 of these different types of emitters with respect to the emission uniformity. There is a table which has been provided by the American Society of Agricultural Engineers design standards, the emission uniformity gives the emission uniformity which is achievable or which is possible for different types of emitters and also with respect to the crop spacing, the field topography is another which has been used in the information, the emission uniformity in percentage, the emitter type is a point source type and your crop spacing is in this case wide is taken as more than 4 meters. The field topography is uniform and the uniform is the category where it has been, the slope has been taken as less than 2 percent than the emission uniformity by into 95 percent. If you have steep slope which is greater than 2 percent, your emission uniformity will reduce in comparison to the previous case, on this case everything else is same, you have the point source with the wide spacing but your field topography is steep or undulating then this will be the achievable uniformity coefficient or emission uniformity as is known in this case. If you have close spacing which is taken as less than 2 meters, the spacing between the crops is less than 2 meters, the spacing between the plants and you have uniform field achieve the same value of emission uniformity but if it becomes the case of steep topography I am sorry, this is 85 to 90, so if it is a steep topography with the close crop spacing you will have emission efficiency of 80 to 90 percent, when you have line source and a close crop spacing normally in the case of line source you will be using the line source mainly when you have the row crops. So you will in general you will find that the crop spacing is close in all the cases when you use the line source, there is only one case when you have the close crop spacing. If the topography is uniform, this if it is steep then you have a lower level of emission uniformity, so this give you a range that how the emission uniformity changes with respect to the various conditions prevailing in the, these are the general guidelines, the general average values which have been observed. How do you evaluate evaluation of emission uniformity? Because emission uniformity is something which you will have to go in for the evaluation of such uniformity, what is the, is a field level data which has to be evaluated and then you can find out what is the level of emission uniformity as we have seen in the other cases also all the other irrigation systems. You have to go in for these evaluations where you do some experimentation and then come out with the relevant values and see, check for yourself whether those values are really prevalent in the actual case or what you are getting is much different than what is, what is said to be achievable. This you, if you look at the overall layout which you have, you have the main line, you have the sub-main, then you have the laterals, on the laterals you have the emitters. So when you go in for such a evaluation you choose one sub-main and on the sub-main if you have a sub-main, choose at least 4 laterals on the sub-main, you can have one lateral at the inlet point, very first point on the sub-main, the very first, immediately first lateral at the beginning of the sub-main and you choose one at the furthest point, you can take another one to third position, the fourth one at to third position. The idea is to have these laterals, the selected laterals well spaced so that you are not getting the sample as you are trying to collect only some sample values. So these sample values should be representative values, they should be, they should be representing the various conditions which are prevailing in that setting. So for that purpose is very essential that you choose the, because what you are going to do, you are going to make measurements on what is the actual discharge, only then you will like to, you will see that what is the actual discharge which is being made available at different levels of the emitters. So you have tried to make a selection of those individual emitters in such a way that they are representing the average conditions, not the average conditions, average conditions you will find out but they are representing all the conditions, the maximum conditions, the minimum conditions and the in between conditions also. Similarly you can, when you come to, suppose you have selected 4 laterals, on each of these laterals again there will be variation when you go from 1 emitter to another emitter because of the fact that as you know that there are losses which are taking place, there is the discharge which is reducing, all those things which we have already discussed with respect to the sprinkler irrigation system is happening here also. So on, on each selected lateral again choose 4 emitters and these 4 emitters again you will have one immediately at the first one the inlet then the next one at far end there is the end of the lateral and then 2, 1 at one third position and the second one as 2 third position. So you are, you are repeating a similar trend which you have done over the laterals. So within the laterals also you have, you are trying to adopt the same strategy. Now ultimately you have now 4 laterals and on each lateral you have 4 points, 4 emitters which are which are selected. So you have in all 16 emitters where the observations have to be taken, the observation is only where the discharge, where the volume of water collected or to find out what is the flow rate, what is the discharge. Because you normally have the volume you collect graduated cylinder where you can directly see that how much is the volume collected and thereby you can find out what is the rate. So the quantities which you will like to find out is, what is the minimum discharge since you have those 16 individual values, you can find out what is the minimum, your minimum is required when you try to find out the emission uniformity. So q minimum is required, you can find out from there the q average, you can again find out the average of those 16 individual values and all the other things are known. So you can now from the sample you can find out what is the value of