IWA Webinar - Making the Invisible Visible – Technologies for Groundwater Management

Good afternoon, good evening and good morning to all the participants who have joined uh us today in the webinar titled making the invisible visible technologies for groundwater management. Uh myself Afia Siddiki from IWA and I'll be moderating the session today. Next slide. So just a few housekeeping rules for our participants today. This webinar will be recorded and it will be made available on demand on the IWA website as well as the IWA member exclusive connector platform. And the speakers are responsible for securing their own copyright permission and any opinions, hypothesis, conclusions or recommendations contained in the webinar are the sole responsibility of the speaker and do not necessarily reflect IWA opinion. Next slide. So for all our participants today we I would encourage them to uh introduce themselves in the Q& in the chat box and you know to have any questions general questions and for uh questions related to the panelist and the speakers I would like you to post it on the Q&A box only. Next slide. So quickly going through the agenda for today. So I'll do start with welcoming the participants and the speakers and introducing the webinar. Then we have two exceptional speakers, experienced speakers uh professor and Mr. Rahul uh who will each be presenting their own uh case studies and which will be then followed by the panel discussion and Q&A and then with the closing ceremony. Next slide. So just to give a brief brief background of today's webinar. So this webinar is part of our series which is groundwater the invisible lifeline which aims at understanding how groundwater is perceived from an unseen extractive resource to a dynamic living system. And this today's webinar is the third session which will focus specifically focus on the technologies and innovation that are transforming groundwater assessment monitoring mapping and decision making. Both the speakers will share their own experiences from both the theoretical and practical experience and point of view. Next slide. So without further ado, I would like to now welcome our both the speakers. So our first speaker is professor Ilango Lakshmaran who is a visiting faculty at Indian Institute of Technology Madras, India. So uh professor Ilango has over 38 years of experience in hydrogeeology. He's currently a full-time visiting faculty uh at IIT. He and he has also served as a vice president of international association of hydraological sciences from 2015 and 2019 and also the president of IIH's international commission of water quality. Our second speaker is Mr. Rahul Bakri. He's the CEO and founder of Utam Environmental Technologies based out of India. to uh uh Pune, India. By education, he has done his MS in mechanical engineering from Michigan State and has done his executive MBA at IIM. And he has worked for around 14 years in software and IT and he has in-depth experience in project management, product and people management and PRP, CRM etc. So uh without further ado, I would like to now invite our first speaker, Professor Ilam. The floor is yours. Hello to everyone. Hope my screen is visible and it is in presentation mode. >> Uh yes sir, it's visible. >> All right. >> Uh can you put it in slideshow? Yeah. >> Is it there on slideshow now? >> Yes. Yes. Thank you. >> Hello to everyone. Thanks for the nice introduction. I'll share basically out of uh several works which we did. I just picked up a few for presentation today. How can we make the invisible groundwater visible? So there are several tools. Some of the tools I'm listing it here. Basically geophysical exploration methods help us to understand where the groundwater is. Though we don't see with our eye, we make use of certain techniques to understand where is it located. Is it viable to tap yeah an acryifer system with limited amount of groundwater? All this can be answered using geohysical tools. Right? One of the most important tool is the electrical resistivity method in which what we do is we are going to apply current. As you can see in this uh picture on the right hand side bottom right we apply current between two points and the effect of that is steady in between the two. That means we apply current we measure the potential. As we increase the distance between the electrodes, we are able to we are able to understand greater depth of the subsurface. Right? That means as you increase the distance, we are able to increase the depth of penetration of current. So this is how we are able to understand whether the formation is saturated, whether it is a clay formation or sandy formation where the water table is. Right? So here is an example right wherein we are able to understand the spatial variation in a cross-section and the electrical resistivity values that mean the horizontal line is the surface ground surface this is the ground surface what you see here is vertically below your long profile. So in your profile we have now come out with the variation in the spatial variation in your vertical section with reference to the electrical resistivity with the scale given at the bottom. Right? So what we are able to get from here though the water is invisible. We are standing on the surface but we are able to clearly demarcate a zone which is having very high amount of salinity because blue color as you can see here is the zone which is having the lowest resistivity in this section. Right? Whereas this section has got high resistivity probably they are devoid of any groundwater most likely they are hard rock formation. So this is how we are able to see what is present below the surface of the earth using electrical resistivity method. Then the other tools are ground penetrating radar which is often used to study the shallow subsurface. Here are the two case studies in which we deployed this ground penetration radar tool to understand the subsurface beneath a river bed. Right? What you see is a river. The river flows this way. Right? wherein there was a check dam to be constructed to mitigate the issue of seawater intrusion just north of the city of Chennai before the commencement of the site selection itself we did several traverses to understand the location where we don't have any confining layer very close to the river bed that means so only then yeah recharge structure will perform better for that we had deployed ground penetrating radar right similarly at another a need for improving the groundwater quality since it had got it has completely saligned sea saline seawater wherein a percolation pond with a shaft was tried to identify a suitable site ground penetrating radar can be a ideal tool to understand the subsurface characteristics. The limitation however is it cannot go beyond 25 m below the surface below ground surface. So this is ideal tool for locating recharge structures. Another major tool which is very popular since last one decade which is surface nuclear magnetic resonance imaging. In