Asessing CC impacts and adaptation ìn cnetral VN using water shed and comunity based approach

Assessing Climate change Impacts and Adaptation in Central Vietnam using Watershed and Community Based Approach: Case study in Quang Nam Province Nguyen Kim Loi(1), Nguyen Van Trai(1), Hoang Thi Thuy(1), Nguyen Thi Huyen(1), Le Anh Tuan(2), Suppakorn Chinvanno(3) (1) Nong Lam University, Ho Chi Minh City, Vietnam (2) Can Tho University, Vietnam (3) Southeast Asia START Regional Center, Bangkok, Thailand ABSTRACT With the changes in climate, biophysical, socio-cultural, economic and technological components, paradigm shift in natural resources management are unavoidably adapt/modified to harmonize with the global changes and the local communities’ needs This research focused on climatic change risk, vulnerability and adaptation in Dong Giang district in response to climate change impacts as case study The Soil and Water Assessment Tool (SWAT) model was applied to assess climate, land use change and practice impacts to soil and water resources in Dong Giang district as upstream of Vu Gia watershed, Quang Nam province This part focuses on the relationship between upstream and downstream in Vu Gia watershed and using sustainable watershed management in response to climate change in Quang Nam province, Vietnam The research also concerns with changes in ecological and socio-economic conditions driven by climate change and human activities in Dong Giang; and adaptation measures in agricultural production and livelihoods to suit the new conditions Keyword: Climate change, Watershed management, Community Base, Quang Nam INTRODUCTION Current climate change estimates indicate that major environmental changes are likely to occur due to climate change in practically every part of the world, with majority of these changes being felt through modification of hydrological cycle as e.g, floods, droughts and storms Climate change impacts are also estimated to be particularly severe in many developing countries of the world and especially in Vietnam The recent studies (World Bank Study, Dasgupta et al.: 2007, IPCC, 2007) have concurred that Viet Nam will be one of most vulnerable countries to climate change in the world Gradual changes such as sea level rises and higher temperatures, more extremes of weather such as drought, and more intense typhoons are all on the horizon and will have a potentially devastating impact on the country’s people and economy Dong Giang District is one of eight mountainous districts that locate in western part of Quang Nam province – the centre of Vietnam, with 70 km far way from Da Nang city The area often have tremendous catastrophically natural hazard by flood and typhoon Recently, the number of events occurring such as landslide, drought, flash flood, etc has increased rapidly In addition, developing activities in the area such as hydropower construction, road building, and deforestation contributed to changing of ecosystem in Vu Gia watershed Hence, this research attempts to assess climate change impacts on ecosystems and livelihood in Dong Giang district, Quang Nam province and to make policy recommendations to decision maker on climate change impacts to adapt to the new context STUDY AREA DESCRIPTION Dong Giang District is one of eight mountainous districts located in western part of Quang Nam province and upstream Vu Gia watershed – the central Vietnam, with 107o 30’ to 107o56’ longitude and 15o35’ to 16o10’ latitude and 70 km west of Da Nang city The region occupies an area of approximately 81,000 as shown in Figure The Dong Giang district has been divided into 10 villages and town Dong Giang locates in mountainous area associated with small valleys and distributed by small and middle stream networks The area is classified into categories by height, i.e the area of higher than 1000m over sea level accounts for approximately 22,600 which is 27.81% of the total; from 500m to 1000m height is about 38,400 ( 47.25%) and below 500m is 24.94% Statistically, the population of the district was 23,635 people in 2008, of which 73.21% were C’tu ethic-a minor group and the rest was Kinh people Eighty percent of the local population relied on agricultural production and forestry activities for their livings The value of Dong Giang district has been based on its diverse natural, cultural and historical resources including forest and its products, ethnic culture, etc On the other aspect, the area often suffers from tremendous catastrophically natural hazard causing by flash flood and typhoon Recently, these disasters are in increasing trends In addition to natural disasters, developing activities such as hydropower construction, road building, mining and stone exploitation have accelerate the hazard Figure Vu Gia watershed map METHODOLOGY Brief description of SWAT model The Soil and Water Assessment Tool (SWAT) has been widely applied for modeling watershed hydrology and simulating the movement of non-point source pollution The SWAT is a physically – based continuous time hydrologic model with Arcview GIS interface developed by the Blackland Research and Extension Center and the USDA-ARS (Arnold et al., 1998) to predict the impact of land management practices on water, sediment, and agricultural chemical yields in large complex basins with varying soil type, land use and management conditions over long periods of time The main driving force behind the SWAT is the hydrological component The hydrological processes are divided into two phases, the land phase, which control amount of water, sediment and nutrient loading in receiving waters, and the water routing phase which simulates movement through the channel