THÔNG TIN TÀI LIỆU
Application of MapWindow GIS and SWAT Model for Watershed Classification Case study in Dong Nai watershed, Vietnam Nguyen Duy Liem, Le Hoang Tu, Nguyen Kim Loi Department of Applied Geomatics, Faculty of Enviroment and Resources, Nong Lam University, Ho Chi Minh City, Vietnam ABSTRACT As population and development pressures increase in developing countries, soil erosion, water pollution, and environmental deterioration can become serious problems Watershed management is an important task in these situations for protecting land and water resources The watershed classification is very important in watershed management The division of a basin with closed border determines spatial extent of the basin, has important significance in land and water resources management, and is basis for development of ecological perspective to scientific research This paper studied Dong Nai Watershed, a major river basins in southern Vietnam, to delineate and divide the basin into sub-basins, the Hydrological Response Units (HRUs), using open source software MapWindow GIS and Soil and Water Assessment Tools (SWAT) Data needed for research was collected from various sources including DEM, land use, soil The results identified a total basin area is 2,883,408.11 ha, divided into 15 subbasins, 119 HRUs Keyword: Watershed Classification, MapWindow GIS, SWAT, Dong Nai watershed INTRODUCTION A watershed is a topographically delineated area of land from which rainwater can drain as surface runoff through a river system with a common outlet, which could be a dam, irrigation or domestic water-supply off-take point or where the river discharges into a larger river, lake or sea (PCARRD et al., 1999) Watershed classification, according to the MRCS's Watershed Classification Project, is defined as “a method of dividing a landscape into different watershed classes on the basis of selected topographic features” The purpose of watershed classification is to aim at giving an indication of the sensitivity of watersheds, whereby supports to watershed management Dong Nai watershed is the largest river basin in southern Vietnam It has important implications in terms of natural and socio - economic development of provinces and cities in the basin However, the current spatial extent of Dong Nai watershed has no consistency among documents This causes difficulties in research and watershed management The objectives of this study, therefore, are to: (1) delineate Dong Nai watershed, (2) divide the watershed into subbasins, HRUs Tools used in this study are open-source software MapWindow GIS and SWAT model METHODOLOGY Study area Dong Nai watershed is one of the major river basins in Vietnam, including four major rivers such as Dong Nai, Be, Sai Gon, and Thi Vai river Dong Nai watershed area is about 37,400 km2 , covering approximately 11% of the total country area, with a total annual water flow about 36.3 billion m3 Population of the 11 provinces in the basin in 2005 is about 16.4 million people (accounting for 19.7% of the country’s total population) in total of which 8.3 million are rural