this method a magnetic field is generated using a transmitter. The effect of transmission leads to change in the way in which the protons are oriented in beneath the surface of the earth due to the external mag external magnetic field. As and when we stop the application of the magnetic field these protons realign themselves according to the earth's magnetic field. So during realignment it produces some signal that signal is measured in using this surface nuclear magnetic resonance imaging. The greatest advantage is these protons are present only in mostly in water present water present below the surface of the earth. Hence indirectly we make the groundwater which is invisible visible using the surface nuclear magnetic resonance imaging. In fact this is the only method which directly help us to identify where the groundwater is below the surface of the earth. There are several techniques right that means we measure the data by varying the generation of magnetic field over the surface of the earth and study the response of that and we can also do what is known as a inversion technique wherein we assume certain subsurface model for that we produce the signal then we measure with the we compare the measured data by doing so and there is also an option to understand about the water content present below the surface of the earth. Due to the fact that the water molecules are able to move freely in zones where the porocity is considerably moderate. That means if you take a sandy formation, the water is able to move very freely. Though porocity is high for clay formations wherein water is held so tightly wherein they won't be able to spin as I have indicated in this diagram. Hence with the help of this we are able to demarcate which zone has got movable water which zone has got immovable groundwater. That is the advantage of this particular tool. So these are all some of the important geohysical tools that help us to understand the subsurface. Today we are heavily dependent on satellites for everything. Right? One such tool is the grace mission since the year 2002. We have this two satellites going around the earth in the polar orbit that help us to understand whether the whether there is any gain or loss of groundwater on the surface of the earth. There is also another set of satellites which are sending radar waves. Right? These radar waves touch the surface of the earth and then they get reflected or refracted back using which we are able to understand the elevation difference whether there is any land substance. These two data can be synthesized to understand whether or withdrawal of groundwater is causing land subsidance. So these tools are now available right especially grace data is free whereas sentinel data we have to pay and get the uh information right here we have made use of grace data to understand how efficiently it is able to predict the groundwater head in and around Chennai region. So what we have plotted both the measured groundwater level along with the grace derived groundwater storage there seems to be very nice correlation. Similarly with respect to time here you can see the blue line is the blue that is gravity measurement that is grace derived value and the red is the measured groundwater level. There seems to be a reasonable comparison except for certain years towards later which is attributed to seawater intrusion. Right? Similarly, land subsidence I as I told you previously can be estimated using synthetic aperture radar satellites. Here there is a tool called SRscape. This tool help us to understand the land deformation. Since the satellite goes over the same site at least on a once in a month's time. Suppose if you take a data after a gap of 2 3 years we will be able to know whether the land surface has deformed whether it has emerged or whether it has whether it has witnessed subsidance. Right? Here is an example from Kolkata city wherein you can see it shows the land surface is going down with respect to time. This is a bit old study from 2003 to 2010. We carried out this study uh using the data from 2003 to 2010 that corresponds very well with the measured decline in pometric head. So here too the white lines here indicate the pometric surface which is the lowest here where we have witnessed highest amount of land substance. So here is this is another tool to rapidly understand the variation in the land surface ge geographical information system right uh using any of the tools here we have used this particular tool to understand the variation the variation in the groundwater recharge potential zones or southern India right in which we had used AHP technique which is nothing but a multiriteria decision making wherein we fix up your goal that mean the goal here in this case is differentiate the entire southern India into highly potential moderately potential poor and very poor for recharge right so by assigning different criterias for example geology soil slope and so on we can come out with different alternatives so using this tool we had identified groundwater recharge potential zone for entire southern India. Over there we had the novelty of this study is over there we had also identified groundwater recharge potential as well as groundwater potential zones right. So we need to integrate this right whenever we plan for any new managed aer recharge structures we need to identify poor groundwater potential area wherein recharge potential is very high. This is another tool using the same multiriteria decision making tool. We had selected ideal sites for recharging groundwater in Bangaluru city. More than around 10,000 such recharge wells were constructed in Bangalore city making use of the same technique. So we could also get a visible improvement in groundwater level as and when we completed the construction of these 10,000 recharge wells. There are several tools that require uh for groundwater monitoring we use several tools in one of our case study involving construction of a percolation pond which I had indicated previously wherein we did ground penetrating radar. A percolation pond was constructed to improve the groundwater quality for supplying water to a small rural community living there. The entire area is highly salonized due to proximity of the proximity of this side to the sea as well as the backwaters right wherein we constructed a percolation pond. In order to understand the efficacy of this speculation, we had also drilled four pometers adjacent to that and these were heavy instrumented using several advanced automatic sorry automatic weather station and also multi multiple probes to understand the groundwater potential in the pond as well as a nearby well in all the pometers. Right? So here this research was published as a part of this book published by IWA. Those who are interested can have a look into this for more details. And one of the common problem which we face especially after severe rainfall right even suddenly the ground surface gets flooded right and the water table is