 we have seen that what are the various steps to be taken, what is the various uhh level of data which is required for the purpose. Let us look at the various analysis component, what we do with this data or we can make use of this data which has been collected from the the motor strip or a set of motor strips which have been the actual area. To do that I think it will be quite appropriate if we take a sample example and go through that sample example which will also give us some in-depth details on how the data is recorded, what are the elements of data which we have already uhh listed in the previous lecture and then we will go on to the analysis, what type of analysis we perform and how that analysis is useful in our latron design or even for finding out as the manager of the water distribution or as farmers, how effectively you are utilizing the water. This example which has been taken is the result of actual test run which has been performed on the field and some of the the details, the initial details which are uhh important in terms of knowing some of the quantities, these are that the crop is wheat crop on which the test was performed, the roots on depth of uhh this crop is 1.8 meters, the AMD, AMD is management allowed deficit is 50 percent and the soil which is in question is a sandy loam soil. For this soil it has been found that the available available moisture is 124 millimetres per meter depth, so if it is 124 millimetres per meter depth then for 1.8 meters the amount of moisture will be this will be 223.2 millimetres, this is per meter depth 124 millimetres of moisture available for 1.8 is around 223.2 millimetres and if you now find out what is the 50 percent of that is around 112 millimetres, so the management allowed deficit you can have a deficit of up to 112 millimetres in that soil and this deficit signifies that if you remain within this deficit level the yield of the crop would not be affected, if you go beyond this deficit it means if you let the soil moisture deplete below this level or beyond this level then there will be some impact on the crop yield. The other data which is given here is that SMD the actual soil moisture deficit which was prevailing at that time when the irrigation was done is only 73.6 millimetres, the other information which is available is the stage of the crop is crop is that flowering stage with this initial data which is either observed on the field or is available already existing with the organisation or the farmer, this is the data which is taken from the cylinder infiltration test. There are different tests which have been performed in the field, this is the first surrender then at location number 2 there are 2 more observations, so these are the actual observations which have been taken, we will just concentrate on this particular part, what type of observations have been made and what analysis or what is inferred from those observations, you can see here that this is the time in a minute, these are the watch, the hours which at which the observations have been made, 1055, 56, 59, in the beginning the interval is much closer because the infiltration rate will be higher and then the difference in time has been noted here. So while making the observations you might be observing only this and the depth, this is the depth, the infiltration in centimetres, so these 2 observations in the column number 1 and column number 4, these are the 2 which have been put and later on then these have been derived from the observed data, you have the difference in time and then the cumulative values that after this time how much is the the cumulative time, that cumulative time is also written here, similarly in the case of depth, how much is the depth per interval 6.25 centimetres and the next is 6.5 after 1 minute, so in that 1 minute is 0.25 which is the difference and that this the last column gives the cumulative value of the infiltration. So basically these are the cumulative time and the cumulative infiltration that is what you will need to plot the the data or to analyse the data to find out the infiltration characteristics. Similarly the other observations have been made and there are 2 more on this side because in general you will find that these observations are required to account for the variabilities in the soil characteristics and also to sometimes to account for the inaccuracies which might we might incur while observing the data. Then this has been plotted over a log log paper, all these 4 cylinder tests, the infiltrometer tests, data has been plotted and these are the numbers, number 1, number 2, number 3 and number 4 samples which have been taken and that those are plotted the time versus cumulative depth. Now you will see that all these are quite different in terms of the scatter, these 4 different samples are giving quite different values, that is the reason that you will you will need to arrive at some average value. So the typical value has been interpolated this lower dash line which is given here, is it visible? This lower dash line is the typical value which is the average value may be, fine. Having computed this average value you have the you have the characteristics, the infiltration characteristics available with you for that representative area or for that particular field. After that you will have to go in for the other observations which are the observations on the the water movement, how the advance curve and the recession curve will be with respect to a selected stream size. So in this particular test the various observations which are made before you have started the supply at the upstream end, these are that the border width, the border width might different than what is the the vector width because there will be the ridges will also have some slope. So you will you can note down both the things, what is the border width that means the clear width between the two ends of