 Good morning, good afternoon, good evening to everybody and it's my pleasure to be today with you in this first alumni online seminar of the year. My name is Maria Laura Sorrentino. I'm a alumni officer at IHE Delft and I will have the pleasure to be the moderator of this session today that we will have as a guest speaker and alumna Dr. Afuwabusu that is alumna of IHE Delft and works nowadays in the International Water Management Institute as a doctoral researcher and she is also associate editor at the hydrological science journal. Afuwab, that is at the moment in Africa, completed her PhD program at IHE Delft and TU Delft in November 2022 and she received or has won the inaugural Falcon Mark Award for the best PhD thesis for her work on the protection and restoration of natural flowing rivers through the provision of environment flows or e-flows. The prize awarded by the International Association of Hydrological Science recognizes our standings contributions of hydrological understanding of water scarcity and water supplies. Well today is an honor to have Dr. Afuwab as our speaker where she will tell us about her research and her findings but before passing the word to her I would like to invite you all of the attendees to keep the microphone and the camera off so that to focus on the presentation of Dr. Afuwabusu and also to introduce briefly in the chat where are you from and where are you working if you wish and later please write there also in the chat the questions that you would like to ask to Dr. Afuwab please I would like you to put your camera out please so without further ado I would like to pass the word to Dr. Afuwabusu, welcome and the floor is yours. Thank you Maria, hello everyone it's a pleasure to present my work from my PhD to all of you and I hope that by the time I'm done you'll all become ambassadors of environmental flows wherever you are so I just like to go and get started I'll share my screen so yes this is the title of my thesis and it's been two years and I admit I had to go and pick up my thesis to read a few sections but generally I think I'm up to date so the title is the practice and opportunities in re-operating dams for the environment and this was done at IIT Delft to Delft's part of the sense program and it was a Marie Curie project sponsored by the U. So I'm beginning with just a short history of dams so as human beings have been dam in reverse for centuries beginning with simple stone and as in dams but then dam construction really picked up in the 20th century and by the estimates of the World Commission on dams by 1949 there were about 5,000 large dams but by 2000 this was about 45,000 dams and this is a graph showing just different databases and the actual numbers may differ but the trend is generally the same it's quite low in the 19th century and then by the 20th century there's a huge jump so this is a map showing the general distribution of the dams the darker the color the more dams there are the bigger the dots the larger the capacity so this is the grand database so you generally see in America in China in Australia in Brazil and then in Africa we have southern African countries and a few West African and Northern countries to India as well and yeah Europe so you see the general distribution of dams and I like to read this quote because it gives you an idea of just the the mindset behind dam in in the 20th century basically water flowing to the sea was considered wasted and so it was like we're going to tame the river we're going to control it we're going to take as much as we need from it so yesterday the Colorado river was a natural menace unharnessed it talked through deserts flooded fields and ravaged villages it drained the water from the mountains and the plains rushed it through sun-baked thirsty lands and dumped it into the pacific ocean a treasure lost forever man was on the defensive he sat helplessly by to watch the Colorado river waste itself by attempted in vain to halt its distraction today this mighty river is recognized as a national resource tomorrow the Colorado river will be utilized the very last drop so the whole idea was that if water was flowing to the sea was wasted and we were going to dam it divert it use it as much as we could so that if we have our way there'll be no water flowing to the seas but then generally when times society's views on dams change and the reports by the world commission on dams were the landmark reports in this regard so this regard one of the points made in the world commission on dams report is that dams have made an important contribution to human development have an unacceptable and often unnecessary and high price has been paid especially in social and environmental terms to secure those benefits and alongside this there was also the science of environmental flows which is defined as the quantity timing and quality of freshwater flows and levels that is required to sustain aquatic ecosystems which in turn supports human cultures economies sustainable livelihoods and well-being so we have all of this happening and under the environmental flows science there's the whole thing about the natural the natural flow regime is the best flow regime for a river because that's what encompasses everything that a river should be but then there's also the pragmatic approaches which accepts that rivers were done for a purpose we can't go back to being natural and that's called the design flow regime so in addition to all of these you know paradigms and arguments and environmental flows there were there was also this paper by Bunn and Arthanson which identified four principles on the mechanisms that link hydrology to apathic biodiversity and then there was also a review by Rebecca Tham and like everybody in the environmental flows world knows this paper in 2003 but like I said God knows how many times and she actually got the whole organized the whole science