network The SWAT considers both nature sources (e.g mineralization of organic matter and N-fixation) and anthropogenic contributions (fertilizers, manures and point sources) as nutrient inputs (Somura, H et.al 2009) The SWAT is expected to provide useful information across a range of timescales, i.e hourly, daily, monthly, and yearly time-steps (Neitsch et al., 2002) 2 The Scenario Planning Process for watershed and community approach 2.1 The SWAT Model The principal planning task is aiming at the efficient planning of future in Vu Gia watershed The objectives of each plan will assist in deciding upon the socio-economic, physical and environmental data that required formulating the different planning scenarios The derived objectives are also used later in the methodology to evaluate the efficiency of each proposed planning scenario The next step of the planning process is to formulate possible land-use scenarios Two landuse scenarios are formulated for Vu Gia watershed as input of SWAT model Scenario A: Vu Gia watershed Land use map in 2000 Scenario B: Existing land use map in Vu Gia watershed in 2008 Impact assessment of changes in land use practices and human practices in Vu Gia watershed on surface water, sediment yield during the period from 2000 – 2008 The SWAT model requires meteorological data such as daily precipitation, maximum and minimum air temperature, wind speed, relative humidity, and solar radiation data Spatial data sets including digital parameter layers such as parameters (R, K, C, P) and topography (LS) was digitized from the associated maps LS factor of the watershed is derived from digital elevation model (DEM) obtained from topography The SWAT model was applied in Vu Gia watershed as shown in Figure 3, 2.2 PRA (Participatory Rural Appraisal) Method In order to conduct a comprehensive assessment of climate change impacts on ecosystem and livelihood in Dong Giang district, the PRA method (as shown in Figure 2) was applied to collect data for additional analysis Specifically, the PRA method in combination with field visit were conducted in Dong Giang to collect information for an overall picture of the district regarding concerns in livelihoods (including agricultural productions and other living activities) in relation with climate change issues and natural disasters; and adaptation capacity of local people to the new context Especially, the discussion also aimed to identify the perspectives of local people on climate change issues that affect their living conditions Participants in the PRA discussion comprised of research team members (from RCCC of Nong Lam University, Dragon Institute of Can Tho University and SEA-START Center, Thailand) who played a role of facilitators to guide the discussion and local authorities, other stakeholders (Social Unions and farmers) Figure Photos of PRA discussion in Dong Giang District, Quang Nam Province Figure The SWAT model Figure Application of SWAT model in Vu Gia watershed RESULTS AND DISCUSSION Evaluation of land use change effect on surface runoff and sediment yield In Vu Gia watershed have sub-basins as shown in Figure based on SWAT model In order to develop sound management schemes of protecting the Vu Gia watershed and to have clear picture of the impact of climate and land use changes specifically on surface runoff, and sediment yield The calibrated model was run to simulate two land use change scenarios Land use change scenarios are: Scenario A: Vu Gia watershed Land use map in 2000 Scenario B: Existing land use map in Vu Gia watershed in 2008 For developing the scenarios, the key processes and related model parameters such as P factor of USLE, infiltration rate were modified in the appropriate SWAT input files An USLE P factor of 0.6 to 1.0 was used in simulations to reflect the condition of the watershed with and without soil conservation intervention The predicted surface runoff and sediment yield in 2000 and 2008 were summarized in Table The daily simulated surface runoff and sediment yield in the watershed is shown in Figure 6, Figure The Vu Gia watershed along with its sub-basin automatically delineated Table The SWAT output (monthly) with different land use scenarios Rainfall (mm) Surface runoff Q (mm) Scenario A Scenario B Sediment yield (ton/ha) Scenario A Scenario B Scenario A Scenario B 11.90 21.10 0.01 0.70 0.00 0.59 81.01 26.90 17.03 0.26 11.74 26.26 66.96 71.78 7.19 11.03 18.42 13.65 183.50 183.50 49.18 70.79 45.50 51.41 195.47 195.47 57.69 80.41 19.62 78.94 126.83 126.83 49.84 89.08 11.50 5.40 328.80 398.80 99.53 190.34 0.23 15.48 435.76 465.76 90.40 210.54 61.08 130.04 393.16 393.16 91.34 196.34 13.56 156.40 482.41 482.41 110.65 219.87 28.82 118.87 328.80 228.80 70.32 87.87 0.16 91.91 68.35 58.15 8.05 7.50 8.84 10.95 Figure Simulated surface flow in sub-basin (Dong Giang district) in Vu Gia watershed Figure Simulated Sediment yield loading to reservoir in Vu Gia watershed To assess the effects of land use change in the study area, the SWAT model was run to simulate two scenarios of land use changes on surface runoff, sediment yield Results of the simulation shown that surface runoff increase when forest converted to agricultural land An increase about 42.22% in surface runoff occurs when 21% of the forest area converted to agricultural land Meanwhile, sediment yield increase about 54.2% compared between 2000 (28.96 ton/ha) and 2008 41.66 ton/ha) Table The SWAT simulated statistics for Vu Gia watershed using land use scenario A (2000) and land use scenario B (2008) Scenario 2008 2000 Precipitation (mm) 2652.66 2702.95 Surface runoff (mm) 41.89 29.44 Sediment yield (ton/ha) 41.66 28.96 Effect of extreme weather phenomenon on