ABSTRACT
Bhabar Lift
Irrigation Project has been proposed based on the genuine demand of farmers who
have agreed to comply with the Irrigation Policy/procedures throughout the
sub-project development process and operation and maintenance after completion.
The project has a gross command area of 30 Ha, with a net command area of 25
Ha. Water is pumped from the intake to the tank at the head of 80 m through a
proposed 80 mm dia GI pipe to deliver water from the well to the reservoir. The
project aims to benefit 122 households with a population of 800 people, by
providing them with a consistent water supply. Currently, agriculture practices
in the area are completely dependent on rainwater and the present cropping
intensity is 130%, with maize and pulses being the major crops. However, after
the completion of the project, the future cropping intensity is expected to
reach 232%. The proposed development plan includes an intake, pipeline works,
reservoir tank, and electrical pumping system installation with a total cost of
Rs. 15,136,000.00. Farmers have been extensively consulted and involved in the
development of the project plan, with their active participation being a vital
aspect. Comprehensive economic analysis shows that the project is technically
feasible, environmentally friendly, socially acceptable, and economically
viable, with an EIRR of 19.91% and a B/C ratio of 1.91 and 1.66, respectively.
Overall, the feasibility study concludes that the project should be
implemented, and the farmers are enthusiastic about its potential success.
Further training in areas such as O&M, water management, and leadership
development will be essential to ensure that farmers can take full advantage of
the project's benefits.
Keywords: Cropping Intensity, EIRR, Reservoir, Pump
INTRODUCTION
Lift irrigation is an important source
of water for agriculture in Nepal, especially in areas with limited water
availability. However, the feasibility of implementing lift irrigation systems
and the economic benefits they can provide for farmers are often unclear.
Therefore, conducting a feasibility study and agri-economic analysis of lift
irrigation systems is necessary to assess their viability and potential impact
on agriculture in Nepal. This analysis should consider factors such as the
availability and quality of water sources, the terrain and topography of the
area, the cost and maintenance of lift irrigation systems, and the potential
impact on crop yields and farmer incomes. The results of such a study can
provide valuable information for policymakers and investors to make informed
decisions about the implementation of lift irrigation systems and their
potential impact on rural communities in Nepal. Reviewing the literature, “ The
study Assessing the Operation Management: A Case of Narayani Lift Irrigation
System, Nepal” used field visits, surveys, and interviews to collect data,
which was analyzed using various methods. The system's past performance showed
limited irrigation coverage, occasional supplements, and frequent disputes
during water distribution. The role of NLIWUA was effective in managing these
disputes. The system has brought about changes in the socioeconomic and
agricultural status of the users, including an increase in economic status and
a shift from rice plantations to cash crops. The system needs proper
rehabilitation as the allocated budget is only sufficient for temporary
maintenance, and sediment management is a significant problem. The study
“Enhancing Water Productivity in Agriculture at Fokshingkot Lift Irrigation
System” briefs that a high-head lifting/pumping system was constructed that
successfully delivers 1.94 liters per sec of water for drinking and irrigation.
This has benefited 102 households, saved time for women and children, and increased
household income through farming.
The Bhabar Lift Irrigation Project is
located in the Alital-5 region of Sudur Paschim province in Nepal, with a
proposed lifting point at a latitude of 29° 7'54.29"N & longitude of 80°29'46.68"E.
Access to the project area is provided by nearby roads such as the Bhimdutta
Panta Highway & Mahakali Highway, and the specific road for the site is
Jogbuda-Alital or Budor to Alital. The water in Rangun Khola is sufficient for
the pumping requirement.
The study of Bhabar Lift Irrigation
includes feasibility analysis, the construction of necessary irrigation
infrastructure to ensure reliable water supply, providing year-round irrigation
to the area, and increasing cropping intensity and productivity. Additionally,
the project aims to strengthen water user associations and institutions,
promote advanced farming technologies, and increase farm income.
METHODOLOGY
To
achieve the objectives, the project team conducted field visits, topographical
surveys, and focus group discussions to identify the location of the lifting
point, source, and reservoir. GPS surveys were conducted to determine the
altitude and location of the source and command area. The results of the
digital data were then imported into CAD and GIS software for further analysis.