of environmental flows into how do we establish environmental flows so there's the hydrological method the hydraulic method holistic method she just curated all of these approaches and then organized it very well and that was great so this now I come to my PhD and the whole idea was to um have and I we know that environmental flows are generally good it's accepted that how dams are operated it's not working out exactly as we thought there are numerous scientific methods like I highlighted by over 203 but we are not seeing the implementation I guess it's a bit it's not as it's like climate change in a way we all know the science but in terms of changing our ways of living and everything that we need to do it's not influencing practice so the red arrows and the red dots basically are showing where the gaps are in the understanding of how a flow theory becomes policy how environmental recommendations become dam operation policy and in addition to that we also want to understand the practice of it so once environmental flows are being released what it's how what's the outcome and then what's the tradeoff between the environment we're trying to protect and services services from the environment and the conventional users that we build the dams for like hydropower irrigation navigation and all those other benefits that make our lives very comfortable so this table is just showing you the link between the research objectives which were two deepened understanding of dam re-operation policy processes to accommodate e-flows and then the second one is to investigate synergies and tradeoff between e-flow conventional users and yeah so I won't go into details on the research questions the activities linked to the research questions the outputs and luckily now all the papers have been published so um that's for further reading if you're interested so jenny there's the part one the part one is looking at the history of dam environmental flows implementation and part two is looking at a specific case study so i'll start with part one and that was answering the question how do environmental flows recommendations develop into actual dam um operation and I use a simple logic model to understand this and a logic model it's like a flow diagram which captures the inputs activities output outcomes and impacts of a project so in this respect the inputs are like the drivers the conditions which led to recommendations or a decision to re-operate dams for the environment activities are the practices adopted to implement the decision and the output is hopefully successful dam re-operation I didn't look at the long-term outcomes because a number of people that looked at that trying to make the case that hey look at the outcomes of environmental flows um why isn't everybody re-operating dams I wanted to understand the first bit what is planned and what comes out as results so basically looking through literature a systematic literature review was done and we started with thousands of papers and ended up with I think the specific numbers I think about 61 papers and cases of dam re-operation and the general trend it goes with the countries that have the most dams generally we have a lot of cases in America cases in New South uh New South Wales in um Australia case in China cases in South Africa a few cases in the West Africa and then Europe so we can see that we are missing like even a whole continent over here but that these were the places where there had been documentation of um environmental flows so the USA had 28 Australia had 12 cases and of course it's very few compared to the existing dam database irrespective of the database you're using so what did we find we found that generally legislation provides a legal basis for changes to be made however reluctantly so if you go by law and it doesn't necessarily need to be an environmental flows law it can be a flow uh ecology or endangered species though when you have that generally they trigger a process to protect the river which a lot of the time has to do with changing how the dam is operated so environmental flow assessments um and also there are cases where litigation so you've got like an existing river and there are laws there and then whoever is in charge is not doing as the law says and then you have environmentalists or people taking them to court and then they win and they want natural events like a shock to the system like the millennium drought in the marital basin in Australia that was a shock to the system and then they realized okay things need to change now I'll just move to um the activities that then you have to experiment which are kind of um we are testing out the system let's see if we release a flood what happens if we release a small pulse of what's what happens and these are activities that are done most frequently in dam re-operation and then of course there are workshops physical modifications of the dam which are done and then finally in terms of output what is generally done when we say we are releasing environmental flows and you'll find a lot of the time is the release of a a minimum flow which is the whole thing that um the river is diverted and water is used up to an extent and then you have time where it dries out or the temperature gets so high that fish scales are pairing so let's ensure that there's a certain minimum amount of water flowing in the river all the time but then there's more to environmental flows than minimum flows yeah I mean flood releases if you will recall the ban and earthen thing graph I showed I didn't dwell on it so probably you won't but there's more to it than just minimum flows there are high flows pulses flood releases and how you increase and decrease the flow rates that also has an impact on the river ecology so now the next question was what's happened in cases where dam re-operation has been attempted but has yet to be implemented so in this case we're looking