 So, let us get started with today's topic which is water resources. This is a topic that is very important for everybody and it is something that we can very easily relate with because water as you know is so essential for life. And there are so many problems related to water which we will see in this presentation. There are so many things that we can do in order to stop or reduce this problem. So, this topic is actually very interesting and even my students when I teach them this kind of makes a good connection with them. So, this is the outline of my talk I will first I know there are a few teachers who are teaching this course for the first time and although we have all studied the water cycle sometime in school it does not hurt to just have an overview. So, I am going to talk about that water cycle and the reason it is important to actually start from the beginning is because we need to intervene from the beginning also. So, the first topic is the water cycle for which let us watch a short video rather than me explaining something which you are already very familiar with. I thought it will be good to show you a video. I thought that was a very nice video and I hope you all enjoyed it. It introduces all the various terms that are often used in this context and which some of your students may need a little help with. So, here in case you cannot show videos in your class you know here is a relatively good diagram of the water cycle which you could also show. The thing that I like about this is that there are numbers on each of those flows or fluxes and reservoirs and you see that I mean you can refer to this in your leisure time. But there are actually numbers over here of how much rain how much of the water vapor comes down as rain and things like that for each of these different features that you see like the mountains and the rivers and things like that. So, it is a pretty good image ok. So, this is the water cycle and you know that we all depend heavily on it the it is extremely important for the biosphere and life and biodiversity as we know it today depends on this water cycle. So, let us look at what is happening presently and more specifically in India. So, this trend is in many parts of the tropical world you have water scarcity and in India if we observe the period from just around independence 1951 you see that we had 5000 odd meter cube per year per capita. So, the per capita availability of water since 1950s has now reduced to under 1700 now 1700 per capita per meter cube per capita per year is said to be the threshold for water stress. So, our country now is a water stressed country. So, half a century plus of development later we have successfully managed to take our country into a water stressed condition from where it was. So, 5000 was a pretty decent number, but unfortunately today the situation is very different and in India today we have several villages that do not have a reliable source of drinking water and particularly in the hot dry summer months it is really horrible people have to walk and particularly women have to walk kilometers to get water for their family. And in urban places you know how polluted our rivers are you take the case of any important city in India take Delhi, take Pune, Mumbai, Chennai any city you will find water bodies that are horribly polluted like this I mean you cannot imagine drinking that water or even bathing it bathing in it for that matter. So, this shows how this water stress and scarcity all over the world is actually a major problem and it is going to worsen it is likely to worsen and you see that India is already spread which means there is a high stress. So, some things got to be done and it has to be done soon. So, the question that comes to our mind as soon as you hear that we have a water shortage immediate thing that comes to our mind is let us construct new dams and the larger the better. There is a problem there have been major people's agitations against large dams and we are all familiar with all the benefits we have when you have large dams you have plenty of water that can be supplied to large cities to industrial centers, but and you can have long distance canals you can supply water from one state into another state. So, those are the benefits there are so many other things that come along with that hydroelectric production the benefits that the public gets due to reliable supply of water and electricity. So, those are all the nice things, but there are some other things which are also which need to be considered and they have probably not been considered adequately. So, some of them are that the large numbers of people that get displaced in these large dams they are often not rehabilitated well and they happen to bear the bear disproportionate costs of this whole thing. So, there are in constructing a dam project or any project for that matter there are some costs and then there are some benefits and you have to weigh the benefits against the costs. So, the benefits should exceed the costs. The problem here though is that the people who bear the cost do not get the benefit. So, it is somebody else bears the cost for the benefit of someone else. So, that is a big problem. The there are also issues with the way the cost benefit ratio has been calculated and some major costs have not been accounted for. So, let us say you have the benefits in the numerator and you have the costs in the denominator and if you understate the costs the factor appears to be artificially larger than it is. So, it the project goes through whereas, people suffer and the environment gets damaged. Rivers are supposed to be flowing they require a natural flow. You cannot simply intercept the flow of a river and expect no adverse impacts. The water that flows through supports aquatic life. The sediment that goes through the river is very important for the riverine ecosystem as well as to the estuarine ecosystem. The estuary is the place where it meets the sea. So, if it does not get adequate quantities of fresh water flowing through and sediment and nutrients that come along with the sediment if you intercept that then it has major impacts on the ecosystems. So, moreover you know you have migratory animals within the rivers. So, their migration upward and downward is hindered by this. You must have heard about the the Narmada Bachao Andolan and there are. So, I have some I know this large dams versus so, the large dams are perceived to be in national interests and anybody who opposes that is perceived to be against development and against the country. I do not think we should take any such drastic view. There is a there is a report and