Ten major Dam reservoirs of India- safety storage of India

Hi, 

 This article mentions the names of the dams in the water resources map of India.

These are the major dams which form the reservoirs that are the major water resources of India.

1. Bhakra Dam - in Himachal Pradesh

It forms the third largest reservoir named as Gobind Sagar, with a storage capacity of 9.34 km^3. With an height of 226m, Bhakra dam is the highest vertical concrete gravity dam in Asia. 

clicked on the way to Naina Devi of Bilaspur. (source: wikipedia)

It is constructed just on the border of Himachal and Punjab, on the Sutlej river in the Bilaspur district of Himachal Pradesh.

 2. Tehri Dam  in Uttarakhand

Tehri Reservoir on 1st March 2008.

civil engineering students from NIT Hamirpur, on an industrial visit to Tehri dam on 1st march 2008 .. with CP Sir.

 With a height of 261m its the highest dam in India. It's an rock and earth fill dam, constructed on the Bhagirathi river near Tehri in Uttarakhand. Reservoir has a capacity of 4.0 Km^3.

3. Sardar Sarovar (Gujrat)

With an installed reservoir capacity of 9.5 Km^3, it is one of the largest reservoir.

Sardar Sarovar dam, undergoing height extension in 2006 (source wikipedia)

Length of the dam is 1.21 Km, while the height is 128 m and growing. 

4. Rihand Dam (Uttar Pradesh)

Witha a length of 934 m and a height of 91 m, this dam create one of the biggest reservoirs with total impounding capacity of 10.6 km^3.

Jawahar Lal Nehru at Rihand Dam (source; wiki)

But due to the siltation problem, mostly the alkaline ash from the nearby many thermal power plants, it has only 8.9 km^3 as its active capacity. The dam is constructed on the Rihand river in the Sonbhadra district of Uttar Pradesh. 

5. Indira Sagar Dam (madhya Pradesh)

Constructed on river Narmada, and with a capacity of 12.22 Km^3, it creates the largest reservoir in India.

6. Hirakud Dam (Orissa)

It is the longest dam in the world with a composite length of 25.8 km. Main dam is a concrete dam of 4.8 km while the dykes of 21 km makes the total length. It has the largest artificial lake in the India.

It was constructed to control the wild floods on the river Mahanadi.

7. Nagarjuna Sagar (Aandhra Pradesh)

8. Mullaperiyar Dam( Kerala)

9. Tunga-Bhadra Dam (Karnataka)

10. Sholayar Dam (Tamilnadu)

I have the dream of visiting the other dams too. How many of them have you visited? 

Please leave a comment.

thank you :)

GATE 2014, PSUs- irrigation Engineering - one liners - part 11

Hello there,

Here is the 11th part of our notes for the preparation of the GATE and PSUs exams.

• Fertility of a soil is adversely affected, when the pH value is more than 11.
• Optimum depth of kor watering for rice crop is nearly 19 cm.
• Average delta of rice crop is nearly 120 cm.
• The duty of a crop is 432 hectares/cumec, when base period of the crop is 100 days. Delta for the crop will be 200.
• Water consumed in irrigation, when compared with the total water used for all purposes in our country, is about 90%.
• Water consumed for producing one tonne of wheat and one tonne of rice will be of order 2000 tonnes and 4000 tonnes.
• Lime concrete lining is used when velocity of flow is below 2 m/sec, irrigation channel with capacity upto 200 cumec and where economy is required.
• Thickness of concrete lining, for discharge upto 200 cumec varies from 10 to 15 cm.
• Force considered for the analysis of an elementary profile of a gravity dam under empty reservoir condition is self weight.
• Uplift pressure on a dam can be controlled by pressure grouting in foundation, constructing drainage channels between dam and its foundation and by constructing cut-off under upstream face.
• In a gravity dam total force due to wave pressure acts at a height of 0.375.hw above the still water level.
• Horizontal acceleration due to earthquake results in hydro-dynamic pressure and inertia force in the body of the dam.
• Vertical acceleration due to earthquake results in increase in the effective weight of the dam and also decrease in the effective weight of the dam.
• In the elementary profile of a dam having empty reservoir condition, vertical stress at heels and toe are respectively given by 2W/B and 0.
• In gravity dam, main overturning force is water pressure.
• For economical design of a gravity dam, shear friction factor should be 0.65.
• In Ogee shaped spillway, discharge is proportional to H^(3/2).
• Garrets diagrams are based on Kennedy's theory.
• Discharge co-efficient of an Ogee-shaped spillway is 3.7.

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Six Points of Comparison Betweenn Kennedy's Theory and Lacey's Theory

Hello,

Here is a point-wise comparison of Kennedy's theory and Lacey's theory for the design of channels for canals etc.

