 course on remote sensing and GIS for rural development. This is week 2 lecture 3. In the past weeks and lectures we have been constantly focusing on rural development and different segments of rural development. Then we also looked at what are the current issues in managing the rural development scenario. So, let us move on to today's lecture which is lecture 3. In the remote sensing sphere we discussed what is remote sensing basically collecting data without touching an object. There could be multiple reasons why you want to avoid touching an object while collecting data. Maybe you did not want to disturb the sample or is too expensive to monitor in close contact and scale and temporal issues. All these are definitely addressed using remote sensing data. So, this is the core of why we are using remote sensing for rural development. Across the world cities, suburbans and even very urban areas which is in between rural and urban areas we do see a lot of data collection for development scenarios. Let us say for building roads, managing water, infrastructure, food, connectivity etc. This is however very less in comparison at rural agencies and rural areas and that is the core reason this course has come into existence of using remote sensing and GIS. So, the introduction to remote sensing was given in the previous lectures and some NPTEL resources were highlighted. You would have noticed that if you had seen the NPTEL courses in the last two lectures the introduction to remote sensing is itself a course. I would like you to take such courses to update the knowledge or go through the rural development course which is the current NPTEL course and then specifically take remote sensing day courses that you need. This will help you either way in selecting the remote sensing data for your rural development scenario. For example, it could be infrastructure, it could be water aspects, it could be crop, agriculture, health. So, we will discuss this in some examples in today's lecture. So, what we will cover today is how is remote sensing used as a tool for rural development, focusing on water resources, crop yield and rural infrastructures. We will give you some examples in this course, in this today's lecture and while we build the course throughout the 12 weeks, we will also give you some live hands-on experience of using such tools for rural development. So, there is rural development, there is remote sensing and GIS. We are clubbing all three together where it sometimes or most of the times is segregated separately. You have GIS separately, you have remote sensing separately, you have rural development separately. So, this course is forming a bridge between these sectors and within the rural development, there are multiple schemes that you can look at, multiple themes that you can look at. We are going to focus on only a handful, specifically water, crop, rural infrastructure. Other aspects would definitely pull a longer time, maybe it warrants for another course, but for now in this introductory based course, we will only cover these parts as also given in the syllabus. So, let us look at the first example where we want to use remote sensing. Right now, what you see is an example of water resources, maps, data, visualization, etc. So, in this slide, I will be explaining in detail where and how you would use remote sensing as a tool for rural development, focusing on water resources. This is much needed. However, I would like you to first think while this lecture, while this slide is discussed, I would like to think with the questions I am going to ask. It is kind of an interactive lecture. However, since you are not in person, I will try my best to make it interactive. I will pause in between to make you think and why and how this could be useful. So, the first example is mapping of rivers. You could see that the India map has most of the rivers mapped. I will put my pointer so that you can also see. Yes. So, you could see the Ganges, the major, major rivers, Kaveri, etc., running across India, the Brahmaputra. But what is more interesting is to understand at a rural scale, which is district, village, those kind of boundaries, how are these maps correct? This is not asking questions about a legitimate or are we trying to correct a existing map? No, that is not the aim of this course. If you understand how this data was created and developed, it would have induced or it could have used a field measurement and mapping and then bringing it on a photographic map. So, this image I am showing. However, that takes long time, a lot of cost and manpower. So, people had to be trained. They had to go to the village or areas, map the rivers on paper and then check it, come back, map it back into a cartographic map. And then it has been converted to GIS layers now. But we need to understand when was it done. It does not get updated every year. So, that is the first bullet I am trying to say. Why is it important to update? Someone might ask in a rural setting, for example. As I said, India is developing at a high pace. Development includes infrastructures, let us say roads, tunnels, bridges, etc. When you build such structures, definitely the hydrology gets altered. The water movement, when I say hydrology, it is the water movement. It gets altered. And with that alteration, some of the rivers are having low flow or no flow. So, for example, let us take Kaveri river in the south. In some pockets where I used to go and have a bath in my childhood rural days, I could not see it during my college days. The water was not flowing. It was a perennial river which means it flows every day, every part of the year. However, when I went to college, within span of 10-15 years, the water was lost. Only during seasonal times it came, which is the monsoons. So, what has happened? So, in the 15 years, definitely the cities have changed. The villages have changed. There has been more groundwater pumping which definitely influences