uniformity or emission uniformity. The general criteria which you normally have which is which is used that if you have more than 90 percent emission uniformity is excellent, if it is between 80 to 90 percent good, 70 to 80 percent is fair but anything less than 70 percent is poor. Now this is the this anyway you have seen earlier but this is sort of level of general level of acceptance which is given by this that if you have something up to 80 percent of emission uniformity which is reasonably good and you can accept that. Similarly you have seen that in this particular case the only thing which is known is the value of the coefficient of variation can also be computed basically using these individual values you can find out the coefficient of variation but if you do not want to indulge in all that you want to have a order of magnitude or a simplified way of finding out what is the uniformity what is the level of uniformity which you are achieving you can also use a parameter which is known as the discharge variation and this is a much simplified expression than what we have discussing so far which just gives you what is the what is the q maximum what is the q minimum and what is the level of q variation and this is again in percentage. So the q variation in percentage a simplified way of finding out this can also be used if you do not want to indulge in all the detailed calculations which you are performing when you are finding out the emission uniformity you can also use this as a indicator. So in this particular case everything is defined we do not have any term which is this is the discharge variation the general criteria is that if discharge variation is less than 10 percent desirable 10 to 20 percent is acceptable but anything less than anything greater than 20 percent is not acceptable. So if you are trying to find out these the discharge variation in terms of discharge variation this is the range which is the general criteria which is used similarly when you talk in terms of the relationship between the emitted discharge and the operating pressure let us call it H the general expression this is the relationship between the discharge and the operating pressure. Now X is the the emitted discharge exponent this exponent is also given by the manufacturer you will find that the value of this X will also be made available but this X is also a function of the flow regime and K is a empirical factor. Now the value of X varies to have a value of X as 0 when you have the emitters which are the pressure compensating you get a value of 1 or those emitters which are in mineral flow regime a value close to 0.5 is obtained for emitters which are in turbulent so in general you can derive from this that the higher the value of X you will have to take more care in terms of the fact that if the value of X will be higher then a small pressure variation can make lot of variation in the discharge. So that is the very is the indicator that if you have a level of X or the value of X which is higher you will have to be very careful when you are looking at the variation of discharge over the lateral and you have to you have to check you have to make thorough checks that what is the what is the variation which you are getting in actual case. Let us now go on to the lateral hydraulics now we want to find out the final the final aspect of design that what are the actual losses now you want to find out the pump requirement and for that you will have to find out how much are the losses what are the pressure requirements how the pressure varies over the total network that the relationships might be slightly different but the philosophy is the same as you have in the case of a sprinkler irrigation system. So I would not go into the details and in this case the total dynamic head which is required the principle is going to be similar the only thing is that in this particular case there will be some additional things which might create more hindrance in terms of the loss. Example in this case the losses which will be prevalent because of the other equipment like the filter unit you have more number of filter units in this because you want still the water which is more clearer because of the fact that in this case the clogging is much more problematic. So any pressure which has to be lost in those individual equipments has to be catered for in terms of the local or the total requirement which is required at any level whether is the pump level or whether is the procedure will remain same you will start from the farthest point and you will reach up to the pump and find out how much is the total requirement at the pump level. This was the other aspect of using the factor F to take into consideration the effect of reduced discharge is again similar which we have already looked into in detail in this in the case of sprinkler irrigation system. But let us try to go through the some other aspects for example in this case again the head loss a particular lateral the head loss is found out using the Darcy-Weisbach equation which is more common in this particular case and this is the expression to be used for using the Darcy-Weisbach equation for finding out the head loss this is the friction head loss assuming that there is no loss of discharge for the total lateral. So this H f is the friction head loss along the lateral with no discharge if you have a head loss there is no discharge through the emitters that means it is only the pure pipe flow as we have seen earlier. Then this is the expression where all the other terms we already know we know that this is the friction factor and this friction factor has to be computed using the proper equation depending on the which regime you are in, this is the friction factor, this is the length of the lateral expressed in emitters, Q is the total lateral litters per hour and D is the lateral diameter and this is expressed in millimeters. So again we have earlier also we have seen that to account for the actual friction head loss we had introduced a factor f if we call that as actual that is f times H f and this f this f is the Christensen friction factor and we have helped with that at how to compute the f that procedure will remain same. In