FIELD TOUR REPORT TOUR TO ISLAMABAD, ABOTABAD, MUREE, MUZAFFARABAD, MANGLA, AZAD LASHMIR, BALAKOT

2013

FIELD TOUR REPORT

TOUR TO ISLAMABAD, ABOTABAD,

MUREE, MUZAFFARABAD, MANGLA, AZAD

LASHMIR, BALAKOT

SADIA RAHAT ROLL NO: 43

4/1/2013

Field Tour Report 2

TABLE OF CONTENTS

Topic Pg.No:

DEFINITIONS 4TYPES OF DAMS 7

EARTHQUAKES 7

MANGLA DAM 9

SEISMIC OBSERVATORY 13

TRANSISTORS 14

BATRASI FOREST 17

GARIHABIBULAH 18

MIANDER 19

KBT 19

MBT 20

FLOODS 20

ALUVIAL FANS 21

MUREE FORMATION 23

SAFETY WALL 25

RETAINING WALL 26

WATER DIVIDE 27

PHAGWARI LANDSLIDE 28

Field Tour Report 3

DEFINITIONS

DAM:

Dam is a barrier. It stops water and underground streams. Its primary purpose is to retain water. While other structures like flood plains and levees also known as dikes are used to manage or prevent water flow into specific land regions.

Hydropower and pump storage hydroelectricity often used in dams to generate electricity.

MAXIMUM FLOOD LEVEL:

Constructed dam should contain the water level or volume at least equal to maximum flood level that has taken place before.

NORMAL STORAGE LEVEL:

By considering the past floods we can determine the storage capacity of dams.

CAUSTIFICATION:

Some lithologies undergo solutioning especially soft rocks. Caves develop due to solutioning. Examples include the rock salt and limestone that undergo solutioning.

RUN OFF RIVER:

If many checks are not present on river channel, level of river channel almost remains the same.

SILTING:

Embankment of reservoir could be raised in order to increase the capacity of reservoir. Example is Mangla raising project.

CELLOSE:

A provision due to which sediments comes out in the form of channels below the reservoir.

ABUTMENT:

The part of the valley site against which the dam is constructed.

RIGHT AND LEFT ABUTMENTS:

These are the respective sides as an observer when viewed downstream. It is a raised portion or natural topography. Dam will be formed against this topography.

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The way towards which water flows, from upstream to downstream, topography on its left side is the left abutment & the topography on its right side is the right abutment.

CREST OF DAM:

The crest of dam is the top of spillway and top of dam that should be used for referring to the overflow section and dam proper.

EMBANKMENT:

Fill material (which fills valley) usually earth or rock placed with sloping sides. In case of Mangla dam it is sandstone & shale.

FOUNDATION OF DAM:

The natural material on which dam structure is placed called as the foundation of dam. It is basically the natural valley present before dam is constructed.

FREE BOARD:

Vertical distance from water surface to the lowest elevation at which water would flow over the dam at a section not designed to be overflowed. In rainy season, water overflow through the embankment.

Example: Warsak Dam.

SILTING BASIN:

Basin containing angular, spherical gravels, gravels in river is always rounded.

FORMATION:

Body of rock which is extendable or map able over a large area and unified by its distinct characteristics is called as formation. For example: Fauna and lithology.

CORE:

Core is the impervious zone. It’s a zone of material of low permeability in an embankment dam. Hence it is termed central core, inclined core and road clay core.

CUT OFF :

An impervious construction by means of which seepage is reduced prevented from passing through foundation material.

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CUT OFF WALL:

A wall of impervious material (concrete, steel sheet, piling) built into the formation to reduce seepage (100% seepage cannot be controlled but can be reduced).

DRAW DOWN:

Resultant lowering of H2O surface level, due to release of H2O from reservoir.

INTAKE:

Any structure in a reservoir, dam or river through which H2O can be drawn into an outlet point or tunnel is called as intake.

RIP RAP:

A layer of large uncoarsed stones, broken rocks placed in random fractions on the upstream slope of embankment dam, on a reservoir shore or on side of channel as protection against waves.

HEEL OF THE DAM:

The junction of upstream phase of a gravity or arch dam with the foundation surface.

SPILLWAY:

A structure over or through which flood flows or discharge if the flow is controlled by gates,

it is considered a “controlled spillway”, if the elevation of the spillway crest, is the only

control it is considered as “uncontrolled spillway”.

