Topography andLandform Survey

Shahpori Dwip & St. Martin Island

Supervised By

Professor Dr. M. Shahidul Islam

Professor Dr. Hafiza Khatun

Professor Borhan Uddin,

Assistant professor Faruk HossAIN

Team Members • Presented By: Afrida Asad(Roll:20) On behalf of,Dola Dutta (28)

Meher Negar

Tuli (202)

Md. Nazmul

Hossain (46)

Raisa Noor (206)

Sadia Afrin (27)

Hafsa Binta

Yunus (148)

Rabeya Islam

(207)

Khadiza Akter

Rema (132)

Flora Nasrin (45)

Mst. Nisat

Taranum Akter

(114 )

Golam

Mohiuddin

Masum (36)

Md. Tanvir Al

Imamhasan(43)

MD Nurullah (30)

Rakibul Islam (38)

Md.Tanvir Ahmed (51)

Shahed Ahmed (17)

Jahiduzzaman Rajib (80)

Halima Khatun (104)

Amar Shanti Chakma (118)

Tahmid Hossain Rafid (04)

Nazia Nowrin Rob (144)

Kabir Hasan (138)

Khondokar Tahmina Nasrin (16)

Shudipto Biswas (52)

Study Area

17/10/2016 (Shahpori Dwip, Teknaf)

19/10/2016

ST.Martin Island

Survey Under Topography & Landform Study

• TASK 1: Leveling to study the elevation of Shahpori Dwip, Teknaf from the sea level.

• TASK 2: Sand dune profile study in St. Martin Island.

• TASK 3: Vegetation or ecological survey of the sand dune in St. Martin Island.

Levelling survey

Levelling is a branch of surveying, the object of which is to find the elevationof a given point with respect to the given or assumed datum. Establish a pointat a given elevation with respect to the given or assumed datum.So, leveling is the measurement of geodetic height either from the sea level orother known value (BM value)

Study Area

• Area: ShahporirDwip, Teknaf.

Instruments used in levelling

Tools Used in Levelling Survey:

• Angle measuring instrument

• Two ranging rod

• Measuring tape

• Rope

• Leveler

Method That We Followed

• At first the location of mean sea level were identified where the

elevation is zero.

• A rod was held vertically on that point and the instrument

Sunnometer was used to read the rod scale. This gave the height of

the instrument above the starting (backsight) point and allowed the

height of the instrument (H.I.) above the datum to be computed.

• The rod was then held on an unknown point and a reading was

taken in the same manner, allowing the elevation of the new

(foresight) point to be computed.

• The procedure was repeated until the destination point was

reached.

Glimpse of Levelling Survey

Outcomes of Our Survey

• Highest elevation : 1.57 meters(Primary School)

• Average elevation: 1 meter

• Drilling point elevation: 0.2 meter

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Outcomes of Our Survey

A Map showing the pathway of the survey

Analysis

From above Data representation we can say the area is not that much higher in elevation where the highest relies in approximately 1.6 meter ( a primary school) above sea level. The drilling survey point, the penetration points elevation, profile survey elevation are shown which are also very close to sea level.

Challenges whichWe Faced

• Insufficiency in GPS tools

• Prior observation of whole area should be done before starting survey

Sand dune study

A dune is a hill of loose sand which occur in different shapes and

sizes, formed by interaction with the flow of air or water. It occur in some

deserts and along some coasts. Some coastal areas have one or more

sets of dunes running parallel to the shoreline directly inland from the

beach which protect the land against potential ravages by storm

waves from the sea.

Sand Dune

• Protect island from coastal water intrusion.

• Resilient barrier to the destructive forces of wind and waves.

• Important ecosystems supporting unique flora and fauna

including rare and endangered species.

Importance of Sand dunes

Our Survey Area

Sand Dunes studied in St Martin Island.

1. Near Golachipa

2.North West part

Method That We Followed

• Leveling method were followed using angle measuring instrument (suuntometer) to measure the elevation of sand dunes from the shoreline.

• Six stations were selected in both survey areas.

• From five stations (1-5) leveling started toward the sand dunes perpendicularly and one (station 6) horizontally.