The
float method was used to measure discharge, and the cross-sectional areas at
the start and endpoints of the reach were measured and plotted in the graph
using a suitable scale. Discharge was computed by multiplying the average area
and velocity. MIP (Medium Irrigation Project) was used to estimate mean monthly
flows at ungauged sites. Nepal is divided into 7 hydrological regions, and the
project location lies in Hydrological Region 1. Once the low-flow discharge
measurement data is taken, long-term average monthly flows can be determined by
multiplying the unit hydrograph with the measured catchment area according to
the MIP Method. The criteria for the selection of design discharge were based
on agro-technical considerations such as crop water requirement and command
area.
In
addition to the design discharge, high flood design discharge was also taken
into consideration. The catchment area of the river source was computed to be
50 square kilometers, and the high-flood discharge was computed using five
different methods. The average of these values obtained is taken into
consideration, and regional analysis is adopted for high-flow calculations.
This
study aimed to design an irrigation project to provide water to the command
area for crop cultivation. The study involved a joint walk-through survey and
site investigation to identify river stability problems and high-risk zones for
laying the pipe network. A focus group discussion was conducted to assess the
agricultural situation of the command area. Agro-economic data collection was
carried out through household surveys and discussions with key informants. Crop
water requirements and water balance were calculated using CROPWAT software and
the mean monthly flow was determined using the MIP method.
Cropping
intensity was calculated to evaluate the extent of multiple cropping on the
farm. Engineering design involved the design of major components such as the
intake well, pump house, electrical accessories and fittings, transformer and
power connection, sump well, pipe networks, distribution system, and protective
devices. The economic analysis was undertaken with two major assumptions: a)
the project life is 25 years, and b) the maintenance cost is taken to be 1% of
the total investment cost, occurring from the second year.
Sensitivity
analysis was performed to assess the economic viability of the chosen
irrigation project at several selected input scenarios. The analysis included
examining the risks that occur when investment costs increased, incremental
benefit shortfall, and when both investment costs increase and incremental
benefit shortfall. The internal rate of return (IRR) and benefit-cost ratio
(BCR) were applied in the economic analysis, and sensitivity analysis was
carried out.
The
study showed that the project is feasible as the lift height is 80 meters. The
water balance was calculated and found that the crop water requirement meets
the design discharge.
Figure 1: Water Balance
From the
figure in the horizontal axis 1, represents the January First half and 2
represents the Second half and is similar in the case of other months
respectively It was found that for every half month, the mean monthly flow is
excess, indicating that water is enough for the command area.
The
proposed project involves the construction of a lift irrigation system in
Rangun Khola to provide year-round irrigation to the command area. Water is to
be lifted from the river to an upper tank using an electrical pump and then
distributed to the command area through a network of main pipes, sub-main
pipes, and laterals. The pipes are made of GI and HDPE and have been designed
based on the necessary discharge to effectively irrigate the command area. The
farmers in the project area currently follow traditional subsistence practices
of agriculture, with terraced agricultural lands and a moderate gradient. The
existing cropping intensity is 130%, and the proposed Cropping intensity is
232% the irrigation facility will have an impact on increasing the intensity of
crops and modernizing the cropping pattern with more valuable crops, which will
further enhance the potential to achieve the expected benefits.
The
project has conducted a detailed item-wise rate analysis based on prevailing
government-approved norms and district rates. The analysis has also considered
transportation costs to the rate of market materials at Dadeldhura or nearest,
wherever it is available. The rate of labor and market materials are adopted
from the district rate of Dadeldhura FY 2078/79.
In terms
of technical specifications, the capacity of the tank is 73.13m3 and the main
riser is made of GI pipe (Medium class) of 80mm dia with a length of 900m. The
total length of the main pipe is 750m, the sub-main 1100m, and the laterals
3800m.
Figure 2: Sensitivity Analysis of the Study
- The lift irrigation project proposed for the command area near Rangun Khola is expected to cost NPR 15,136,000.00.
- The economic viability of the project has been evaluated using several parameters. The Benefit Cost Ratio (BCR) of the project at 10% and 12% discount rates are computed to be 1.91 and 1.66, respectively, indicating that the project is economically feasible.
- The Economic Internal Rate of Return (EIRR) of the project is computed to be 19.91%, which is considered good.
- The cost analysis also considered different scenarios, such as a cost increase of 10%, a benefit decrease of 10%, and a combination of both, and the BCR values were still greater than one in all cases, indicating that the project is viable. Overall, the lift irrigation project is expected to have good economic returns and would benefit the farmers in the command area.
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