BS 3rd Report

Abstract

The area is the surrounding of Susalgali village along the Khaki-Oghi Road is regionally

metamorphosed. There is alignment of minerals and foliation in mansehra granite known as

Susalgali granite gneiss. This susalgali granite gneiss is intruded in the Tanol formation

which is metamorphosed into quartzite. Dolerite dyke and sills, quartz veins , Aplite bodies of

feldspar are common in the granite.

Rumli is a sedimentary succession. The youngest formation has Miocene age and older has

Paleocene in observed sequence. This area is located on the backside of Quaid-e-Azam

university, Islamabad. The area is in the vicinity of Main Boundary Thrust(MBT) that is why

this area is intensively affected by the tectonic activity. The major lithologies of rock units

are Sandstone (Murree Formation) , limestone (Lockhart Limestone, Margala Hill Limestone and

Chorgali Formation) and Shale (Kuldana formation and Patala formation). Shale of Kuldana

formation and Patala formation , limestone of Margala hill limestone and Lockhart limestone is

richly fossiliferous in this area. Whereas Chorgali formation has no fossils as it has lagoonal

environment conditions.

The Mangla Dam is located on the Jhelum River about 30km upstream of Jhelum city, in Mirpur

district of Azad Kashmir. It was constructed in 1967 during the reign of Mr. Ayub Khan with

reservoir capacity of 5.88MAF for irrigation purpose and also there is a power house of 1050

MW.

Introduction

The field tours are very necessary for the study of geology. By studying text books only

theoretical knowledge is gained but real practical knowledge only can be gained by observing

closely rock units in the field tour. Once such field tour arranged for our class from our

respected Sir Syed Mahmood Ali Shah. The consists of different areas including Rumli area (

sedimentary), khaki-oghi road section (metamorphic) and Mangla dam ( for engineering site).

The field areas were easily accessible and we went there through our university bus. The

tract was smooth and journey was pleasant. On very first day we travelled form Lahore to

Abbottabad. We did field work along the khaki- oghi road for three days from 2nd to 4th March,

2011.

We travelled from Abbottabad to Islamabad stayed in youth hostel. Here in the rumble

area, we also did field work for three days from 6th to 8th march, 2011.

O Wednesday, March 9, 2011 we visited Mangla Dam and a historical place “ fort Rohtas”. On

next day we aimed to do field work in Kundla section but it was fully covered with snowfalls

making it impossible for us. We enjoyed snow and take memorial photographs and return to

Murree. In fact, we enjoy that day a lot.

The area near the town of susalgali along the khaki- oghi and is regionally

metamorphosed. The area is easily accessible form Abbottabad youth hostel through Mansehra by

khaki- oghi road. The area is covered b toposhet no. 43-F/3 under the title of “geological

map of mansehra and khaki- oghi road section”. The concerned area lies between latitude

34.25 to 34.26 and longitude 73.3 to 73.8. The areas is drained by siran river and is covered

by vegetation and trees which constitute the beauty of the area and act as natural purifier of

atmosphere.

Geologically the area is composed of granite and met sedimentary rocks regionally

metamorphosed into gneiss and quartzite and quartos schist. The basic dykes and sills along the

aplite and quartz veins are also present in the granite.

Rumli is the small village on the back side of Quaid-e- Azam University, the area is

sedimentary succession composed of sandstone, shale and limestone Islamabad. The area is

sedimentary succession composed of sandstone, shale and limestone. There is a small nala which

cross out the strike unit. There is a fair road along the nala and good exposures of rocks

unit. The area is covered by thick cover of vegetation and is highly mountainous. It lies

between latitude:33.45 to 33.46 and longitude 73.7 to 73.8.

Geological area is sedimentary deposit with youngest formation of Miocene age and

oldest formation of Paleocene. We made the traverses in this area and found that as we move in

the direction of dip, older formations were present. So we inferred that rock units are

overturned limb of overturned fold.

Mangla dam is earth fill dam with 70% material composed of clay, silt and sand. It is

located on the Jhelum River in Mirpur district of Azad Kashmir under the control of Pakistan.