at how dams are re-operated we have that from the logic model who was involved in the process what dams they worked on why the release of ethos was desired and what hurdles did they encounter so in this case we've got better representation across the globe um yeah so basically the red ones are the ones that have stalled the blue ones are the ones that have been successful so it was very good that we go a fairly good distribution and this survey was sent out I think for about three months to all the people who had written on environmental flows people recommended you know just a snowballing method to send it out so again information on what really went into the process and why have some cases stalled so um uh using the fifth exact test to read some statistics and we found out that gen b heaven legislation and its scientific research base as input is a big determinant there's your odds of successful dam re-operation is very high and um having flow experiments as an activity is also makes it very high that you'll re-operate the dam and then having a stakeholder scientist as a general public is also very important for increasing your odds of successful dam re-operation so we had this open-ended question where we were asking so just to get more details what are the hurdles that are encountered and we could group them into four classes technical or science-related hurdles with a hurdle to do with stakeholder network involved um head held on policy and then head held from the fiscal constraints in available what's our infrastructure um results in the high trade-off between let's say environmental flows and hydro power whatever the dam is being used for so you'll see that generally when you compare the successful implemented to the stalled cases the issues have to do with stakeholder and a lack of legislation while for successful cases the the physical hurdle was mainly the the problem for stalled cases was stakeholders and legislation how are the hurdles overcome and you'll see that consultations was a big thing and then scientific studies a few cases and the interesting thing with stalled cases was nothing was done and if you have a hurdle and nothing is done then nothing will happen so we move to the next section yeah and that was on the case study and in that case it was to look at a real-life case and though what made this case interesting was the fact that it had quite a number of the features of successful cases mainly the fact that it was like a multi-year project with multiple stakeholders involved we the the effect of the dam was very clear to everyone for everyone to see and yeah so that was it and we're interested in I'd understand in what's the equal requirements of the case study was and then what were the trade-offs between environmental flows and what are users so the case study was on the lower Volta River it's in West Africa is the most downstream sub-basin of the Volta River which is cuts across Burkina Faso Ghana mainly but also a bit of Mali and Benin and Togo and Kodifua and the most interesting thing about the dam the lower Volta is the dam which creates as the largest man-made river by surface area in the world so that gives you an idea of just the amount of shear flooding that occurred so in the dam the Kusumbo Dam was built in 1965 and in 1981 a smaller dam was built downstream it's called the Kong Dam and it has a much smaller capacity of 160 megawatts so this is a nice picture which I didn't take but it's a nice picture of the dam I think and what we use was in terms of an indicator species so and we need after a bit of literature it going back and forth we settled on using the Volta Clam as an indicator species and what makes it wonderful is that it's a micro macrobenzic vibe up so it's not going to swim away conditions conditions become bad so you'll see what happens to its life cycle and extent habitat when things are not going right in the river and it was previously abandoned in the lower Volta and since the dam was built you can see the huge difference in where you can find the the clam so just pay attention to the stars initially the Volta Clam could be found here from Akusei to the yellow star to Sogakupe and that's a reach of about 80 kilometers after the dam was built pay attention here you'll see two green stars it shifted the range and narrowed the range to just 10 kilometers from 80 but what did we get as a trade off when the dam was built upstream over 80,000 people resettled one of the worst cases when it was occurring and then you had a whole whole industries of creek fishing flat plainer culture clam fishery which made up 75 percent of total real income of the riparian population just collapsing you have aquatic invasive oops sorry aquatic invasive species and then that they create a habitat for disease vectors and diseases and then we have that issue with post star irrigation so fortifying the coast of Ghana is something that just it's something we just have to keep doing and it's not when we do that we impact Benin impacts total so this was the yeah the pre dam flow generally average monthly so you have very low flows and then it peaks and this is the range it could go this high in September and October and then it would come down but now with the dam we want steady reliable energy so it's always at 1,000 meters per second which is great for hydro power but not so great for every other living organism in the river and around the river so in exchange for all of these issues created we have lovely results in the dam because affordable hydropower as I mentioned we've got irrigation schemes if you squint you'll see we've got tourism and lake transportation so using the lifestyle the climate the volter climbers that indicates as species the whole thing was we need to understand its life cycle and where it cares so the blue is the current flow regime post dam the red is the pre dam flow regime in a q-max and these