Lift irrigation scheme

Irrigation Schemes mainly comprise canal irrigation and lift irrigation schemes. In such schemes, the most important and yet the most neglected portion is distribution of water. Let us first consider lift irrigation schemes

Importance of lift irrigation schemes (LIS)

As per the NABARD – National Bank for Agricultural and Rural Development (India) - data, there are 1401 LIS financed by them. The total financial outlay (TFO) is Rs. 6462.5 million . The proposed area under irrigation is 22000 hectare. Out of these LIS, as many as 573 LIS are defunct. The main reason is poor distribution of water. In addition there are LIS which are financed and implemented by government, sugar factories and individual farmers.In case of irrigation schemes, the importance of “Lift Irrigation Schemes” is unique and distinctive. In such schemes, many farmers can come together and implement a large lift irrigation scheme on private or co-operative basis. This way, they get certain benefits of large schemes. Such large lift irrigation schemes comprise of two main parts.
1. To carry water by means of pumps from the source of water to the main delivery chamber which is situated at the top most point in the command area
2. To distribute this water to the fields of the beneficiary farmers by means of suitable and proper distribution system.

Of these two, the first part is comparatively easy and there are some technical guide lines for its design. If this is properly implemented for selection of pipes (diameter and pressure rating), valves and pump sets, there does not arise any problem in this part.But the second part of distribution is very important and comparatively complicated.
The reasons are:
1. The distribution system totally comprises gravity pipe lines. The gravity lines are designed totally on the basis of the available head, with out any pumping system. This limits the job of design engineer.
2. The area under the irrigation is scattered with varying topography. Therefore, each gravity pipe line has different available heads and different lengths.
3. The area of individual farmers is different.
4. The design engineer has to select the diameter of pipe from the standard diameters available in the market. The pipe diameter selected is the next higher diameter (than the design diameter) available in market. Higher diameter pipes are used and this affects the discharge through the pipes. The pipe line carrying water to the low level fields carry more water than the similar requirement on the elevated field. The distribution is not proper and dissatisfaction and frustration on the part of farmers leads to indifference and apathy towards the scheme.
5. The distribution system is controlled by valves on the basis of time schedule. The farmers operate the valves to their benefit which results in altercation and quarrels among the farmers.

With all these limitations, there are the following prevailing systems to distribute the water in the command.

Conventional system

In this system, the pipe lines are designed from the Main Delivery Chamber (MDC) to the respective fields a sunder: Thereafter,
*The area under irrigation is divided in to different blocks according to topography determined by contour plan. The water requirement of individual blocks is determined. Then the pipe lines are designed for these blocks depending on the available head and discharge required.
*The next available diameter than the design diameter is selected for the pipe line. E.g. if the design diameter is 95 mm, the next higher diameter of 110 mm OD in PVC pipes will be selected and fitted.
*Field Delivery Chambers are constructed on the distribution pipe lines, and valves are fitted to control the flow of the pipe lines.
*Water is distributed from the MDC at a time or as per some pre decided time table.
*The flow is controlled by the valves.
*In this system the above reasons lead to unequal and disproportionate distribution. The lines for lower fields carry more discharge. The control of valves is misused or is at the mercy of influential farmers.This way, some farmers get more water and some get less. Some farmers do not get any water at all. The differences amongst them increase. The lack of interest results in non cooperation to run the scheme. This results into shut down of the scheme.

Irrigation schedule system

This system is similar to the above. The only difference is that instead of supplying water to all blocks at the same time, the area is divided into three or four equal parts, and each part is given the entire discharge for one day. This means each part gets rotation of the full design discharge on the fourth or fifth day. This system has all the drawbacks of the conventional system. In addition, its another drawback is that the diameters of the distribution pipes increase due to the supply of entire discharge to one third or one fourth area. This leads to the increase in the cost of the scheme which becomes a burden on the beneficiary farmers.Therefore, we have invented and developed a system having principle of equal and/or proportionate distribution. The salient features of this system are:

*Every farmer gets precisely equal or proportionate water at the same time. For example, if the discharge of the scheme is 100 LPS and 20 members in the scheme, every farmer precisely gets 5 LPS discharge as long as the pump is running. OR
*Every farmers gets precisely proportionate water to his area under irrigation and investment, at the same time. If the scheme is on the basis of area, and if a farmer has invested for two hectare area, he will precisely get double the water of the farmer investing for one hectare. A farmer investing for six hectare will get three times as much water; and so on. As long as the pump is running, all the farmers will get PROPORTIONATE discharge.
*There is no scheduling or time table such as so many hours or so many days in a week for farmers or their groups. As per the availability of electricity, as long as the pump is running, all the farmers will get EQUAL or PROPORTIONATE discharge.
*No need of control valves: Control valves are NOT needed in this system. The problems of malfunctioning of valves and unauthorized operating of the same do not arise. The cost of the valves also saved. The dependability or reliability of the scheme is increased among the farmers.
*No need of an operator: Since there are no valves, valve operator is not needed, thereby saving the expenses for the same.
*As the total discharge is delivered at a time, distribution pipe diameter required is less with saving in the cost of the distribution system.
*Since equal or proportionate distribution is foolproof, certain and doubtless; farmers willingly and happily share the capital expenses (loan and investment) and recurring expenses in that proportion. The repayment of the loan is in time and recurring expenses like electric bill, water charges, maintenance cost are shared in time.The principle used in this system is very simple and commonly observed. ‘Water maintains its level in a closed container’ is that principle. In main delivery chamber, pipes are fitted at precisely on the same level. The number of pipes depends on the number of farmers or groups. The pipes deliver water in to a distribution tray. They are grouped for further conveyance through a common pipe line. At the further delivery point, the same type of field distribution chamber is constructed, and so on.While designing new schemes, we give water on the basis of units rather than based on crop and area to be irrigated. We therefore decide a unit of water and farmer decides how many units he wants, and shares capital and recurring expenses accordingly. He has then freedom to take any crop and to irrigate any amount of area by using water saving techniques like micro irrigation and mulching etc.

Applications:

*For the new irrigation schemes
*For the rehabilitation of the schemes which are closed up due to improper distribution, thereby reutilizing the vast amount of funds blocked in these schemes.
*"Applicable to any size of scheme from two farmers to thousands of farmers or from a few hectares to thousands of hectares".

Application to canal distribution system

This type of distribution system is applicable for distribution from canals also. From all the dams, irrigation water is distributed through canals and distributaries. There are many water distribution co-op. societies on these canals.Since the key point in equal and proportionate distribution is the delivery chamber, it can be used in canal systems also with equal effect. The farmers at the tail point will also get their share of water without any doubt. And all the benefits described above can be reaped by the member farmers.We have successfully implemented many small and large LIS in this way. The satisfaction level of the beneficiary farmers is very high.

Comparative chart

Some schemes implemented on equal distribution basis

This system has been invented, developed and successfully implemented by MR.Yashpal Morey. He is an Agricultural Engineer and Agro Consultant based in the city of Nashik in India. Mr. Morey has been working on numerous irrigation projects in Maharashtra and India, and his experience of over 30 years helped him to develpo this pioneering system.

"Yashpal Morey, Agril. Engineer and Agro Consultant. Eastern Star Consulting EngineersNashik 422 001 India"