Dam was started to construct in 1962 and completed in 1969. It is a multi- purpose dam, main

purpose is irrigation but a power station of 1050 mw is also working. Height of the Mangla dam

is 265 ft with storage capacity of 5.88 maf. Dam is placed on the Nagri and Dhok Pathan

formation.

Previous Work

Wynne (1879) was the first geologist who mapped the area on the scale l to 8 miles. He

classified rocks into crystalline and metamorphic. The area remapped by middle miss (1896) on

the scale 1 to 9 mile. Rehman (1966) submitted on account on the geochemistry of granites and

associated rocks of manshehra area, of field et.al(1966). Calkins et. Al. (1988) and Sabri et.

Al. (1967) gave and account of general geology and structure of mansehra, garhi h-k and oghi

guardangless shams (1961, 19630 and shams et . al. (1966, 1967) describe geology petro

chemistry of metamorphic and igneous rocks and also determined the radiometric ages of

granites of Mansehra area. Ashraf M> (1974) also compiled his thesis of phd on geochemistry

and petro-genesis of acid minor bodies of mansehra and batgram area.

Rumli is a part of hazara basin which has been a site of deep interest for the geologists

working on stratigraphy and tectonics sicne a long time Lydekker (1876,1883) and Middlenmiss

(1896) carried out their work in Kashmir and hazara. They determined geology of this area and

named some of the rock units. Calkins, Offield, abdullaa an dlao (1975) dealt with stratigraphy

and structure of a sequence of rocks that range in age from pre- Cambrian to Miocene. For many

years, a number of B.Sc and MSc students of geology department, university of the Punjab,

Lahore carried out mapping and completed basic mapping and geological information of eh area.

Objectives of field tour

Geological excursion of about 11 days with following objectives.

Identification of different lithology and rock units.

The mapping exercise is aimed to make the students practically exposed to different

field geological techniques and procedures of various ideologies, field relationship of

rocks , geological mapping , outcrop studies of different rock units, major mineral

content, textural and structural aspect s and relevant field measurements .

To learn how to analyze and describe the geometry of structures, practice how to use the

brunt on compass for structural features and acquire knowledge o the origin & conditions

of format of various rock types based o the field recognizable criteria.

The program enables the students to identify and distinguish among a large variety of

igneous, sedimentary and metamorphic rocks, typical field features.

The students also collect samples and make snaps of rock units for subsequent

interpretations.

Visit engineering site and learn then geological aspects of that site.

Geological Mapping

Geological mapping is the transformation of ground information to flat sheet of paper. Base

map such as topographic maps are used for this purpose.

Mapping Principles:

Following are the principles of mapping which should be kept in mind while working.

First of all physical reconnaissance of the area is done.

Locate yourself in the field according to your map and orientate map withiest to the

north.

Mapping should be started from a definite point such as bridge, stream or spring etc.

An important thing is to locate yourself on map, with reference to ground features,

natural and manmade features.

Rock units are establish on the basis of lithology.

The following instruments are used for geological mapping.

Dynameters and brunton:

It is used to measure the dip and strike of the rocks.

Geological Hammer:

It is used to differentiate the color of weathered surface, it also gives the idea of

hardness of rocks and to break rock for taking rock samples.

Measuring tape:

To measure the thickness of beds.

Camera:

It is used for taking photographs , now a days, digital cameras are perfectly used.

Dip:

It is the angle between the inclined rock beds and the horizontal plane.

True Dip:

True dip is measured in the direction normal to the strike.

Apparent Dip:

Apparent dip is measured in the direction to the strike.

Strike:

Strike is the trend of rocks. It is formed by the intersection of the horizontal surface with

bedding.

Specification for Mapping:

There are some specification for mapping;

Marks your position on the map with the help of brunt on and GPS.

Place the contour on the premade toposheet of that area properly orientated with respect

to the considering longitudinal and latitudinal lines.

Exposure of rocks and their structural features are marked along with their dip and

strike. Take help form the legends of the toposheet to recognize the cultural, nalas, huts

town etc.

Reconnaissance:

The first step is reconnaissance. Two or three traverses are made along different lines

to know about the geology & structures of eh area.

