that's why the Weir equations and the the simplifications work for me um but also the biology isn't there yet to say this fish requires this turbulent value if you're thinking about turbulent kinetic energy we don't have the studies yet that say American Shad can only handle X River Herring why and so there's no criteria to judge against we can say yes this is more turbulent this is less turbulent but we're also seeing now some studies come out that say there are some benefits of having some edes with controlled edes I'll say with sort of Upstream migrating flow pattern so that you see Fish begin to grab onto those and use that to sort of Dart Upstream through some uh small jet or small openings um so I think it's useful um I would acknowledge turbulence is very important when you have attraction water coming in um I'll share that York Haven example that Chris and I worked here um let me Zoom back out a little bit and while you're pulling that up I just want to make a clarification for everyone listening to when you say when we're talking about using turbulence and Raz turning that on Raz doesn't actually simulate turbulence it simulates the Fusion that results from turbulence in the river so when you're looking at a Ras Model results you're not going to see the turbulence like you see just behind Tyler's head there right in the model that doesn't show up in the model but you get the diffusion that comes from that and that's what you're modeling and you get diffusion anyway with the natural equation even without turning on turbulence the turbulence is just an additional way to add diffusion into your process if you think you need it so anyway sorry claric that's a good a good thought there I just generally think of turbulence and generally in a fish way we try to avoid it for the most part um it's something that for a long time people have said oh don't let's not have any turbulence there we want to try to keep it nice and neat and um not sort of have that um I was looking for a photo to represent this and I'm not seeing one right off hand but this one Mike do you have any thoughts on on turbulence and and whether you that in the modeling that you've done project we haven't I asked U folks in the office too we they played with it a little bit but we really haven't and it and um I did see a lot of good presentations at fish passage uh 2024 last week looking at you know they were um instead of using turbulence and this is also people that were studying the fish they were using um slope and velocity as an as kind of an analog or as a surrogate for turbulence um because of the the uncertainty around turbulence and then looking at fish Behavior relative to those parameters um yeah well one of the one of the unique things about a nature like fishway and a roughing Channel compared to other Raz type applications out there is the resolution is usually very very tight very small right you need really small cells and one of the reasons to turn on turbulent or to include that added diffusion in a hecz model is when you do have cells that are very small when you do have a nearfield model especially if those cells are small in size relative to depth so if you've got a relatively deep Channel and a relatively small cell then you start under underestimating diffusion without using the turbulence termin RZ so this is something to think about for the NL natur like fish is because you do have very small cells but also at fish passage flows you tend to have smaller depths as well so yeah I did find that photo I'll just share sort of a graphic in a case where turbulence is maybe necessary um or or very much worth considering this is the project I showed the hecz terrain of earlier but now we're looking from sort of the land out towards the river and it's a big broad crested Dam um you can see all the energy being dissipated here right at the toe of this Dam um in our hydraulic modeling for the fishway we're actually going to open up sort of this upper little speed bump portion here and let more flow in as some attraction water over in this corner um and to be able to see that water come through there and realistically represent how much energy it has I think turbulence does have a place there because if we go over to our hecz model so I would that photo was standing up here sort of looking out through here when we open up that speed bump we see a lot of veloc coming through there and thinking about what that does to the system um I mean there's a lot of that energy gets dissipated right here and without recognizing some of that energy loss that carries on his velocity Downstream which makes for fish passage barriers um and other things so I think there's definitely a place for turbulence um but I again ask your question what is your design criteria and if you don't include turbulence you may be a little bit higher velocity and you may be a little bit lower depth both of which from a fish passage criteria are like okay if you're too fast and you're too um and the depth is influenced if you're too fast the fish can't pass you're conservative by not including turbulence there now if you actually are turbulent you dissipate more energy you might have a little more depth which could be bad for water levels and you may miss on some of your wear settings um and has other sort of ancillary effects but that just is a little bit High think about it what is the benefit of putting it on and so it's a little bit of a sensitivity analysis maybe you run it with it see what that gives you and run it without it sort of like