the border and what is the wetted width? In this particular case the wetted width was found to be 7 meter and then you can also take how this width is changing from one station to the other station when you go in the stations which have been installed at those levels how the width is changing, if there is a change in width you will have to again account for that or take an average width. Then the slope again you had taken the observations on the elevation points, what is the elevation at all those stations? That will provide you the slope and in this particular case the slope is 0.5, 5 percent which has been observed. The selected stream size we had said that will stream size, suitable stream size will be selected and that selected stream size will be used on one strip. On the other two strips you will have some variation of that stream size may be in one slightly lower in another one slightly more stream size. So in this particular case we are only discussing one strip data. In this particular case the stream size which is used is 33 liters per second and since this is a border strip case it will be per unit width per meter or width of the border. Then the duration of irrigation can be pre-decided or at that time when you it again depends on what type of soil you are using and what is the slope in general. You might if there is a light soil you will stop the water when it reaches around 70 percent of the length of the border whereas now is the other way round if it is light soil you will let the water spread up to around 90 percent and if it is heavy soil you will stop the supply of water when it has the waterfront has reached around 70 percent of the length of the border. This is a thumb rule basically but you can also vary in this case you can in different which are segments or in different strips you can use different timings of the supply of water as the idea is that you should have the minimum surface runoff and since in the case of light soils the infiltrations are higher you will find that if you stop it too early the last bit of the field might not get any water. So is a function of along with the stream size is also a function of the slope and the soil type. In this particular case the irrigation has been done for 88 minutes and the data the other data which has been recorded is again this is the data which has been we will see we can concentrate on this segment first this is the first segment. These forms are pre-designed forms which can be used which I was referring to in the last lecture that the pre-designed forms can be used which can reduce the inaccuracies because of the recording of the data. So here you can again say that this is the watch hours what hours the readings have been made and this gives the a different when these are the stations which are 30 meters apart which we have installed on the this particular border strip. In this case in this example the border strip is 255 meters long so that you can see here that 0 meters is the first station then the next is 30, 0 plus 30, 60, 90 and this is 1 plus 20 that means 120 meters 150 and so on. Now what we are recording is that at what time the water reaches each individual station so this is the time when you have started the supply of the water. At the next station the water has reached at 59 minutes at the next station it has reached at 11, 12 and so on. So what you have what you can found in turn is that what is the time taken between the two intervals there is a difference and then the cumulative value also can be recorded. Now these two data the distance versus the cumulative time or the elapsed time will give you the advance curve. Similarly for the recession curve you have recorded the data in this particular segment where this is the same thing as this what is the time of start and then after 88 seconds this is the difference at 12.19 which is the difference is 88 minutes, so after 88 minutes you have supplied stop the supply of water then you have found out that when the water disappears from this station so it did not disappear till 12.27 so that means at 12.27 the water just disappeared so it has taken around 8 minutes for the water to disappear that is the lag time, that is the time that the water has taken to the detention storage has taken 8 minutes to disappear from that station and then similarly you find out the time this is the at each station what is the time when the water the recession uhh part of the water that got disappeared. So you have noted down that time against each station and that is how it will give the cumulative value that what is the cumulative value at which your water is getting disappeared so that will this and this will give you the recession curve okay and along with that this is the uhh this segment is used to get the slope this is the the reading of the elevation with respect to some data at each of the stations and that will give you the slope of that. Having uhh observed these basic data then the data is plotted and this is the plot of the data the same data the way it has been plotted you can see here that these are the stations station number at 0 this is the upstream end and this is the downstream end and the total length is uhh uhh coming up to here somewhere here and at each station you have used data of the the accumulative time or the elapsed time and this is the advance curve this is the recession curve which has been plotted and these values which have been written these values are nothing but these are the the values of the opportunity time the difference between this time and this time. So at each level what is the time at which the water has disappeared was the time when the water was available and these are the timings at each station for how long the water was available at those respective stations and this gives quite a good uhh picture about what is the what is the the time and uhh since you know the time you