there is some reading material that I would like to direct all of you because this is one topic where you can have a lot of discussion and debate in the class. And I commonly in my class I have like a debate with two sides and you know the people spontaneously form groups you know I asked them to just divide up the class into two and I say anybody who is pro you know move from your seat and go over to the other side and vice versa. So, you split the class and then I have another student who notes down points on either side on a blackboard I make like two sections A and B pro and against large dams and you know that one person he or she notes down various points that are raised in the in the debate. So, it is really very interesting and students enjoy that activity and at the same time they learn so many things. So, it is important that when you conduct such activities in class that you yourself are familiar with some facts and some details and that you should share with your students beforehand and tell them it is coming. So, one fine day if you suddenly spring a surprise on them for such an activity then it generally degenerates into you know just kind of you know hushing up the other other party. So, nobody nobody then is interested in learning, but what I think we should encourage our students to do is they should read up before and then they should come prepared so that there is there is a lot of learning that happens during these sessions. The entertainment is incidental it always happens you know everybody gets entertained when there is such a hot debate ok. So, you know faced with the water scarcity we generally tend to think that large dams are the solution, but I just told you that there is another side also. So, let us not jump to the conclusion that dams, large dams are the solution. There are there are alternatives too I am not saying that the existing dams should be dismantled or something like that we have the existing dams and in order for them to meet their expected anticipated benefits they must run properly. But in future I do not think we can we can build a many more large dams because most of the river systems we have already built very large dams and from a social point of view it is going to be more and more difficult to construct more dams. So, that is probably not the direction in which we need to go. The other thing that automatically comes to our mind is ok forget about the rivers and damming the rivers. Let us simply drill bore wells that is what we normally do if we purchase a house somewhere and there is no reliable city water supply then we construct we drill a bore well to get water and that is what farmers do too because not everybody is fortunate to have a canal irrigation canal run next to his or her own farm. So, they drill bore wells and with the bore wells you can drill holes really deep into the earth and you can get water. So, they have been very popular, but again if you look at whether that is going to serve us in the future and to what extent it is going to serve us in the future you have this map where the red regions are where there is a severe depletion in the ground water. So, there are regions very large regions which hold very significant populations which are where the ground water is declining the levels are going down and in places I mean I am sure in this crowd of 4000 people you must have had a similar experience the place I come from I know that the water table is falling by several feet every year. So, this can be a very serious problem and this immediately puts a limit to how much ground water we can extract. You may then say that if the surface water there is a limit to how much you can extract in terms of building dams and the ground water also is depleting then why not reduce water use absolutely water use should be reduced, but again there is a caution over there because 87 percent of water in India goes for agriculture. So, if you reduce the irrigation water if you reduce the overall countries overall water consumption then it is likely to impact agriculture. So, what I am trying to get at through various I am kind of giving various arguments and I am trying to help you understand how a simple solution is probably not going to come out. There are ways and definitely we will discuss some of the solutions, but maybe some of the things that come to our mind immediately are maybe not workable. Since we are talking about irrigation and agriculture it turns out that roughly 50 percent of our food comes from the irrigated lands and the rest 50 percent comes from the rain fed lands. So, 35 percent of India's arable land is irrigated rest is the 65 percent is rain fed. These are rough numbers so what it tells you is that the lands which are irrigated are highly productive or relatively more productive as compared to those which are rain fed which is kind of obvious, but I just wanted you to so now it looks like we are in a trap. So, you cannot you cannot build more dams, you cannot drill more bore wells, you cannot right away reduce the water that is used. So, what went wrong? I mean why did we get into this trap? Isn't India supposed to be the land of great rivers and lakes? Sujalam, Suphalam, Malayajashi, Talam. So, we are in the India that we imagine has actually such beautiful rivers Ganga, Chaiyamune, Chaiyva, Godavari, Saraswati, so many rivers that we have. So, what has happened to them? Well before we see what happened to those rivers and water bodies, we also have to see that I give you the numbers for the water availability per capita. So, part of the reducing water availability is due to the increase in population. So, if you look at 1950, it was something like 359 million and 2014 it is more than 1200 million. So, the naturally that would have an impact on the per capita availability. Moreover, water pollution in India is very very serious, some 70 percent of India's surface water resources are polluted by sewage and toxic chemicals. Very few cities have full sewage treatment facilities. There are there is somewhat of a larger number of cities which have partial sewage treatment facilities and number of cities in India are dumping untreated sewage into either surface water bodies or some of it is just seeping into the ground. The Ganga, Yamuna, you know how polluted they are and the present government has taken that as a very very important agenda to clean up the Ganga which is a matter of our nation's pride. Sewage treatment in India which is the point that I raised in the previous slide is only the installed sewage treatment facilities are only sufficient for about 31 percent of the sewage that we generate in the larger