we used to do with Mannings equations you run a little bit above and below just to bracket it if your model doesn't take forever to run yeah I think I think a combination of sensitivity analysis and obviously the importance of the verification that both of you all talked about with these types of projects right because the verification is going to capture any of the uncertainty that might be included in in in including turbulence or not so I think both of those both of those processes are important to kind of try andant ify turbulence I think it's an interesting thing because it feels like there's been a lot of research and work done on like Manny's values in hydraulic modeling um not as much on the turbulence side of things I think generally it's models aren't as sensitive to the turbulence coefficients that are being used but seems like it's just kind of hanging out there and nobody knows exactly when or how or why to to use it um so an interesting topic nonetheless uh last techn last oh go ahead to I was just going to say I think in of our models you said it's not super sensitive to it but in one of our models I think it did swing the head Pond by a tenth or so and for somebody who's generating water and power that can matter a lot Point um it also matters for overall fish wave flow if you get 500 CFS versus 450 I mean that can change a lot of Dynamics Downstream so while it may not change a lot it is something to consider there just as a I think there's like we all acknowledge there's a lot more research needs to be done but it's I risk to ignore it as well um yeah because we all know it's there you can see it in the field when you're at at these sites yeah yeah and I think that's why the sensitivity analysis becomes such an important factor there right because then you can present hey you know this is the possible range of head Pond elevations that we're looking at are the stakeholders that are involved comfortable with this potential range of outcomes and if the answer is no well then we need to do a little bit more research a little bit more refinement there if the answer is yes then no matter what the outcome is you know people can kind of be at least Le up to speed on why there might be some variations and outcome cool um last technical question for you guys on this topic is around uh fish Behavior so um this was a question I was thinking about in preparing for this conversation and that is you know we can use our 2D modeling output to come up with uh evaluation of what the fish habitat is within our our uh natural like fish way whether the hydraulic conditions depth and velocity are suitable for these different species that are going to be potentially up migrating or down migrating through our project but when it comes to potentially using these 2D results to actually answer model fish Behavior type of questions within our project domain what are your all thoughts on the applicability of that is is it just way too much to ask the the mod 2D modeling results to be able to answer those questions or is it possible and and it's dependent on the size of fish Mike do you have any thoughts on that yeah um I mean definitely the size of the fish matters um I think I mean we can use it for behav I mean you can start from the bottom the behavior attraction flow as we call it or attraction so you know are are your do if you have the flow split and some of it's going through the nature like fish way and some's not the 2D model is very informative in terms of like do you have a stream of water fast water coming out of the nature like fish way so the fish can find it that's kind of a behavioral piece of like they need to find it they need to feel like that's where they want to go rather than try to go over the the Weir the dam um so that that that's where it's very useful um Eddies um you know recirculation patterns I think that can be really useful um you know large recirculation patterns can be in uh can be bad or good depending on the size of the fish and the type of fish um so working with a biologist I think is good that a field biologist that knows and a fly fisherman that knows how Mo around where they use what they use and they could look at the velocities patterns too and tell you something um yeah but behavior is a tricky one each each species and life stage is going to be different on you Tyler have you used any of the output from some of the modeling that we've done on nature like fishways um to analyze or assess fish Behavior or has it mostly been on the habitat and and uh kind of passibility criteria yeah so I think the fish Behavior I mean obviously we can't think like a fish but some people have tried um and created what they call an individual or an agent-based model um so with the agent-based modeling I think there's some benefits there that we can start to think like fish you can program a fish with a range of characteristics as far as velocity preferences depth preferences as we acknowledge we don't know enough about some of the turbulence parameters um yet but in this case here this is from our Workshop presentation that Mike and I contributed towards you can actually set in motion uh these fish that are in the system and you can take that 2D output and sort of release them into your system and use the 2D output to see what is passable and start to think about okay each fish is thinking for itself based on its parameters and how many of those can make it Upstream is there all of them or none of them it begins to allow us using this 2D modeling to think about that Passage