BENCH MARKING
The overall aim of benchmarking is to improve the performance of a system as measured against its mission and objectives. Benchmarking implies comparison either internally with previous performance and desired future targets, or externally against similar system or systems performing similar functions. Benchmarking is a management tool already in use in both the public and private sector organizations. By using appropriate performance indicators of benchmarking it is possible not only to improve the water use efficiency and financial viability of the system but also ensure adoption of best management practices and the environmental sustainability in the irrigated agricultural systems.
It is proposed to take up Bench Marking of Malampuzha and Peechi Irrigation Projects for the Financial Year 2020-21
BENCHMARKING OF MALAMPUZHA AND PEECHI IRRIGATION PROJECTS IN KERALA
OBJECTIVE
To assess the system performance, agricultural productivity and environmental and financial aspects of Malampuzha and Peechi irrigation project using standard indicators published by Indian National Committee on Irrigation and drainage (INCID), Government of India for further improving the system.
BACK GROUND
Of all the various uses, irrigation takes place the pride of place with as much as 60 % of water needs. Security for food grains, vegetables and cash crops can be ensured only adequate provision is made for irrigation during summer and especially during peak drought years. Hydrological condition of Kerala rivers necessitates storage of monsoon water for use in summer. There are 18 completed/ongoing irrigation reservoirs for improving food production and economic development. Out of this, 13 have storages and 5 are barrages. It is realized, however, that scientific management of irrigation water and irrigated croplands is the only way to make our agriculture productive and competitive. With the increasing pressure on available water resources, irrigation systems of our country have to find ways to improve performance of the existing/ongoing irrigation projects.
Even though, a few irrigation projects have been commissioned in Kerala, for improving food production and economic development, the baseline information on hydrology, agricultural and social aspects of these projects are not available for many of them. These details are often required for the post evaluation of these projects and also for other occasions. Hence documentation of initial status of ongoing irrigation projects is very essential for the post performance evaluation. Benchmarking is a systematic process for securing continuous improvement through comparison with relevant and achievable internal or external norms and standards. Benchmarking would help in deciding appropriate interventions and formulation and implementation of policy for improvement of the projects. By using appropriate performance indicators of benchmarking, it is possible not only to improve the water use efficiency and financial viability of the system but also to ensure adoption of best management practices and the environmental sustainability in the irrigated agricultural systems.
Kerala has lagged behind other Indian states in the adoption of such a management tool. However, there have been some recent developments in this direction. The State Water Policy (2008) underlines the immediacy of performance improvement of irrigation projects in Kerala through benchmarking. Government of Kerala has also proposed to undertake benchmarking activities in the irrigation sector, in its 11th Five Year Plan. A pilot benchmarking study was undertaken by Water Resources Department in Neyyar Irrigation Project of Southern Kerala (Govt of Kerala, 2010).
STUDY AREA
Salient Features of the Malampuzha Irrigation Project
The Malampuzha Irrigation Project (MIP) consists of a gravity masonry dam built across the Malampuzha river and a network of canal system to irrigate mainly the paddy command in Palakkad district. Construction of this project was started in the year 1949. The dam and left bank canal of theproject were first commissioned in 1955. The scheme has been completed and the full anticipated utilization was achieved in 1966. The dam is constructed in five sections. The main masonry dam connects two hillocks on either side of the river, with a central spillway, 56.99 meter long, over the river course with bulkhead sections on either side, aggregating a total length of 550.47 m. Another section at right angles to the left end of this dam is for a length of 583.40 meters, from where, it is connected further to another elevated hill by an earthen dam of 222.20 m long. Independent of these, masonry saddle dams fill up two more gaps in the natural hillocks. The masonry dam is of straight gravity type and earthen dam is of zonal type. The maximum height of the dam is 38.10 meters and the gross and live storage capacities of the reservoir are 226 and 223.60 Million Cubic Meters (MOM), respectively. The head works and the command area of the project lie within the altitude of 15 to 150 meters above Mean Sea Level (MSL).
Salient Features of the Peechi Irrigation Project
Peechi irrigation project, one of the major irrigation projects in Kerala had been formally commissioned in 1957. Built across Manali river in Karuvannur river basin, which has its origins in the Vanyan Para Hills, at Peechi nearly 20 KM away from Thrissur town. The Dam was intended to irrigate 4856 Hectares of new conversion lands 1619 Hectares of single crop land converted to double crop, 4048 Hectares of existing double crop lands and 8095 Hectares of Kole lands (Puncha). Since the commissioning of the project the development of the ayacut has been taken place rapidly and cultivation was attempted in 4858 Hectares of new land converted to double land , 1619 Hectares single crop land converted to double crop land, 4048 Hectares existing double crop land and 8095 Hectares of Kole lands. In addition to this, drinking water is supplied to Thrissur corporation and eight nearby panchayaths.