colors represent when spawning and fertilization occurs which generally peaks from July to okay from July to October beginning September and then when that happens you have Lava village village of the clam which requires certain salinity and that's why it's interesting if you look at the extent of the dam the the clam you'll see that initially before the dam you can have salt intrusion all the way get into where farm dam is now situated but now once the dam created a steady flow the dry season the low flows don't go so low so then the sea is not able to intrude much into land and we found that generally this is as far as it gets so this that's far as the bellica lava of the clam can survive and so that is that's that's requirement for salt a certain percentage of salt became a very important finding from literature and you'll see that recruitment is continuous but then there's a major pulse in October to March so using a Bayesian belief network this involved going on the field and mapping just chemical properties and then talking to fishermen on the clam fishermen trying their trade just again understanding of what they are doing we came up with this Bayesian belief network which links flows and activities stand when in the type of substratums whether there's a sandbar the estuary to the clam extent and this is what we found that once the key flow period is November to March and that's when the bellica lava is is yeah it's it's when the clam is at the at the live stage of the bellica lava that's when flow has to be low it can't be at the thousand meter cube all year round that doesn't work for the bellica lava and because of that they can swim up and colonize or settle in the original stretch they are forced to be where they can get that salt percentage and so using a Bayesian belief network we're able to come up with the conditions that ensure that the clam bed extent is either maintained or increased so using this and I think I have five minutes so I'll just try and be fast this was the final bits of my research where before I we determined the clam environmental flows which I just described there had been two environmental flow this recommended based on the natural flow regime and so we've got the clam ethos which is recommending that we should have 52 steps 300 and 30 meter cube from November to March to support that lava stage but there's also an environmental flow recommendation which I'm calling ethos too which reinstates the natural flow dynamic in September and October to basically the bank full flow and then the rest of the year they're recommended 700 meter cube per second and then ethos three which is recommended even higher flows to extend to cost flooding of approximately 156 km to support quick fishing and flood research and agriculture then a lower dry season flow so the whole thing was to understand what are the trade-offs between these environmental flows and existing water users so we use radial basis functions to privatize the control policy for mapping water levels in the dam and time to how the dam water should be released from the dam and we considered an all hydro power from a custom boat which generally there's a firm power demand of 400 and 4000 gigawatts per year and there's also a phone which generally the run of the river so whatever custom boat releases they release and generate with that and then there's also irrigation current demand is 10 meter cube per second but they have been plans since 2009 to increase this we don't know whether that will happen but we just went to the higher demand and then there's also flood control since the custom boat dam was built people have moved in and encroached and generally we don't want it to flood so there was a control flood control objective of not letting flow releases exceed 2000 meter cube per second and then that's three e-flows I presented earlier so the way to understand this is just to consider a Pareto efficiency that generally I guess that's at some point you can't move on the objectives of the objectives you have without trading off on one thing or the other so if you think about living in the center of town and so that your commute your commute to work is shorter you'll find that generally there's a high cost involved in that because the center of town the houses are more expensive so generally you can't improve on being close to work without trading off on the cost of that passage your pain and this is how it looks when you have multiple objectives so the whole thing is once this is the direction of preference and everything has been standardized so that zero represents the lowest value and one is the highest value so we want ideally a flat horizontal line across everything so that we eat our cake and have it we have irrigation, maximum hydro parts, palm, maximum hydro parts, of course on both maximum environmental flows and no flat but life is not that way and the most important thing is the huge X between hydropower and environment showing that when one is at the highest point you're going to have the other at the lowest and when the other is at the vice versa so red is best hydropower green is best environment and so on when you have a lighter red a pink that's fair hydropower that's fair is being used to represent 80 percent of the time we get we get 80 percent of what we are trying to target and that applies to fair environment and every single line here is a Pareto efficient solution it means that it's really as good as it gets for all the options but if I want to look at the one that's best for hydropower this is the dark red line and if I want to look at what's best for if the environment is the green line and for irrigation is the blue line yes so basically the highest performing dam operation policies for hydropower trade off sharply with environmental flows for all configuration but if you look at the climb and this is climb e-flows e-flows to e-flows three