A complete search of geological area & literature. Distribution of rocks & soil types,

their main features such sliding & faulting, buried channels etc. must be determined.

Self-reconnaissance of the area & of regional outcrops, exposures of rocks and soils in

nearby water well records.

Study of Arial photographs. Base maps and new photographs amps are measured.

Environmental and groundwater conditions are studied.

Susalgali Area

Tectonic And Structure

Tectonically, Susalgali area is part of lesser Himalaya. The area Constitutes hard core of a

major syntaxial loop of the north-western Himalayas. The general strike of this structure

swings in an arcute fashion. From Balakot to Batrasi the strike is almost north-south and then

bends sharply to west-southeast trend that persist up to Darband (out of area). Thereafter, it

again bends sharply to become essentially north-south. In the major area, the strata dip inward

at different inclination but becoming less and less steeply inclined in the northern direction.

The regional structure, this is a gigantic synform with north-East, south-west axis, the plung

of which decreases in the magnitude in north eastly direction.

GEOLOGY OF OGHI – KHAKI ROAD SECTION

Oghi-khaki road section is generally metamorphosed lithalogy from both igneous and sedimentary

origin rocks. It is sleeved that mansehroa granite has been metamorphosed into susalgali

granite gneiss, which shows alignment of minerals in a regular pattern. This granite gneiss has

a wavy and irregular contact known as apophasis with the tanawal formation of sedimentary

origin. The geology and mineralogy of oghi- khaki road section is discussed below;

Susalgali Granite Gneiss:

Susalgali granite gneiss is a foliated augen gneiss with macrocrysts of potash feldspar and

gneissic structure. Dolerite dykes and sills of basic composition are present in it. Aplitic

body of feldspathic composition has also been recognized in area. As being granite gneiss,

major minerals are patash feldspar, plagioclase of albite- anorthite series and quartz. Minor

minerals are bootete, muscovite, chlorite laterally replaced by staurolite, tourmaline,

apatite, zircon, rutitle, monazite and epidote are important minor minerals (shams(1961). Its

contact with tanawala formation is irregular and wavy and known as apophysis.

Tanwal Formation:

The stratigraphic committee of Pakistan formalized “ Tanol group” of wynne(18796) as “ tanol

format or tanawal formatin “ middleniss (1896) called then tanol guarzite marks and ali

(1962) and latif (1970) named then tanol formation. Calkins, offield and alo (1969) made a

detailed study and used the name tanawal formation for this unit of rock.

Tanawal foramtioi consists mainly of guartzite, quartzose schist, quartzite and schistose

conglomerate. Northward the grade of metamorphism is higher than it is in the south. In the

area near susalgali, politic to psamitic rock units showing chlorite to andalusite grade

metamorphism. It has irregular and wavy contact with susalgali granite gneiss in this area. The

format show intense shearing.

The age of formation is Cambrian.

RUMLI AREA

TECTONICS AND STRUCTURE:

Rumli area is the northern most part of potwar plateau ( foreland) i.e. it is the

external part of orogeny. In this area MBT is passing along with its splays. Main boundary

thrust ( MBT) has been marked between the samanasuk format of Jurassic age and Lockhart

limestone of Paleocene age. MBT separates lesser Himalayas form sub – Himalayas. Master thrust

(MBT) thrust which has the maximum displacement lies towards north and towards south

displacement) lies north and towards south displacement decreases. Splays lie between or

towards south. Overall it is forming an in imbricate system. The presence of master thrust

towards south shows that it is a trailing imbricate fan. Master thrust lies towards

hinterland.

In Rumli area overturned stratigraphy can be observed due to the presence of reverse ad

thrust faults. Older formation is present in the direction of dip showing overturned limb of an

overturned fold. The overturned fold shows intense regional tectonic activity which is probably

due to MBT.

This intense tectonic activity can be observed by elongated and crushed nodules of

margala hill limestone. Intrafomational folds and faults are the indicators of a thrust fault.

Moreover the repetitions of formations i.e. Murree format and Kuldana formation is because of

splays in the vicinity of main boundary thrust(MBT).

