[Music] [Music] welcome to you all in the nptel course on the subject ability and management of groundwater resources now today we will discuss the first part of the lecture one entitled introduction to the hydrological cycle as we know the groundwater resources is one of the very important resource on the earth's surface so in this very part of the lecture we will cover the overview of the water ability on the earth's surface some of the important terminologies how the water has been distributed on the earth's surface then the status of the per capita water ability in india and the initiatives by the government for the management of the groundwater resources so this groundwater itself reflects that it remains within the ground so there are several types of water but groundwater is the water which generally remain inside certain rocks certain soil sand etc inside the earth's surface it is stored in the some of the small small pore spaces within the rock surface within the science of the different geological formations so this storehouse or this repository which remains within certain sands or rocks is termed as an aquifer this is termed as an aquifer so this type of water that is groundwater which generally remains within the ground it remains within certain spaces within the rock within the sand within the soil and this type of structure which remains within the earth's surface which holds the water that is groundwater is termed as an aquifer so aquifer is a very very important storage house for the groundwater resource now this the area where water fills the aquifer that just suppose this is the earth's surface so within the earth's surface we are having some rocks some sand sand so the area which fills these because this is the rock which are having the ability to store the water so this aquifer termed aquifer so this aquifer is also known as the saturated zone within the surface so this is the zone of saturation means it is filled up with water so the rock surface the soil surface where the groundwater remains in plenty is generally termed as the saturated zone so inside a surface we are having the saturated zone as well as unsaturated zone so now suppose for a minute that this is a rock and this rock is having the water level because this is a as we have discussed any rock which holds the water inside the earth's surface that is termed as aquifer and generally the ground water which is the basic aim of discussion the groundwater remains within that very rock so this aquifer holds the groundwater quantity within its four spaces so now the upper level of this ground water saturation june is termed as this is termed as water table this is termed as the water table so water table may be located at some shallower depth or it may be at greater depth or more than hundreds of feet down so it depends upon the ability of the water inside the earth's surface so in another way we can unders understand this thing about the groundwater resource see this is the surface so earth surface is having some structure inside it which can which is holding the water at present we will understand only this much the rock the rock this is holding the water and this water this water makes the saturated zone within the their area so this has become the saturated zone because it holds the water whereas this is also a rock but it is not holding the groundwater so it is unsaturated joon it is unsaturated zone and this is the saturated zone so this saturated zone is having some layer of water inside it so now suppose this this rock this is the rock and this rock is holding the water inside it so this this rock is holding the water up to this level up to this level only it is holding the water whereas one more and this is the earth surface whereas one more aquifer is there means one more rock is there one more rock is there which is holding the water so this is also holding the water but the water table is just near to it means the level of the water inside it is near to the ground surface so here it is having lesser depth whereas here it is having greater depth so the point is that groundwater is not evenly circulated inside the earth's surface it is not so it remains at the uneven uneven depth inside the earth's surface so since groundwater remains in certain rocks so the rocks hold the water and the level of the water will differ at different different your aquifer or different different saturated zone so this level of the water varies inside the surface somewhere the level of the water within any aquifer remains near to the just beneath the earth's surface few feet below beneath the surface whereas in some saturated zone we are seeing that the level of the water that is the water table remains at a greater depth so this aquifer is termed as shallower aquifer shallower occupant whereas this aquifer is termed as deeper aquifer so generally we are getting such type of aquifer salover as well as deeper aquifer inside the earth's surface and within that aquifer only the groundwater remains so this is the first fundamental concept that groundwater remains within the ground no doubt but it remains in certain rocks soil formations soil formations and that rock and soil formations are termed as aquifer and within the aquifer the water remains and the level of the water the top level of the water within the aquifer is termed as water table aquifer is also termed as saturated zone so this water table means the level of the water in different aquifers varies where is place to place so at some cases we are getting the shallower aquifer means the level of the water just inside the near to the surface at few feet few meters below the surface whereas in some cases we are getting the deeper aquifer where the water table remains at a greater depth and that is what we are facing the problem of the getting the groundwater resource also so this is the basic problem now after this just within few ah slides we can understand we will see the few points we will see that aquifers are typically made up of gravel sand sandstone or fracture drop like limestone so this may be news new for you but i am just simplifying it that these are the rocks which is lying inside the earth surface inside the earth's surface so inside we are getting the several types of rocks gravel sand sandstone limestone these are very very soft rocks known as sedimentary rocks whereas in some cases we are also getting groundwater in some fractured rock which is the uh type of metamorphic rock in which we are getting the fracture or lineaments so the point is the point the first point of this slide is that aquifers we have already understood that tufas are nothing but these are just the rocky formation which is holding the water that is the groundwater so these aquifers are typically made up of soft rock or hard rock so if the rock is having very good amount of pore spaces then that will hold good amount of groundwater also in some cases the groundwater remains in small small fractures or lineaments within any