somewhere here. This is the groundwater table. But the ground surface gets flooded and leaving lot of air entrapped between the saturated or flooded surface as well as the saturated zone. Due to the presence of these air bubbles, water is unable to get infiltrated into the groundwater. Though we had plenty of flood waters at the surface, they are not really benefiting groundwater recharge due to the entrapment of air. We thought of how about providing a small tubes in the unsaturated zone so that when during floods the air which got entrapped due to the pressure of flood water may escape through this. So this concept was presented to the ministry of science and technology. They funded a project. So we did several experiments in some sand tanks as you see here with some moisture sensors kept at frequent uh distance from the surface. Right? And we had also put a automatic water level recorder to study the effect of this flooding. Then we we had also carried out some field experiments. The experiments support that the presence of vent for example this is one two three and so on help to quickly recharge the groundwater. This technique is able to overcome the problem of entrapment of air. Right? We had also filed a patent of this to this technique. Then coming to artificial intelligence and machine learning in groundwater. There are number of researchers who have very efficiently used AI and ML tools especially for predicting groundwater level as well as groundwater quality and groundwater recharge. Right? So these are all the popular um themes in which people have applied the application of artificial intelligence as well as machine learning. Most of the researchers have used these tools to achieve their objectives. Right? I I'm just presenting two examples. In one example carried out in Germany, the authors have put into use of machine learning to come out with forecasting of groundwater level. So they have achieved a reasonably nice results with nearly 17 monitoring wells they had but they had a long-term data from 1967 to 2015 and they considered three important variables. One is temperature, precipitation as well as humidity. They had made use of three different machine learning or AI models and reasonably all the three performed well whereas this one achieved very highest amount of NSC as well as squared. CNN is also not very much lagging behind. So these tools nowadays are becoming very popular to predict groundwater level. As you can see here right both observed as well as predicted especially by knocks they are more or less going over each other right and here is the performance of the model. So the key finding is though all the models performed reasonably well this model seems to be outperform the other two whereas CNN is also able to give a reasonable kind of results and we had also used something similar to what we had seen previously to predict groundwater quality in one part of India in Karnataka right wherein we have been collecting groundwater samples once in 3 months for a period of about 4 years from over 50 wells for which we had applied machine learning coupled with ant colony optimization tool as you can see here let us not go into depth this is published in this uh details are available in the paper which I'm giving at the bottom right what is interesting is we use nearly 70% of our data for draining then the Rest of the data was used to test the results of the model. Since we had observed the groundwater quality with regard to major ions over 50 wells every well we had we had measured about 10 parameters such as sodium chloride potassium. I'm just showing you the results of couple of them right in one particular well I'm showing similarly we have results of 50 wells. You can see reasonably the the orange color line or the saffron color line is the model predicted and the blue is the measured value. There is a reasonable comparison between both and also here I'm showing you for uranium concentration which is very important. So there is a reasonable comparison between the model predicted as well as the observed value. Then we also checked whether 50 at 50 wells 50 different models predicted the concentration and then we came out with a inverse distance method to extrapolate the concentration over the entire area. Then we compared that this left hand side green one is observed and the right hand side is the model pred predicted there is a reasonable comparison. So these models are able to very nicely predict the groundwater quality. It though we are using several other contaminant transport models. This machine learning tool seems to be a very good way to estimate the groundwater quality. There are also several other ge digital tools. One such tool is a popular tool is the water evaluation and planning tool which we deployed for the city of Chennai to understand to forecast the unmet demand in water supply right considering the expected population growth in future right if according to the estimated population growth suppose the demand if it increases using this tool by considering different sources we'll be able to forecast the unmet demand demand. So here is the demand unmet demand right on the y-axis you have the unmet demand and the x-axis is the time axis right time axis and we played with the model by considering different rainfall patterns. Suppose if you have excess rainfall every year suppose if you have normal rainfall every year if you have deficit rainfall how will the how much will be the unmet demand? Suppose if you put forth of used water, let us assume 200 ml of used water is put into the supply chain, how we'll be able to meet the unmet demand. Details are available in this uh paper. So this is how deep model can be used and of course groundwater models are excellent tools to forecast or run scenario analysis of different including engineering solutions. In this case, as I had told you previously, 15 check dams were constructed across these river basins located just north of the city of Chennai. Even before the commencement of construction of these check dams, we estimated the possible impact of these check dams in this area using this numerical model. Then we had also run the model to forecast different climate change scenarios. So what you see here is the impact of this right. To conclude, we are currently working on a major digital twin. Digital twin is nothing but replicating what exist in nature into a computerbased system with realtime analysis and also people's participation right wherein we are coupling several models. It is a collaborative project between India and Delft. That is it. Thank you very much for your attention. Uh thank you so much professor Elango for that uh you know detailed description about the tools and the models that we can use uh you know for groundwater uh mapping and assessment. So thank you thank you so much for sharing your insights and we will take up the questions in the uh panel discussion. So now I would like to invite our next speaker Mr. Rahul Bapri