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TYPES OF DAMS

Dams are of following types on the basis of structure:

ARCH DAMS:In the Arch dams, stability is obtained by a combination of arch and gravity action. For example is of Rawal dam.

GRAVITY DAMS:

In the Gravity dams, a force that holds the dam in place against the push from the H2O is earth gravity pulling down on the mass of the dam.

ARCH GRAVITY DAMS:

A gravity dam can be combined with arch dam.

EARTH FILL DAM:

Also called earthen dam or simply earth dam are constructed at simple embankment of well compacted earth.

SADDLE DAM:

A saddle dam is an auxiliary dam constructed to confine the reservoir created by a primary dam either to permit a higher H2O elevation or storage or to limit the extent of a reservoir for increased efficiency.

An auxiliary dam is constructed in a low spot or saddle through which the reservoir would otherwise escape. On occasion a reservoir is continued by a similar structure called a dike to

prevent inundation of nearby land.

EARTHQUAKE

CAUSES OF EARTHQUAKE:

Earthquakes are caused by faulting, a sudden lateral or vertical movement of rock along a rupture surface. Earthquakes often occur in volcanic regions and are caused by both of the tectonic faults and movement of magma in volcanoes.

FORMATION OF EARTHQUAKE:Earthquakes are formed when there is a vibration in the earth crust, causing a sudden release of energy. This energy is radiated out from earthquake epicenter, in the form of seismic waves.

Field Tour Report 7

DAY 1

VISIT TO MANGLA DAM

VISIT TO SEISMIC OBSERVATORY

Field Tour Report 8

MANGLA DAM

INTRODUCTION:

Some part of Mangla Dam is located in Jehlum (Punjab) while most part of this dam is located in Mirpur Azad Kashmir.

In the flood season emergency spillway of dam becomes open. 1000MW energy is being generated from here. 10 turbines are located in hydro

power generation plan each of which produce 100MW electricity. Saddle embankment is formed in order to keep water accumulated in reservoir so

that water would not flow towards low lying area. During Mangla raising project, water could move into nearby areas. In order to give

compensation to residents a new city was proposed. Mangla dam is constructed on river Jhelum and Poonch.

LOCATION:

The project is located on Jhelum River at Mangla in the district of Jhelum and province of Punjab. Project is accessible by the road.

REASON FOR FORMATION:

Primary Purpose: Irrigation Secondary Purpose: Power Generation.

Field Tour Report 9

HISTORY:

Terraces and moderately high mountains with steep slopes covered with vegetation and Peak with snow are present in Jhelum River Basin.

The weather of River Jhelum basin is extreme and lies in monsoon belt. Mangla dam reservoir is the catchment area between Mangla & Muzaffarabad. Mangla reservoir is present in the range of Siwaliks rocks at the south western edge

of Jhelum Basin.

HYDROLOGY:

Basic source of runoff into Mangla is the precipitation, both as snow as well as rain. Upper part of the basin, upto Kohala, supplies snowmelt while the lower part, below

Kohala, supplies is essentially a rainfall catchment. The Mangla catchment characteristics show that it has two peak flow conditions, one

in June and second during July-September period. The higher June flows are caused by the higher snowmelt due to the increased temperature, while the July-September peaks are the result of the rainfall combined with the snowmelt.

There are 22 stream-gauging and climatologically stations in and around Mangla catchment which are being used for reservoir operation and flood management purposes.

Floods pose a problem to designers of dams, because of uncertainties associated with occurrences of extreme events and decisions have to be made as to the best way to handle these uncertainties. The objective therefore, is to make dam safer and reduce any risks to acceptable limits.

Issues such as passing high concentrations of sediment through the turbines and irrigation valves and blockage of the power intakes-due to turbid density currents, progressive sediment built-up in the basin or its liquefaction during an earthquake-will become increasingly important and threaten the continued optimum operation of the project.

If the dam is raised, there will be the potential for sedimentation problems to reduce substantially for many years.

The hydrographic surveys are mostly carried out from boats, when the reservoir is full or nearly full, using, echo sounder, station pointer and digital distance measuring units.

GEOLOGY:

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Understanding of the geology, seismicity and hydrology of the area around Mangla has advanced significantly since construction. Design standards have changed, communities have grown on the shoreline and sediment has deposited in the reservoir. It was therefore considered prudent by WAPDA that feasibility of the original provision for raising is established in the light of these changes.

