Importance of dam design in Nepal

1. MAN MADE LAKE
dam
and
reservoir
A BARRIER BUILT TO BLOCK
THE FLOW OF WATER
PREPARED BY :
JANGBAHADURB PD. YADAV
Under Department Of Land And Water Engineering
IOE PURWANCHAL ENGINEERINGCAMPUS
DHARAN

2. advantage of dam
There are common advantage of dam
• Control of downstream flood problem.
• Store run-off water which increase recharge of ground
water.
• Store water for irrigation, water-supply, hydro-power,
local-navigation.
• Used as farm-pond and recreation.
• Debris control of river.
• To guide and regulate the flow.
• Supply water to those areas where, natural water
resources aren’t enough to support survival.
• To distress the surrounding enemy areas by flooding
them.

3. Dis-advantage of dam
There are common two types of dis-advantage of dam
1. At failure of dam
• Loss of life's in downstream.
• Loss of cost ( at downstream loss and also for re-construction/repair cost).
• Destruction land.
2. At failure of dam
• Detraction/ruin of river from natural setting.
• Inhibited the season migration of fish.
• Creates of endanger condition for some species of fish.
• Change the archeological potential of downstream.
• Creates damp area on upstream which decrease the temperature at upstream.
• Creates drought at downstream.
• Water burning diseases and mosquitoes breeding at reservoir area.
• Creates significant loss of evaporation.
• Causes of earthquake (In a paper prepared for the World Commission on Dams, Dr. V. P Jauhari wrote the following
about this phenomenon, known as Reservoir-Induced Seismicity (RIS): "The most widely accepted explanation of how dams cause
earthquakes is related to the extra water pressure created in the micro-cracks and fissures in the ground)

4. need of damand reservoir in Nepal
• Reservoirs are man made lake formed behind a dam to store water for
specific or multi-purpose.
The needs of the dam and reservoir is very well connected by the
following question and answer in the context of Nepal :
Question Answer for Nepal
• Where does your water come
from?
• Mountains, rivers
• Why is there always water
coming out?
• Rainfall and snow melt
How much water is coming out ? • Approximately 70% of dry season flow and
40% of annual flow of the ganga
river.(38,129 m3/s)
• How much water do you use? • Approximate 20% of total discharge of
Nepal
• How much run-off is created? • Approximate 80% of total discharge created
• What is the condition of floods in
downstream?
• 28 eastern districts of Nepal is endanger.

5. need of damand reservoirin Nepal contd.
Answer of that all question shows that there is enough water is
available in Nepal but the demand of
• Irrigation water
• Hydropower
• Water supply
• Farm found
1. Navigation and recharge of ground water is also not
maintained in Nepal
2. so with use of small as well as big dam the water going waste
in ganga basin can be utilized to meet the demand of water in
different field and also can maximize the productivity of
agriculture and high hydropower production
3. To guide and regulate the water to minimize the flood affects
in downstream.
4. Hence Nepal has high need of dam to make sure the
availability of water in future.

6. scope of damand reservoirin Nepal
1. Most of the Nepalese rivers are perennial rivers so its flow is
continuous all over the year while the requirement of
irrigation water hydropower water in most of the drought
seasons are not available so to provides the continuity its
can play a big role in Nepal.
2. The geology of Nepal is very good for the design of small
head as well as medium and high dam design with proper
sites in the hilly areas.
3. Amiability of open markets of electricity also creates scope
of dam and reservoir in Nepal.
4. Flood problem in plain area of Nepal also creates
environment for dam design in hill area.
5. Lowering water tables of ground water in Nepal also force to
makes artificial recharge to ground water for this dam is
important.
6. Scope of local navigation, fishery, water supply and the use

7. Limitationof damand reservoir in Nepal
The main limitation of the dam design in Nepal is
1. Neither a proper planning of watershed nor any past feasible
study is done for dam location.
2. experts or experience manpower are not available.
3. Young geology
4. lack of technology and materials to provides stability for high
dams
5. No specific fund is separated or utilizes from budget for
water resources management
6. Downstream habitats' nature.
7. Downstream boundary is strong