Geology Of Rumli Area

Murree Formation

The Mari Group of Wynne(1874), Murree Beds of Lydekker (1876), Murree Series of pilgrim (1910)

have formally named Murree Formation by Stratigraphic Committee Of Pakistan. The name is

derived from the Murree hills in the Rawalpindi district. A section expose to the north of the

Dhok Maiki (lat.33’25’N ; long.72’35’E) in Campbellpur district has been designed the type

section.

Murree formation is arenaceous and consists of medium grained Sandston, interrelated with

shale. Fresh color of the formation is greenish grey to light. While the weathered color is

maroonish to brownish. Its environment of deposition is shallow marine lacustrine.

In this formation we found the joints and fractures. We also found cross bedding in sandstone.

With the help of cross bedding, we can map the top and bottom of the bed. Traction of bedding

shows the younger side while the parallelism shoes the older side. Its contact with underlying

Kuladana formation is disconformable.

Its age is early Miocene.

Kuldana Formation:

The term kuldana formation has been formally accepted by the stratigraphic committee of

Pakistan following Latif(1970), Kuldana Beds of Wynne(1874), Kuldana Series of Middlemiss

(1896), variegated Shale of Pinfold(1918), Lower Charat Series of Eames (1952) and Mami khel

Clay of Meissner et al.(1968). The type section is located near the village of Kuldana

(lat.33’56’N; long.73’27’E) North of Murree Hill Station in the Hazara District.

Kuldana formation is composed of variegated beds i.e. argillaceous bed and gypsum bed. Marly

and chalky type is also present. It is highly shared due to tectonic activity and sometimes

mixed with murree formation. It is basically of variable environment while the red shale in

this environment is formed as a result of digenetic process due to the circulation of

underground water.

We observed localize folding in gypsiferous beds. Kuldana formation has its upper contact with

Murree Formation and it is disconformable, while its lower contact with Chorgali formation is

normal.

The formation is of Early to Early Middle Eocene in age.

During the field of Rumli section we observed the kuldana formation two times.

Chorgali Formation:

The term Chorgali beds of Pascoe(1920) has been formalized as chorgali formation by the

stereographic committee of Pakistan. The formation is also represents the passage beds of

Pinfold(1918) in the attack area , Bhadrar beds of Gee and Evans(1937)in the salt range and

Lora formation of Latif (1970) in the Hazara area. The section exposed in the chorgali pass

(lat.33’26’30’N; long.72’41’E) in the khiar-e-murat range, has been chosen the type

section.

It is mainly composed of cream colored argillaceous limestone. In locality it is nodular and

nodularity is due to tectonic activity. Its environment of deposition is lagoonal super tidal

and shallow marine. We observed concentric fold. In concentric fold tensional joints were

developed. Its upper contact is with Kuldana formation is normal and lower contact with Margala

hill limestone is also normal. The age of formation is early Eocene.

Margala hill limestone

The term margala hill limestone of Latif (1970) has been formally accepted by stratigraphic

committee of Pakistan. For nummulitic formation of Waagen and Wynne (1872) the upper part of

the “hill stone “ of Wynne (1873) and cotter (1933) and the part of nummulitic series of

Middlemiss (1896). The name is derived from the margala hills in hazara. The Shahdara section

(lat.33’48N ; long 73’10’ E) of southeastern hazara is considered the type section of the

formation.

It mainly consist of lime stone with subordinate marl and shale. Fresh color of the formation

is grey. Weathered color of this formation is pale grey. It is fine to medium grained and

medium to thick bedded and nodular. We also observed thinly bedded calcite veins nommulities

and assilina fossils are observed. The margala hill limestone was deposited in carbonate rich

sequence. The nodules of the formation were quite bigger.

Its upper contact with Chorgali formation is conformable.

On the basis of foraminifera the age of formation is early Eocene.