to discuss more about his work in the uh in technologies and innovation and groundwater. So over to you sir. Thank you. >> Yeah thank thanks for this opportunity Afia and welcome all uh to this uh webinar. Um I'll quickly share my presentation. I hope it is full screen. >> Oh yes sir. Yes. >> Yeah. So uh the topic given to us is basically making the invisible visible the technologies for groundwater management. Um I would like to go through various uh types of uh uh problems various types of issues uh faced by groundwater and I would like to discuss on practically what and all we do to basically uh give solutions to the problems what we are facing. So for example India is the largest user of groundwater. It has around 8 8 crore that is 80 million existing bore wells and open wells and through that we are overexloiting groundwater to a great extent so much so that farmers are committing suicide women have to walk far away places even water has to be applied through tankers and water quality is becoming a major issue in some cases uranium chromium has started coming in groundwater as such so groundwater in the Indian context is one of the major water sources 80% of India depends on groundwater as such and uh this is problem what we are we are facing. So when we mapped the water utilization flow we realized that basically there is something called as natural resource and the source needs to be developed treated then basically it's used and waste water is generated and waste water is treated uh and that is something which is the the the kind of water utilization flow and from source development to waste treatment uh is there a lot of crowded engineering product space. So we provide solutions to the sustainability of the natural resource may be groundwater, surface water or rainwater and we use lot of IT, IoT, robotics, mobile technology to solve the people's problem on the ground as such. So why we need to think about groundwater? Because groundwater is invisible. It is unseen hence understood, unappreciated. Uh but it is creating tremendous amounts of problems and that's why we should learn about groundwater. Water, water because of water, groundwater basically droughts and desertification is happening all across the world. As such, groundwater also is one of the the reason why deforestation is happen. So a lot of forestation is also happening because of climate change the recharge regimes are changed and because of the recharge regime because of the change in the uh basically rainfall patterns intensity etc. uh it's also creating lot of deforestation and as I said the droughts as a matter of fact desertification and earth forestation is a solution for that but currently the earth forestation doesn't take into account the groundwater regimes as a matter of fact and actually that is something which uh people certainly should know where to uh uh plant which kinds of trees depending on the hydrogeeology part of it right typically based only on the clim aggroclimatic zones the uh forestation is done. But probably for the plants to uh basically leave, sustain and move on and and grow one needs to understand groundwater hydrogel. Rivers are drying up as we know it. Uh many places rivers flow only during the rainy season as a matter of fact and during the non-raining season there is no water because the base flows have dried up. And why the base flows have dried up? Because water in the unconfined aquifers uh in many parts is used for pumping at a much uh faster rate than what nature can replenish and because of that the base flows are reducing and because of that rivers post monsoon are not providing any water to the civilizations as such. Water also is a major problem because when we construct a roll when we when we create a escarment that creates a a weak zone for the hydrostatic pressure to get applied and that's what creates the landslides. Landslides also are caused because of the friction between the the the the w between between the different particles and the pebbles and stones uh gets reduced because of too much of water uh uh basically getting seeped into location. So unfortunately many such uh construction activities maybe houses may be roads maybe even watershed kind of uh uh treatments are done without any understanding of hydro geology that creates more problems than solving the problems as such. We have seen uh in in in my uh near my city village which was entirely swiped away by by by by a landslide because unfortunately without understanding the hydrogelology a huge tank was constructed upstream uh which was a farm pond and that farm pond during a very torrential rain evening basically succumb to the uh uh to the water and basically that water created tremendous amount of I would say force on the slopes and basically the entire village was flooded and entire village village was actually buried under the mud but because people didn't understand the hydro geology when they considered constructing that farm pond in that location um at the same time we also have seen many places sink holes happen as we know sink holes also happen because of not understanding the underground water regimes uh which are out there and because of that many places a lot of uh basically destruction happens. Uh water also groundwater also is a is a problem which causes foundations to fail or foundations to topple over and hence the households also kind of topple over. uh land subsidance is another major issue which is faced by many people in Califura context uh 9 m subsidance is seen in some places there's a tremendous amount of subsidance creating tremendous amount of problems to groundwater assets so what I'm trying to say is that again these are the basements which are flooded during every rainy season in uh uh in in India uh because again hydrog taken into consideration while constructing those basements as such so hydrogen critical and crucial But unfortunately it is not taken into consideration. It is taken certainly into consideration while mining but there also in many places flooding of the uh uh shafts and mining uh shafts is already seen as a matter of fact. And lastly, groundwater also needs to be considered while developing the sanitation uh infrastructure because uh in the in the in the Indian context for example, pit type recharge systems pit type uh uh toilet construction creates tremendous amount of problem in the rainy season because lot of that water uh becomes groundwater and gets transported downstream. So for even something as simple and as distant as sanitation also needs to take into consideration the hydro geology as such. So there are three major gaps in groundwater motor domain. What we have seen uh first of all awareness and education in general masses doesn't exist. People don't know they have very imagination about groundwater motor whether is there any stream flowing underground or there's a pond or there is a sea of sweet water but nothing of that sort exists but unfortunately people have that kind of a