towns and cities in India. So, it means that 68 plus percent of sewage is simply discharged untreated. So, if more than two-thirds of our sewage is not even treated I mean there is there are no facilities to even treated that is something very very disturbing. So, with such a large number of number that we saw of the sewage that does not get treated then you know it is no wonder that the water bodies are polluted. So, somehow or the other we must purify the water. So, if it is polluted anyway then we simply purify the water before we drink it, but there is a problem here providing purified drinking water is not easy because water which has so many pollutants it has untreated sewage probably some industrial waste then some hardness in different areas you have problems like arsenic, fluoride, contamination, pesticides and things like that. So, when you have so many different possible pollutants in water then treating it becomes very difficult. There are there are some cheaper methods of purifying water and there are some more expensive methods. The cheaper methods are not effective for all pollutants and the more expensive methods are expensive. So, they cannot be applied everywhere. So, just for your to satisfy your curiosity here are the drinking water specifications this is an Indian standard 100500 which you can go through and look at look at what the standard of drinking water is for India and then there are the WHO guidelines for drinking water as well as bathing water. So, maybe maybe you could you could have some discussions or assignments based on based on this and I am going to give you an example of something something like that for your class. See rather than simply having students read through it and maybe memorize it or you know face a quiz or something like that maybe involving them in some creative activity makes it worthwhile for everybody. So, there are some people who think some people particularly nanotechnologists who think that like me I am also a nanotechnologist. So, who think that maybe we can develop some nanotech filters water cheap water filters that are highly effective and still cheap. Yeah that is a good idea and we should do that we need to use water filters because we have to survive the water is not if the water is not clean you still have to drink it. So, we need some solution, but that is I mean stopping at that is probably not the best thing because it completely misses the big picture and the big picture is why are we allowing so much of pollutants to get into the water in the first place. So, we need to address the larger problem as well as providing an immediate solution. There are some people who who even say that look this polluted water and all that is not such a big problem there is no need to panic Indians have a very tough immune system and our bodies can surely handle a little bit of water contamination. After living several years in the US when I came back I actually I had a similar kind of mentality, but after I came back to India I could not drink water anywhere outside and even today you know this problem bothers me a lot. So, again this approach is not good because the health effects of water pollution are staggering. The WHO has published several reports and you see that water sanitation and hygiene all that put together leads to some 0.4 million deaths per year. And in India roughly 1.5 million children under the age of 5 died due to water related diseases. So, you have extremely high social costs and as well as economic costs because leads to something like 200 million percent days of work lost for the country. So, which amounts to maybe a loss of something like 366 billion a year. So, I have some references over here and you could dig out more references, but I think it is this much is adequate to convince anybody of how serious the problem is. If we say that you know the the socio economic costs of water pollution are so high you might wonder you know where all those infectious agents those pathogens how they get into the water. The first one thing we already know we saw that untreated sewage is entering our water body. So, that is one very important reason why our water gets polluted, but there is another important problem which is open defecation. India is probably the world capital for open defecation. This reference says that you have improved sanitation in only 54 percent of urban places and only 21 percent of rural places. Now you may say that so basically you do not have adequate sanitation facilities for some 839 million people. Now you may say that India is a poor country and we cannot afford sanitation for everyone, but it turns out that Bangladesh and Brazil they are they are also poor. If we want to consider India as a poor country, I do not think that is fair to say, but if you want to take that excuse then Bangladesh and Brazil they have open defecation only 7 percent and China only 4 percent. So, I do not think really there is any justification for such a huge number in India. Now if you say that lack of sanitation is a problem then the solution is very easy. Just provide modern sanitation to all not so fast providing sanitation requires more water. So, it increases the water demand but the supply is already short of the demand. I mean if you really try to think of how much water we are simply flushing down and in most cities in India there is only one city water supply. So, that is the same water that you use for drinking is the same quality of water that you use for washing and bathing and everything and it is the same water that you simply flush down the toilet. So, when so many people do not have adequate water to even drink how fair is it that we people who live in urban places simply flush it down. Moreover, if you if everybody is provided improved sanitation then the problem is that we have to treat all that water. So, but the treatment capacity as we saw is only about 30 percent. So, if the total amount of wastewater to be treated increases very drastically then you know we are in a much bigger problem than we already are. So, this is about the conventional sewage treatment. If we do not have installed capacity let us increase the installed capacity of sewage treatment but it takes money to do that and it takes energy to do to run the effluent treatment plants. Our conventional effluent treatment plants consume quite a bit of energy and a large portion of that energy is actually in is consumed in aeration. So, if we are if you are talking about providing sanitation to everybody and which would lead to a very large quantity of sewage generated and if all that sewage is to be treated using the conventional