the river and there has been considerable uptake of water for agriculture. I will show you in the crop maps. So, with this, we are limiting the water that flows in the river channels and then which gets divided into downstream areas and downstream farmers, which needs to be updated. So, this map is not to find reasons but first to update. So, for example, let us take this river. If people are extracting more water on the upstream, then downstream farmers downstream villages will not get water. So, that is how we need to document it. Yes, the river flows. As per the map, the river is flowing from north to south however, over the years, this region is being expanded more in terms of water demand and so, when water is being pumped and pulled, downstream people, downstream farmers, rural communities do not get water or in other words, the river does not flow. So, is it right to have this river still shown as a flowing river is the question or should this map be color coded in terms of blue for perennial, annually flowing rivers in blue and then seasonal in different colors so that we can understand how and where to supply water for rural people. Again, supply of water for rural people is very, very important for development. You need water to cook, clean, wash, drink to participate in development activities. So, these are the basic amenities a human being would need in order to develop. So, we need to give that in terms of this water maps. So, a mapping of rivers has to be updated. Number one, one was it needs to be updated because of some stresses as I showed you as I told you the city has developed, people started to take more water so we need to map. The next is changing river morphologies. What does that mean specifically for the Ganges? So, the Ganges is a paleo channel having river. The Ganges has paleo channels which means multiple channels run underneath the riverbed. It is a very, very old river. Suddenly Ganges will wake up one day and she will flow in a particular channel. So, what you see here at a larger scale may be okay but when you zoom down you will see multiple lines going, not all lines will get water and that is only controlled by Ganges herself. No engineering, no human anthropogenic activity will has been used to channelize the water. It could be reason why she flows in one direction but there is no stopping and turning the water as you see down in the south. It is too powerful in this region of the Ganges water. It cannot be stopped and turned around as like even the Cauchy barrage on the top. It only is successful up to a particular extent. So, what happens is suddenly the Ganges will wake up one day after a big flood and then take another route. If she takes another route all the land all the houses along those river channels will be submerged and the following development scenarios like livestock rearing, farm produce, agriculture, milk produce everything is stopped. So, if you go to Bihar you would see these kind of people moving from one bank to the other bank because the river suddenly changes direction. So, isn't it important to map these to update these data? Yes. So, that is where changing river morphologies have to be mapped. Also as I was saying in the previous example, if you have rivers being disturbed by construction like a big road coming along the banks stills being put bridges built, it will alter the river morphology. How the river flows? It will alter because you are engineering the water to go in a particular direction. It will at low flows okay, but high flows it will change. These have to be mapped. So, constant updation needs constant in the older days as per the older days, you need to go constantly to the field, map the data, bring it on to the map, put it on GIS and then the portal. This takes time. So, for that remote sensing gives you a better, faster and more importantly cost effective method. Changing discharge factors, I have pressed upon it in the previous example, which means the quantity, the volume of water that comes in a river will be changing and that has to be mapped in different colors or thickness of lines. If you can see here, Ganges lines are almost the same as your Kaveri, Narmada, etc. thickness. Does that make sense? Because you know, Ganges can be very huge whereas Kaveri is maybe one-tenth of the size in some segments. So, it is very important to catch this thickness and with the thickness how much water passes through the cross-section and that gives you the discharge. And this discharge is also not the same as 10 years ago mapped, 20 years ago mapped. Why? Because the demand is changing. The alteration of the land, the climate change, sudden floods, sudden outbursts of clouds, we call them here. So, we have seen in Uttarakhand a lot of glacial outbursts, sudden melting all would bring excess volumes of water and the discharge is changing. So, these have to be mapped at a very, very high scale. So, at an India scale, for administrative purposes, maybe it is good but for development and managing water, you need to zoom down to smaller locations and reports and see caps because you can do it every 10 days whereas this took maybe 5 years, 10 years to make a map. Remember the census data takes one complete 10-year interval for us to map the population. Another thing for water is this is reverse we have discussed. We also need to look at surface storage structures and natural and man-made structures. Could be dams, ponds, lakes, all man-made different structures or natural ponds, natural lakes, etc. This is important to map because rural water supply and irrigation is being fed from these sources. Let us take an example. In those days, a lot of religious places had tanks and those tanks, in the villages I am saying, the people would go in the morning, take water and come and during the flood or rain event, water will come from all the streets and go into the tanks and the tank was kind of recharging and also storing the water. So, people