1. The concept of silt transportation is same in both the cases, both agree that the silt is carried by the vertical eddies generated due to friction of the flowing water against rough surface of canal. Kennedy considered a trapezoidal channel section and, therefore, he neglected eddies generated from the sides. For this reason, Kennedy's critical velocity formula was derived only in terms of depth of flow(y).  Lacey considered that an irrigation channel achieves a cup-shaped section(semi-ellipse) and that entire wetted perimeter of the channel contributes to the generation of silt supporting eddies. He, thus, used hydraulic mean radius(R) as a variable in his regime velocity formulas instead of depth(y).
2. Kennedy stated all the channels to be in state of regime provided they did not silt or scour. But Lacey differentiated between two regime conditions, i.e. initial regime and final regime.
3. According to Lacey, grain size of material forming the channel is an important factor, and should need much more attention than what was given to it by Kennedy. He connected grain size(d) with his silt factor(f) as f= 1.76(dmm)^0.5.
4. Kennedy used Kutter's formula for determining actual generated channel velocity. The value of Kutter's rugosity coefficient(n) is again a guess work. Lacey, on the other hand, has produced a general regime flow, after analyzing huge data on regime channels.
5. Kennedy has not given any importance to bed width and depth ratio. Lacey has connected wetted perimeter(P) as well as area(A) of the channel with discharge, thus, establishing a fixed relationship between bed width and depth.
6. Kennedy did not fix regime slopes for his channels, although, his diagrams indicate that steeper slopes are required for smaller channels and flatter slopes are required for larger channels. Lacey, on the other hand, has fixed the regime slope, connecting it with discharge.

Thanks!

Types of Open channel flows

Hello there,

Open channel flow can be classified in the following broad categories and then the subsequent sub-categories:

1. Steady flow
2. Un-steady Flow

Further each is classified as:

1. Uniform flow
2. Non-uniform flow

Non-uniform flow or varied flow is further classified as:

1. Gradually varied flow
2. Rapidly varied flow

Now let's discuss them briefly here,

• Steady and un-steady flows  When depth of flow and velocity does not vary with time, flow is called steady flow and if depth and velocity vary with time then this is un-steady flow.

• Uniform and Non-uniform Flow When the depth,slope,cross-section and velocity remain same/constant over given length of channel, flow is called uniform flow and if they vary then this is called non-uniform flow.
• Rapidly varied flow(RVF) is the flow when the flow conditions changes significantly in a relatively short distance of the channel.
• Gradually varied flow(GVF) is the flow when the flow conditions changes gradually over a long distance of the channel.  e.g. flow behind a dam at a channel transition.

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Gradually Varied Flow(GVF)

The Assumptions used while analyzing Gradually Varied flow(GVF)

A steady, non-uniform flow in which the depth of flow varies gradually along the length of the channel is called a gradually varied flow.
To analyze Gradually varied flow, the following assumptions are made:

1. Channel is a prismatic channel section and alignment remains the same.
2. Bed slope is small, i.e. So=Sf.
3. Energy loss is the same for a uniform flow at a section having the same velocity and hydraulic radius.
4. Energy correction factor a=1.
5. The roughness coefficient is independent of the depth of flow and constant throughout the channel.

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GATE questions from Hydrology - GATE PSUs preparation -part 10

Hi,
Here are few statements from Hydrology which has made their place in GATE Civil Engineering(CE). The bold letter represents the answer which are absent in actual question.

1. A linear reservoir is one in which storage varies linearly with outflow rate.
2. When there is an increase in the atmospheric pressure, the water level in a well penetrating in a confined aquifer does not undergo any change.
3. During a 6-hour storm, rainfall intensity was 0.8 cm/hour on a catchment of area 8.6 km^2. The measured runoff volume during this period was 2,56,000 m^3. The total rainfall that was lost due to infiltration, evaporation, and transpiration (in cm/hour) is 0.304.
4. Vertical hydraulic conductivity of the top soil at certain is 0.2 cm/hr. A storm of intensity 0.5 cm/hr occurs over the soil for an indefinite period. Assuming surface drainage to be adequate, infiltration rate after the storm has lasted for a very long time, shall be 0.2 cm/hr.
5. While applying Rational formula for computing design discharge, the rainfall duration is stipulated as the time of concentration because this leads to the largest possible rainfall intensity.
6. The plan area of a reservoir is 1 km^2. Water level in the reservoir is observed to decline by 20 cm in a certain period. During this period, the reservoir  receives a surface inflow of 10 hectares-meters, and 20 hectares-meters are abstracted from the reservoir for irrigation and power. The pan evaporation and rainfall recorded during the same period at a near by meteorological station are 12 cm and 3 cm respectively. The calibrated pan factor is 0.7. The seepage loss from the reservoir during this period in hectare-meters is 4.6.

to be contd...

GATE, PSUs - Hydraulics, Irrigation, water resource Engg. notes - part 9

Hello there,
How have you been? Here is the 9th part of our notes for preparation of GATE and other examinations related to Civil Engineering.

1. The displacement thickness of a boundary layer is the distance by which the main flow is to be shifted from the boundary to maintain the continuity equation.
2. The range of specific speeds in MKS units for Francis turbine is 60-300, for Kaplan turbine is 300 - 1000; for Pelton with one jet is 10-35 and for Pelton with two jets is 35-60.
3. If the height of submerged portion of a symmetrical right circular cone is 'h', then the centre of buoyancy will be at a height of 3/4(h) from the apex on the bottom side.
4. Loss of head for various pipe fitting is given by (K.v^2)/(2g). The value of K in will be in increasing order for the following sequence of fitting: 45 degree elbow, 90 deg. elbow, foot valve of pump and close return bend.
5. In a pipe network at a point, if a pipe diverges into two other pipes of smaller diameters and if those two again converge into one at another point, then the potential drop between these two points will be same for both of the pipes.