International Meeting on Land Cover and Emissions in South and Southeast Asia Ho Chi Minh City, 17 19 October 2016 MONITORING LAND COVER CHANGE IN THE UPPER PART OF DONG NAI RIVER BASIN, VIETNAM BY USING REMOTE SENSING AND GIS Pham Hung 1, Ho Quoc Bao 2, Vo Le Phu 2, Le Van Trung 2 and Nguyen Van Minh Man 2 (1) Department of Natural Resources & Environment (DONRE), Lam Dong Province (2) Ho Chi Minh City University of Technology (HCMUT) VNU
Dong Nai River Basin is the largest entire river basin located in the country s territory. Dramatic changes in land cover due to accelerated socioeconomic activities. Concentrated cascade hydropower and water infrastructure projects.
International Meeting on Land Use and Emissions on South and Southeast Asia, Ho Chi Minh City 17 19 Oct 2016 La Nga River Cascade Hydropower Plants and Water Infrastructure in the main flow of the Dong Nai River Basin Be River Main Flow of Dong Nai
Cat Tien District, Lam Dong Province The Upper Dong Nai river basin 4
Located in the upper part of Dong Nai River basin, under the administrative boundary of Lam Dong Province. 5
Boundary of Lam Dong province Boundary of Study Area Study area: About 80% of areas of Lam Dong province (7,755/9,773 km 2 ) 6
The study area was divided into 16 sub-basins in terms of flow and topology and current land use. Sub-basin Overall topology Ave. Elevation (m) Land use Area (ha) Rate (%) Dong Nai 4 Highlands 714 Forest, annual crops 9007 1.16 Ta Pao Low mountain ran 587 Forest, industrial crops 9318 1.20 Dong Nai 6 Hill country 372 Forest, industrial crops 17131 2.21 Da Tam Highlands 1321 Forest, annual crops 22693 2.93 Dong Nai 5 Highlands 637 Forest, industrial crops 23956 3.09 Dong Nai 2 Highlands 907 Industrial crops, settlement, forest 33171 4.28 Dong Nai 3 Highlands 847 Forest, industrial crops 35114 4.53 Don Duong Highlands 1141 Forest, annual crops 36895 4.76 Cat Tien Hill country 285 Forest, industrial crops 41881 5.40 Da Quyn Highlands 978 Forest, annual crops 55067 7.10 Da Teh Low mountain ran 414 Forest, industrial crops 59809 7.71 Da Nhim Highlands 1500 Forest 71939 9.28 Da Huoai Low mountain ran 592 Forest, industrial crops 74156 9.56 Dai Nga High plateau 811 Industrial crops, forest 122920 15.85 Da Dang Highlands 987 Forest, industrial crops 125712 16.21 Others More than 5 sub-basins of which area has less than 5000 ha 36827 4.75 Total 775596 100.00 7
The northeast: High mountains, belonging Langbiang plateau ( >1000 m) The middle: The low mountains belonging Di Linh plateau ( 700m -1000m) The southeast: Transition zone between the highlands and the plains (200m - 500m) 8
There are two seasons, the rainy season (May November) and dry season (December April) of the following year Tropical monsoon climate, affected by altitude The mean annual precipitation was 2,500 mm, and humidity was 83% (from 1981 2014) 9
1. Acquisition of satellite images: Characteristics of Landsats Year Image Landsat_Scene_DI Resolution Date_Acquired 2001 Landsat-7 ETM LE71240522001034SGS00 30x30m 2001-02-03 2007 Landsat-5 TM LT51240522007027BKT00 30x30m 2007-01-27 2011 Landsat-5 TM LT51240522011038BKT00 30x30m 2011-02-07 2016 Landsat-8 OLI/TIRS LC81240522016068LGN00 30x30m 2016-03-08 10
2. Image classification processing: Geometric correction Sampling design Image classification (MLC - maximum likelihood classification) Post-classification change detection technique Sampling based Google Earth images by integrating ArcGoogle Tool with ArcGis 10.1 11