population and the remaining is urban This is one of the economic development regions with a high and sustainable growth rate and is considered as an economic momentum for the economic growth of the whole country Figure Map of relevant provinces in Dong Nai watershed (Source: VEPA) The topography is inclined gradually from northeast to southwest with an average slope is 4.6% Three forms of topographical formations can be identified: a mountainous area in the north, a basaltic plateau in the south, and between them is a transition zone of alluvial valleys Dong Nai watershed has tropical monsoon climate with two seasons- rainy (starts in May and ends in October) and dry The average annual temperature is 26.0- 27.0 0C, and average yearly precipitation is 2,000 mm Basin has 30 soil types of main soil groups: arenosols, solochaks, thionic fluvisols, fluvisols, gleyic fluvisols, luvisols, acrisols, plinthic ferralsols, leptosols The various land use are: agricultural land, forest land, buiding land, specialized land and others Method SWAT is a river basin, or watershed, scale model developed by Dr Jeff Arnold for the USDA Agricultural Research Service (ARS) SWAT was developed to predict the impact of land management practices on water, sediment, and agricultural chemical yields in large complex watersheds with varying soils, land use and management conditions over long periods of time The model is a set of regression calculations to show relationship between value of input parameters and output parameters SWAT allows a number of different physical processes to be simulated in a watershed For modeling purposes, a watershed may be partitioned into a number of subbasins, which are then further subdivided into HRUs that consist of homogeneous land use, management, and soil characteristics MapWindow is an open source "Programmable Geographic Information System" that supports manipulation, analysis, and viewing of geospatial data and associated attribute data in several standard GIS data formats MapWindow consists of the main MapWindow application, Core Components, and plug-ins In this study, MWSWAT plug-ins (MapWindown Interface for Soil and Water Assessement Tool) of MapWindow GIS is used to modeling the basin through parameters on topography, soil, land use Implementation process is illustrated by Figure below Figure General methodology application of SWAT in Dong Nai watershed Data collection Data required for this study were complied from different sources They include: DEM data that extracted from SRTM data (Shuttle Radar Topographic Mission) USGS / NASA, with a spatial resolution of 90 m Land use map obtained from GLCC (Global Land Cover Chacterization) database with a spatial resolution of km and distinguishing 24 land use/ land cover classes The soil map was obtained from the global soil map of the FAO Global, which provides data for 5,000 soil types comprising two layers (0-30 cm and 30-100 cm depth) at a spatial resolution of 10 km Table Data description/ properties Data DEM Land use Soil Spatial resolution (m) 90 1000 10,000 Format GeoTiff Raster GeoTiff Raster