can also find out using the characteristics of the soil how much will be the infiltrated water at these locations Now there comes a problem when you do not have uhh on this side you have plotted the surface profile again the readings which have been recorded and sometimes you might find that there is a depression or there might be a hump at some place and that uhh give you the indication whether uhh what what type of problem you can face so if that is observed somewhere in some of the steps you can try to remove in the next uhh if it is a crop which is already available crop you might not be able to do anything but you will be able to associate your reduction in the efficiency or the the relevant efficiency to those observed uhh things or uhh those problems which you have observed and the data itself. Now using suppose this data which has been observed you use this data to find out how much is the the depth infiltrated depth let us have a look that we know these are the various uhh uhh if we see that we have stations 0, 1, 2, 4, 5 these are the various stations and we have recorded that what is the the net time with the water is available at these stations and we have said that we have found uhh this is in minutes 96 minutes 118, 126, 123, 112 minutes. Using the average soil characteristics which we have using those infiltrometer tests we have found out the soil characteristics in terms of that equation y is equal to A t to the power b plus c and using that equation we can find out what is the depth of infiltration in millimetres the depth of infiltration which we find for the corresponding uhh locations in the present case this is the these are the actual values which you derive by using that infiltration uhh curve characteristics that this this much is the depth which can be infiltrated depending on the time which you have observed at this location using the actual data. Now here if I try to take the average depth because in each of these cases when we have the various stations we have said that this is our the advance and recession curve at each one location we are finding out how much is the infiltration time at each of these locations we are having a value which is only a single value. So if we assume that this part is representative of this this segment we can always take a average of uhh the previous and this one and that is what is being uhh represented by this segment. So that way you can you can take the average and those averages uhh you can note down at this location that is this is just trying to reduce the the impact of discretization you are taking the individual values so if you take the averages you will get some average value for all these different segments which are 30 meters each and then you can take the overall average the average depth for the total length which is 255 meters comes out to 97.6 millimeters using this data. The average if you take the average depth these are the actual depths uhh for uhh for example in this particular case you will find that between this and this the average will be 80 between this and this it will be it is 6.25 and so on. So if this 80 is representing the first 30 meters then you can find out that for the total segment of or the total length of 255 meters the average works out to be 97.6 millimeters and if you take we are also trying to look at another if you see here we are trying to find out that if the length would have been 100 and uhh 210 meters only then what will be there because in this segment you can see is quite obvious that the distribution would be very daily very poor because the time of infiltration is very low. So if you go beyond beyond this segment up to here you still have uhh these two curves are not uhh trying to converge the the opportunity time is still quite reasonable we will have to check that because we might ultimately find that even this length is not sufficient you might have to choose a length which is another 30 meters on this side. So that is where you can make various various options and let us try to make a option that if we select 210 meters of the border length what will be there? The average uhh depth which we will get using this the the soil typical soil characteristic curve which we have assumed or which we have selected from those 4 samples you will get a depth of 105 and uhh 0.7 millimeters. So these two that are the ones which you are uhh getting from the the data which you have observed. Now at this juncture it will be quite worthwhile to check are these depths because this depth is totally constrained this depth which you have which you are uhh finding out is totally constrained with the fact that whether the soil properties or the soil characteristic curve which you have obtained is reasonable or not because the range was so much if you again have a look on this the range is too big. So you have to you have to justify you have to have a in depth study of that uhh characteristics whether the selected characteristics are reasonably representative of the area or not. So to do that we make a analysis depending on how much volume has been sent to the strip, how much volume we need to do some analysis on the the basis of the supply of water. We know that we have stream size which is 33 liters per second okay. We also know that the elevated width of the border is 7 meter and we also know the time of application. So the width is known the time of application is known this is 88 minutes. Using this if you want to find out what is the volume and convert that volume into the equivalent depth that depth will be if you use 255 meters length because it will be a function of what length you are using. So if you use 255 meters length this volume will work out to be 33 liters per second and uhh these are the 88 minutes seconds divided by the area and this will about to be 97.6 millimeters. There is a slight mistake which has been made here in giving you this