IRRIGATION WATER RESOURCES MANAGEMENT OF COMMAND AREA OF BAPATLA CHANNEL
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Date
2018
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Acharya N.G. Ranga Agricultural University
Abstract
Irrigation in India is mainly dependent on various sources, including the
availability of canal water and ground water. In India, most of the prominent canal
command areas suffer from either excessive or inadequate water supply resulting in
wide gap between irrigation demand and supply. Hence it is necessary to evaluate the
conjunctive use of irrigation water resources management. The computer software
provides demand-based water release strategies for reducing the gap between canal
supplies and demands. Bapatla channel is selected as study area for management of
irrigation water resources (canal water, groundwater and drain water) available in the
command area.
The command area of Bapatla channel is 6548.27 ha. Command area map was
generated using Arc GIS. The total water demand (TWD) of major crops grown in
command area was calculated for 5 years (2012-13 to 2016-17) in two seasons.
Similarly total water supply (TWS) (i.e. sum of canal water, groundwater and drain
water supply) was calculated for the study period and compared TWD and TWS. The
computer software was developed to give quick information about canal, drain and
ground water supply and total water demand in the command area.
The study area received 62.23 per cent of annual rainfall during South West
monsoon season and 28.80 per cent in North East monsoon season and 6.64 and 2.32
per cent during summer and winter seasons. The daily discharge of Bapatla channel has
never crossed the design discharge (7.50 Cumec) during study period. TWD of Bapatla
channel command for two seasons (kharif and rabi) of crops paddy and maize was
found to be 6500.04 ha-m in the year 2012-13. Similarly for 2013-14, 2014-15, 2015-16
and 2016-17 years TWD was found to be 6325.18, 6521.42, 3102.40 and 5376.19 ha-m
respectively.
The performance indicators of the delivery system present a poor performance in
terms of adequacy and dependability. Irrigation efficiency of Bapatla channel for the
study period were 50.55%, 62.52%, 66.06%, 12.84% and 47.54% for the years 2012-13,
2013-14, 2014-15, 2015-16 and 2016-17 respectively Irrigation efficiency (IE) for
Bapatla channel is high (66.06 per cent) in the year 2014-15 and lowest (12.84 per cent)
in the year 2015-16, this may be due to lack of water availability. Water use efficiency
(WUE) was highest (4.19 kg/ha-mm) for the rabi paddy in the year 2014-15 because of
more paddy crop yield and lowest WUE (1.94 kg/ha-mm) was observed in the year
2013-14, maize crop during rabi season due to heavy rains damaged the crop at
maturing stage and less crop yield.
Canal water supply to field (CWSF) in the Bapatla channel command area for
the study period were 1194.46 ha-m, 2504.28 ha-m, 3462.81 ha-m, 85.98 ha-m and
1194.46 ha-m respectively. Similarly groundwater use (GWU) for the study period from
2012-13 to 2016-17 were 1300.32 ha-m, 1475.86 ha-m, 1105.92 ha-m, 1475.86 ha-m
and 1713.60 ha-m respectively. And drain water use by the all lift irrigation systems in
the command area for the study period from 2012-13 to 2016-17 for each year was
about 1163.00 ha-m. TWS in the command area for five years were 3657.58 ha-m,
5142.94 ha-m, 5731.53 ha-m, 2724.64 ha-m and 4229.04 ha-m for the years 2012-13,
2013-14, 2014-15, 2015-16 and 2016-17 respectively. Total water demand is more than
the total water supply in the study period during two crop seasons. Total water demand
is more in the year 2014-15 of about 65.21 MCM and total water supply of about 57.32
MCM. Total water demand is less in the year 2015-16 (31.02 MCM) and total water
supply is about 27.25 MCM.
In the command area, on an average; it was observed that the canal water supply
to the field was very less from 33rd week to 43rd week. So, there is need of ground
water use during this period. During rabi season, canal water supply was very less or
nil. Therefore, application of ground water is required at the middle end and drain
water to the tail end of the command area for maximizing the crop yield.
IWRMMOD (Irrigation Water Resources Management Model) was developed in
the form of a computer program using PHP (Personal Home Page), which was simply
mixed with HTML codes. In the IWRMMOD, seven forms were developed in the input
data, i.e. crop, climate, canal water supply, canal hydraulics, special needs including
efficiencies, groundwater supply and drain water use. Eight forms were involved in
evaluation module namely Consumptive use, ET0 (Reference evapotranspiration), ER
(Effective rainfall), Seepage loss, CWSF, GIR (Gross irrigation requirement), TWD,
GWU, and also three output module forms like WUE, IE and TWS were developed.
IWRMMOD was provided mainly demand-based daily water releases for reducing the
gap between canal supplies and demands and to help irrigation engineers, agronomists
and agro-meteorologists in planning, operation and management of irrigation systems
efficiently.
Description
D5741
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