technologies then we are putting a large demand on energy. So, and our country already has power outages and the grid is so unreliable and many places they do not even have electricity to light a simple lamp. So, in such a power hungry country how far is it to divert whatever precious little power we have to treating sewage. There are there are many other related complicating factors. So, before we before we even move towards solutions I want you to just try to wrap your mind around these related problems which are so many which which are complicating this situation. We just looked at the connection between water supply irrigation and agriculture where I said that 87 percent of the water goes for agriculture irrigation which supplies 50 percent of our food. Now, the reason for low agricultural productivity is not only the lack of irrigation there are other issues also. One one such issue is land degradation in India something like 32 percent of the land is degraded and out of that 24 percent of land is degraded due to desertification which essentially can be in a simplistic manner can be understood to be loss of soil organic carbon and loss of soil moisture. Now, for such soils organic carbon inputs can actually in the form of let us say compost or something like that would I would actually be very beneficial. So, I just want I have put I have marked it in green because I want you to hold on to this thought and we will see where it where we can use this fact very constructively. Now, there are again there are many related problems which you must have faced there are many of our cities are they are unplanned they are just growing in all directions there is hardly any planning they are overcrowded there is bad governance. The present government is taking a lot of effort to improve governance and I think that is exactly what the country needs. So, these problems complicate any possible solutions. So, even if you have a good solution these problems are such that they would not allow the solutions to work. So, now this is the point where we are going to take a small break and to discuss one activity. So, I have what I have covered so far I want you to just mentally again make a note of it or maybe it is a good idea to actually use your notepad most people you know sometimes forget that I would like to remind you to just simply make a few notes of what we did so far what we have seen so far because all those things are we will have to tie them together in a short while. So, what we did so far is we saw that the water available we initially we saw the water cycle and how it actually is kind of the basic support structure of life and as well as of humanity and what we are doing to that natural water cycle how we have polluted the water bodies in in places where you have cities and things like that and how we are over extracting groundwater how we have dammed the rivers disrupted ecosystems and things like that. And we have got ourselves into such a situation where coming out of that or to or improving our lot is becoming very difficult. So, I gave you various options of you know why not develop a water filter why not do this why not do that and it seems that we are we are kind of trapped. So, let us pause at this point where we have only seen the problem and now let us move to the solutions part but before we do that this is an interesting activity that I think is very easy to do in most places in around most colleges and universities because I am pretty sure that there must be a water body somewhere nearby maybe a river maybe a lake maybe anything else which is polluted this can ideally it can be integrated with a field trip. So, you take students on a field trip maybe you ask them to to prepare you can give them some reading material before that there are there are like newspaper clippings there are technical reports there are some papers published. So, you can maybe the teacher also needs to do some homework beforehand identify the water body give supporting material to your students. Take them out on a trip have them make some observations now if you have a civil engineering program in your college or institute where you can do some water quality testing that will be great or if you have access to some some some lab which will share the information with you and that is also a good idea. So, I mean it is it is up to your up to the facilities that are available to you and your interest and motivation but this can be a very good assignment where you take them on the field you show them various things you can even tie up with a non-governmental organization or you can take them to a governmental office representative from there if they are willing to work together with you and try to estimate or at least get a field maybe you can design a form where you have let us say the hardness or the coliform organisms or a few parameters which are easy to measure in your lab or for which you have the data and you can have the students fill out those forms either based on the material provided by you or based on some observations that they make and things like that and then have them compare it with again the Indian standard over here is mentioned the WHO guidelines are there. So, maybe they can tabulate their observations or their whatever their the local data with these standards and try to maybe write maybe a small essay on what are the main water quality issues of that water body near your institute and if there are any other issues like eutrophication or drying out during the summer or flooding during the monsoon let them document that also. So, this can become a very interesting assignment and activity. So, rather than rather than having them learn this topic you know in the conventional mode where you initially draw the water cycle on the board and have them copy it down and then have go through some definitions and things like that makes it extremely boring. They can do the same thing centered around an activity. So, let us say you promise them to promise to take them on a field visit, but in order to come for that field visit that they need to understand some basics and they need to demonstrate some some confidence some level of confidence in their ability to gather data or things like that and then they will learn you know because now it is a good motivation for them then it does not become a burden for anyone and I am sure everybody will enjoy that. Okay, I have what I would suggest is I know you do not have much information right now and most of you probably do not have good information about the water quality at least you probably do not have quantitative data on the water quality of a nearby