Patala Formation:

The term patala formation was formalized by the stratigraphic committee of Pakistan. For the

patala shale of Davies and Pinfold(1937) and its usage was extended to the other parts of the

kohat-potwar and hazara areas. The formation included the Takhabi shale of Eames (1952) and the

part of hill limestone of wynne (1873) and cotter (1933). The part of the numulitic formation

of Waagen and Wynne (1872) part of the nummulitic series of Middlemiss (1896) and the Kuzagali

shale of Latif (1970). The section exposed in Patala nala (lat.32’40’N; long.71’49’E) in

the salt range has been designated as type section.

The formation mainly consists of shale mudstone, marly materials. Its color is brownish grey.

Its environment of deposition is restricted to shallow marine.

Its upper contact is with margala hill limestone while its lower contact is with Lockhart

formation. We observed the nummulities in this this formation. On the basis of foraminifers

late Paleocene age is assigned.

Lockhart limestone

Davies (1930) introduced the term Lockhart limestone for Paleocene limestone unit been extended

stratigraphic committee of Pakistan. To similar units in the other parts of kohat-potwar and

hazara areas. This unit remarkably represent numulitic series of Middlemiss (1896). The lower

part of hill limestone of wynne (1873) and cotter(1933). The Khairabad limestone of Eames

(1952) and Mari limestone of Latif (1970). A section exposed near fort Lockhart (lat.33’26’N;

long 70’30’ E) in Samana range has been designated as type locality of the formation.

It is mainly consist of nodular limestone. The color of limestone is grey to light grey. The

environment of deposition of Lockhart formation is shallow marine and logoonal.

The upper contact is with patala formation. There are abundant foraminifers in limestone.

The age of this formation is Paleocene.

Dam

Dam is check against the course of river to create a reservoir. Dam is structure constructed

for

Water storage

Community and commercial use

Irrigation

Flood control

Diversion of river

Silt and debris control

Classification of dams

Uni-purpose dam:

A dam which is used for only one purpose is called uni-purpose dam.

Multi-purpose dam:

A dam which is used for more than one purpose is known as multi-purpose dam.

Classification on the basis of uses:

Storage dams

Diversion dams

Detention dams

Classification on the basis of Hydraulic:

Overflow dams

Non-overflow dams

Classification on the basis of material:

It is most commonly used classification.

Earth fill dams

Rock fill dams

Earth & rock fill dams

Concrete dams

Concrete Dams:

There are three types of concrete dams.

Gravity dam

Arch dam

Buttress dam

Gravity dam:

Gravity dams use only the force of gravity to resist water pressure i.e. they hold back the

water by shear force of their weight pushing downward.

Arch Dam

Arch dam are concrete or masonry structures that curve upstream into a reservoir stretching

from one wall of a river canyon to the other side.

Buttress dam:

A buttress dam consists of a wall, force supported by several buttress on the downstream side.

The vast majority of concrete that is reinforced with steel.

Embankment Dams:

Any dam constructed of excavated natural materials or industrial waste materials.

It has two types:

Earth fill dams

Rock fill dams

Earth fill dams

Earth fill dams:

Earth fill dams also called earthern, rolled-earth or simply earth dams are constructed as a

simple embankment of well compacted earth. A homogenous rolled-earth dam is entirely

constructed of one type of material but may contain a drain layer to collect seep water.

Rock fill dams:

Rock fill dams are embankment of compacted free draining granular earth with an impervious

zone. The earth utilized often contains a large percentage of large particles hence the term

rock fill.

Parts Of dam

Abutment:

The part of a valley side (wall) against which a dam is constructed. An artificial abutment is

sometimes constructed as a concrete gravity section, to take the thrust of an arch dam where

there is no suitable natural abutment. Right and Left abutment are those on respective sides of

an observer looking downstream.

Reservoir:

The lake behind the dam is called reservoir of dam.

Rims:

The highest parts on the slopes of the valley.

Channel Section:

The part of valley where water is flowing.

Crest of dam:

The elevation of the upper most surface of a dam, excluding any parapet wall railing etc, in

international usage it refers to the crown of an overflow section of dam.

Heel of dam:

The junction of the upstream face of a dam with ground surface.

Toe of dam:

The junction of downstream face of a dam with ground surface.