METHODOLOGY
Benchmarking is a very powerful management tool for analyzing and improving the performance of water resource projects. To analyze the impact of irrigation management a set of performance indicators (such as system performance indicators, agricultural productivity indicators and financial indicators) which were developed by the Indian National committee on Irrigation and drainage (INCID) is to be used.
The study involves the physical survey of the both irrigation schemes by GPS survey for the identification of different lined and unlined portions in the canal system. The discharge rate at the starting point of branch and field canals during the operating time is to be noted for the estimation of conveyance loss of the canal system. The study will estimate the conveyance losses such as operational, seepage and evaporation loss. The inflow outflow method will be used to calculate the conveyance efficiency of the schemes.
Also the study will check the water requirement of various crops in the study area using suitable Decision Support Software (CROPWAT). The computer programme uses FAO (1992) Penman Monteith methods for the calculation of crop water requirements from existing or new climatic and crop data. Furthermore, the programme allows development of irrigation schedules for different management conditions and calculation of scheme water supply for varying crop patterns. All calculation procedures as used in CROPWAT are based on the FAO guidelines. For the calculation of Crop Water Requirement, CROPWAT needs data on reference Evapo-transpiration (ETo), It uses monthly climatic data to estimate ETo using Penman-Monteith formulae. Rainfall data are also needed, and used by CROPWAT to compute effective rainfall data as input for the CWR calculations. It uses climatic data on wind speed (km/day), temperature ( °C ), Relative humidity (%) and Sunshine (hrs.).
Where, ETc = Standard Evapo-transpiration (mm) = Kc * ETo
SAT = Water used for land preparation (mm)
PERC = Percolation loss (mm)
WL = Standing water to be provided in the field
To know the aspirations of farmers or public towards the schemes a socio economic survey will be done. This survey will collect the information such as crop details, land holding details, marketing of crops, farming equipments, labour issues, existing difficulties etc. Also the study will identify the erodible areas in the catchments of both irrigation schemes by universal soil loss equation. Based on the above studies a set of performance indictors will be derived and this will be used to evaluate the performance of the system on various aspects. In this study the approach recommended by IPTRID (International programme for technology and research in irrigation and drainage) for performance evaluation of irrigation sector will be used.
A brief description about the set of performance indicators is described below:
1.System performance indicator
In order to study system performance, field application efficiency is to be used. It is the ratio between water used by crops by Evapo-transpiration to the water delivered at the field head.
2.Agriculture productivity indicator
Indicators of output per unit served area, output per unit irrigated area ,output per unit irrigation supply and output per unit crop water demand is to be estimated to evaluate Agriculture productivity.
Output per unit served area = Total annual value of agricultural production/total command area serviced by the system or subsystem
Output per unit irrigated area = Total annual value of agricultural production/ total annual irrigated crop area
Output per unit irrigation supply = Total annual value of agricultural production / total annual volume of irrigation of water inflow
Output per unit crop = Total annual value of agricultural production /total annual volume of water consumed by the crops
3. Financial indicators
Indicators of total operation and maintenance cost per unit area, total cost per person employed on water delivery, staffing members per unit area and total operation and maintenance cost per unit water supplied are to be used to evaluate financial performance.
⦁ Total operation and maintenance cost per unit area= Total MOM cost/ total command area serviced by the system or subsystem
⦁ Total cost per person employed on water delivery = Total cost of personnel engaged in I&D service/Total number of personnel engaged in I&D service
(c) Staffing members per unit area = Total number of personnel engaged in I&D service/total command area serviced by the system or subsystem
(d) Total operation and maintenance cost per unit water supplied = Total MOM cost/Total water supplied
4. Environmental indicator
(a) Land damage index = (Waterlogged + Saline/alkaline affected area)/ Total CCA
(b) Average depth to watertable (m) = Average annual depth of watertable calculated from watertable observations over the irrigation
area
⦁ Water quality: Ph/Salinity/Alkalinity = Ph/Salinity/Alkalinity of the irrigation supply and
drainage water
⦁ Salt balance (tones) = Differences in the volume of incoming salt and outgoing salt