The feasibility study has further shown that raising the dam by 30 ft and 40ft is technically feasible and economically viable. However the incremental benefits of raising the dam from 30ft to 40ft are relatively small against substantial costs and displacements of population. In view of these considerations, a final choice of 30ft raising the dam has been made.

DIFFERENT DAMS IN MANGLA:

MAIN MANGLA DAM:

The main dam area rocks comprise alternating beds of sandstone and siltstone and clays.

Relevant to raising the main dam, the following aspects were considered important: Foundation conditions under the dam and the downstream toe area. Seepage in the raised condition. With the raising of dam, the increase in the pore pressures and seepage through the

dam foundation may be expected.

SUKHIAN DYKE:

Sukhian dike follows the crest of the ridge for a distance of 2.5 miles eastward from Mangla to Bala Gala ridge. Alternating beds of clay, silt, siltstone, sandstone and gravel of the Siwaliks formations underlie the whole area of sukhian dike.

In case of raising, the sukhian dike will require extension towards its western end and construction of a saddle embankment on its eastern end.

JARI AND KAKRA DAM:


Jari dam is underlain by a series of layers of clay, silt, siltstone, sandstone and gravel of the Siwaliks. The bedrock in the center of the site is covered by alluvium of the Jari and Kakra Nallas.

The Jari sandstone beds are much weakly cemented and both clay and sandstone beds contain a higher proportion of silt as compared to those in other areas of the project.

The performance of Jari and Kakra dams has been satisfactorily as confirmed by physical inspection, periodic inspections and thorough the study of data of monitoring instruments.

In Kakra dam area, silt blanket especially in gravel beds area requires particular attention from seepage point of view with raised conservation level. Nullahs downstream of Kakra have steep gradient and erosion is already active. Seepage and erosion aspects will be carefully studied.

SADDLE:

Raising of Mangla dam will require construction of an embankment across a saddle just east of sukhian dike.

The saddle in this area is formed of siwaliks gravels which outcrop towards the reservoir side of the ridge.

The design of the saddle embankment incorporates an upstream impervious blanket to prevent seepage through these gravel beds.

SEISMIC OBSERVATORY


Mangla dam is the16th largest dam in the world. Its central recording station is in seismic observatory.

There are 10 field stations of it that send earthquake reports. In seismic observatory earthquakes of magnitude less than 3 are recorded and their

effects are being recorded here. Loading and unloading of water in reservoir also be observed here.

When stress changes there are some changes in pore pressure that causes micro earthquakes.

Recording of earthquakes possessing greater magnitude is important from engineering point of view.

There are two types of network for recording earthquakes. One is digital record that is electrical record. While other is analogue that is actually the record on paper.

Digital record is useful while doing analysis while analogue record is useful for at a glance observation.

Seismic observatory lies in the Murree Siwalik formation. Alternative forms of sandstone, clay and loose gravel are present here.


Modulation is carried out in order to increase the amplitude and frequency of earthquake waves while demodulation is carried out when amplitude and frequency comes back to original position.

Faults of this region are divided in 7 zones. MBT, Jhelum and bong canal are major faults of this region. Distance between s and p waves is calculated in terms of latitude and longitude. On average 50-60 micro earthquakes are recorded in this observatory. The area of Mangla dam is of 50km. S=VT is used to calculate distance of earthquake. It is difficult to identify S wave but it is very important to detect correct distance

between s and p waves. Seismometer demodulates the modulated waves. S waves are shear waves hence cannot pass through water because shear waves do

not pass in water. Surface waves passes through layering. In analogue system we cannot view the difference between s and p waves due to

this limitation digital system is being used. Magnitude of earthquake remains same while the intensity is different at different

places.


Transistors

Sensor senses the seismic waves and converts mechanical energy into electrical energy.

If station is 30-40km far away from epicenter then transmitter, amplifier and receiver are used.

Seismometer sends signals to analogue network when forces acts on rocks after passing through plastic deformation they break.

Sensor senses the vibrations and amplifier amplify the signals if these are weak. Magnitude is actually the energy released. It is independent. Intensity is the consequences or effects in terms of human perception. Change in

topography.