Cutoff:

An impervious construction or material that reduces seep rate or prevents water from passing

through foundation material.

axis of dam:

The horizontal center of a dam in the longitudinal direction.

Maximum water level:

The level to which we allow the water to rise, it is less than crests.

Freeboard:

The difference between crust level and maximum water level.

Minimum water level:

The level below which we can’t draw water.

Embankment:

Artificial hill or ridge constructed of fill material, usually earth or rock placed with

sloping sides and usually with a length greater than its height.

Rip Rap:

Layer of stones broken rock or precast block placed in random fashion on the upstream slope of

an embankment dam, on a reservoir shore or on the sides of a channel as a protection against

waves. Ice action and flowing water.

Suitable Location

One of the best places for building a dam is a narrow part of a deep river valley; the valley

sides can then act as natural walls. The primary function of the dam's structure is to fill the

gap in the natural reservoir line left by the stream channel. The sites are usually those where

the gap becomes a minimum for the required storage capacity. The most economical arrangement is

often a composite structure such as a masonry dam flanked by earth embankments. The current use

of the land to be flooded should be dispensable.

Significant other engineering and engineering geology considerations when building a dam

include:

permeability of the surrounding rock or soil

earthquake faults

landslides and slope stability

water table

peak flood flows

reservoir silting

environmental impacts on river fisheries, forests and wildlife (see also fish ladder)

impacts on human habitations

compensation for land being flooded as well as population resettlement

removal of toxic materials and buildings from the proposed reservoir area

Dam creation purposes

Function Example

Power

generation

Hydroelectric power is a major source of electricity in the world.

Many countries that have rivers with adequate water flow, that

can be dammed for power generation purposes. For example, the

Itaipu Dam on the Paraná River in South America generates 14 GW

and supplied 93% of the energy consumed by Paraguay and 20% of

that consumed by Brazil as of 2005.

Water supply

Many urban areas of the world are supplied with water abstracted

from rivers pent up behind low dams or weirs. Examples include

London - with water from the River Thames and Chester with water

taken from the River Dee. Other major sources include deep

upland reservoirs contained by high dams across deep valleys

such as the Claerwen series of dams and reservoirs.

Stabilize

water flow /

irrigation

Dams are often used to control and stabilize water flow, often

for agricultural purposes and irrigation. Others such as the Berg

Strait dam can help to stabilize or restore the water levels of

inland lakes and seas, in this case the Aral Sea.

Flood

prevention

Dams such as the Blackwater dam of Webster, New Hampshire and

the Delta Works are created with flood control in mind.

Land

reclamation

Dams (often called dykes or levees in this context) are used to

prevent ingress of water to an area that would otherwise be

submerged, allowing its reclamation for human use.

Water

diversion

A typically small dam used to divert water for irrigation, power

generation, or other uses, with usually no other function.

Occasionally, they are used to divert water to another drainage

or reservoir to increase flow there and improve water use in that

particular area. See: diversion dam.

Navigation

Dams create deep reservoirs and can also vary the flow of water

downstream. This can in return affect upstream and downstream

navigation by altering the river's depth. Deeper water increases or

creates freedom of movement for water vessels. Large dams can

serve this purpose but most often weirs and locks are used.

The Mangla Dam

The Mangla Dam is located on the Jhelum River in Mirpur District, part of disputed Kashmir

under the control of Pakistan. It is the sixth largest dam in the world. It was built from 1961

to 1967 with funding from the World Bank. The project was designed and supervised by Binnie &

Partners of London, and it was built by Mangla Dam Contractors, a consortium of 8 U.S.

construction firms, sponsored by Guy F. Atkinson Company of South San Francisco. Mangla Dam

Contractors employed Pakistanis, Americans, British, Canadians, Germans, and Irish.