water source, but why do not we take about 5 minutes for people to just write down maybe just identify a particular lake or river or whatever whichever water body is close to your institute or your maybe your native place if you are if you are living far away. Just make a note of it and just to the eye what you feel is the biggest concern related to that water body why do not we take a few minutes I will go through various centers and see what they have to say about it. So, please take this time to make a note of the water quality of an important water body around your institute or around your home. Tecno India West Bengal can you make some comments about a nearby water source which you which you are aware of. Yes, I am from West Bengal as you can see from the name of my college and the river Ganges flows just beside my flat. Oh excellent. So, I have seen people polluting the massive river right from the morning. Okay. So, it is like if you go to bed in the ghats the water at the level where people can just go down and take a dip is extremely dirty. Yes. And every possible human activity is alongside I do not see the government taking any concrete steps as of now. There is a lot of writing in the papers etc and I guess Benares is first on the list. So, maybe someday I see it is it is sad that there is not much happening over there but that is an interesting observation. Thank you for sharing it with us. So, can you can you imagine maybe a class activity which you could take up with your students related to since you are right right by the Ganga maybe you could think of some way of introducing that to your students and involving them. Yes sir it is possible because my institute is perhaps around say could be 20 kilometers away but it is nevertheless it is not impossible to take them along for a field trip to such sort of a location. It is not impossible. You may have heard of Dakshineshwar in West Bengal. Sorry could you Very nice. Yes of course. My house is say about 3 kilometers alongside the banks of the Ganges on the opposite side. Wonderful. On Hoogli. Wonderful. Thank you so much for sharing. Thakur College, Kandivili. Hi. Wow. So much energy in this class. Hello. What did you all have for us? Yes. Give them a big hand. Awesome. Good evening. Thank you. Good evening. We have Daisan Nadi near our college near our area and it is highly polluted after when it comes out from the core forest that is Sanjay Gandhi National Park. And we the people as we as professor in earlier session he said that we are the collectors and we have done that. We put lot of dirt into that and which is not treated. There is no management for the sewage that is the solid waste management is not been done properly. So there should be some or other action to be done in this area. As well as Mithi everybody knows that Pavei which runs from Pavei and comes to Bandra Creek. It is also highly polluted because of the industrial activities in between. That is the two areas which I could share to you. Thank you so much. It is actually an interesting point. I was talking about the lack of water treatment. So one thing that actually disturbed me a lot when I actually saw those numbers that when we use the toilet and we flush the toilet, you know it is two thirds of the sewage since it is not treated. It is almost certain that somebody is going to die because you use the toilet. So because we are not treating it and you saw the so many millions of deaths due to water and of children under five. It is so pathetic. It is very disturbing. So I have still not got to terms with that. There should be some action from the people side also. Yes, certainly. Can you think of something you can do with your students? Maybe along with some organizations that are working in the area of water? In the college itself the actual service scheme that is NSS also works for certain activities but they are insufficient. I do think so because at a certain level the students can go and clean it up but later on it is the stakeholders that is the public that has to take care of it. Every time students can go and do the cleaning job. No, I understand. It is more about sensitizing and educating them because today your students may appear to be helpless students but they are decision makers of tomorrow. So you do not know who they are going to be. I mean I know a bunch of my students they have taken the civil services exam. So some of them are within a short period of time they are going to be very powerful people. Yes, the students can be a key role to play. Those who are coming into the public domain and they can use solution for us but they should have that decision power and policy making powers also. Sure. Thank you so much for sharing. K S Rangasamy College. Hello, Dr. Ramesh from K S Rangasamy College of Technology. We are using RO water continuously long time sir. Is it good for health? Sir, we are using RO water long time. Is it good for our health sir? I do not I do not see any problem I mean at least I am not aware of any problem related to RO water. I mean if the RO is working fine it should be fine. Sir, good afternoon sir. Sir, you have explained the sewage base water treatment is it? Can you explain any recent technology of treating this sewage water which will be useful for us for the future and which will be easier and less economic which will be helpful for our area. Can you explain any recent technology? Yes, we are going to see some such technologies and obviously they are not developed by me but I will definitely share some very nice ideas with you and maybe if you come across better ideas please share them with us so that everybody can benefit. Okay, thank you sir. In the first part we saw the water cycle after that we saw the various dimensions of the water problem that India is facing in terms of the depleting resources, pollutions, dams and scarcity and all those things. Now it is we are at the point where we are going to discuss solutions and in the solutions I am going to divide the solutions into two broad areas. One is the demand side and the second is the supply side. So in the demand side what we will be concerned with is how to make sure that adequate water is made available and in the supply side how do we ensure that we are using that water well whatever water is made available how do we use it well. So the supply side is how to use the water efficiently and the demand side is how do we make sure that adequate water is available. Now in the in that I want to emphasize the importance of rainwater harvesting. If you just look at the rainfall map of India maybe you will observe something that is quite obvious that something