A.K.M. Saiful Islam

Associate Professor, IWFM, BUET December 2010 Email: [email protected]

 Changes of River Banks  ◦ ◦ ◦ ◦ Change detection using Satellite Images Types and sources of Satellite Images Image Acquisition Processes Image Analysis Tools: ILWIS, ERDAS ILWIS: A Open Source Software  ◦ Google Earth: As a free image source & analysis tool  Hands on Exercise using ILWIS and LandSat Images

 Most of the Major rivers of Bangladesh are either Meandering or Braided.

 Every year, millions of people are affected by erosion that destroys standing crops, farmland and homestead land.

 It is estimated that about 5% of the total Floodplain of Bangladesh is directly affected by erosion.

Changes during 1984-93

Jamun a Ganges Padm a Upper Megh na Lower Megh na

Bank erosio Left n rate (m/yr) Right Maximum bank erosion rate (m/yr) Bank erosion (ha/yr) Bank accretion (ha/yr) *100 *84 *784 *5,020 *890 -20 56 665 2,240 1,800 1,010 38 121 620 233 7 -9 NA 66 182 824 48 1,172 49 402 Change of width of the rivers Averag e width (m) Rate of change of width (m/yr) 1984

Jamuna Ganges Padma Upper Megh Lower Meghn na a

9,720 1993 *11,220 184 4,367 5,689 3,406 6,661 4,693 7,116 3,391 8,897 36 159 2 248 Source: ISPAN, 1995 Note: * Rates derived for the period 1984-92

Teesta River at Sundarganj

 Satellite data is useful for monitoring changes of Bank lines.

 However, careful inspection and Ground Truthing is necessary to verify the changes.

 Using images of various Bands, False Color Composite images are developed to identify various features of the landscape.

True Color Composite False Color Composite image

Spectral Images can be used  ◦ Low resolution (<=1km): NOAA, MODIS  ◦ Moderate resolution (<100m): Landsat, SPOT  ◦ High resolution (<5m): ICOKON, Quickbird, IRS, World View-2

Spectral Reflectance of Water, Vegetation, Soil and Rock

1 2 3 4 TM 5 7

     Landsat-7 Orbit: 705 km, 98.2

0 inclination, sun-synchronous Swath width: 185 km (FOV = 15 0 ) Revisit time: 16 days Spatial resolution: 15 m (PAN), 30 m (bands 1-5, 7), 60 m (band 6)      SPOT-1, 2, 3, 4 Orbit: 832 km, 98.7

0 Swath width: 60 km Revisit time: 26 days inclination, sun-synchronous Spatial resolution: 10 m (PAN), 20 m (Multispectral)

 SPOT-5 Orbit: 822 km, 98.7

0 inclination, sun-synchronous Swath width: 60 km Revisit time: 2-3 days Spatial resolution: 5 m (PAN) 10 m (Multispectral)  IKONOS Orbit: 681km, 98.20 inclination, sun-synchronous Swath width: 11km Revisit time: 1-3 days Spatial resolution: 1m (PAN), 4 m (Multispectral)

QuickBird WorldView-1 WorldView-2 Panchromatic (B&W) 450 - 900 nm 400 - 900 nm 450 - 800 nm Multispectral: Coastal Blue 400 - 450 nm Blue 450 - 520 nm 450 - 510 nm 520 - 600 nm Green Yellow Red Red Edge Near-IR 1 Near-IR 2 630 - 690 nm 760 - 900 nm 510 - 580 nm 585 - 625 nm 630 - 690 nm 705 - 745 nm 770 - 895 nm 860 - 1040 nm QuickBird 23 m WorldView-1 WorldView-2 6.5 m 6.5 m

 High Resolution images need to be purchased.

 However, some of the moderate resolution images can be downloaded freely.

 Landsat TM and ETM images can be downloaded from USGS Global Visualization Viewer.  MODIS Images can be downloaded from LP DAAC web site at https://lpdaac.usgs.gov/lpdaac/get_data/wist

11 November 1989 4 November 2005

Bank Shifting of bankline from base year (1989) to present year (2010) in meter Left Bank Right Bank +240.8

At the bridge Location 1 km upstream -198.94

-157.16

1 km down stream -34.2

+190.5

+67.35

November 11, 1989 November 17, 2000 November 04, 2005 January 21, 2010

February 19, 2006 February 27, 2004

At the bridge Location Shifting of bank line from base year (2004) to present (m) -1.9

1 km upstream -1.3

16.2

15.3

1 km down stream -2.9

15.3

A.K.M. Saiful Islam

IWFM, BUET

 ◦ ◦ Input Data: Landsat Images of Year 1989 and 2010 of Band 1-4 Bridge Location Text File (Lat, Long)  Software: ILWIS 3.7  ◦ ◦ ◦ ◦ Assignment: Develop False Color Composite Images Show the location of the Bridge Site Determine the Bank lines during 1989 and 2010 Detect Changes of Banks

 Import Bridge Location Text File “Bridge_Sundar_Teesta.txt” Longitude, Latitude 90.33028611, 23.09426389

   It will imported as Table Create a Point Map from the Table Assign coordinate as “Lat-Lon”

 Use Import Wizard, Select Text files, Press Next Button

 Import as “Comma Delimited” ILWIS Table

 Skip 1 Lines as Header

  Change domain as “value” Change precision as “1e-006”

 Finish importing table “kalkini_bridge”

 Open Table, Column1 as longitude and Column 2 as Latitude Create Point Map from the Table by Clicking right mouse > Table to Point Map

   X Column as Long and Y Column as Latitude Coordinate System as LATLON Output PointMap “Kalkini_Bridge” > Show

Shows Bridge location As point map

  Band 1, 2, 3, 4, 5, 6, and 7 in folder 2010 and 1989 Import using via GDAL as TIF format Band 1-7 as TIF images Import Geo-Tif Images to ILWIS format

 Import using TIF format and write file name Change image format as (TIF) and give a name

 Import Band 1 to 7 using the same tools with and save file name as b1 to b7.

 Make a Map List using Band 1 to 7.

 Make map list using “>” and name it as “maps” Add all 7 layers to create a maplist “Maps”

Use display tool Select band 7-4-2 as RGB

False color composite of landsat image

Use add layer button Select bridge point map and add it

Change color to red Location of the bridge in red color

Use zoom tool Zoom the map over bridge site

Create new segment For bank lines Write segment names

Customize Using right Mouse button Change tolerance Values to small value

Insert tool Start digitizing using Insert tool and then save

Bank lines in 2010 Bank lines in 1989

Changes over 21 years Field visit to the bridge site

Bank Shifting of bank line from base year (2000) to present year (2005) in meter At the bridge Location -332 +398.57

1 km upstream 1 km down stream -266.55

-121.33

+389.108

+206.10