information but this is not my fault. This is not 97.6 millimeters this is the value which is less is 73.2 millimeters and this is also accordingly this is the value which will be the value which is after the adjustment has been made. So it is observed here at this juncture that because it cannot be if you look at these values it cannot be 97.6 the average value. This average value has to be lower and looking at these values also is 60, 48, 217 and there are some higher values so the average is around 73.2 millimeters okay. Now this depth which works out to be 97.6 is if you try to visualize what is this depth? This is the average depth depending on the fact that you have depending on how much water has been sent to the strip, how much volume of water has been sent to the strip. So your infiltration characteristic curve is giving you under simulation. This signifies that the infiltration characteristic curve which you are using is giving a under simulation and that needs adjustment. How you adjust that? Because even if you look at there will be some surface runoff there will be some other losses also. This 97.6 is corresponding to because the minimum which you want to send if you find out what is the where is that term. If you look at this particular place the average time if you look at the typical curve which we have selected this is the lower curve which has been selected and at that curve you are getting a value of 73.2 which is the average depth. At 73.2 what is the time? The corresponding time is around it works out to be around 96 minutes. So if I take a value of the average depth which is 73.2 which I have found out from here that this is the average depth which I was getting. If I use this typical curve which I have found out on the basis of the average data or on the basis of the actual data I have found out the average curve and I am not sure whether that average curve is still representative of the total area or not. Verify that I went to the volume basis I have found out that that volume will create how much depth on the average. So in this situation if I find out that 73.2 depth how much time it takes to get the 73.2 depth is around 96 minutes. Now for that 96 minutes in that 96 minutes I should get a depth with respect to the volume or with respect to the stream size which has been selected I should have got a depth of 97.6 centimetres. So I take this point to a level which gives me a cumulative depth for the same time which is equivalent to around 97.6 millimetres. So I shift this curve up and then I draw a line parallel to the previous typical curve that is how I make the adjustment. I have kept the same slope but I have changed I have shifted I have adjusted the the the infiltration rate in such a manner that for the same time I get a value at least which is equal to the value which I spread using that average stream size and that minimum that average value of depth I should get from that infiltration curve which should be the representative curve. Having got the suggested curve now I I try to verify that and I find out how much is the or in other words I get a new curve which give me a analyzing this this particular adjusted curve I get a new set of values which I analyze for A, B and C and use that curve in turn to find out how much is the how much will be the depth for these infiltration opportunity times okay. So that is what I do here and I find out what is the change depth I will write at this level the change depth in this particular case is 95 point 97.5 at this station will be 112.5 instead of 85 and then I will have 117.5 117.5 110 millimeters 102 millimeters and the 92.5 77.5 and so on. So these values are the adjusted values or the revised values with respect to the new characteristics and this I analyze again to find out what is the average depth now. The adjusted average depth if I take the total length of 255 meters works out to be 97.6 millimeters okay which is the same now which is the same as what I have found from the the criteria of the steam size by analyzing the volume which has been put on to the total length. At the same time if I decide to reduce the length because you know the last segment is quite poorly represented or the the infiltration opportunity time is very low in that. So if I decide to take only 210 millimeters of the length this quantity works out to be 95.7 millimeters. This is important because you have seen that how the whole computation changes so either you have to have lot of those infiltration tests made and take average which will be representative of the total but still it will be much better if you can verify those characteristics because these characteristics are varying so much in the the location of the test or even otherwise the soil characteristics are so much variable that when you are doing the point test infiltrometer test is a point test in fact you are using a very small area of the total area which might not be representative and they can be some other inaccuracies also because when you are using the infiltrometer test we have seen that even if you have the double cylinder the double that two cylinders you are using but still there can be some lateral dispersion. So it can give some values which are not always the representative values so having that you can use the actual test to find out what are the general characteristics, what shape it takes, what slope it takes that slope might be a representative slope because the slope will change when you go from one type of soil to another type of soil that is what is reflecting the rate of change of infiltration and once you have done that then you must at least verify how much is the variation or whether that that infiltration characteristic curve which you have arrived at is it really representative or not and that is how we do it that is what we have just gone through. Now having done this then the next part is to find