visualization. Second is that people want more and more supply for their day-to-day activities and their economic activities as well and people want more and more water. Uh and whatever water which is generated uh uh through groundwater supply uh it is not managed properly. So the demand management also needs to happen because lot of water is given to plants especially in agriculture in uh basically in in furrow and and and that kind of a way. uh and because of that uh a lot of water goes gets lost in the uh evaporative losses as such. So we work in awareness and education as I said awareness education is a very important part of it. We have developed a gamified visualization for education and awareness generation on groundwater motor behavior because as I said uh giving people animations people are not able to imagine. So we have developed this see-through uh model of uh groundwater behavior on which kids or even adults can basically put uh rain on top of it and how the groundwater behavior happens. It can be simulated through gamification of education kind of a methodology where uh difficult to visualize 17 to 18 scenarios they can generate by themselves through play and by that they are able to understand the uh groundwater behavior. So because it is gamified there is a better retention of this uh understanding in their brain and longtime recall happens. So that's what we have seen and observed in the Indian context. As such we also work on supply augmentation. Uh we have developed a patented smart motor technology that recharges and revives existing low yielding or dry or wells uh in which we uh basically do interacquifer transfers uh obviously with due scientific understanding. So when the rainfall happens the topmost part of the system there is an animation uh gets filled up very quickly but through different hard rock layers for the water to reach up to 200 ft for example it takes hundreds and thousands of years and from there to reach up to let's say 600 ft takes millions of years. So is the slow nature of groundwater recharge as a matter of time. But when we drill a bore well, a drill is the driller makes one hole up to let's say our board is 600 ft within one day. And what we see borewell on the surface actually is a casing pipe which is impervious PVC MS steel pipe and that doesn't allow any debris to fall in the bore well. But along with that replenishable water from the topmost aquifer also doesn't enter the bore wells. So bore wells typically get water from the lower aquifers whose u natural recharge is very low and slow but our electro mechanical pumping is very fast and because of this imbalance typically initially good yielding bore well slowly become seasonal and many of them they go dry completely. So in bore charger technology our trained hydro geologist undertake angography of the bore well and we uh put our patented tool uh after in the bore well and we perforate that casing pipe at hydro geologically appropriate depth so that only filter water will come in the bore well and it artificially gets injected in this bore well and it reaches 600 ft within few seconds but it takes millions of years and it gets readily stored in those uh uh greater depths. So this is kind of a vertical uh smart rainwater harvesting uh technique what we have been able to develop and we have implemented more than 7,000 u well recharges and uh we have seen tremendous amount of traction so these are some of the classical successful implementations as a matter of fact what are the real world problems faced by people and what's the impact of board charger kind of a technology nabis a farmer whose agricultur agriculture income was very low because his water level used to go down to 450 ft every year because of bore charger technology. His agriculture income rose by 85% within one year itself because he started getting 6 hours per day water compared to 1 hour per day during summertime. Shivaji surunch a local uh uh body chief he's pumping drinking water village drinking water bore well was pumping only 30 minutes per day and his village was insecure. After bore charger implementation was done this pumping increased to four hours per day and his village became water basically secure. Rakkesh Koti an urbanite he had 15 minutes per day worth his bore well water it increased to three and a half hours per day and he's completely dried up bore wells also started yielding because of this interacquifer transfer as a matter of fact and because of that he saved 600,000 rupees uh a year towards tanker water supplies as such. So overall the soio economic and eological impacts of bore charger are quite clear. We are able to increase the recharge rate four to 20 times anywhere between 200,000 to uh uh 8 million liters of rain water gets added to the bore well every year. This increases supply by additional 1 to six more months and along with quantity in quality improvement. We have seen 95% plus success rate. We have seen and we have reduced the vulnerability of farmers to weather shocks and we also have reduced lot of tanker water supplies as such. So when we were analyzing this uh problem about deeper awards not getting recharged and that was one of the reasons why bore wells go dry. We also uh we also thought why the borwells go dry in the Indian context especially is because uh the source is not the location of the source is not identified properly scientifically. uh typically in the Indian context diviners which are coconut divining or rod divining and those sorts of uh uh uh things are used to basically find a spot by using divining methodology but unfortunately that is highly inaccurate only maybe 20% accuracy is there so we have developed this source identification and accurate mapping uh kind of a technique which professor langu also mentioned vertical electrical sounding uh I won't go into deep uh about this whole part of it. But this is the topmost side of the image. You can see it's a 5 acre land on which this vertical sounding uh uh uh survey was done and the the red blue the red and pink zones are the zones which are highly compact in nature. Green yellow ones are having some moderate porosity and the dark blue zones are the ones which are having very high porocity and good potential to find water. So now how do we use this kind of an ultrasonic or a kind of a cross-section of the earth system which is invisible to our naked eyes is that when a diver gives a borewell location here obviously this borewell won't fetch much water because the dark blue zones which are highly porous in nature don't have much interface with this borewell but if we would have done this scientifically we would have shown this as the location which would yield much much more water. Same as the rainwater harvesting pit. If the rainwater harvesting pit is done here, this uh uh yellow green zone doesn't have that much amount of porosity. So it won't be that efficient. But if we do this through scientific methodology, we can use this location for better rainwater