used to use it very carefully. One of the reasons because it is religious, because people would say that okay, it is religious purpose also so they would not pollute the water. You would not see much irrigation from a religious tank but it is mostly for domestic water and cows, cattle, livestock, etc. So, this was very, very important for rural water supply. However, when the villages started to expand, you would see that these small tanks are all not having enough water because the roads were disconnected, the drainage to the tanks and ponds were stopped, encroached and so there was not water much coming in. In fact, a lot of religions in the south are called, they have a lot of tanks and lakes. For example, Bangalore or Bengaluru was known to be a city of lakes. However, if you go now and see, the number of lakes have diminished considerably. They have been converted to urban settings, drained and then converted to plots. It still has the lakes name. So, if you go there, you will see that the name of that land, the area is still the lake name. But when you go search for the lake, it won't be there. It will be drained and all the drainage which is coming into the lake is disconnected. So, these are the outskirts of Bangalore. So, those are the rural areas I am saying. So, all these have been disconnected and changed. So, it is important to map it, to understand and help the rural development economy. And that is what I am talking about. Mapping of ponds and lakes are also important. So, if you could see here, this is the example of the Noyal River Basin that we did in Coimbatore, in Tamil Nadu. And you could see that we have mapped all these tanks. When you map the tanks, you also look at the water level and water quality, which is very, very important. If you have water there, it should be portable for drinking and usable for irrigation, if you call it as a rural tank for irrigation or for domestic use. What is the point of having a water structure, water inside and quality is not good. The quality can be compromised by multiple reasons. We would not get into that. But it has to be mapped. So, you could understand that this map was one of the first to put all the tanks in the basin, also update the size of these tanks. The size on the Gazette, on the administrative portal might be big. But now because of encroachments and the land change, it could have been made small. This happens everywhere, sometimes legally, sometimes it has to be challenged. So, this is where Noyal is, as I said, South India, Tamil Nadu and the Noyal gets to be. We also need to see the mapping of LULC, which is land use, land cover. I have said about converting a lake into an urban setting. So, that is the land conversion. How does the land conversion impact rivers and flows? So, these points are important for rural development. However, since data is not available at regular intervals, we will have to use remote sensing to augment the data. That is the argument that we like to keep here. Let us see why are these important for rural development in the next slide and how this can help in the management. As I mentioned, if you map a water body, you can look at the water quantity, how much volume, as I said, the thickness of the river or the thickness, the boundary of the lake pond, etc. You can see here, all these are encroachments or this is a lake, but now there is no water. So, you can understand the water quantity. Is it really coming in? How much is coming in? Is it being encroached? People dumping waste in it? All these can be mapped. See, landfills along the borders or boundary of the channels. It is also important to understand the water quality. Again, please look at these images. There is water flowing, but would you call it water? It is liquid. Yes, it is water, but it has high pollutants. It does not satisfy the common man's understanding of water, which is to bathe or drink or use it for agriculture. See, water is different. We are talking about inland water. So, all these water issues are happening and the government cannot be monitoring at every single inch. It is super expensive, time consuming. So, for that remote sensing data, satellite data can be very helpful. Identifying sources of water and distance. This is also important because if you know where your water source is, like a well which is operating or a land, a piece of land where agriculture water is needed, you can know from a GIS-based map the distance required to commute to take the water. And that estimation can help you to put a budget for it. Let us say pumping cost or taking a tanker and bringing the water for domestic use or for urban setting. The cost is very important for transportation. So, you need to identify the distance to provide supply and demand estimates. So, as I said, if you know a field is there at a particular distance, how much water does it need for a particular crop? And that can be estimated by the mapping of water bodies. Because when you map the water body, you also map the volume, the quantity and the quality and knowing that you could easily map the demand and supply ratios. To protect water resources from pollution, natural and anthropogenic. The natural pollution occurs because of the underlying rocks, like for example, arsenic or inundation because of seawater. All these are natural pollutants. Anthropogenic is, as you could see, people dumping waste, fertilizers washing in, landfills. These are industrial effluents. You could see like frothing, chemicals, etc. All these are, you can be mapped because a satellite can capture the different colors. And if there is a big color change after some time, you could say that, oh, it is because of pollution. Encrochements, yes, if there is a channel 10 years ago and 20 years ago, it was this big and then 10 years ago, it becomes this big and then now it is this big, then you know that it has been encroached. People build houses along the water channels. Blockages, I