GeoTiff Raster Source USGS/NASA SRTM v.4 USGS GLCC v.2 FAO Year 2007 2000 1995 a) DEM b) Land use c) Soil Figure Data used in the study RESULTS, DISCUSSION The delimitation of Dong Nai watershed in MapWindow GIS is done by MWSWAT plug-in Based on DEM, flow direction and water storage capacity will be calculated Then, network of river basin and its outlet is created, results are shown in Figure Total basin area is 2,883,408.11 ha, divided into 15 subbasins (with the threshold size for subbasins is set 944.0278 km2), the smallest and largest subbasins respectively 2915.91 and 540,849.66 Characteristics of the basin were shown in Table Next, SWAT will be divide each subbasin into HRUs having unique soil, land use, slope properties (Multiple HRUs, Landuse/Soil/Slope thresholds: 10.00 / 10.00 / 10.00%) Details of 119 hydro units are described in Table Figure Watershed classification result of Dong Nai watershed Table Characteristics of Dong Nai watershed Characteristic Land use Soil Slope (%) Classification BSVG (Barren or Sparsely Vegetated) WATB (Water Bodies) FOMI (Mixed Forest) FOEN (Evergreen Needleleaf Forest) FOEB (Evergreen Broadleaf Forest) FODB (Deciduous Broadleaf Forest) SAVA (Savanna) SHRB (Shrubland) GRAS (Grassland) CRWO (Cropland/Woodland Mosaic) CRGR (Cropland/Grassland Mosaic) CRIR (Irrigated Cropland and Pasture) CRDY (Dryland Cropland and Pasture) URMD (Urban and Built-Up Land) Jt14-3a-4527 (Thionic Fluvisols) Fr33-3ab-4494 (Rhodic Ferrarlsols) Ag16-2a-4264 (Gleyic Acrisols) Vp64-3a-4588 (Pellic Vertisols) Ao90-2-3c-4284 (Orthic Acrisols) Af61-1-2a-4261 (Ferric Acrisols) Af60-1-2a-4260 (Ferric Acrisols) Fo102-3ab-4491 (Orthic Ferralsols) 0-0.6 Area (ha) 4929.69 13319.21 87283.48 8010.75 909317.03 187348.84 50050.34 131888.16 14075.91 126652.83 8561.23 1280030.70 53706.53 8233.41 110238.13 930854.77 189093.62 112285.46 463294.81 630198.16 293799.22 153643.95 453397.07 % Watershed 0.17 0.46 3.03 0.28 31.54 6.50 1.74 4.57 0.49 4.39 0.30 44.39 1.86 0.29 3.82 32.28 6.56 3.89 16.07 21.86 10.19 5.33 15.72 0.6-1.5 1.5-219 Watershed area: 2,883,408.11 125505.43 2304505.61 4.35 79.92 Table Details of HRUs Subbasin HRU FOEB/Fr33-3ab-4494/1.5-219 FOEB/Fr33-3ab-4494/0-0.6 FOEB/Ao90-2-3c-4284/1.5-219 FOEB/Fr33-3ab-4494/1.5-219 FODB/Fr33-3ab-4494/1.5-219 CRIR/Fr33-3ab-4494/1.5-219 CRIR/Fr33-3ab-4494/0-0.6 CRIR/Vp64-3a-4588/1.5-219 CRIR/Vp64-3a-4588/0-0.6 FOEB/Fr33-3ab-4494/1.5-219 FOEB/Fr33-3ab-4494/0-0.6 FOEB/Ao90-2-3c-4284/1.5-219 FOEB/Af60-1-2a-4260/1.5-219 CRIR/Fr33-3ab-4494/1.5-219 CRIR/Fr33-3ab-4494/0-0.6 CRIR/Ao90-2-3c-4284/1.5-219 CRIR/Af60-1-2a-4260/1.5-219 CRIR/Ao90-2-3c-4284/1.5-219 CRIR/Af60-1-2a-4260/1.5-219 FOEB/Af60-1-2a-4260/1.5-219 FOEB/Ao90-2-3c-4284/1.5-219 FOEB/Af61-1-2a-4261/1.5-219 FOEB/Af61-1-2a-4261/0.6-1.5 FOEB/Af61-1-2a-4261/0-0.6 FOEB/Fo102-3ab-4491/1.5-219 FOEB/Vp64-3a-4588/1.5-219 FOEB/Vp64-3a-4588/0.6-1.5 FOEB/Vp64-3a-4588/0-0.6 FODB/Ao90-2-3c-4284/1.5-219 FODB/Fo102-3ab-4491/1.5-219 CRIR/Af60-1-2a-4260/1.5-219 CRIR/Af60-1-2a-4260/0.6-1.5 CRIR/Af60-1-2a-4260/0-0.6 CRIR/Fr33-3ab-4494/1.5-219 CRIR/Fr33-3ab-4494/0.6-1.5 CRIR/Fr33-3ab-4494/0-0.6 