DAY 2BATRASI FOREST GARIHABIBULAH

VALLEY MUZAFFARABAD

MIANDER KBT

MBT ALLUVIAL FANS

FLOODS

BATRASI FORESTField Tour Report 16

In Pakistan Less than 4% of the land is covered with forests. Forests have economic, environmental and climate control benefits. Forests help in controlling or reducing the floods. The area of Batrasi Forest is located on the way to Muzaffarabad, Pakistan.

BATRASI FOREST:

Organisms present there are mostly the mesoorganisms that is they can be seen by naked eye. These are basically the soil engineers that include

Mesofauna (invertebrates including nematodes, mites etc.)

Microfauna (nematodes, small arthropods etc)

These nematodes move by the feeding activities. As a result of their movement different changes occur that lead to the formation of three layers of organic horizons

LAYERS OF ORGANIC HORIZON:

The three basic layers of organic horizon are:

a) Organic Litter (OL)

b) Organic Fragmented (OF)

c) Organic Humus(OH)

ORGANIC LITTER (OL):


This layer is dominated by organic material.

It consists of freshly fallen needles, twigs, and other debris that have undergone only slight decomposition, that has been deposited on the surface of soil.

This layer is identifiable.

Shape of Horizon starts changing as a result of decomposition by the activity of certain mesoorganisms, humidity and temperature, a new layer i.e. organic fragments starts.

ORGANIC FRAGMENTED (OF):

This layer contains the organic material beneath the litter layer. Decomposition in this layer is very active. Fragmentation of litter starts in this horizon layer. Thus the small fragments of litter such

as leaves twigs needles can’t be identified and this layer becomes unidentifiable.

ORGANIC HUMUS (OH):

It is the layer next to organic fragmented. This layer consists of Humus that is unrecognizable, dark brown or black, amorphous

organic material that has undergone complete decomposition.

ROLE OF ORGANIC HORIZONS:

Soil organic horizons are critical components of forest soil productivity.

Organic Horizons play an important role in improving the humus morphology i.e. the structure of humus.

These horizons play unique roles in moisture retention and nutrient cycling.

They reduce the impact of Global warming.

GARIHABIBULAH VALLEY

River Neelum & River Jehlum meet at Muzaffarabad and flows down into River

Kunhar.

The rainfall in Kaghan valley and Garihabibulah will ultimately fall into river Jhelum.

Mangla dam is constructed over the river Jhelum.

MUZAFFARABAD (Azad Kashmir)


MIANDER:

River Neelum & River Jehlum meet at Muzaffarabad and flows down into River

Kunhar.

A large meander moves from north to southeast and combines with Kunhar River. At the inner side of the meander deposition takes place that area is known as Point

Bar. At opposite side erosion takes place. Due to erosion rocks became unstable and safety or retaining wall is formed there to reduce fall and erosion.

LITHOLOGY:

In North of the meander, Muzafarabad Dolomite (Grey colord rock) is present. River Neelum joins here with River Jehlum. Below Muzafarabad, a dark red colord rock is present which is termed as Murree

formation.

KASHMIR BOUNDARY THRUST FAULT (KBT)

In the middle of black and red rock a central fault KBT is present between Muzaffarabad dolomite and Muree formation.

KBT is the main cause of earthquake in 2005. KBT is responsible for Murree fault in Murree formation.

MAIN BOUNDARY THRUST FAULT (MBT)


MBT is the fault present between Murree formation and Hazara formation. MBT is the largest fault along which minor faults are associated. Due to these minor faults sliding takes place in Hazara formation. There is the prominent age difference between Hazara formation and Muree

formation. MBT runs from India towards these formations.

FLOOD 1992

In 1992 flood drainage basin was became closed due to heavy precipitation. River Neelum and Jhelum were flooded as a result flash flood occurred.


ALLUVIAL FANS

Streams incoming from River Jhelum flows downward, sudden drops in velocity as water

finds gentle plain and wide area, deposition took place and alluvial fans develop.


Day 3

MUREE FORMATION


MUREE FORMATION

DEFINITION:

Body of rock which is extendable over large area and unified by distinct characteristics like lithology and fauna.

It contains more than one lithologies, if only one lithology is present then the name will refer to that lithology only like sandstone, shale e.g.

LOCATION:

Muree express way passes below the Muree while its one branch passes from Muree. Lowertopa is the place where this branch combines with main Muree. Jhika gali joins Muree with Lowertopa.