this particular case the only major difference is that in this particular case there are other losses which are which can take a very significant value which are those losses up to this place there is no problem is the same procedure but in this particular case we cannot ignore the other losses which are the losses due to the emitters, the other connectors. These losses can be, order of magnitude can again be very high that we have just said but more than that it also takes, it also depends a lot on how the emitter has been used, if the emitter has been used online the loss will be different, if the emitter has been used inline the loss will be different. So in general emitter which is used inline it will create much more higher loss than the emitter which is used online. Some experimentation has been done where it has been seen that the inline emitter can have loss which is around 5 times higher than the loss in the lateral without emitters. So it can even surpass the total loss of the emitter in the lateral when there are no emitters that is the h f which we have just found. When you have the inline emitters the loss, the additional loss can be 400 percent higher. Now to account for this additional loss what can be done, there are various ways by which you can handle that but the designers have found this, the simplest possible way they have found is to find out what is the additional length, what is the equivalent length, equivalent length which will produce the same level of retardance or what is the equivalent length which will which should be taken along with the original length to account for this loss. So this is a very indirect way of handling this, the connector and the emitter loss is quite effective and equivalent length to account for friction due to emitters and connectors expressed in meters and the expression is used to find out this equivalent length and this equation, what are the various parameters, these we have defined earlier, this is the lateral diameter, this is the millimeters and Q is the flow rate in liters per hour, H e emitter connector friction loss meters. Now this emitter and connector friction loss has to be varied separately in the field setup, you will have to find out how much is the loss under for specific emitter or any other connector which you are using and that experimentation has to be there are many emitters where the friction loss, the connector loss and the emitter loss are not known, people are making that available even the manufacturers have started looking into those things. So once that is known then you can find out what is the equivalent length which has to be increased by which the original length has to be increased and then you can use the combined length and the other previous expressions to find out how much is the how much is the change because of this additional head loss which is because of these connectors and the emitters. So that can be taken care of, okay. Otherwise all the other details remain same, you can again you can look at the worst possible lateral or any lateral which is which you feel is the critical one and if you have a computer system where the program is there you can check each and every lateral and find out what are the whether the extreme critical points they are getting satisfied value of discharges or the pressures there are quite sufficient and those pressures can be used to find out the pressure requirement at the other locations of the system. In general gives us reasonable insight into what are the various design procedures then there are some other related topics for this specific system in this case the filter unit is a very important unit and the filtration is basically required because of the fact that the emitters get clogged. The clogging in the emitters is due to various reasons, it can be due to the suspended solids, it can be due to the physical particulates, the clogging can also take place because of chemical precipitation, biological can be either bacterial, algae formation. So they are the different range of reasons for clogging and that is the reason that you will have to use a very high level of infiltration process, there are many filters which are commonly used, they belong to different classes, there are some filters which are called the media filters where you are using the sand or some other gravels, same type of filters which you use for the sieve treatment and these type of filters which are sand filters which are quite useful and the quantity of water which can be treated that can also be much larger because of the infiltration rates which are prevalent and it can also remove not only the sediments but it can also remove some other biological element which might be going through the water. So in the case of a sand filter, a typical sand filter, you might have such an arrangement that you have, you have a unit, this is the entry of water, water comes through this and these are the various levels where you can have the control, if this is the portion which is having the filter medium is the sand, so in the normal operation water will move in this direction and then pass through the filter unit, so this is the clean water which is coming out of the outlet point. This part is used when you want to have the backwash of this filter because all the material which is the different types of particles which are getting accumulated over the surface of the filter, they can be backwashed by sending the water, closing this side, sending the water now from here and then the water will passing through the sand, it will remove the particles which are deposited and it can be sent out of this, this is the backwash water. Now this process can be repeated as often as is required depending on the capacity of the filters and the type of water which you are using, how much deposit is being made in this particular area and that is why if you remember that you have the pressure gauges also which are provided before the filter and after the filter unit, so you can calibrate that in terms of the pressure difference also, if the filter unit gets clogged the pressure variation will also increase, so if the pressure variation is more than 70 kPa then in general you