hard rock so the point and the concept is that this groundwater what we are going to discuss in this subject ability and management of groundwater resources we must understood first that how and at which places the groundwater remains available so the general concept is that the groundwaters will remain available in certain rocks or the geological formations sand etc so general generally the groundwater remains in soft rock known as sedimentary rock and the example is gravel sandstone limestone etc these are the sedimentary because because in this sedimentary rocks we are getting very small small pore spaces suppose this is the sedimentary rock so this sedimentary rocks are having some grains some mineral grains but in between the grains are having the spaces so here we are getting the space here we are getting the space so these are the mineral matters and and here we are getting the space so point is that in the sedimentary rocks we are having lots of option to store the water why because we are having the plenty of pore pore spaces so water will remain here more clearly i am just telling you that this is one rock and this is another type of rock this rock is having good number of porous places so first i will draw this one four spaces and then the grains are just interlinked with each other interlinked with each other so this type of rock is known as sedimentary rock because this rock is having good number of pore spaces whatever is being filled these are the porous places and with the water remains whereas this is also a rock inside the surface but this rock is having not put a good number of porous spaces but in between it is having some fractures some small small lineaments some fractures so here here large number of porous places we are getting why because this is a soft rock that is the sedimentary rock this is sedimentary rock this is soft one whereas this is having these are the pore spaces whereas in this this is the your lineaments fractures etc so what is happening here here we are getting the metamorphic rock in metamorphic rock which is a hard rock hard rock but derived from the parent sedimentary rock we are having some space and these spaces are termed as your fractures and lineaments so what we have seen we have seen that the rocks inside which the groundwater remains are generally sedimentary rock or the metamorphic rock in sedimentary rock the water will remain within the pore spaces present between the interlinked grains whereas in the metamorphic rocks the hard rocks we are getting the groundwater but in a lesser amount why because it remains in the fractures or linear means this type of the distribution remains within the surface that is why at some places we are getting plenty of groundwater resource through the well or dug well or two well but at other places we are not getting good amount of groundwater through well dug well your tube etc this is the basic region because at one place we are getting good amount because the area is having good sedimentary rock which is having plenty of pore spaces which can hold large amount of groundwater but other places which is having not good amount of groundwater resource is because the area is having hard rock area the rock is having only the pore space only the fractures and lineaments so these concepts should be built should we build in our mind about the ability why we are getting groundwater at some places in a very good amount and another place we are not having so why so the question and the answers are here only because the ability of the geological formations that is the rocks now third point is the speed at which groundwater flow depends on the size of the spaces in the soil so inside also it is not so that outside we are seeing the flow of the river water inside also the water moves from one aquifer to another aquifer so inside the surface suppose this is the earth's surface so inside also if one is occupied equipment one is here for two a q for three is here so what is happening inside also it follows the gravity it moves towards the from occupier one to aquifer two aquifer three to aquifer two in this way groundwater flows inside the earth's surface also and what we have seen in the nature groundwater is sufficient almost everywhere but it depends the quantity depends according to the geology of the area so the we have seen just now that the level of the water which is generally known as the water table it may remain shallower it may remains deep so somewhere it may rise or somewhere it may go down so this also generally happening in the nature sometimes uh perhaps in the during the monsoon season when we are having the plenty of rain that time if you will see in any well any dug whale if you will see you will notice that the level of the water what you have notice already during the summer period because after summer the monsoon has come then the level of the water has just moved up how why because the saturation level inside the rock has also exceeded so that's why the water table sometimes remains up or sometime it fails down so heavy rains or melting of snow may cause the water table to rise or heavy pumping so when the heavy rain is there or melting of snow is there we can see in the well that the level of the water table is rising up whereas when sometimes we are also pumping the water huge amount of pumping we are doing for certain purposes that time you will notice that the level of the water in the well which is the water table it falls gradually when you will start the pumping you can notice the level when you just off keep it off just you please note note down the level you will find the difference the level has gone down so in this way the water level inside the earth's surface is varying now this groundwater suppose you have just withdrawn the water from any well but generally you will notice suppose throughout the day you have just withdrawn the water for certain purposes maybe your portable purposes may be your commercial purposes just you have taken out the water from the well if you will notice the next day again the level of the water has come to that place from where you have started just in the earlier days so why and how because these groundwater supplies are replenished or recharged it can be replenished from i have told you just inside we are having several types of aquifers aquifer one is here eq for two is here aquifer three is here so in this way what is happening is suppose you are withdrawing the water from a q41 so the level of the water may go down water table may go down but this level is go down but after if you will leaving it for a period ah if you will notice it the level again come to this place so what is happening the water from this aquifer is just replenishing or recharging the aquifer one why because of the gravity because water inside also flows according to topography just like on the surface of the earth where the water flows according to the topography so inside also we are uh noticing that if we are just