At this location lithology is best describe hence it is known as Murree formation.

COMPOSITION:

It contains Greenish grey sand stone and Maroonish shale.

COLOR:

Its weathering color is brown while inner side is of grey color. It is the typical diagnostic feature of Muree formation.

FOLD:

MBT moves over Muree formation. The rocks of Paleocene, Cambrian and Muree formation lies on syntaxes. From

bottom the rocks are exposed hence we can see Murree formation. In the core of fold, dolomite of Paleocene age is present; as a result fault develops

along limbs of fold. Along one limb of Murree formation fault is developed while along other limb MBT

(Hazara Formation) is present. Muree formation is younger than Muzaffarabad formation hence Muree formation

lies over the Muzaffarabad formation. Muree formation contains grey limestone while Muzaffarabad formation contains

dolomite. Muree formation is the footwall of MBT and KBT. Muree formation does not develop after MBT.


DAY 4

SAFETY WALL

RETAINING WALL

WATER DIVIDE

PHAGWARI LADSLIDE


SAFETY WALL

Depending upon various altitudes the relief of Muree formation is low. There is the gap between the rocks so that if landslide occurs restriction took place

and angle of slope changes due to accumulation of material. If there is a rainfall occur then pebbles and cobbles can move hence safety wall at

the base of toe of rock is formed.


Clay starts flowing after saturation. Escaped water then cannot flow towards the road but flow in drains and holes in safety wall.

PURPOSE OF SAFETY WALL

Accumulation of material in depressions and drains takes place hence angle of repose became stable. If angle of repose increases then landslide occur and if decreases then landslide became controlled.

There is a gap between rocks and safety wall so that material like shale and sandstone can accumulate.

RETAINING WALL

Retaining wall can be constructed on low relief. Usually it is built on the river.


If there is a gentle angle and after that there is an instant slope of 6 feet and downward there is a road. So the instability of this slope may be in this area of 6 feet. So we construct a retaining wall exactly here. So that chances of damage through landslide could be reduced.

This is not compulsory that the retaining wall should be constructing in the river but this is one of the conditions.

Slopes have various segments. It may be steep slope, gentle and both of them may occur together.

On the upper side of slope there may be escarpment. Slopes may be concave or convex slopes.

In convex slopes the instability is greater and slope is more prone to movement. In concave slope the stability is greater. The precautionary measure in order to control the movement of soil is the

construction of safety wall retaining wall and gabbians. If escarpment is low then there will be construction of gabbins while if escarpment is

high then the construction of gabbians and safety wall is carried out. If stones fall down under the action of gravity they will move into the drain and flow

along with it.

We often cover the gabbianns with net so they can never be separated apart.

PLANTATION:

Another method of landslide precaution is the plantation. The small plants are grown manually.


When the plants are small there is a possibility that they also can move due to land sliding but when the plants grow up their roots spread into the soil and they become stable. Now these plants provide stability to the slope.

WATER DIVIDE

Water divide is the upland or elevated area between two valleys.

On the field site, there are three valleys. These valleys are the part of continues

series of rocks. One of these rocks is leading to the Murree (city).

All valleys have two outcrops & here the one outcrop of the middle valley is on the

front of field site and the other one is on the back of field site.

Here one valley is the Soan valley while the other one is of the Bandi Nalla.

These three valleys divide water, hence termed as the water divide.

The basin of Soan valley is different from the other valleys.

Behind water divide there is the river Jhelum.

Soan is very active tributary ultimately fall into the River Indus.

When rainfall occur in the water divide. Water will accumulate in soan valley and

then transform into Soan River.


PHAGWARI LANDSLIDE

LOCATION:

It is located in Kohala valley formed by river Jhelum. Road is going towards Muzaffarabad towards Neelum valley. It is the occasional slide named as a slump or rotational slide, locally called as

“Phagwari Land Slide”. Large amount of loose (shally) material is present while sandstone is in lesser

amount. In case of this landslide, safety walls and gabions provide no benefits. Whenever rainfall occurred, due to increased water load, landslide became active

again & traffic block on both sides of land sliding area. Land slide next to it is the Kohala Land Slide which is actually very active land slide.


Environment

FIELD TOUR REPORT TOUR TO ISLAMABAD, ABOTABAD, MUREE, MUZAFFARABAD, MANGLA, AZAD LASHMIR, BALAKOT