like 70 to 80 percent of India gets at least 40 centimeters of rain. So if it gets that much rain then maybe rainwater harvesting and watershed management might be workable solutions for most of India. I made this quick calculation which you could repeat for yourself also. Let us say that per capita per day the drinking water need is something like 5 liters. If you if you prefer a slightly larger number like 7 liters you feel free to do that assuming 5 liters per capita per day of drinking water. So it is the water that you use for drinking and the water that you use for cooking water that is ingested. So if you assume 5 liters per person per day it works out to something like 18 25 liters per person per year. Now if we if we look at the rainfall at 40 centimeter average annual rainfall let us say you you live in a place where you do not get too much rainfall you get only 40 centimeters of rain per year and it turns out that maybe 70 or 80 percent of India gets that much of rain. So you are probably the majority which get at least 40 centimeter. So how much of rooftop area would you require to satisfy that need of drinking water and it turns out that roughly 5 meter square of rooftop area would be sufficient assuming no losses. So if you want to assume some losses then then you know you can increase the area slightly. So if you have had 5 meter square per capita rooftop area with 40 centimeter rain you would collect 2000 liters and that 2000 liters would last you for the entire year for one person. So it is actually very interesting in that the rain even in places where they do not get much rainfall is actually adequate to supply you with drinking water that may not be the case for all the other water but at least for drinking water there is not a major problem. So then what happens is that collecting the rain water is not a big problem storing it is a problem. So storing it can become a little expensive for instance I think most people maybe people living in small apartments probably have these plastic overhead water tanks. The common size that they have is 1000 liters. So you would need two such tanks for every family member. So if you are a family of 5 then you would need 10 of them. So that is quite a large quantity of water to store. Now of course not all that water needs to be stored because during the rainy you actually need to store only for the dry spell which maybe like 8 months or so in India because we get monsoon in 3 or 4 months. So it is only in the dry months that you need to store. So you do not actually need to store 2000 liters but you need to store little less than that maybe 1500. But nevertheless it is a large quantity of water that has to be stored. But storage costs you know the plastic storage tanks are probably among the more expensive methods of storing water but there are cheaper ways and it turns out that these cheap ways of storing water have been around for hundreds of years. I am from Maharashtra and many other people too are here from Maharashtra and they know that in Maharashtra we have these hill forts of Shivaji. In Rajasthan also I think there are similar forts. So on top of these forts and they are they may be as high as maybe 3000 plus feet above sea level and they are the Sayyadris in these parts they are flat on the top. So on top of these hills you have hundreds of water tanks and as well as wells that have been developed. So like whole armies could actually live on those forts and survive armies including soldiers and horses and everything and there have been incidents when the the fort had been surrounded these forts had been surrounded by the enemy for months together. But because there was so much of water on there and mind you that that in Maharashtra you don't have rains during the rest of the year it's only during the monsoon that you get rains. I am presently living in Coimbatore and there are two monsoons there's a return monsoon also. So that is not the case in Maharashtra it's a fairly dry region but the Sayyadris do get a lot of rainfall. So all that rainfall that falls in the monsoon there are there are these water tanks that they cut cut into the rock it's a very impervious rock and they cut these water tanks into it and there's a lot of water that they store. So this has been going on for for hundreds of years. In South India there are these temple tanks. So every temple has got these ponds or tanks that you know basically all the water from the paved surfaces drains into those ponds and a large amount of water is collected. I think that's very common in many temples. So you have some sources or some reservoirs of water and because particularly these temple tanks and ponds because they are sacred they are preserved and they are at least in the previous centuries it was kept very clean. Things have changed and they have fallen into disuse and people have polluted them nowadays but if similar systems can be developed in those days if people could think of so many things and they could as in an extreme case I give you the example of how entire armies can sit on top of a mountain and still have no water shortage. I mean can we not do better than that can we not store water today. Through community self-help the cost of storing water in such tanks can be drastically reduced. In the Sayyadris there are so many umpteen examples of storing water in places other than Maharashtra also there are many many examples. So this is again something that you could share with your students. I suggest that people do some homework on this and try to identify local water harvesting structures that are there in your area and either integrate it with a field trip or maybe you take a trip down there and maybe make a video out of that and share it with your students. I am sure that they will they will appreciate it much more than if you nearly tell them. So the benefit of collecting the rainwater is actually that instead of taking water from either a groundwater source or a surface water source which has lots of pollutants including the sewage or industrial waste or all these nasty pollutants instead of taking water that is heavily polluted and then finding out a high tech way to to clean that up at a low cost which is almost like an impossible situation. Instead of doing that you already take water that is clean. So the rainwater is quite clean and with very very little treatment it can be made fit for drinking. So this kind of circumvents that problem and the loss of life can be drastically reduced that way. So here is another activity that that can be done very easily in your class or again I request the faculty members to first try out these simple