pumping out the water this wa level of the water again comes to your original place after few hours or few minutes okay so this ah this groundwater resource is generally naturally the plan is it is replenishing naturally in areas where material above the aquifer is permeable it is very important point so in areas where material above suppose this is the area and this is the aquifer just this is the aquifer this aquifer one is here and this aquifer one is having some formation which is permeable which is permeable so this aquifer is a is a place from where we can withdraw the water or a place where the water water remains and this area is become permeable it is naturally permeable area means permeable means ability to transfer the water this is called as permanent permeability so the aquifer is just the material is permeable just above this aquifer then what will happen suppose if any pollutant will come from certain activities so that activity suppose from this the pollutant is coming to this place means the material above the aquifer which is a permeable material then what will happen this pollutant will directly sensitive permeable is having the ability to transmit so this pollutant is directly entering into the groundwater resource and thereby making the groundwater pollution so this is also one of the very very important concepts why the groundwater has become polluted the reason is that we have seen that the groundwater where it remains it is a saturated zone fill of water that's why saturated feel of water so above and the structure is known as the aquifer but what is happening just above it if the permeable zone remains then what will happen the pollutants can readily sink into the groundwater source this groundwater regular wire is there aquifer is groundwater reservoir just a rock holding the water so this pollutant will move to the groundwater and thereby the groundwater pollution will take place another see another aspect is that groundwater can be polluted by landfills there are several landfills area also septic tanks people are making septic tanks at for houses for industrial activities etc leaky underground gas stands inside the earth surface also there are several pipelines to which the gas are being passed so if it has some leakage then what will happen the groundwater pollution will take place even from the fertilizer and pesticides which are being used for the agriculture activities they are also polluting the groundwater resource inside the surface general concept is that groundwater is inside the earth so there will be very difficult to have the pollution of the groundwater but no i told you if if at any aquifer just above it will remain the permeable zone then there are more more chances to get the groundwater pollution in that very specific water so groundwater becomes polluted it will be no longer and no safer for the portable purposes for the drinking purposes so the two concept we have understood till now first concept is that the groundwater is remaining available in certain rocks within the earth's surface the rocks which is holding the groundwater is termed as aquifer this aquifer is a saturated zone it is having the level of the water inside it the upper level of the water is termed as groundwater table water table this water table may remains just near to the earth's surface or may remain at the deeper depth that's why at certain places on the earth surface we are getting the water in a well to just two or three meter down whereas in some well on the earth surface we are getting the water at 100 or 200 feet down so the reason is that at some places the water table remains near to the surface at some places the water table remains at greater depth so it is very difficult to withdraw the water from the deeper aquifer generally the rocks which are holding the groundwater is the sedimentary rocks sedimentary rocks is having very two good important properties first it is a having good storage capacity which is known as storativity this is a very good storage space it is having good number of porosity means number of pores divided by volume is called as porosity so sun sedimentary rocks is having a good porous rock whereas metamorphic rock is having less porous i've told you generally in metamorphic rock which is a hard rock the groundwater remains in some cracks or lineaments some fractures okay so this is the basic difference of the two different rocks or the two different types of aquifers which are present inside the surface in which the groundwater remains another concept we have understood that this groundwater may become polluted how we have discussed already that if the permeable material will remain just above or near to the aquifer and if the some sort of effluent effluent means your effluent means some industrial influence from waste water from some industry is coming and just dropping near to the permeable formation then this permeable formation will just allow the effluent the toxic chemicals to go inside the groundwater quantity and this whole groundwater will become affected become polluted so this two important concept we should keep from the very beginning now apart from this we will just see how the distribution of water remains on the surface the first concept we have understood where the water will remain inside the earth now just we have our look on the distribution of water on the earth so 97 percent of the water on earth is salt water 90 percent of the total 100 water we will see we are having the continents as well as water in our globe if you have noticed that 97 percent of water in the salt water which remains in ocean on seas so only three percent of water remains such a fresh water and if you will see closely about its distribution this fresh water is having about sixty eight point seven percent in the form of ice creams and glaciers sixty eight point seven percent about ice caps and glacier remains packed at certain places so of very little you don't know used now rest 0.3 percent water flows on the earth's surface which is known as surface water in the form of streams rivers lakes ponds etc some other type of water also remains present on the surface which is 0.9 percent but the groundwater remains only 30.1 percent of the total fresh water of three percent which remains within certain formations that is the aquifer so this is the important point that since 97 percent of water is we can't use since it is having saline in nature so fresh water remains only three percent and out of this freeze three percent only the groundwater is thirty point one percent rest remains in the form of ice caps and glaciers and the surface water and others so itself we are having a very very lesser quantity of groundwater inside the earth's surface in the form of fresh water so if you will see the statics of the surface water here the surface water covers about about 9 87 percent in the form of leaks it is a seven percent water in the form of lakes and ponds 11 percent in the form of swamps and rivers