harvesting. Same is for the location of open well as well as a recharge pond structure for a uh for a uh uh for waterershed. uh we have seen many places I'm asked if I've evaluated many water sheds where uh the the the end user says that sir in in in February say see so much of water in this percolation pond but you cannot call it as a successful implementation because the fact that there is water in that tank till February means that it has not percolated so you have created a storage pond as compared to a recharge pond and we have worked with many CSRs many NOS's uh many government programs And we have first studied the uh the watershed with the help of hydro geology uh with land use, land pattern change uh slopes and so many other factors we take into consideration and based on that we do acquirer mapping of the entire space and then we provide uh scientifically uh correct accurate effective and efficient location for the structures which are supposed to be constructed there. So groundwater is extremely important. As a matter of fact, we also use geomagnetic technologies to understand the the uh the potential to find water underground as well. Lastly, from the demand management side, we have developed this Jester scientific groundwater measurement and prediction technology uh which is basically a pometric sensor which is IoT enabled which gives realtime visualization and also can provide predictive analysis. So just to give a classical example for a farmer or an end user for one sensor or one bore well data uh we can see when the pump starts the water level is here after the after some time the water level goes down with the pumping and uh when the pumping ends the water level attains another depth right which is much lower than the the earlier depth but after the pumping start the water level also recuperate slowly. Now this is for one bore well but with the within this bore well we are able to provide what's the volume of pumped out uh water pumped out from this and with this uh the farmers are not able are now able to undertake tremendous amount of informed decision making such as next crop next crop which crop to take what cropping area cropping variety so on so forth and based on that many farmers have increased their income many farmers also have been able to uh uh take uh additional crops for their uh during summer time. Many farmers have been to a good amount of animal husbandry because of uh this kind of a uh advisory and input which is given. Now the the core offerings are we are able to provide very high frequency data real time visualization analysis and most importantly the advisory on data analysis and prediction. So as you can see uh we have this data from November 24 to January 26. The pumping for the domestic use of this bore well was clearly showing certain pattern but during monsoon the recharge happened and again the pumping uh happened for the domestic use. Now with the help of a lot of contiguous data we would be able to we have been able to now predict uh the the the data. So in November 25 when we started prediction the green line on the right hand side u uh uh actually the the the dotted line on the right hand side is the uh uh is a test and the forecasted uh water line based on the the past previous data but the green line is something which is quite matching which is the actual data which we have been able to measure and predict. So the prediction based on a IML uh and as well as c certain stat statistical methodologies we are able to achieve a good amount of accuracy. So we are able to provide tremendous amount of uh uh input which people are not currently getting as a matter of fact. Um but when we look at this prediction over long period of time we are able to predict water level data as well as predicted quantity and duration of water supply as well. So that's the the predictive behavior advisory we are adding value into we with this uh sensors put in in a specific watershed or a village we are able to develop aquifer health status which the uh the the villagers can see on their uh being monitor in their raanch are able to see what's the water level and the animation something like this animation uh which they are able to understand. So again through gamification of the information we are able to give them better understanding and visualization and also 3D visualization also can be done uh with this kind of a continuous data at a uh at at a at a very frequent level. So we have been able to tremendously uh impact farmers, rural communities, households, industries as well as NGO, CSR, uh social impact, environmental impact programs as well and we are working with governments and regulators as well. So now how do we convert all these things into a scalable model is basically we have a regional offices and we are serving the far industry, townships which are the real world uh beneficiaries of our services. But through this model we cannot scale up. So the idea is by training local youth and converting them into parah hydrogeeologist in which they are not hydro geologist but they would be able to uh collect lot of data uh on a on a very frequent basis and they would be transferring the data to us over IoT and through automation of our technologies which would give in their hand we would convert them into our franchises. So they would be our uh onfield implementation arm and through that we would be converting them into franchises and those are the ones who would provide tremendous amount of uh affordable scalable uh services at that uh uh local level wherein we uh using IoT and and the cloud technologies can uh do lot of visualization, modeling uh assessment, analysis in our head office and we would be able to provide uh advisories there is to people. So with that let's recharge, replenish and revive ground water especially for our future generations. It means if there is water there is tomorrow. Thank you. Uh thank you Rahul sir for sharing your experiences and you know deep insights about especially in the field work and how you have interacted with uh you know the different communities and how your uh you know product has helped different communities and stakeholders in improving their uh produce and also their livelihoods. So thank you for sharing. uh so I think we have limited questions because which means that participants do not have much doubts and they are very clear with both the uh speakers presentations so I would request Mr. Ilango to uh you know come on board and I would now request both the speakers so I'll just read some of the questions and then based on your uh you know understanding you can reply or uh you know you can give your suggestions so the first question is uh for Mr. Ilango. So u uh dear professor thank you for your informative presentation. Uh the question is is sinkhole occurrence related to land subsidance? And the second question related to it is what are the factors that should be considered to assess the spatial risk of sinkhole occurrence. >> The land