• GPS value were taken from each stations.

• The Land use of both sand dunes were observed.

Glimpse of Sand Dune Survey

• Place: Golachipa

• Highest Elevation: 3.00 m

• Land Use: A resort and a

fisherman’s house

Dune Survey 1

• Place: North West of St Martin

Island

• Highest Elevation: 2.67 m

• Land Use: There were hotels &

Resort

Dune Survey 2

As we know sand dune protects coastal habitat from storm and sea level rise.

Our surveyed sand dune with not more than 3 m elevation shows that it is still

in the young stage but can be disrupted due to the excessive human

intervention as hotels, resorts and homes were spotted and these sand dunes

played a part in allowing these to be built by creating a high ground safe

from sea. Some interesting observations may be shared. People placed rocks

to reduce erosion of the dunes. Keya trees were found growing inclined.

Also, if the wind was sufficient, some movement of sand could be observed.

We need to pay heed on protecting these sand dunes as it protects the

coast.

Analysis

• We could have analyzed the soil quality and compaction of sand

dune.

Limitation and challenges:

Vegetation surveyof Sand dunes

Vegetation of St. Martin Island

Surveying the enormous diversity of the world’s vegetation and for biodiversity conservation, research on ecology and environment of an area; vegetation survey is a must which is basically a technique or method to identify, monitor the flora, plants of an area and creating the biodiversity index.

Our survey

Area: Vegetation over Sand Dunes which have studied before.

Study Areas of Vegetation Survey (zoomed view from satellite image)

Method That We Followed

Quadrate Method:

• We decided our survey area first where we found

• We selected 2500 meter square covering area that we were interested in with 25 grid squares each with 100 meter square.

• These 13 grids were chosen by ‘simple random sampling numbers’.

• then collected the specimen of plants from13 grid out of 25 grid for later identification.

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Glimpse of Vegetation Survey

Outcome of Our Survey

Both group found almost 27 specimen from the survey. Later by taking help from experienced botanist we identified all the specimen and measured frequency, abundance, density along with Importance Value Index (IVI).

[CATEGORY NAME]

[CATEGORY NAME]

[CATEGORY NAME]

0%

Percentage of Species

Tree Shrub Herbs

• Scientific Name: Pandanus fascicularis

• Type: A shrub or a small tree, many

areal roots, narrow leaves up to 150cm

long, fragrant flowers, large fruit of

pineapple-like shape, grows all over

India.

• IVI : 25.68

Some Abundant Species

KEYA

Some Abundant Species

• Scientific Name: Cocos nucifera

• Type : The Coconut Palm is a long-lived plant that may live as long as 100 years. It has a single trunk, 20-30m tall.

• IVI : 12.5

COCONUT

Some Abundant Species

• Scientific Name : Ipomoea pescaprae

• Type: Growth Form: It is a latex-bearing, trailing creeper, with up to 30 m-

long stems, and deep tap roots.

• IVI: 5.66

SHAGORLOTA

Some Abundant Species

• Scientific Name: Acanthus

ilicifolius

• Type : It is a small shrub

growing along lakes and

marshes and sea shores.

• IVI: 6.06

NISHINDA

Analysis

The flora of St. Martin’s Island is similar to that of the mainland. However, it has been significantly changed due to human interventions from 1880s.St. Martin Island still has quite diverse vegetation. The “morning glory“ (Ipomeapescaparea) is an unique species found in sand dune area.

Challenges That We Faced

• 50 meter square area was not enough to cover enough vegetation

• Due to our preservation method, some specimens were quite unrecognizable because of humidity and lack of light.

• fruits and flowers should be taken along with 12 inch size.

• In these case enough photographs should be taken

Conclusion

From our topographic survey of Shahpori Dwip we can see the elevations of different locations from sea level are not so high. The average elevation that we measured is almost 1 m from the sea level which indicates that the area is a low land like many other areas of Bangladesh. Some parts are gone under water during the high tide and during the low tide the scenario is just opposite. The landform survey of Dune gave us the idea of how dune is formed and the land use pattern of it. We also learned the main vegetation of the St Martin Island of our survey which gave us basic knowledge of the ecology of St Martin Island.