two percent so this is just the distribution of the surface water so importantly we are having the two important types of water the surface water and the ground water in this subject we will discuss specifically the about the ability and management of the groundwater resources because this groundwater we are directly drink taking it for our drinking purposes so it should not remain contaminated it should be in the fresh form that's why we can take it so every life forms are depending on the ability of the groundwater resources yes just have a glance on the water resource of india in countries in which we are living we are having if you will just compare it from the world area we are having point four percent area and this two point four percent area the population is about seventy point seventeen point one percent uh of the world population in our country we are having 17.1 percent of the world population water as well percent of world water if you will see we are having our indian subcontinent is having only four percent of the total your world water statistics four percent only per capita ability ranking if you will see only one 132 per capita ability whereas in water quality quality if you see the water quality because quality is very very important we are having the ranking of 122. so what is the important part important part is that in many parts of the world especially where surface water supplies are not available domestic agriculture and industrial water needs can only be met by using the water and that water is especially the groundwater so you may get surface water insufficient but if not you are getting the sufficient surface water you you you have to have the application for taking out the groundwater resource from inside the surface and use it so this should be because we are having some limitations also now what are the problems of the overuse of groundwater resources suppose we are using it and we are using it but not replenishing the groundwater resource then what will happen the problem will take place in the form of groundwater depletion groundwater will deplete the level of the water will move down and down so and if you will not think of for its management a day will come when the the well will become dry the well will become dry and this is the situation we are facing in several parts of our country also where earlier the persons who were living in the villages they were having good amount of sufficient amount of groundwater in their wells but at the present day they are not having such type of well in through which they can take out the water and use for their day-to-day livelihood works so what are the causes the groundwater depletion how it is taking place lowering of the water table already i have discussed that if you will excessive pump from any dug wheel it will just lower the groundwater table and cause wells to no longer be able to reach the groundwater so excessive pumping is a very dangerous and generally it is excessive pumping are also being done why for irrigation purpose the farmers they need water because they have to do irrigation so they are not having sufficient amount of groundwater but anyway they are just pumping continuously taking out the groundwater continuously so what is happening the water table is going down and down secondly increase cost as the water table lowers now the water table has become lowered the water must be pumped further to reach the surface then what will happen more capacity pump you will use more energy it will be used then the cost will also go high so in another way we are again going to increase the cost in the for the sake of taking out the water withdrawing the water from the earth surface now reduced surface water supplies suppose ground water and surface water are connected it remains connected so what is happening groundwater is overused the lakes if you are over using the groundwater then lakes streams and rivers which are they are also connected to the groundwater and then what will happen the they will again start to become dry why because they will supply their water when surface water will reach to the ground water in a rock which is drying inside the rock so gradually the river water will become dry so in this way what we are seeing that if we will overuse the groundwater resource then we will face the groundwater depletion problem groundwater depletion problem if you will see the per capita ability of our indians condition indian condition we are having only an only 31 35 liter lpcd 135 liter per capita we are having for the urban water water users whereas for the rural we are having the 55 lpcd according to the ministry of housing and urban affairs this is the per capita water ability population wise we are seeing that in our india we are getting the groundwater problem why because we are having the increase in population gradually our population are increasing so the per capita ability is also decreasing day by day now some initiatives are being taken by the government water being water is a state subject it uh water itself remains a state subject so steps for its augmentation conservation and efficient management are the prime duty of the state governments only however the central government they are generally technically and financially helps to the state government for various schemes and programs through which the conservation measures can be done ministry of javascript government of india has launched jalal sakti abhiyan a campaign a very good campaign for water conservation and water security in our country and during this campaign the officers groundwater experts scientists from the government of india all sit and work together with the state and the central and the they just demarcating the water stressed districts within the state and then they are just proposing for the water conservation and water resource management plan and in this way the government is helping for the conservation of this valuable water resources central government is having also very um national perspective plan etc through which it transfer of water from water surplus basins to the water deficit basins to improve the ability of water so through this national prospective plan it can be used because we have learnt that some places may have the sufficient amount of groundwater resources whereas some places may not have so through this plan the transfer of water from one basin to another venetian can be done government of india in partnership with the states is implementing gal given mission hergerjal which aims at providing potable water in adequate quality of prescribed on standard quality on long term basis to every rural households including tribal areas of the country through tap water connection by two zero two four so this is a very good movement by the government of india gharjal so this is about the the very first topic about the ability and the management of the groundwater resources this is all about the lecture on the specific topic thank you very much