Image classification: Sixteen (16) types of land cover 12
Class I Class II Description Water Water bodies_turbidity and bodies Water bodies_clear Residential area Post-Classification: Combined classes Residential area Natural (lakes, rivers, etc) or man-made water bodies (e.g. reservoirs). Urban and settlement areas; Roads and built-up (roads, built-up areas and other transport, industrial and commercial infrastructures); Mining (Land used for extractive subsurface and surface mining activities). 13
Class I Class II Description Agricultural land_ Others Forest Post-Classification: Combined classes Agricultural _Coffee, Agricultural _Opened Land, Agricultural _Plastic House, and Bareland Bamboo Forest, Coniferous Forests, Evergreen_Broadleaf Forests, Mixed Broadleaf & Coniferous Forests, Mixed Wood Bamboo Forest; Clouds, Cloud shadows Mix of agricultural rand uses; Land under cultivation; Miscellaneous tree crops (e.g. coffee, tea trees), orchards and pasture); Bare land (exposed soil, sand, or rocks). All types of forests (Evergreen Broadleaf Forests, Coniferous Forests, Mixed Forests, Bamboo Forests, etc.). Clouds, Cloud shadows (almost areas where were covered by clouds, cloud shadows were stable forests). 14
Post-Classification: Combined classes Kala Reservoir Type of Land cover 2001 Water bodies Residential area Agricultural_ Other land Forest Total Area (ha) 6970 32391 318207 418028 775595 Per. (%) 0.90 4.18 41.03 53.90 100.00 Type of Land cover 2007 Water bodies Residential area Agricultural_ Other land Forest Total Area (ha) 6916 25937 361865 380878 775596 Per. (%) 0.89 3.34 46.66 49.11 100.00 15
Post-Classification: Combined classes Dong Nai-3 HP (340 MW, operated in 2011); Da Dang HP (34 MW, operated in 2011); Dai Ninh HP (300 MW, operated in 2008); DamBri HP (75 MW, operated in 2013); Type of Land cover 2011 Water bodies Residential area Agricultural_ Other land Forest Total Area (ha) 10276 28832 371375 365113 775596 Per. (%) 1.32 3.72 47.88 47.08 100.00 Type of Land cover 2016 Water bodies Residential area Agricultural_ Other land Forest Total Area (ha) 9602 28672 372056 365266 775596 Per. (%) 1.24 3.70 47.97 47.09 16 100.00
Classification Accuracy Summary of combined classification accuracies for 2001, 2007, 2011 and 2016 2001 2007 2011 2016 User (%) Prod. (%) User (%) Prod. (%) User (%) Prod. (%) User (%) Prod. (%) CLASS NAME Water bodies 99.67 98.22 99.73 95.90 98.89 91.18 99.75 98.76 Residential area 99.69 92.86 99.18 95.78 85.35 99.21 99.87 93.05 Agricultural land & Other land 89.06 99.83 98.32 99.38 99.12 90.10 80.96 99.00 Forest 99.96 100.00 99.65 99.92 99.1 99.98 99.64 100.00 OA 96.9% OA 99.1% OA 95.0% OA 96.7% Kappa 0.9565 Kappa 0.9854 Kappa 0.9310 Kappa 0.9521 17
Classification Accuracy Comparison of classification accuracy to statistic data of the local authority Types of Land cover 2016 Area (ha) Per. (%) Water bodies 9602 1.24 Residential area 28,672 3.70 Agricultural land_ Others 372,056 47.97 Forest 365,266 47.09 Total 775,596 100.00 Types of Land cover Area (ha) Rate (%) Water bodies 11,862 1.53 Beyond forest land (Agricultural, Residential land, Bare land, ) 385,662 49.72 Forest 378,072 48.75 - Special forests (National Park) 41,501 5.35 - Protective forest 121,271 15.64 - Production forest 215,300 18 27.76