natural and socio-economic conditions of Dong Giang District Result from the PRA discussion is presented in Figure Figure Ecological and socio-economic changes caused by extreme weather conditions and adaptation to suit the new context The above flow chart conveys a key message that the destructive phenomena including extreme weather conditions that occurred recently in Dong Giang was partially caused by climate changes For instance, more landslide incidences were due to heavier rainfall and torrent that occurred at higher frequency in the district recently Similarly, higher temperature events and more frequent storm tend to increase in the last few years In spite of human activities such as construction of hydropower plants and gold mining were also key sectors caused adverse impacts on the environment, climate change phenomena are believed to significantly contribute to the livelihood changing Most of the mentioned phenomena caused adverse effects on local people in various aspects such as ecological changes, socio-economic disruption and some other gender issues In terms of ecological changes, the most frequent reported events included loss of agriculture land, disease occurrence in human and agricultural productions, change in water quality and current pattern leading to loss of fish species Other concerns were that custom and livelihood changes due to home loss and resettlement In order to adapt to new conditions, local people have adjusted their farming calendar and changed varieties for cultivation and husbandry For example, cow has been raised instead of buffalo because it can tolerate better in hotter weather However, eco-tourism has been further developed because it benefit from a longer dry season and drought which prompt tourists to searching such environment in the District CONCLUSIONS This research is just the first step apply SWAT in Vu Gia watershed The SWAT model performed well in simulating the general trend of surface runoff, sediment yield, at watershed over time for daily, monthly time intervals The results shown that the land use change and practices was affected surface runoff, sediment yield Results of the simulation shown that surface runoff increase when forest converted to agricultural land An increase about 30% in surface runoff occurs when 21% of the forest area converted to agricultural land Meanwhile, sediment yield increase about 54.8% compared between 2000 (24.96 ton/ha) and 2008 (38.66 ton/ha) These simulated effects of forest conversion to agricultural crops clearly indicate an alarming situation of watershed elsewhere having the same land use pattern In Vu Gia watershed, we recommend that policies addressing this problem should be formulated both at the local and national level Parallel to this, an intensive information and education campaign on the consequences of forest conversion and ways of rehabilitating the watershed should likewise be done Finally, alternative livelihood opportunities for upland farmers should be considered in policy implementation While simulation results are subject to further validation, this study showed that the Soil and Water Assessment Tool (SWAT) model can be a useful tool for modeling the impact of climate and land use changes in Vietnam watershed The recent adaptation to deal with changes in ecology and socio-economics requires further attention from the authority for more appropriate policies and strategies to support local people for better livelihoods REFERENCES Arnold, J.G., Srinivasan, R., Muttiah, R.S and Williams, J.R 1998 Large area hydrologic modeling anh assessment part I: model development J American Water Resources Association 34: 73-89 Dasgupta, S., Laplante B., Meisner, C., Wheeler, D., and Yan,J (2007) The Impact of Sea Level Rise on Developing Countries A Comparative Analysis World Bank Policy Research Working Paper 4136, February 2007 IPCC (2007) Climate Change 2007: Impacts, Adaptation, and Vulnerability The Fourth Assessment Report of the Intergovernmental Panel of Climate Change Cambridge University Press Loi N.K., and N Tangtham 2005 Decision support system for sustainable watershed management in Dong Nai watershed – Vietnam Paper presented in International Seminar on “Synergistic Approach to Appropriate Forestry Technology for Sustaining Rainforest Ecosystem”, March - 9, 2005, Bintulu Kinabalu, Malaysia Neitsch, S.L., Arnold, J.G., Kiniry, J.R., Srinivasan, R and Williams, J.R 2002 Soil and Water Assessment Tool User’s Manual Version 2000 GSWRL Report 02-02, BRC Report 2-06 Temple, Texas, USA Somura, H., Hoffman, D., Arnold, J.G., Takeda, I and Mori, Y 2009 Application of the SWAT Model to the Hii River Basin, Shimane Prefecture, Japan Soil and Water Assessment Tool (SWAT) Global Applications World Association of Soil and Water Conservation Special Pub No.4 ACKNOWLEDGEMENTS The authors acknowledge the APN (Asia-Pacific Network for Global Change Research) funded “Building research capacity on assessing community livelihood vulnerability to climate change impact in central Vietnam and Mekong River delta” project for funding this research  ... possible land-use scenarios Two landuse scenarios are formulated for Vu Gia watershed as input of SWAT model Scenario A: Vu Gia watershed Land use map in 2000 Scenario B: Existing land use map... Land use change scenarios are: Scenario A: Vu Gia watershed Land use map in 2000 Scenario B: Existing land use map in Vu Gia watershed in 2008 For developing the scenarios, the key processes and. .. B: Existing land use map in Vu Gia watershed in 2008 Impact assessment of changes in land use practices and human practices in Vu Gia watershed on surface water, sediment yield during the period