success because ultimately that's what we're designing a fish wve for we want to pass as many fish Upstream as we can and with it with this 2D modeling you can begin to get at that and start to understand and utilize that for preferences in addition to the uh the depth and velocity mapping that Mike and I talked about earlier I don't know that we know enough to think true fish yet but we're we're getting some initial thoughts in that direction and so for that perspective I think 2D modeling is very useful sure what why so I've heard the same thing Mike that you know the size of the fish depending on the size of the fish the 2D results can be more or less applicable to trying to anticipate kind of fish Behavior why is that you know why can't a model with let's say one foot cells simulate the fish behavior of a of a twoin two inch fish well yeah exactly I mean it's a lot of the fish we're looking at are two to three inches and and so you're just not getting that resolution of what they're feeling um they're feeling an Eddy a turbulence that's in the 2inch range you know that that's really severe to them a big Eddy that's in the 4 foot range you know they're just they're just going with it that's really not not a problem to them so often you got to look at what they're feeling um just like us humans you know what it's got to be an our scale turbulence that that's pushing us around um is when we're swimming is kind of in our body lengths type uh size for sure yeah I mean I guess as you get smaller and smaller too the the the depth average assum assum assumption that you have with a 2d solution becomes less and less valid right because of the fact that that small fish is going to really experience that velocity and depth the velocity uh you know not on an average basis they're going to have that column velocity and the location of where those higher and lower velocities is going to become a lot more impactful in terms of how that fish is moving through the and I I think some of the video some great underwater video of little fish where the the velocity above is six s feet per second and they're just H you know they're they're moving along the bottom between Stones um just little bad of time with no problems so would never pick that up so yeah yeah so in the same way is it I guess we have these sort of habitat suitability or passage suitability criteria depth and velocities that are you know stated for certain fish and then we're using our 2D results to ass whether or not it's just a yes no is this pass or not is really is that kind of like a conservative assumption because of the fact that there are in all likelihood um more passage routes in an actual 3D um nature like fish way than our 2D approximation of that yes it is except that we don't know about the turbulence piece so yeah sure you could be creating a barrier because it's too turbulent below but yes and I think a lot of the the the biologists from the AG gencies that review these they're they're starting to understand that a lot of those criteria they came from basically flumes you know was it was the velocities that the fish felt versus what is really the models giving us like you say depth averaged and there's there's going to be an area of lower velocity somewhere yeah in these some of that relationship between the fish depth the water depth and the roughness depth and how those all correlate if they're all in the same order of magnitude of inches the fish is going to have no problem navigating that if your water's shallow your fish can swim in shallow water and your roughness is all over the place they'll be great keeping in mind that as it's as we talked about the hecz cell size relative to fish length I think also just of depth and roughness impacts as well yeah it's all interconnected so I want to know just I mean how are these things performing how do they work um sounds really awesome really cool it's fun to model I love doing that but like we've got enough of them out there right now right that that we're getting results back and how would this compare to say your traditional hardwired engineered fish ladder yeah a great question it depends please tell me they're doing better ah well yeah I would say in U in the best of cases they are equal to the best technical fishways because there are technical fishways that pass very high percentage of the population that gets there um often times there's limitations around entrances as with technical fishways the entrance of a fishway dictates so much about a fish can even find it let alone pass through it I know what they're finding is I think generally nature-like fishways have a lot more variability so for a range of species you're better off because you have more velocity variability across your whole fishway width um like showed in some of the parameters there for the physical modeling you can see the Deep zones in the center your shallow habitat on the edges you're going to have eels on the edges you got your stronger swimmers in the middle um and so for that range of species they're definitely I would I personally think they're better hands down for the suite of species across the board um I don't know if there's a published paper to support that but unfortunately there are still some limitations and things we don't know with nature like fishways that there are some that are barriers and we're not seeing great attraction um to even get the fish into them and most often those are ones that are more of a bypass reach or it's sort of a percent of the river flow if all the river goes