out the various efficiencies that is what we have the main aim of doing this total analysis was to arrive at to check various efficiencies whether those efficiencies are reasonable or what are the upper limits of those efficiencies all those things you have to uhh you are interested in. To do that this is the another depiction of the same data but drawn in a different manner. Now here the same thing has been uhh redrawn by taking the this as the the starting point for every individual value at each section how much is the the total infiltrated water. So we had found out that that in the first case this is 96 97.5 millimeters and so on. So this gives you a depiction that how much is the total water which has been infiltrated at different stations and this is the level the actual soil moisture deficit level was in this particular case we had mentioned in the beginning that 73.6 millimeters is the deficit which is prevailing in the field. That means you needed basically this much water if you take the total length then you needed up to this level you needed the water so all this amount is the water which is stored in the root zone. Any amount which is above this level is the water which has gone into the deep percolation which has gone beyond the the root zone depth and if you decide that you will end this trip at 210 meters then this will become the runoff component. This will be there will be some still some water which will be available and which will go as runoff. So finding out the the efficiencies the different ways by which you can evaluate those efficiencies one is that you can use these areas directly because areas are depicting the volumes. So if you do that you can find out the efficiencies using that or you can use only the depth you can you can find the the suitability of these different ways or procedures and they are they are not giving much different results the results obtained are almost similar. So if we we try to look at what are the various values of these efficiencies I will if we if we note down the areas the areas which are observed the total curve under the total curve the area is 33.2 units okay either you can have a mesh or you can use a transparent graph anything you can do is or a graph paper can be used to find out the unit areas and the unit can be any unit is immaterial. The runoff is observed to be 73.7 units I will just say units and depoculation is 9.2 amount stored in root zone is 20.3 units okay. Now using this you can you can find out the various efficiencies which we have already discussed earlier. For example if you want to find out the distribution efficiency, distribution efficiency in this case let me also mention that another if we look at this value 77.5 millimeters this value is the the minimum depth which has been observed up to the spreader level. The minimum depth which has been noted down which is required for example in this case this is 77.5 millimeter is the depth required up to 210 if you take the length of the border up to 210 meters only then 77.5 is the minimum of the total but every location the minimum depth which is required is 77.5. So with respect to that depth if you have to achieve that then you will have to provide some water which is in the the stored in root zone will be more if you would have got more deficit okay. In other words you can also say that the potential value of the the efficiency the application efficiency could have been slightly different if you did not decide to irrigate the the field at this soil moisture deficit level if you would have allowed the irrigate the the soil deficit to increase to 77.5 millimeter depth then it was possible to because in any case you are getting this much water throughout this length so it was possible to achieve a higher efficiency and the area up to this level of 77.5 millimeters is that area is between 77.5 and up to that 210 meters level this area is 21.7. So this give you a value which is achievable value and in that situation the distribution efficiency would have been 21.7 is the depth which is applied depth and if you take care of the surface runoff you are left with this is the depth which is required this is the depth which is applied 33.7 uhh 0.2 minus 3.7 which is gone as the runoff. So multiplied by 100 this is 74 percent so the distribution efficiency can be walked out from here. Similarly the application efficiency on the basis of the the actual actual case actual SMD the actual soil moisture deficit this is basically 20.3 and how much you have the water you have applied this works out to be 61 percent only whereas the potential value of the application efficiency this could have been higher this could have been 66 percent had you waited for some more time and had you let the soil moisture deficit go to that level. So that is where the management allowed uhh deficit comes into picture that if you if you can manage your irrigation in such a manner that you let the deficit which is reasonable deficit reach a level which is optimum level you will find that the efficiencies can be much better. Similarly you can find out the other uhh efficiencies which are which we have already looked at and we also know the procedure how we can make use of those efficiencies this is only one aspect which we have seen. Similarly in this particular case now this is with respect to the stream size which is 33 liters per second if you use a different stream size you will find that all these quantities will change. So in the evaluation procedure your aim is to come out with those combination of parameters which give you the optimum efficiencies and that is only a possible if you analyze more number of uhh these strips with variation in these parameters and is more of a trial and error procedure when you are doing the evaluation okay. With that we will close this uhh chapter on the border irrigation system if you have any questions you can ask.