can say that you require the filter to be cleaned. These days there are there are many new equipments which have come because the difficulties which were earlier being faced by the operators, they have a dual, they have a twin system, the filter can have two chambers, one chamber can be used when the other chamber is being cleaned through the backwash process so that you do not have to stop your system, you can do that when the system is remaining on and the last time because if you have chosen a system where you can act wait or let us say for more than one day for the next irrigation to start, otherwise you might not be able to complete your total area in the desired irrigation interval. So in that situation each lost day can be very detrimental, can be very problematic, so you can either use a filter unit which needs very little cleaning or it is very quick to be cleaned or you use such a system where you have a standby which is inbuilt so that you do not have to stop the functioning only because of the fact that you have to be in this filter unit. Then you have the other type of filter units which are quite equally popular, they are the screen filters, in the case of screen filter you use for filtering the wire mesh and you might have such a situation that you have, here you have a core which is this is having a mesh, in this case the water is coming from this end, this is the entry point, water goes through the and then so this is the exit point, so the water when it moves through the filter unit it can, it is not as simple, there can be a situation where it will move, the length of the segment which it has to pass through, it can be forced to the water, the water can be forced to pass through that total segment so that the cleaning is much better and much proper and then the water, the clean water will come through. In this case again this is the outlet which can be used when you clean the filter and you want to flush the whole debris out of this wire mesh portion which is the filter portion in this particular case, the sizes of these meshes can vary depending on the requirement, depending on the quality of the water which you are using. So that in general is the very brief details on the filter units and there can be another type of filter unit where you are using the concepts of the centrifugal force, there you try to churn the water and if you have only the suspended solids which are heavier than water that can be forced to settle down and through that those type of filter units you can only remove the suspended particles which are not exactly suspended particles, they are in transition, they can be forced to settle down. So those type of filters you might use as the primary filters which are only the first level filters then when you come closer to the subnames you use the secondary level filters which are more effective which can be which can ensure that all the other debris all the other particles which can clog the emitters they can be removed. So with that I will close this topic on the drip irrigation system, if there are any questions, yes the question is whether the sand filter and the screen filter they can be used simultaneously, there are filters which are having both these things put in the same segment also but they can be used, the screen filters can be used as a primary filter because screen filters are not as effective as the sand filters can be. So that is basically which filter should be used where and how many filters you have to use will depend on the quality of water which you are using. If the quality of water is very poor you might have to use series of filters, you might have to use even a filter which is before the pump unit because that can also if the water is really bad you would not like the pump to be damaged. So you might use filter even before the pump, it all depends on it all is dependent on what type of quality of water you are having at your disposal and in some cases you might find that you will have to analyse the water if your quality is susceptible or if there are situations where biological activity is quite active you might have to go into the depth into details because you realise one main aspect that in this particular case if even if some of the emitters are not functional you are having a big problem because the meter is ultimately the last device which will let the water move from the system from the lateral onto the field and the pressure once you go past the meter there is a very drastic difference, there is a drastic drop in the pressure from the point which is just upstream of the emitter and when you go then the water goes outside the emitter. Let me tell you that the water is almost at the atmospheric pressure when it comes out of the emitter. So if you have any situation where because the pressures are really very low so in most of the cases even if there is a very small chance of having any of these things affecting the emitter it will have its intensity to clog because there are days when you are not using the system even if you are letting the water stand for 2-3 days as we have seen that 2 days is a normal duration which when the emitter might not be functional. So within that much period if the algae formation is there then you have it because then it is going to you would not even know the other major problem is that you would not even know that which are the emitters which are not functioning because there is no think of the situation where you have many many hectares of area and the number of emitters can be really run into 100s far even a small area, how many of those emitters you can physically see and even the automatic controls are not possible because they will be making a very the whole system very very expansive. So those sensing the remote sensing and all the automatic sensing mechanism is not possible. It might be feasible but it is not it might be possible but it is not feasible. You can you can sense how much is the water going past the emitter that is at a cost which is not permissible within the present circumstances. So you have to be very careful at this stage that the water which you are sending is not by any chance is not clogging those emitters, thank you much.