subsidance and uh he was asking sinkhole right sinkhole. Yes. >> Land subsidance is a very slow process. That is how we can distinguish sinkhole collapse, right? Even Rahul showed some nice videos which are all probably due to some issues below the surface. Maybe a limestone or a sudden failure in a subsurface uh storm water drainage, right? They cause something like sink holes, sudden caving, right? Land substance is a very very slow process. This is how both can be distinguished. And the second question I didn't get you. >> Uh yes. So what are the factors that should be considered to assess the spatial risk of sinkhole occurrence? >> What are all the factors that needs to be considered right? The most important factor is to understand what is the extent of this sinkhole which is very difficult to estimate. We need to rely heavily on the geoysical tools right including major structures as he nicely showed in videos big buildings without considering the presence of sink holes beneath huge structures are being constructed. So the role of geologist is very very vital. They should first of all test the site using geohysical tools. The geohysical tools are the ultimate one to give us information about the strength of the subsurface. Right? There is nothing nothing else available. I hope I answer I have answered your question clearly. Right? If you have anything else you can correspond with me or with Rahul G. >> Yes. Thank you sir. Rahul sir do you have any uh pointers to add on that? So I think certainly um just like uh professor Young also mentioned uh land use land pattern change uh also needs to be considered slopes needs to be considered rainfall patterns especially in the climate change context storm water management existing and older uh stormwater management practices have to be considered uh hydrogeeologically what's the strata what's the certain maybe certain test bwells needs to be taken uh because those are the ones which can provide some sort of a understanding of the underlying geology and hydrogology as well. Maybe even in some cases even pumping test needs to be taken into consideration to understand the the yield. Uh some of these things are the the things which can certainly a detailed hydrogelological study uh if if it is undertaken uh many of these future problems can be solved. >> Great. Uh thank you. Thank you to both. And uh the second question is more related to the data part. So the question is what would be the minimum amount of data in terms of years ideal for uh ML or AI uh analysis and then yeah so that is the first question. So if you know anyone of >> we don't have a straightforward answer for example in any statistical analysis we say at least 30 time data is necessary the same is applicable here too right when we are talking about water in India we need to at least consider one year minimum one year data is necessary even one year is not really sufficient to understand whether the cyclicity is getting repeated. So I will say suppose if you are using monthly data at minimum of five year data is necessary right 5 into 12 60 times you have measured let us say groundwater level so 60 times measurement I will say is the minimum requirement anything beyond that is a bonus any model will perform better if you have more observed data >> thank you sir Rah sir do you want to add >> yeah so I 100% agree Professor Alang was that more is the marrier. Uh but in real world scenario we may not get that kind of a prolonged uh timeline uh kind of a data. Uh so there we we get as as much data as possible and based on that we can run certain uh analysis as well as certain modeling which we can build and um in absence of any data something is better than nothing. So whatever is the data which we are have available uh we we tend to use that and provide uh applied solutions to people. >> Great. Uh thank you. Uh so I think now we getting a lot of questions as well. So I'll take another one. Can we always conclude low resistivity areas as potential acryer zones? Um not really right we are if the resistivity is low maybe a war body or most likely it will be a clay formation so resistivity should not be too low if a very low resistivity most likely indicating clay zones. Suppose if you take a coastal area maybe like Chennai you may have sandy formation over there at the lower part of the sandy formation we would have measured very low resistivity resistivity over there it points to seawater intrusion. So we cannot attribute the value of resistivity directly to a formation. So you need to put in your collective expertise to come out with a meaningful interpretation. So in order to refine your interpretation always it is necessary to go for couple of test board holes. Right? A no resistivity survey is complete without carrying out one or two test board holes to test our interpretation or hypothesis we have made. So to answer your question straightforward simply low resistivity zones are not acifers. Thank you. >> Great. Uh so uh there are another question u okay so I think this question might go for both actually. So uh web has asked the study used many instruments for respective objectives. My question is are there any proxy exits to complement the outcome or an absence of availability of any highly sophisticated instruments? >> Uh I didn't get you for which study is referring to >> uh the he has not mentioned so I think commonly if the if so what we can understand is if there is an absence of highly sophisticated instruments what are the different alternative ways that we can use for uh you know such studies. Absolutely right. Always we need not go for highly sophisticated instruments. Right. For example, if you are exploring for groundwater, a mere field work understanding the formation at the surface. Is it a sandy formation or is it a clay formation? Are there any wells? Are there any excavations existing in that area? Right? Geologist will be able to guess even without visiting the site from the satellite image itself. we can come out with some idea about the terrain. Yes, site visit will certainly enhance our idea. Right? So all we need not always depend on the sophisticated tools to get some simple answers. That is my view. >> Thank you sir. Rahul sir, another question is specific to you. You do do you want to answer this as well? >> Yeah. Yeah. So actually see the instrumentation need not be sophisticated because more sophistication more is the cost right and more difficult it is to also uh basically analyze and all. So I think just like professor langu said that for unconfined acryer which is shall acquifer probably certain uh existing secondary data or satellite image analysis vegetative uh basically indicators uh there are a lot of botanical indicators which can also tell you about especially the shallow aquifers but for the deeper aquifers yes there has to be certain instrumentation applied uh and that instrument instrumentation need not be basically sonic or acoustic or you know something like that which is