Historic development

As part of the Indus Waters Treaty signed in 1960, India gained rights to the waters of the

Ravi, Sutlej and Beas rivers, while Pakistan, in addition to waters of the above three rivers

Recreation

and aquatic

beauty

Dams built for any of the above purposes may find themselves

displaced by time of their original uses. Nevertheless the local

community may have come to enjoy the reservoir for recreational

and aesthetic reasons. Often the reservoir will be placid and

surrounded by greenery, and convey to visitors a natural sense of

rest and relaxation.

within Pakistan and some monetary compensation, received the rights to develop the Jhelum,

Chenab and Indus river basins through construction of the Indus Basin Project. Until 1967, the

entire irrigation system of Pakistan was fully dependent on unregulated flows of the Indus and

its major tributaries. The agricultural yield was very low for a number of reasons, the most

important being a lack of water during critical growing periods. This problem stemmed from the

seasonal variations in the river flow due to monsoons and the absence of storage reservoirs to

conserve the vast amounts of surplus water during those periods of high river discharge.

The Mangla Dam was the first development project undertaken to reduce this shortcoming and

strengthen the irrigation system. The dam was damaged due to an Indian Air Force raid during

the Indo-Pakistani War of 1971. As a consequence, the hydro project was temporarily out of

service.

The Mangla Dam project

The Mangla Dam was constructed in 1967 across the Jhelum River, about 67 miles (100 km) south-

east of the Pakistani capital, Islamabad in Mirpur District of Azad Kashmir, Pakistan. The main

structures of the dam include 4 embankment dams, 2 spillways, 5 power-cum-irrigation tunnels

and a 1,000 MW power station.

The main dam is 10,300 feet (3140 m) long and 454 feet (138 m) high (above core trench) with a

reservoir of 97.7 square miles (253 km). Since its first impounding in 1967, sedimentation has

occurred to the extent of 1.13 million acre feet (1.39 km), and the present gross storage

capacity has declined to 4.75 million acre feet (5.86 km) from the actual design of 5.88

million acre feet (7.25 km). The live capacity has declined to 4.58 million acre feet (5.65 km)

from 5.34 million acre feet (6.59 km). This implies a reduction of 19.22% in the capacity of

the dam.

The power station of Mangla dam consists of 10 units each having capacity of 100 MW.

In order to remedy the storage capacity decreases, the Pakistani government has decided to

raise the dam by 40 feet (12 m), to 494 feet (151 m) high. This will increase the reservoir

capacity by 18% and provide an additional 644 MWh of power, but will displace 40,000 people

currently living near the reservoir.

The project was designed primarily to increase the amount of water that could be used for

irrigation from the flow of the Jhelum and its tributaries. Its secondary function was to

generate electrical power from the irrigation releases at the artificial head of the reservoir.

The project was not designed as a flood control structure, although some benefit in this

respect also arises from its use for irrigation and water supply. The Government of Pakistan

had agreed to pay royalties to the Government of AJK (Azad Jammu and Kashmir) for the use of

the water and electricity generated by the dam. Over 280 villages and the towns of Mirpur and

Dadyal were submerged and over 110,000 people were displaced from the area as a result of the

dam being built. Some of those affected by the dam were given work permits for Britain by the

Government of Pakistan, and as a result, in many cities in the UK the majority of the

'Pakistani' community actually originated from the Dadyal-Mirpur area of the disputed region of

Jammu & Kashmir.

Mangla Dam is approx. 67 miles (100 km) south-east of the Pakistani capital, Islamabad while

Tarbela Dam is 60 miles (100 km) northwest.

Mangla Dam Raising

Since its first impounding in 1967, sedimentation has occurred to the extent of 1.13 MAF, and

the present gross storage capacity has declined to 4.75 MAF from the actual design of 5.88 MAF.

The live capacity has declined to 4.58 MAF from 5.34 MAF. This implies a reduction of 19.22% in

the capacity of the dam. Unless measures were taken in time, this mega project would have

become a dead dam in years to come. Since the design feature of the dam includes its raising to

an additional 30 feet, the government of Pakistan decided in 2004 to go ahead with its raising

project. Raising of the Mangla Dam will help into regain the reservoir capacity lost to

sediment deposition and make provision for future sedimentation. Main features of the project

include four earth dams with a maximum height of 454 ft. (154 meters) and total length of about

13 kilometers. For flood routing, two spillways are provided. The raising project will also

generate construction activity and employment opportunities at large scale. The dam has already

contributed significantly towards improvement of the environment in terms of agriculture

growth, job opportunities and improved standard of living. Availability of additional water and

hydro power will further enhance these positive impacts.