mentioned in the previous slide. There could be some blockages of channels to go, the water can go through and come to the water bodies. This can be mapped. And the final thing is for sure, the climate extremes, floods and droughts. So this drying of a lake would also be because of a climate impact, which is drought, big rainfall deficit. So you do not see water in the lake. How do you know because of satellites? Because every month, you cannot expect to get an observation data. And mapping of hot spots. Hot spots are important to collect data and immediately put action on the ground. See, every region may not be impacted equally. There could be some hot spots like the Ganges, the Yamuna. So at once people can go and start some interventions to save the water. That is what mapping of hot spots mean. The next part is we look at crop yield. So crop yield estimate is important for preparing food security. So I am going to talk about now, how do you use remote sensing data for estimating crop yield? And why is it important? First, let us say why do you need to estimate crop yield, crop acreage, crop growth, etc. Because as I said in the previous slides, the population is always increasing. And it is sometime until we taper off. Until then we need to cater to the food security. And that job is predominantly done by our rural villagers. So we need to support them for the development of food security initiatives. Understanding trends. So which kind of crop is needed? How are they growing? For example, you could see here the trends. So there is a population trend. And the land used for cereal has not changed much. This is the change percentage. From 1961 to 2021, the land used is not changed, which means the no extra, much extra land is added for cereals. But the production is kept on push to increase. How? By alternative methods. Excessive water use, excessive fertilizers, pesticides, or different hybrid crops, etc. So this is very, very important for food security. And to understand this, you need to map these areas, acreages and crop yield. Again, sending observation data, collecting by government does take time, so you can use remote sensing data. You also need to understand that you need to save some money and water if you know the crop yield is not going to come. So that can also be mapped using remote sensing data. Satellite data can give you a picture every 10, 15 days. So if you know that the crop is not growing well, you supply water, still the crop is not growing well, then you can stop and save the money because this is where farmers put excessive water and money and then they lose the crop, thereby ending in farmer suicides, etc. Because sometimes the loan is taken. So this managing of money and resources is very important for rural development, farmers' lives and crop yield. Understanding fertilizer and pesticide demand. As I said, if the image shows that the crop needs more fertilizer, it's not going enough or it's changing color because of some pesticide attack or pest attack. So you need to apply pesticide. So these can be discussed mapped through remote sensing. Understanding the water supply and demand, yes. If you know how much acre, how much land, acreage the crop is being used, you can estimate the water demand. The water supply is how much water is supplied. Water demand is based on the crop whereas supply is how much you give and that is very, very different. Planning for labour shortages. So labour shortages is a big issue. There's been a survey done by a lot of NGOs and what comes out big across the world. So across the world, what comes up big is finding temporary labour. Why? Because you don't, the farmers won't need a person to work every day of the year. Even if it is sugar cane which grows 18 or 16, 12 months, you don't need a person to manage it every time. So you need to find temporary labour. So while sowing, while cutting, while harvesting, while weeding, taking care of the plant, you need these kind of people. So that is very, very hard and in fact in the south you could see people being brought from different states, different districts to work in lorries. They work for two or three days and then they go back. So it's very, very expensive and sometimes it is not worth for the farmer to bring that money people with so much cost and then still the product is not getting profit. For example, tomatoes, now bintis are thrown away because in some parts of the states because it's not getting the right price. The 38% is more finding qualified workers. So that is a different story of how do you map these kind of qualified workers for agriculture. Planning transportation for the yield, now you have, let's say you have done all the budgets, water budgets, pesticides, fertilizers and then you have harvested using the labourers and taken it in sacks, in bags. Where do you store it? How do you transport it? This is very, very important. Otherwise the farmer will get into loss and it is a big, big issue because around 4 to 6% of annual loss of just cereals is experienced in India because of storage issues, transportation issues. You could see how the bags are not properly used or proper bags are not used for storage and it has fallen down and it's all wet. Once it's wet and the cereals mix there, it's not good enough for anything. You cannot set it at the price the farmer wants. So it is a big loss for the farmer, for the government which stores this in their government good owns and storage units. And the government can also not plan unless they know this yield. So this is on both sides. The farmer will know the yield by these remote sensing maps and then take it to the storage. Now the storage unit will be more prepared to house all these crops, crop harvester yield as long as they know what is the demand. So with this I will stop here. We have looked at remote sensing for water and remote sensing for crop yield. We will look at the infrastructure in the next lecture. Thank you.