calculations. You can find out the actual average annual rainfall of your city and the total rooftop area of that is available to your family. So in case you live in a three-story department you have the total terrace area and let us say there are three stories so you have to divide it by three. So that is the actual amount of rooftop area that is available to you and you can estimate how much water rainwater you can harvest out of your rooftop based on the average annual rainfall. Is everybody confident about being able to do this simple calculation? Okay, I am going to check on people. I am going to ask people how to calculate that. You could probably assume let us say 20% losses for evaporation and first wash. There is something called as rejecting the first wash. So the surfaces on which you are collecting the water could be dirty and so when the rain falls it is a good idea to first reject some of it and in polluted places you know as the rain falls to the atmosphere it could pick up some contaminants. So it is a good idea to reject a small part of the water that falls first on your surfaces and then collect the rest of it. Now this is a kind of an interesting idea. How do you design if you are designing your own rooftop rainwater harvesting system? See you have these hardware stores and you have these various pipes of standard sizes and things like that and you have some storage tanks, all the nice stuff. Do you think you can design your own rooftop rainwater harvesting system and within that how would you design a first wash rejection system? If my question is not clear how do you design an automatic system by which the first wash, let us say the first X liters of water is rejected, it does not go to the storage tank. How can you design a system like that? I have thrown this question to my students and they have come up with really innovative solutions to do that. There are solutions out there but it is it is more important for some good ideas to come from the students. So I am putting this question to you and there is one maybe one suggestion I can give in that if you can design a first wash rejection system without any moving parts, all the better. There are some which have let us say they have a tilting bucket kind of thing where there is a lever and there is a suspended bucket and the water first wash water goes and falls into a bucket and when it fills up the bucket due to the weight the lever kind of tilts in a direction and then the water goes through a different channel. So that is that is one thing that you could do but how about something without any moving parts? Do you think you can design something like that? I will just I will just go to the viewer and ask a few colleges if they are able to do that. Ohm Institute, how you could design such a system? Hello architect Nagendra Narayan here. Yes sir. In our area basically the water crisis is the main problem. Yes. So there are a number of factors beside this behind this sir. First is that water table of this particular area is very low due to which we can't got the water through the different types of means and another another basic thing is that this particular destick is adjacent to the district of Churu Rajasthan. So these are the factors that is working on the particular water crisis. Another issue the TDS of the water is very high that is not able or for the drinking as a drinking water. Although government and number of NGO working in this particular field and try to solve the problem because water is essential for the life. So what is the average annual rainfall of your place? About sir approaching to 35. Oh I see. This area is very hot. This area is very hot in the summer season and very cold in the winter season due to the adjacent to the Churu district. I see. So Rajasthan has got a number of very innovative water harvesting structures. Do you normally introduce your students to those techniques and do you take them on out on the field for visits? But the the the district Churu is actually water crisis is the main issue in that particular area and in that particular area sir basically RWH technology they adopted basically dig out the a well and collecting the water and purified water by by mixing the red oxide whatever the chemicals and that is that is for the purifying of the particular water. I personally visited number of well such type of reservoir made by the ruler in particular ruler area exclusively in the Rajgartha shield. Maybe if you have visited if you take pictures or maybe take some small video clips of what you observe over there and share it with your class I mean it is I know it's not the same thing but it's probably the closest you can get to actually taking your students out on the field. You know sometimes I know it's a bit difficult but I think it makes it much more interesting to to actually see things that are out there rather than nearly learn from textbooks. Yeah definitely I will I will will share in the future classes I will try to provide the details information sir. Thank you so much. Sir I have a question. Yes. Sir there is so much pollution in our country that we are putting so much waste in the different rivers mainly in the Ganga why there is not any obstruction on the different different industries why they are putting so much waste that we have to apply so much cost we have to need to clear the Ganga. I don't think I have an answer for that but I think the best answer I have is that we love creating problems we simply love creating problems so that we can we can be busy solving them. I have another question sir just now my colleague was telling to me that in Kudugama in Haryana the different societies they are employing the water harvesting system in the society or the buildings. I want to know that there is a success of these rainwater harvesting that the groundwater level has improved from the past years. Is that a question or are you telling me? Yes I want I know I am asking the question that is there is a success of these rainwater harvesting systems we are using them since last many of the years the groundwater level has been upgraded or not. I good question I mean I hope it has increased it is something on the right track so I really hope that in Kudugama the levels have increased after a large-scale adoption of rainwater harvesting but I I am not able to comment on whether it has actually increased or not. Okay sir. Thank you so much. Thank you sir. SDM Institute so does anyone have a have an answer to my question. Hello. Yeah that rainwater harvesting how would you reject the first wash do you have an answer to that? Hello. Some easy nifty design. Is it in your