CRIR/Fo102-3ab-4491/1.5-219 CRIR/Fo102-3ab-4491/0-0.6 CRIR/Vp64-3a-4588/1.5-219 CRIR/Vp64-3a-4588/0.6-1.5 CRIR/Vp64-3a-4588/0-0.6 CRIR/Jt14-3a-4527/1.5-219 CRIR/Jt14-3a-4527/0.6-1.5 CRIR/Jt14-3a-4527/0-0.6 CRIR/Ag16-2a-4264/1.5-219 Area (ha) % Subbasin % Watershed 86346.03 11220.60 14026.81 97816.64 16409.25 19563.58 3016.27 1959.84 782.00 74353.85 10478.42 50337.87 27167.23 13022.31 2496.21 60935.05 42376.18 55971.06 54320.12 16326.26 56885.73 12306.02 2658.38 2982.27 15155.70 11593.83 2674.48 4022.14 30321.23 20490.64 29792.06 6684.11 11656.39 24273.93 4122.56 5467.49 65489.22 8847.43 40147.42 11602.37 27672.82 22421.63 12098.52 26753.25 57944.34 77.38 10.05 12.57 85.63 14.37 17.76 2.74 1.78 0.71 67.50 9.51 25.64 13.84 6.63 1.27 31.04 21.58 50.75 49.25 3.97 13.84 2.99 0.65 0.73 3.69 2.82 0.65 0.98 7.37 4.98 7.25 1.63 2.83 5.90 1.00 1.33 15.93 2.15 9.76 2.82 6.73 4.83 2.61 5.76 12.48 2.99 0.39 0.49 3.39 0.57 0.68 0.10 0.07 0.03 2.58 0.36 1.75 0.94 0.45 0.09 2.11 1.47 1.94 1.88 0.57 1.97 0.43 0.09 0.10 0.53 0.40 0.09 0.14 1.05 0.71 1.03 0.23 0.40 0.84 0.14 0.19 2.27 0.31 1.39 0.40 0.96 0.78 0.42 0.93 2.01 10 11 12 13 CRIR/Ag16-2a-4264/0.6-1.5 CRIR/Ag16-2a-4264/0-0.6 CRIR/Af61-1-2a-4261/1.5-219 CRIR/Af61-1-2a-4261/0.6-1.5 CRIR/Af61-1-2a-4261/0-0.6 FOEB/Ao90-2-3c-4284/1.5-219 FOEB/Af60-1-2a-4260/1.5-219 CRIR/Af60-1-2a-4260/1.5-219 CRIR/Af60-1-2a-4260/0-0.6 CRIR/Fr33-3ab-4494/1.5-219 CRIR/Ao90-2-3c-4284/1.5-219 FOEB/Fr33-3ab-4494/1.5-219 FOEB/Fr33-3ab-4494/0-0.6 FOEB/Af61-1-2a-4261/1.5-219 FOEB/Af61-1-2a-4261/0-0.6 FODB/Ag16-2a-4264/1.5-219 FODB/Ag16-2a-4264/0-0.6 FODB/Fr33-3ab-4494/1.5-219 FODB/Fr33-3ab-4494/0-0.6 FODB/Af61-1-2a-4261/1.5-219 FODB/Af61-1-2a-4261/0-0.6 FODB/Vp64-3a-4588/1.5-219 FODB/Vp64-3a-4588/0-0.6 CRIR/Fr33-3ab-4494/1.5-219 CRIR/Fr33-3ab-4494/0-0.6 CRIR/Af61-1-2a-4261/1.5-219 CRIR/Af61-1-2a-4261/0-0.6 FOEB/Fr33-3ab-4494/1.5-219 FOEB/Ao90-2-3c-4284/1.5-219 CRIR/Ao90-2-3c-4284/1.5-219 CRIR/Fo102-3ab-4491/1.5-219 FOEB/Fr33-3ab-4494/1.5-219 FOEB/Ao90-2-3c-4284/1.5-219 FOEB/Ao90-2-3c-4284/0-0.6 CRIR/Fr33-3ab-4494/1.5-219 CRIR/Fr33-3ab-4494/0-0.6 CRIR/Ao90-2-3c-4284/1.5-219 CRIR/Ao90-2-3c-4284/0-0.6 CRIR/Af60-1-2a-4260/1.5-219 CRIR/Af60-1-2a-4260/0-0.6 FOEB/Ao90-2-3c-4284/1.5-219 FOEB/Ao90-2-3c-4284/0-0.6 FOEB/Af60-1-2a-4260/1.5-219 FOEB/Af60-1-2a-4260/0-0.6 CRIR/Af60-1-2a-4260/1.5-219 CRIR/Af60-1-2a-4260/0.6-1.5 CRIR/Af60-1-2a-4260/0-0.6 FOEB/Fr33-3ab-4494/1.5-219 FOEB/Fr33-3ab-4494/0-0.6 FOEB/Ao90-2-3c-4284/1.5-219 FOEB/Af60-1-2a-4260/1.5-219 CRIR/Fr33-3ab-4494/1.5-219 25062.83 56609.80 157693.70 35927.72 69794.54 40931.99 6143.39 4730.56 1603.86 11004.34 30331.24 95853.26 12642.11 43716.56 11381.38 18705.45 4186.52 35715.78 5353.44 18193.07 4148.19 10395.90 1434.67 99341.05 20647.90 118260.75 40873.63 45773.28 40411.16 21689.23 43660.96 176690.83 27910.75 5246.79 11116.80 1618.47 4899.45 12321.31 4237.42 8811.13 4025.74 608.90 1478.13 315.48 20740.76 4384.23 9667.21 5235.15 958.17 6440.50 21461.26 5611.44 5.40 12.19 33.96 7.74 15.03 43.20 6.48 4.99 1.69 11.61 32.01 17.72 2.34 8.08 2.10 3.46 0.77 6.60 0.99 3.36 0.77 1.92 0.27 18.37 3.82 21.87 