climb e-flows that's better because the requirement is just the restriction on flows just it's for November to March and the rest of the year you could maximize hydropower to what you need it to be the thing with e-flows two and three is that you need flood and that is not a Pareto efficient solution under any circumstance so the best environment you can get for those is at 0.83 so I don't know Maria if I have extra time then I would go into the work we did for future scenarios you can take a few minutes more if who are and I would like to invite all the audience to start to write the questions on the chat box please okay thank you so we looked at different scenarios where we have an annual based on a literature review another not so systematic but fairly good systematic literature review we found the prediction that made about flows to the balta link and what we saw was that there's there's generally one that talks about an annual increase for five percent annual decrease story in flows for five percent annual increase of 12 percents fairly low and then 65 percent increase too and then there's also the seasonality changes where in the dry season we have a decrease but in the wet season we have a small increase and then we have the one dry season decrease wet season very high increase so running that in the model what we see is when there's 45 percent decrease then I mean we're in trouble for hydropower the best we can do is 2,700 gigawatts when the target is 4,400 or so so in that case a hydropower shifts down on their axis but we are still able to make a climate environment afterwards because what we need is actually low close so if there's no water we're able to write low flows not so well on them if those two and three but similar to baseline because they also require low flows for about seven or so months and then the floods which is not happening because there's no water and so we move to the next two which is the slight increase of 12 percent slight significant increase of 65 percent and you'll see that they are showing that we can have all the hydropower we want but yeah it's a similar thing with the environment where we can maximize in the other months where we don't need to ensure the lava is okay and then we have a seasonality now that if you remember the graph of a custom inflows naturally it's a very seasonal river where you've got 75 percent of the flows are carrying in about four months of the year so when you have seasonality that the changes that dry season is not in absolute terms is actually quite small so you'll find that this scenario it's quite similar to this slide's annual increase and it's similar to this scenario where the wet season increase being very large makes it similar to the annual increase so it's just the relative placement of the the parietop to mal lines for hydropower which slightly change for the two comparable scenarios so what are the conclusions that dam re-operation attempts usually follow a non-linear collaborative analysis which makes use of existing supporting framework but also takes advantage of opportunities that may arise to advance the process we got new insights on the importance of collaborative positioning of signs local level legislation and flow experiments in the process of dam re-operation and also the in-depth examination of the unique case it shows that things don't generally fit into what you see for the whole grand picture when you're looking at lots of cases together and so local context is very important in the success of dam re-operation and for the lower falls that we saw that the designer e-flow does a better job than the environmental flows based on the natural flow regime just talking about the pragmatism of it that we can't go back a gonna depend so much on hydropower from aquasembo we we need environmental flows that I don't want to say fits in but consider the hydropower requirements as well and then insights into the trade-off and notably both an increase in the DPs and annual flows to the aquasembo dam which is a trade-off and creates synergies between environmental flows and hydropower generation so that's it these are the papers associated with the thesis and thank you very much for your attention thank you very much dr. Afua Busu it's our great pleasure to have you as a speaker today and you can take one second to to have a glass of water after your presentation and I will remind all the attendees please to write the questions in the chat and in the chat too I have added some links that you will get it also in the final email that we'll I will send with the link to the video of this presentation and let us go to the question so the first question is by Avel in Marais that is from Australia and of course he said thank you very much dr. Afua very informative and well presented the question I couldn't quite see the detail in the pre-dump post-dump seasonable can I see the question seasonable? yes okay so I'll have to share my screen again and then subject to thermal stratification and ducal water releases effect visibility of volta clumps okay so let me share my screen and share so initially I presented the seasonality of the Akosumba Dam so the blue line is the pre-dump situation where you could have peak flows reaching up to 12,000 meter cube per second in September and October and you could get close getting very close to zero so I went on then to represent this in this radial graph where you've got the pre-dump the pre-dump in the red and overlapping and purple with the blue so that way you see the peaks in October and September and then close to zero February March and then you've got the current which is 1000 meter cube per second every year and you're asking about temperature which we did measure here we did measure when we went on the field but I didn't present let me see if I can find it the actual presentation for this part of the work but we found that generally