used typically for oil field uh and oil identification oil zone identification etc. uh but simple vs uh uh is also sufficient as a matter of fact. >> Yes, thank you. And next question is Rahul specific to your presentation. So the patented boat charger really sounds interesting but have you experienced installing it in volcanic formations and is it expensive? So certainly actually it works fantastically well in the hard rock regions which are volcanic uh in nature. Basically we are sitting on world's one of the world's largest bassalt formations, volcanic formations and we have seen tremendous amount of impact. uh we have done more than uh uh 6,000 plus implementations for farmers for uh households uh as a matter of fact for hand pumps as well community hand pumps as well and tremendous impact uh we have seen as I said people have taken more crops people uh the hand pumps which used to get dry in the month of Jan Feb now has started yielding water till May and June uh solving their lot of problems and reducing lot of drudgery of fetching water from far away places so uh yes it works absolutely fantastically well in volcanic formations. >> Uh great. And I think we'll just take one more last question to Professor Elango. Uh can flash flood water in urban areas or cities be screened and recharged? >> Yeah, certainly we can go in for some sophisticated storm water drains, right? Which are engineered to filter the storm water. These are all some of the measures called sustainable urban drainage but which are bit expensive to install but there are successful examples which what it does basically is to drain the storm water which falls on the garden or which falls on the roadways into a small ditch which has got some sophisticated filtering system which filter the water. The filtered water eventually enters into a storm water drain or into something like bio swales where the water is retrained. Of course, the filter requires maintenance as we do at our water filters at home. Yes, certainly storm water can be treated in situ and allowed to run into the bio swelles or into storm water drains. >> Yes. Uh Rahul sir, anything to add? Yeah. So to answer that question uh so certainly why storm water is getting generated is that because of the anthropogenic activities like construction and pavements and other stuff right so I think uh uh uh in absence of that the storm water would not have been as huge as what we are seeing nowadays. So in the urban context a lot of pavements are constructed concretization is happening because of which the storm water is getting generated. Now the typical uh wisdom of people is to basically take all the water in a specific primises to the lowermost point in the uh in in the topology and create a recharge structure there. But it's not going to really work because the the recharge capacity of uh recharge rate of ground is very slow. So the capacity is very high. The recharge rate is very low. So we have to construct many uh uh points of recharges in that facility. uh just like professor also said that in the storm water drain itself it can easily be accommodated but the thing is that it is not one-sizefits-all. It's a one has to first study the hydro geology. One has to understand the the the the capacity to uh uh uh capacity and the rate of absorption of water and recharge of the water and based on that the buffer needs to be developed. Uh then filter needs to be developed but certainly it is not a costly affair. If this uh kind of a study is undertaken first and then a professional does the uh the hydro geologically assess the area and does the implementation. I'll give classical example in our in in my city there have been so many people uh who are civil contractors uh and they think okay just make one ditch and put water in there and that's the rainwater harvesting. But unfortunately there's too much of oversimplification of science of groundwater hydrogelology which is happening which is really not good for people because people are getting fleas. They're spending lacks and lacks of liters of water uh lacks lacks lit lacks and lacks rupees hundreds and thousands of rupees. But unfortunately they are not getting sufficient uh output of that of groundwater recharge because unfortunately it is done by anybody and everybody and not by a by a by a scientist. It's like basically I have a pair of scissors so I become uh I don't become a good surgeon right. Um so if really one has to get uh uh an effective and impactful solution which will solve the problems one has to go to a surgeon and only the surgeon can do the the the surgery per se which will uh save the save the patient as such. So I think very much it is very much important and crucial that hydrogeeology is given uh its rightful share and rightful attention uh by the by the the builders construction urban planning uh and even rural planning uh uh basically entities and the policy makers and decision makers as such. >> Sure. Uh thank you. because of time constraint we would not be able to take any more questions but thank you to both the speakers for their uh you know time and support for making this webinar a success and I hope that we'll be able to uh answer all best of the questions and we'll share it with the participants in the coming weeks. Uh so thank you again to both the speakers for sharing their detailed insights and their experiences in assessing groundwater. Uh now coming back to the upcoming events in IWA. So all those participants today uh so we have next webinar coming up on 19th August uh titled guardians of water indigenous women as knowledge holders and water stewards and if you're interested you can click on the link below. Next slide. Then we have another uh uh exceptional webinar which is uh you know focusing on water sensitive design and planning uh tools and nature based solutions which will happen on 27th August and you can click on the link below and of course we have our IWA World Water Congress and exhibition in Glasgow from 4 to 8th August and registrations are still open so I would encourage all to visit the website next and then for all those interested in the digital aspects of water. Uh we have our upcoming digital water summit in Istanbul from 24th 26th November and registrations are open. Uh and last but not the least, so if you're not an IWA member, uh you can scan the QR code here and become our member to experience many such webinar and knowledge activities. And for all the new members, we are providing 20% discount on our membership fee which you can use the discount code as mentioned in your screen. Next slide. Yes. So I think I would like to thank all our participants who have joined from across the world to make this webinar a success and to listen to our speakers and to actively participate in the discussion. Uh and I would encourage you to attend all our webinars and uh see you in the future. Thank you so much. Thank you to all the speakers. >> Thank you. Thank you very much. >> Thank you. Bye-bye, Aansi.