through it inherently all of the water is drawing the fish to the fishway not to say you can't have a barrier because you can still have bad Hydraulics um I think Mike the general consensus is it's still the studies that have been done included all nature like fishways lump Together bypasses full Channel wids Etc and they don't necessarily outperform form by Leaps and Bounds any of the other fishways but the big difference and why I think um there's a real push among the the resource agencies that that regulate Fisheries is they perform way better often in for maintenance um they don't clog up with debris like a technical fish we they don't require somebody to be out there regularly cleaning things out um they can adjust the boulders move a bit but they still function sometimes they even function better when built so so that that is what they like um if you're at a facility that doesn't isn't manned you know um every day or during High flows but rather somewhere out in the woods or or wherever that's fairly remote or not being maintained like a roadst stream Crossing um these These are more reliable I think um over the long Hall and and I would say even from a very very non-technical perspective they just look more natural they're they're more towards the natural side of things you have to imagine that's going to be better for fish if we getting closer to what Nature has provided them over the you know millions of years we've been here right that's that's the idea yes yeah good um lastly we only have a few few minutes left but I do want to give you guys both opportunity to talk about what your favorite nature likee fishway or roughing Channel project is that you've you've worked on over the years you may have already discussed it or shown a little bit of of Graphics related to it during this conversation but Tyler I'll start with you is there one project that that pops into mind in terms of one that was really rewarding and and maybe challenging to work on yeah so I would say that was the one that we just built last year I mean I agree with Chris the modeling is fun and iterating back and forth all over the place and coming up with these uh different parameters and and looking at all of that is is a lot of fun but it's really fun you get to put the yellow equipment in the in the Water behind the Coffer Dam and start doing the work um you can really begin to get into the what I think of as the fun aspect of that be able to take um something that's not necessarily passable and convert it into something that is fully passible and has that habitat um this is the shikami nature L fishway project that we just constructed last year about 120 ft wide pre- project conditions in the upper left uh this Dam can be drawn down half the year it's an inflatable bag Dam inflatable uh yeah bag I used to be essentially what you call it or bladder and so it only needs to pass fish for about half the year but it's been in place the dam has been in place for 60 years the fish have been had to stop at it essentially every year um but once we constructed that we've got water now flowing into the entrance and coming down through um and we've got really good variability here from three foot of depth out through these Boulder clusters into the flood plane where we've got very thin amounts of flow um and the fun part of this one for me was as we were pulling the stop logs at the upper end here getting ready to release the water and we had a little bit of water seeping through and we had a little eel already swimming up through there about a 12-inch eel just swam right up to the stop logs and we sort of banging on them I was like all right they're here they went through we just go to got to open it up so that was sort of a the most recent one um it's probably always going to be whichever one I'm heading into construction or coming out of construction of but that's one for me that I I really enjoyed here in L Su hanana very cool Mike what about you yeah that's nice um I mean I I would say the ones that are the most enjoyable are the ones that we've kind of gone and studied the most um you know I shared I shared this one um which we learned a lot from um you know and the 2D modeling and seeing how it it simulated the the built project that was really fun Jameson Creek um another was um on a train crossing here um similar did similar post project evaluation learned a lot um these are the kind of projects I I really enjoy uh learning from them and therefore I kind of remember and get a lot out of them um and then I think the others kind of what we're working on right now which I showed some of the physical modeling we're finalizing designs trying to raise the monies for construction um which was the turbo Creek projects um we also um besides doing the physical modeling we did uh NHC did take the physical model results and did a um a cfd model um which here is their their you know their bed that they put into the um open foam uh open source cftd um and we learned a lot from that as well um so you know just I'm excited to build that one and do that post- project evaluation on this project so um yeah very very very cool um I do want to end the conversation today on something a little bit lighter and that's something that I've touched on or I guess I've said a few times and that is um ruffing Channel and nature like fishway you know for those that have been confused throughout this whole podcast you what's the what's the difference between the two is there's one is there one that's right um what are you what are your guys's