Script for presentation
overview
The Ganges-Kobadak Irrigation Project (GKIP) is situated in
western Bangladesh, along the southwestern bank of the Ganges
River. It spans an area of 197,500 hectares, of which 142,560
hectares (72.2%) are classified as arable land. Of this,
approximately two-thirds, or 95,600 hectares, can be irrigated
using the existing canal networks and river water, while the
remaining one-third relies on groundwater for irrigation.
In the project area, there are 62 DTW and 64081 shallow tube
wells (STW) currently in operation, providing irrigation to 57% of
the canal-commanded area. A 740-meter intake canal connects
the pump station to the main river; however, water flow is
restricted due to a sandbar. The project halts operations from
November to December for necessary dredging.
According to the treaty, the average dry season flow in the
Ganges is 1,241 m³/s. The minimum permissible stage level in
the intake canal is set at 3.96 meters, while the corresponding
level at Hardinge is 4.50 meters. This indicates that during the
dry season, there is sufficient water flow in the Ganges at
Hardinge to meet the supply requirements of the GKIP.
Pump station redesign
We propose to install three main pumps, each with a discharge
capacity of 36.9 m³/s and a minimum lift capacity of 3.96 m. The
total design discharge will be 104 m³/s.
1. The required water level at Harding Bridge is +4.5m. This
level is crucial for effective water management, taking into
account head loss due to irrigation abstraction.
2. The sandbar must be carefully removed from both the river
pathway and the upstream side.
3. The subsidiary pump station needs to be installed properly,
featuring a pump capacity of 44 m³/s. The pumphouse will
operate even at river levels as low as +3m PWD. It is vital that
the subsidiary pump station is securely anchored in place.
4. A standby pump will be installed, with a capacity of 30 m³/s,
designed for pumping water from surface storage.
Barrage
A barrage is planned to be constructed 45 kilometers
downstream from the intake on the Ganges River. The proposed
length of the barrage will range from 1.3 to 2 kilometers,
depending on the selected location. The impacts of the barrage
include:
1. *Flow Regulation*: The barrage will ensure effective flow
management and maintain the necessary water level to support
the irrigation project, with a design discharge of 104 m³/s and a
minimum stage level of 3.96 meters. A medium barrage can
elevate the water level by 4 to 8 meters.
2. *Reduced Pumping Lift*: It will slightly decrease the pumping
lift required at the GKIP pump station.
3. *Flood Risk Mitigation*: The barrage will help alleviate the
risk of flooding along the riverbank.
4. *Enhanced Navigation*: It will facilitate smoother navigation
for transportation.
5. *Prevention of Salinity Intrusion*: The structure will help
prevent the intrusion of salinity into freshwater sources.
additional structures
-Check dam
Several check dams will be constructed on the upstream side.
This will reduce runoff velocity and allow sediment to settle
before reaching the main barrage.(pic add)
-Levee
Properly designed levees will be placed along the bank of the
river near the barrage area. This will prevent flooding due to
overflow and excessive rainfall.
Canal redesign
Current Conditions of the Irrigation Canal System:* -
*Total Length:* - Main Canal: 180 km - Secondary Canal: 440 km
- Tertiary Canal: 1,000 km –
*Water Requirements:* - Total requirement: 104 m³/s –
Total loss: 32.3 m³/s (which is 32% of the total discharge) –
*Water Available for Use:* - After accounting for losses, the
available water is 71.7 m³/s. - Of this, 60% is efficient for
cultivation in the fields, resulting in 43 m³/s.
*Design Recommendations for the Irrigation Canal:* 1.
Improved cropping patterns should be implemented.
2. All canals must be designed to run over higher line loamy
ground.
3. A tertiary level buried pump system should be constructed to
achieve an efficiency of 46.3%.
4. Proper maintenance of the canals is essential for optimal
performance.
Gorai river
*Why is it necessary to save the Gorai River?*
1. *Ecosystem Balance:* Maintaining salinity at an acceptable
level is crucial for the local ecosystem in the southwest region.
With rising sea levels expected in the coming decades, it is vital
to ensure the salinity of the water remains stable.
2. *Irrigation Needs:* There is a competing demand for surface
water irrigation during the dry season from the GKIP (Gorai-
Kalindi Irrigation Project).
*Current Situation:*
The Gorai River is experiencing alarmingly low water flow,
averaging around 4.5 m³/s for the past few decades. A sandbar
has formed at the river's mouth and has not been properly
removed. During the dry season, the river reduces to a trickle.
*Proposed Solutions:*
To achieve a targeted discharge of 158-240 m³/s, regular
dredging of the Gorai River is essential. The river’s flow can be
regulated with the construction of a barrage. Additionally, to
manage optimal flow and water levels, a weir should be
strategically built at a suitable location along the Gorai River.
Ground water recharge
Groundwater Recharge:
1. Natural: Proper management of river water flow allows for
groundwater recharge, estimated at around 18 mm/y.
2. Artificial: An artificial approach can be implemented using
specific methods like the V Weir Injection Method.
Location- North east part(where ground water level is low)
additional-ganges water machiene
Reserviour
We will construct several reservoirs for our project. These
reservoirs will be connected to the canals to store water during
the wet season, which can then be used for irrigation purposes in
the dry season.
additional- ganges water machiene