7.56 30.21 26.67 14.31 28.81 69.88 11.04 2.08 4.40 0.64 1.94 4.87 1.68 3.48 9.77 1.48 3.59 0.77 50.32 10.64 23.45 5.65 1.03 6.95 23.15 6.05 0.87 1.96 5.47 1.25 2.42 1.42 0.21 0.16 0.06 0.38 1.05 3.32 0.44 1.52 0.39 0.65 0.15 1.24 0.19 0.63 0.14 0.36 0.05 3.45 0.72 4.10 1.42 1.59 1.40 0.75 1.51 6.13 0.97 0.18 0.39 0.06 0.17 0.43 0.15 0.31 0.14 0.02 0.05 0.01 0.72 0.15 0.34 0.18 0.03 0.22 0.74 0.19 14 15 CRIR/Fr33-3ab-4494/0-0.6 CRIR/Af61-1-2a-4261/1.5-219 CRIR/Af61-1-2a-4261/0-0.6 CRIR/Af60-1-2a-4260/1.5-219 CRIR/Af60-1-2a-4260/0-0.6 CRIR/Fr33-3ab-4494/1.5-219 CRIR/Fr33-3ab-4494/0-0.6 CRIR/Ag16-2a-4264/1.5-219 CRIR/Ag16-2a-4264/0.6-1.5 CRIR/Ag16-2a-4264/0-0.6 CRIR/Jt14-3a-4527/1.5-219 CRIR/Jt14-3a-4527/0.6-1.5 CRIR/Jt14-3a-4527/0-0.6 CRIR/Af61-1-2a-4261/1.5-219 CRIR/Af61-1-2a-4261/0.6-1.5 CRIR/Af61-1-2a-4261/0-0.6 WATB/Ag16-2a-4264/1.5-219 WATB/Ag16-2a-4264/0.6-1.5 WATB/Ag16-2a-4264/0-0.6 CRIR/Ag16-2a-4264/1.5-219 CRIR/Ag16-2a-4264/0.6-1.5 CRIR/Ag16-2a-4264/0-0.6 1345.67 19090.07 10663.73 14487.78 7415.65 27520.55 5839.37 11071.56 3726.20 8871.01 27391.68 6414.91 15158.14 54135.76 9705.36 18667.01 310.26 150.61 1022.97 344.18 293.16 794.73 1.45 20.59 11.50 15.63 8.00 14.60 3.10 5.87 1.98 4.71 14.53 3.40 8.04 28.72 5.15 9.90 10.64 5.16 35.08 11.80 10.05 27.26 0.05 0.66 0.37 0.50 0.26 0.95 0.20 0.38 0.13 0.31 0.95 0.22 0.53 1.88 0.34 0.65 0.01 0.01 0.04 0.01 0.01 0.03 CONCLUSIONS AND PROPOSALS This study applied MapWindow GIS software and SWAT model to classify Dong Nai watershed, one of the major river basins in Vietnam The result is total area of 2,883,408.11 hectares of the basin has 15 subbasins (the smallest is 2915.91 ha, the largest is 540,849.66 ha) and 119 HRUs One thing to note is quality of classification watershed depends on quality of input data as DEM, land use, soil The higher spatial resolution of data is, the better watershed classification is REFERENCES Jeff Arnold et al 2008 Soil and Water Assessment Tool (SWAT) Global Applications Thailand: Funny Le Trinh, Le Quoc Hung 2004 Environment of Dong Nai - Saigon River Basin, Ho Chi Minh City, Vietnam: Science and Technology MONRE 2006 Enviroment report of Vietnam 2006 “The state of water environmet in river basins of Cau, Nhue- Day and Dong Nai river system” Available at: http://vea.gov.vn Accessed 14 December 2010 MRC 2010 Chapter 1.2.2: Critical Watersheds and Watershed Classification Available at: http://wiki.mekonginfo.org Accessed 10 December 2010 ... are described in Table Figure Watershed classification result of Dong Nai watershed Table Characteristics of Dong Nai watershed Characteristic Land use Soil Slope (%) Classification BSVG (Barren... basins of Cau, Nhue- Day and Dong Nai river system” Available at: http://vea.gov.vn Accessed 14 December 2010 MRC 2010 Chapter 1.2.2: Critical Watersheds and Watershed Classification Available at:... Implementation process is illustrated by Figure below Figure General methodology application of SWAT in Dong Nai watershed Data collection Data required for this study were complied from different sources
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