view? The first wash there are I think probably two three methods that can be followed to for to reduce the that first wash loss like one is the charcoal which can be I mean the water which is used for wash it can be stored and the charcoal method is can be used for settling down the whatever the waste and also we can wait for some keeping it into a I mean storing that into a tank later on we can get it to separate the top layer water and like that some part of the waste can. Now my question was when it starts to rain let's say it just starts raining right now okay and I have to wait for five minutes and then I have to manually connect it to the the storage tank can I have it automated without any moving parts? Yeah filter using probably solution. Okay yeah fine thank you I was thinking more on the lines of rejecting the the first wash and then collecting the rest so I was looking for some some way of doing that there is there is a very easy way there are many ways J. J. Magdum college. Good afternoon sir. Good afternoon sir our place I think poor which is surrounded by two famous rivers one is the Krishna Ganga Krishna and second is Panjagang. Sir it is a continuous repeatedly problem we discuss since our independence that rivers are surrounded by textile industries sugar industries the drainage of all cities are getting mixed up with the river so I would rather say it requires the more political will and the low cost of processing plan to solve this particular problem. I want your opinion on this particular problem. It requires political will to solve this particular problem and low processing operating plan which laid the drainage of cities to mix up with whom unfortunately to the river. Yes I missed some parts of what you were saying but I think what you are saying is that there is a need for greater political will on this issue absolutely I totally agree with that there is a need for political will but I think there is also an equal need for the public to be sensitive about this we oftentimes don't care I mean we have seen so many polluted rivers polluted lakes and all that and we pass by through our vehicles and buses and trains and we see all these water bodies polluted covered with water hyacinth and whatnot and we have become so used to it that we don't find that objectionable if we actually stop accepting it the way it is and demand for change only then the political will will follow that is what I feel. Okay thank you. IES college Bhopal. Hello there Bhopal. Good afternoon sir. Good afternoon. Actually I was first time to talk to you and I would like to thank you for this or managing such work and the first was very interesting and this session was also very interesting. Actually last month I have traveled to Patna, Bihar where chance to visit river Ganga where I saw the very many industrial waste where getting dumped into into the river Ganga and very you can say the pollution water pollution is very in very critical situation was there. So is there any any kind of restrictions so that kind of a dump can be you know can be restricted. See we have regulatory mechanisms it is not that our country does not have pollution control boards we do have them but this is the this is the scene in spite of having the pollution control boards. So it means that the there is something going wrong there are multiple things going wrong at multiple points. So the the public also has to take cognizance of that the industries are not following the norms the people who are supposed to enforce the norms they are probably not being that effective maybe some of them are are very very particular about enforcing some of them are probably not. So there are there are gaps everywhere. Is there any kind of such type of programs organized for the industrial person who is actually responsible for that? Workshops organized for polluting industries ok I am I am not the best person to answer that maybe there are I am sure there must be but I I do not have direct information about that. So I suggest that I have throughout this session I have given several ideas of the of activities and assignments that you can give to your students. The idea is not to burden your students but it is to involve them in a positive manner to involve them in you know taking the responsibility for whatever whatever is happening we all need water and we all are facing the socio economic costs of polluted water. So it is very important for each one to even at a in a personal capacity to take some some small steps and these are these are ways by which if not even if there is no no direct impact at least it will educate your your students very well and and the the motivation problem that we discussed towards the beginning of the course that that many students do not know why they are studying this course. I mean when you are talking about these topics I do not think anybody in their right mind can ask how this is relevant to me. I mean is is drinking water not relevant to to us it is obviously very relevant and is the polluted water or the polluted water body near your home is that not relevant to you obviously it is. So I think throughout the course this there the effort should be on part of the teacher to change this perspective of students where they feel that this course is not required for them or is not useful for them they should leave the class thinking that thank god I I took this class I got to learn so many new things. I will just wind up with this slide saying that you know the while I am while I am recommending rainwater harvesting all the all the rainwater it might not be possible and economical to store all that water but what cannot be stored at least it can be recharged to the aquifer there are ways in which that can be done. There are government agencies if you check around your area there are government agencies which will disseminate all the necessary information they will there are also outfits that will help you install a rainwater harvesting system in your home and in some places it is even compulsory. So there is adequate information it is only that we need to take interest in that in in situations where rainwater harvesting by itself is not sufficient or not possible that then the other high tech options which are probably a little more expensive can be considered. So it is not that we are banning all the others but it turns out that we have high levels of poverty we have major pollution and we have adequate rainwater. So it is kind of a no-brainer to use already the already pure rainwater rather than pull you rather than trying to purify already polluted water. So we will reconvene after the break exactly at 3.30