it was the salt that was where the salt starts salinity starts and stops and too high salinity the lava do not extend there so they do not settle as adult clams there and too low salinity to that that was the limit so we found that all the other things were measuring temperature chlorophyll nitrate phosphorus it wasn't helping it was basically the it was basically this extent of salinity that's really showed where you'll find the clams does that answer your question you will let us know and I suppose so because there is no question of him and I have another comment of Efe Parlak who says that in in Turkey in generally northern villages where it says good rain water water is started to be a store underground dams the pots where transfers of water is got hard due to the geography mountainous inclination and there is a risk of landslide there are also hydropower generators placed in water pipes near pumping stations in western municipalities so the question is related with climate change due to the open dams and evaporations of water vapor has considerable effect on global warming I'm not too clear on that so in Turkey there's underground storage kind of like a modified aquifer recharge and yeah asking about whether dams and evaporation has water vapor have punctured or effect I don't think I'm clear on what the question is story you can rephrase it please and I go to the other question of a professor of gupa kumar from India and let's say thank you very much for your presentation and the question is how the change in hydrological patterns due to the climate change can be considered in the decision making process for the re-operation of dams for e-flows yeah so I think in the last part of my presentation I was looking at the different changes so what happens when generally environment flows to the Baltic lake go down and what happens when it increases and you'll find that the requirements for low flows which is that because of the natural flow of the water where you had naturally dry flows most of the air and some peak flows at certain times of the year you can you can restore some ecosystems and some benefits of the natural river if the water flows are low at certain times so if climate change leads to a decrease in the inflows there is some advantage for the environment because then we can strategically reapply the dam to provide those low flows because there's really no water there's nothing we can do but if at least an increase in flows the advantage is that then at certain times we would have to flood which is also kind of going back and you'll find that generally when the the flooding occurs with the natural cycle so just last year they had to release for I think the third time and it caused a lot of devastation but this if this becomes a climate change hopefully we resettle the communities that have moved inland further away and then you've got the flood plains flooding and that also has some benefits so that's great for well that's great in terms of if we have two extremes in terms of climate change we could look at how we can provide environmental fluids. Thank you Afua and I have a comment of Abel Imari from Australia connected with the first question and he writes to some extent yes to your answer sans doctor Afua the reason I ask is that temperature of e-releases could be a trait of consideration similarly I cannot read here so the reason I ask is that temperature of e-flows could be a trait of consideration yes and that's true I know in instances in Zalapka where they released water and then everything died because it was so hot or too cold it was just a shock to the system similarly could salinity be moderated modified to produce a better output so in the way to moderate the salinity in the water is to moderate the flows coming from the dam so initially if you if you think of the salt and freshwater interface um we have a situation where in the dry season because the flow of the river is close to zero the seawater could intrude much much further to where almost the dam is about 80 kilometers inland and then in the high flow season it would be pushed out but now because of the standard thousand meter cube it's at a certain place more or less there's very little variation so we placed in a sensor to monitor during the spring the Australian people know the term but during the time that the tide moves in during spring and we found that yes there are peaks and it's changing but it's not able to move as inland as they used to and because of that the lava is stuck and actually people point out that we are very lucky that the flow isn't a bit higher because I didn't mean a bit higher like 2000 meter cube then that sweet spot of 1 percent salinity would probably have moved into the Atlantic Ocean and then like forget the clams thank you oh yeah thank you very much Afua uh neat answer Abel says thank you it may be useful to review Natan Bowman's 2022 paper on map based decision support framework for the embell system that is his comment and I have a lot of things you have a lot of congratulations for your presentation and thank you for your presentation do we have an extra question I don't see extra questions here well if not I had to say thank you very much to our speaker it was really nice to have your presentation and the participation of all the persons that accompany us today and that they will see your video later again I tell you that these presentations has been recorded and it will be published at the YouTube of Aichi Delph where you can also find previous presentations but for all the person who has registered they will receive it online together with the some point of the presentation of Dr. Afua well thank you very much again and I wish you all the best for the new challenges and it was a pleasure to have you as a speaker of the first event thank you very much to all thank you thank you very much thank you for listening and bye to me