Utilization of Satellite Images. for Basin Management and Environmental Conservation in Mekong River Basin

Transcription

1 Utilization of Satellite Images for Basin Management and Environmental Conservation in Mekong River Basin 29 th October 2018 Global Environment Deartment

2 Comosition of Mekong River Basin Cambodia, 154,730 Vietnam, 65,170 Thailand, 184,240 Yunnan in China, 165,000 Laos, 202,400 Myanmar, 24,000 Total area: 795,000 km 2 Catchment area: 795,000 km 2 River length: 4,800 km Headwater: Tibetan Plateau River mouth: State of Ben Tre in Viet Nam General issues due to deforestation: Increase of natural disasters such as flooding, drought, collase of ecosystems, acceleration of global warming and etc. Location Ma Data source: JICA 2

3 1. Outline of the Survey Basic Information Project Name: Data Collection Survey on the Basin Management and Environmental Conservation in Mekong River Basin Target country: Cambodia, Lao PDR, Thailand, Viet Nam and Myanmar Main counterart: Mekong River Commission (MRC) and 4 National Mekong Committees (NMC) Objectives: 1) To understand forest cover areas in Lower Mekong Basin (excet for China) 2) To clarify triggers of deforestations and issues of forest management 3) To roose effective countermeasures and to recommend effective basin management olicy focusing on forestry sector in LMB Project eriod: Dec 2017 to July

4 1. Outline of the Survey Work Procedure (Evaluation of Deforestation) Ste 1 Ste 2 Collect satellite images Predict the future forest cover area* Execute hydrological and hydraulic analysis Preare historical forest cover mas in Lower Mekong Basin (LMB) Identify actual deforestation areas Preare inut data (land use data considering future deforestation) Set the climate change scenario (sea level rise etc.) River flow Evaluate the results (for identification of otential vulnerable areas) Increase in eak discharge (flood risk) Decline of base flow (drought risk) *Where man-made deforestation is mainly evaluated while the effects of climate change inducted deforestation is not considered. Future (with deforestation) Baseline (existing) Time 4

5 2. Utilization of Satellite Images Prearation of Forest Cover Mas Ideally, Prearing forest cover mas by comiling mas sulied by member countries is the best methods for the roject urose. However, there are certain difficulties for this such as lack of mas in some areas, inconsistencies in image resolutions covering the target areas and limited time for rocessing. Therefore, it is ractical as well as otimum to utilize global observation data. ADCP (Asian Disaster Prearedness Center in Bangkok)* can rovide time series Land Cover Ma (based on Landsat imagery) for free. JICA, MRC and NMC agreed on the utilization of satellite images reared by ADPC to analyze the historical changes of forest cover areas in LMB at Joint Seminar on June *ADPC website: htts:// 5

6 2. Utilization of Satellite Images Basic Condition for Prearation of Mas Duration: 16 years, from 2000 to 2015 Images: Landsat 4 to 8 Land Cover Classification: (1) forest (8 class tyes), (2) urban area, (3) farm land, (4) addy field, (5) others (8 class tyes), (6) unknown e.g. blocking by clouds Data: RGB (Blue, Green, Red),near infrared and middle infrared band of the Landsat images Method: Utilization of indices such as NDVI (Normalized Difference Vegetation Index), NDWI (Normalized Difference Water Index), etc. with machine learning (random forest algorithm) as suervised classification. It is automatic classification Reliability: Over 70% even without manual editing 6

7 2. Utilization of Satellite Images Prearation of Forest Cover Mas Land Cover Classification: Total 19-class (1) forest (9 class tyes) (2) urban area (3) farm land (4) addy field (5) others (7 class tyes) (6) unknown Fig- Land Cover Ma by ADPC 7

8 2. Utilization of Satellite Images Result on Image Analysis (1) The ma indicates decrease/increase of rovincial forest area. By using global observation data such as satellite images, change of forest cover area can be examined even for broad study area. Forest cover change rates and areas can be calculated. Fig- Forest Cover Change Rates in LMB (from 2000 to 2015) 8

9 2. Utilization of Satellite Images Result on image analysis (2) Cambodia Forest Area Farmland Lao PDR Unit: ha Unit: ha Unit: ha Forest Area Farmland Thailand Forest Area Farmland Unit: ha Viet Nam Unit: ha Myanmar Forest Area Farmland Forest Area Farmland Conversion of agricultural land deems to be one of the reason of deforestation. Fig-2 Historical Changes of Forest and Agricultural Area (Farm Land and Paddy field) 9

10 2. Utilization of Satellite Images Utilization of Image Analysis Flow regime, hydrological and hydraulic atterns in the regions, deends on land use conditions. Future flow regime can be estimated by conducting hydrological and hydraulic simulation utilizing redicted land use conditions and the results of this will contributes to river basin management. In this JICA roject, above analysis will be conducted considering future deforestation to evaluate flood and drought risk. River flow Increase in eak discharge (flood risk) Decline of base flow (drought risk) Future (with deforestation) Baseline (existing) Time 10

11 3. Findings and recommendations Findings and recommendations Trend of deforestation in LMB can be clarified by using satellite images. By analyzing deforestation drivers (human activities such as commercial tree logging, conversion to agricultural land, etc.) and historical forest area transition, deforestation near future in LMB can be assumed. For better rediction of deforestation in LMB, it is desirable to utilize the ast forest cover mas, i.e s and 1990 s. *Landsat 1 launched on The roosed method of rearation of forest cover mas in this JICA roject can be alied to other countries and regions for better understanding land use changes in broad areas. 11

12 Thank you for your attention. 12