WAPDA inked a Rs.13.793 billion contract on June 28,2004 with CWE JV led by a Chinese Company

China International Water and Electric Corporation for the construction of main works of Mangla

Dam Raising Project in the stipulated period of 39 months ending September 19,2007. The local

contractors in CWE JV include Descon Engineering, Interconstruct Gammon Pakistan and Sachal

Engineering Works. The major components of the Mangla Dam raising works comprise raising of the

dams and main spillway head works besides constructing a control weir upstream of the emergency

spillway. Construction of an 18 kilometers long Mirpur bypass Road is also included in the

contract. On completion of the project in 2007 the average annual water availability for

irrigation releases would increase by 2.88 million acre feet (3,550 MCM). The power generating

facilities of the original dam were designed for raised Mangla conditions. The average annual

energy output is estimated to increase by about 12 percent of the present energy production.

Salient Aspect of Raising Project

Feature Present Projected

Reservoir 1202 ft. (366.5m) 1242 ft. (378.7 m)

Minimum Operation Level 1040 ft. (317.1 m) 1040 ft. (317.1 m)

Gross Storage Capacity 4.5 MAF (5,553 MCM) in year

2007 7.4 MAF (9,132 MCM) in year

2007

Crest Elevation of Erodible

Bund 1216 ft (initial 1208 ft) Replaced by Concrete

Control Weir, Crest

elevation 1243 ft. (379 m)

Elevation of Control

Structure 1234 ft. (376.2 m) 1266 ft. (386 m)

Main and Intake Embankment

Height 454 ft. (138.5 m) 484 ft. (147.6 m)

Economic Geology

Natural resources present in a country reflects economic and prosperity of that country.

Geological and mineral resources play their role in the economy of country. Nature has blessed

Pakistan with enormous geological and mineral resources. Our concerned area is also rich in

mineral resources. Some are discussed below.

Dolerite Dyke:

Dolerite Dyke found in susalgali Granite Gneiss are intrusive basic rocks of plagioclase

feldspar and pyroxene. These dolerite dykes are being used as dimension stones because of their

good strength and very good polish value.

Aplite Dykes

Aplite dykes are commonly found in granitic bodies. These are commonly found in granitic

bodies. These are light colored equigranular bodies formed from residual melt rich in quartz

and alkali feldspars. These alkali feldspars are used for making ceramics.

These are also used in geochronology and thermo-chronology. Alkali feldspars are also used for

radiometric dating.

Plagioclase Feldspar:

Plagioclase feldspars having albite is most common raw material for ceramics and geopolymers.

Trace minerals:

Apatite, Zircon, Tourmaline, And some other trace minerals are present in susalgali area.

Granite may condition upto $ppm Uranium.

Patala Shale:

Patala shale is one of the formations in Pakistan known as petroleum source rock. These shales

are rich in hydrocarbon compounds.

Murree Sandstone:

Murree sandstone has good engineering properties as it has been used as rip rap in Tarbela dam.

CONCLUSION

Susalgali granite gneiss is metamorphosed from mansehra granite and is member of older

group granites.

The grade of metamorphism of Tanol formation increases northward.

In Rumli areas, the rock represent the overturned limb of overturned fold.

Rock units in this area are intensely sheared due to tectonic activity.

Chorgali formation in rumble area has no fossils indicating lagoonal conditions of

deposition.

The gypsum in kuldana formation indicate tidal environment while the red share is

result of digenetic process due to the circulation of groundwater.

Foundation of mangla dam is placed on sandstone bed of dhok pathan formation.

The basic purpose of Mangla Dam is irrigation.

RECOMMENDATION

Older top sheets should be regularly updated because natural and man- made activities are

constantly replacing the older features.

Urbanization is continuously reducing the geologically important sites. Same is the case in

Rumli area. So there should be a check on urbanization.

Now dams should be constructed on the plane to remove the silt periodically through the

turbulence tunnels.

References