Classification Accuracy Comparison of classification accuracy to statistic data of the local authority Types of Land cover 2016 Area (ha) Per. (%) Water bodies 9602 1.24 Residential area 28672 3.70 Agricultural land_others 372056 47.97 Forest 365266 47.09 Total 775596 100.00 Types of Land Use 2010 (ha) 2015 (ha) 2020 (ha) Per. (%) 2020 Other land 503054 589654 420404 43.01 Forest 474300 387700 556950 56.99 Total 977354 977354 977354 100.00 19
Change Detection 2016 Water bodies Residential area Agri land_ Others Forest Row Total Class Total Water bodies 3436 212 3575 2379 9602 9602 Residential area 308 10900 15264 2201 28672 28672 Agri & Other land 2757 19116 246617 103566 372055 372056 Forest 469 2163 52751 309883 365265 365266 Class Total 6970 32391 318207 418028 0 0 Class Changes 3533 21491 71590 108145 0 0 Image Difference 2633-3719 53849-52762 0 0 2001 20
Change Detection The results showed that forest areas: Decreased 37,150 ha (4.79%) in the period 2001-2007; Decreased 5,765 ha (2.03%) in the period 2007-2011; Stable in period 2011 2016 (4 years): 365,113 ha/365, 266 ha. Total change in 15 years (2001 2016), the forest area in upper part of Dong Nai basin has been reduced 52,762 ha (6.8%). Hydropower Plantation (Rubber) Plantation (Coffee) Water Infrastructure 21
Change Detection Dong Nai-3 Dong Nai-5 Major Change Sub-basin Total Unchanged Total Change Forest Water bodies Change (ha) Forest Residential area Forest Agricultural land_others Area (ha) 35114 23327 11787 1122 47 10618 Rate (%) 100.00 66.43 33.57 3.20 0.13 30.24 Area (ha) 23956 17409 6547 59 146 6343 22 Rate (%) 100.00 72.67 27.33 0.24 0.61 26.48
Change Detection Major Change Sub-basin Total Unchanged Change (ha) Total Forest Water Forest Forest Agricultural Change bodies Residential area land_others Da Teh Area (ha) 59809 47314 12495 2 109 12384 Rate (%) 100.00 79.11 20.89 0.00 0.18 20.71 Cat Tien Area (ha) 41881 33414 8467 3 65 8399 Rate (%) 100.00 79.78 20.22 0.01 0.16 20.05 Da Huoai Area (ha) 74156 59586 14569 45 47 14477 23 Rate (%) 100.00 80.35 19.65 0.06 0.06 19.52
Change Detection The causes of deforestation in these areas were due to hydropower and agricultural practices - Da Siat-3 HP (13.5 MW, operated in 2009); - Dong Nai-3 HP (340 MW, operated in 2011); - Dong Nai-4 HP (150 MW, operated in 2012); - Dong Nai-5 HP (150 MW, operated in 2015) Conversion of forests to agricultural land and rubber plantations of the Government program since 2005. 24
Change Detection Minor Change Sub-basin Total Unchanged Change (ha) Total Forest Forest Forest Agricultural Change Water bodies Residential area land_others Dong Nai-6 Area (ha) 17131 15975 1156 1 7 1149 Rate (%) 100.00 93.25 6.75 0.00 0.04 6.71 Da Nhim Area (ha) 71939 67102 4952 125 67 4645 Rate (%) 100.00 93.28 6.88 0.17 0.09 6.46 25
Change Detection Minor Change 26
The accuracy of classification results was quite high, the OAs of combined classification for 2001, 2007, 2011 and 2016 were 96.90%, 99.09%, 95.00% and 96.76%, respectively. The forest area of study basin has been reduced 52,762 ha (6.8%) over the past 15 years. The highest rate of deforestation loss was in the period 2001-2007 (6 years) with 37,150 ha (4.79%). Dong Nai-3 sub-basin had the highest deforestation rate with 32.3% compared to the others. Significant changes in land cover have taken place in some sub-basins as a result of conversion of forests to agricultural land and rubber plantations of the Government and hydropower development projects.
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