1972 1989 1995 2004 Expansion of urban area from 1975 to 2010 , , Red circle: 2010 Green circle: 2005 Blue circle: 1975 Directional expansion by the axis of Northeast - Southwest Urban area in 1975, 2005 and 2010 overlaid to indicate the extent over times EXPANSION OF URBAN AREA IN HOCHIMINH CITY Hochiminh city is one of the urban areas has the highest rate of urbanisation in Vienam. + By using the archived Landsat imageries from 1972 to 2010, the trend of the urban expansion has been indentified with the add of GIS, spatial analysis. + Based on analysis of spectral response of visible and IR bands with land cover types density and continousity of constructions/ built-up. + Urban area of Hochiminh city has been spreaded out two times in radius and three times in area from 1972 to 2010 (app. 40 years). Urban area is identified by using spatial analysis. + The expansion pattern is spatially unequal. The trend is more extent at the north and the north east than at the south. Urban area in 1972 Landsat MSS Urban area in 1996 Landsat TM, Urban area in 2004 Landsat TM Urban area in 2010 Landsat TM LAND COVER CHANGE IN THE MEKONG DELTA, VIET NAM Pham Bach Viet * and Lam Dao Nguyen ** * Faculty of Geography, Hochiminh City University of Social Science and Humanities - email: [email protected] ** GIS and Remote Sensing Research Center, Hochiminh City Institute of Resources Geography - email: [email protected] LAND COVER CHANGE IN THE PLAIN OF REEDS (TAM NONG AREA), MEKONG DELTA The pattern of land cover/ land use at Tam Nong area has crucial change. The natural pristine land with grass- marshes and Melaleuca forests, covered more than one haft of the area, was the excellent habitat for wild life, particularly for Crane has been replaced by large paddy. A remarkable change of cropping pattern has taken place since 1990s. Double rice crop replaced one crop pattern indicating an intensification of rice cultivation. The area of double crops a year has increased eight times from 1985 to 2005. At the present, this pattern becomes widespread at the Plain of Reeds, and some places with triple crops developed. The land cover change leads to changes of landscape and ecosystem resulting in declination of biodiversity natural Forest and grassland is isolated and surrounded by agricultural land Late 1980 until 1990s (Landsat TM 1989), rice crop encroached into the area, the natural Melaleuca forest and grass land remained as small patches. Canal and dyke system have been constructed to support the intensive cultivation Dense system of canals and dykes has totally fragmented the area. Area of natural forest and grassland is decreased In 1970s, large area was still remained as natural and pristine. Melaleuca forests and grassland are typical landscape of the wetland, seasonally flooded in rainy season 2010 RIVER CHANNEL SHIFTING AT THE MEKONG RIVER, SA DEC SEGMENT Landsat data (MSS, TM and ETM) acquired from 1972 to 2010 used in these researches are obtained from the U.S. Geological Survey ‘s Earth Resource Observation Science (EROS). The USGS homepage is : http://www.usgs.gov In the Sa Dec segment of the Mekong river, river bank are eroded at the south bank and accumulated at the north bank simultaneously, extent about 20km from My Thuan up to Tan Qui Dong, Sa Dec. Result of this process from a long period, observed from 1966 to 2010, makes the river channel shifted southward. The river is narrower and new “bottle neck” appeared at the Sa Dec area. Process of erosion appears at the south bank causes problem for local resident because the town is located adjoin to the river. Mekong river at Sa Dec area in 1966, Topographic map 1: 50,000 Shorelines of 1966 overlaid on Landsat image of 2000 Shorelines of 1966 (yellow) from base map and 2010 (red) from Landsat image Shifting trend of river channel: southward
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1972 1989 1995
2004
Expansion of urban area from 1975 to 2010
, ,Red circle: 2010 Green circle: 2005 Blue circle: 1975
Directional expansion by the axis of
Northeast - Southwest
Urban area in 1975, 2005 and 2010
overlaid to indicate the extent over times
EXPANSION OF URBAN AREA IN HOCHIMINH CITY
Hochiminh city is one of the urban areas has thehighest rate of urbanisation in Vienam.+ By using the archived Landsat imageries from1972 to 2010, the trend of the urban expansion hasbeen indentified with the add of GIS, spatialanalysis.+ Based on analysis of spectral response of visibleand IR bands with land cover types density andcontinousity of constructions/ built-up.+ Urban area of Hochiminh city has been spreadedout two times in radius and three times in area from1972 to 2010 (app. 40 years). Urban area isidentified by using spatial analysis.+ The expansion pattern is spatially unequal. Thetrend is more extent at the north and the north eastthan at the south. Urban area in 1972
Landsat MSS
Urban area in 1996
Landsat TM,
Urban area in 2004
Landsat TM
Urban area in 2010
Landsat TM
LAND COVER CHANGE IN THE MEKONG DELTA, VIET NAMPham Bach Viet * and Lam Dao Nguyen **
* Faculty of Geography, Hochiminh City University of Social Science and Humanities - email: [email protected]
** GIS and Remote Sensing Research Center, Hochiminh City Institute of Resources Geography - email: [email protected]
LAND COVER CHANGE IN THE PLAIN OF REEDS (TAM NONG AREA), MEKONG DELTA
The pattern of land cover/ land use at Tam Nong area hascrucial change. The natural pristine land with grass-marshes and Melaleuca forests, covered more than onehaft of the area, was the excellent habitat for wild life,particularly for Crane has been replaced by large paddy.A remarkable change of cropping pattern has taken placesince 1990s. Double rice crop replaced one crop patternindicating an intensification of rice cultivation. The areaof double crops a year has increased eight times from1985 to 2005. At the present, this pattern becomeswidespread at the Plain of Reeds, and some places withtriple crops developed.The land cover change leads to changes oflandscape and ecosystem resulting in declination ofbiodiversity
natural
Forest and grassland is isolated and surrounded
by agricultural land
Late 1980 until 1990s (Landsat TM 1989), rice crop encroached into the area, the natural Melaleuca forest
and grass land remained as small patches. Canal and dyke system have been constructed to support the
intensive cultivation
Dense system of canals and dykes has totally fragmented the area.
Area of natural forest and grassland is decreased
In 1970s, large area was still remained as
natural and pristine. Melaleuca forests and
grassland are typical landscape of the wetland,
seasonally flooded in rainy season
2010
RIVER CHANNEL SHIFTING AT THE MEKONG RIVER, SA DEC SEGMENT
Landsat data (MSS, TM and ETM) acquired from 1972 to 2010 used in these researches are
obtained from the U.S. Geological Survey ‘s Earth Resource Observation Science (EROS).
The USGS homepage is : http://www.usgs.gov
In the Sa Dec segment of the Mekong river, river bank areeroded at the south bank and accumulated at the northbank simultaneously, extent about 20km from My Thuanup to Tan Qui Dong, Sa Dec. Result of this process from along period, observed from 1966 to 2010, makes the riverchannel shifted southward. The river is narrower andnew “bottle neck” appeared at the Sa Dec area.Process of erosion appears at the south bank causesproblem for local resident because the town is locatedadjoin to the river.
Mekong river at Sa Dec area in 1966,
Topographic map 1: 50,000
Shorelines of 1966 overlaid on Landsat image of
2000Shorelines of 1966 (yellow) from base map and
2010 (red) from Landsat image
Shifting trend of river
channel: southward
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