thoughts on on the debate between those two terminologies Well the West CO the West Coast here we often say rough and channel and nature like fishway isn't a term that's widely used um so definitely came from Europe I think originally and then went through the East Coast has accepted that terminology um and I think maybe nature like fishway is a broader context like it could be log we for example could be nature like um versus the roughing channels usually is kind of like an it's it's Rock and coarse material through the entire project length whether it be step pools with a rock pool bottom or such um that to me is kind of what a roughing channel is yeah I'm being located on the East Coast I've always caught a nature L fishway and that's just what we think of it as that's what some of the federal guidelines have come out as as nature L fishways not to say that's always right um but through our discussions Mike I like the term rough and channel better because it implies that it's an engineered structure it's not just I'll just replicate nature exactly you know it's there's a lot of thought manipulation that goes into that creation of the channel um so I would say nature like has a connotation that for some people makes it think like it should provide all those ecological benefits of uh of a natural stream restoration with your vegetation on the banks and all of your macro invertebrates can pass and all that stream function stuff that we love may be present in a rough and channel but still at the basis basic level it's a hydraulic structure structure to control flow but it also has a goal of providing fish passage um and so I'm leaning towards embracing more the Ruff and channel um I think Mike you guys are on the west coast have done a lot more work with cs and so think working in a CT it's more of a roughing Channel um that's sort of just a generic what a covered bed can be thought of um you don't think about those I don't believe is a nature like fishway inside of Calver it's just a roughened slope and that's what it is so I'm coming around to that term um I think we Lo use them interchangeably I use them interchangeably but I would say NLF is the highest level for anything that's trying to pass fish and represents something more natural than a concrete and steel structure um rough and channel is maybe a little more accurate for what we're we're doing overall it sounds like it's it's a little bit of a whiskey bourbon thing right where all all ruing channels are nature like fishways but not all nature like fishways are rough so maybe nature nature is instead of nature might be a better way so hey I got I want to just quickly uh quiz our guests today before you close out Ben because I want to see how much they were paying attention to uh our uh questions Raz questions so okay guys are we looking at diffusion wave or full momentum Here Eddie there and expansion he must be full momentum there there you go all right Mike way to go way to go I'm glad you were listening but you probably knew that already anyway so nice nice well if nothing else on this podcast we got an East Coast engineer and a West Coast engineer to compromise on language so that's a that's a positive outcome um regardless of whether anybody finds the content on this interesting which I'm sure everybody will find very interesting so um well this has been this has been really really great um thanks Mike and Tyler again for for making the time to have these conversations and it seems to me like this is an area of Water Resources engineering that's continuing to grow and change and evolve um as so many things are within our industry so it'll be really cool to see kind of where these top topics and conversations are at in 5 10 years from now um particularly as you know techn technology continues to improve um we continue to get more data sets of calibration and verification of projects that are actually built um feels like we're kind of at the Forefront of some really really exciting developments so appreciate you guys taking some time to talk through those with us yeah it was a real real pleasure talking with you guys today uh great to meet you Mike um keep finding these kind of opportunities because that's just more opportunities for me and Ben to model them so that's that's a lot of fun yeah thanks for having us it's been fun to chat and hopefully provide us some value yeah thank you yeah absolutely and we will include uh a number of hyperlinks to references studies presentations that we kind of touched on today um in the YouTube channel here so if you're interested in following up with some of the resources or some of the presentations that Mike and Tyler saw and attended um we're going to include links to some of those uh in the chat and Mike and Tyler's personal phone numbers too so you guys can call them up anytime you got questions no I'm kidding just kidding but yeah make sure you add Mike and Tyler on LinkedIn if you want to follow them uh more if you have questions um going to be a good place to reach out to them um and as always if you have questions Fallout questions on on these topics or questions about HC Raz overall make sure to include those in the comments on our LinkedIn page or on the YouTube channel for this podcast um again appreciate everybody who was uh stuck around and and listen to the conversation today uh this has been full momentum in HC Raz podcast until next time

Channel: The RAS Solution

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Length: 98min 18sec (5898 seconds)

Published: Thu May 16 2024