THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY DINH NGOC HUAN TOPIC TITLE: “APPLICATION OF SWAT MODEL TO ASSESS THE IMPACT OF LAND-USE CHANGES ON STREAM DISCHARGE IN NGHINH TUONG WATERSHED, THAI NGUYEN PROVINCE” BACHELOR THESIS Study Mode: Full-time Major: Bachelor of Environmental Science and Management Faculty: International Training and Development Center Batch: 2010 - 2015 Thai Nguyen, January 2015 n DOCUMENTATION PAGE WITH ABSTRACT Thai Nguyen University of Agriculture and Forestry Degree Program Bachelor of Environmental Science and Management Student name Dinh Ngoc Huan Student ID DTN1054110040 Thesis Tittle Application of SWAT model to assess the impact of land-use changes on stream discharge in Nghinh Tuong watershed, Thai Nguyen Province Suppervisor (s) Phan Dinh Binh, Ph. Abstract: The purpose of this research is to implement “Soil and Water Assessment Tool (SWAT)” model and GIS to evaluation, assessment impact of land-use changes on stream discharge in Nghinh Tuong watershed (riverhead Cau river watershed) in Northern Viet Nam. The watershed were cover by 56% forestry land, 30% agricultural land, and remain for others. Stream discharge observed data 2002 - 2012 were used for calibration (2002 - 2007) and validation (2008 - 2012).
The result shown that two coefficients (NSE and PBIAS) to evaluate model performance were 0.54% for calibration period and 0. Stream discharge strongly depends not only on quantity of precipitation but also on land use change. Through the scenario 1, agricultural land (corn, orchard and tea) increases 9782.45%), meanwhile forest (forest-mixed) decreases 1091.75%) as compared to baseline scenario. ii n Additionally, precipitation increases 3.74% in mean wet season, but decreases 0.5% in mean dry season with respect to baseline period.
SWAT model was able to simulate stream discharge and sediment yield for Nghinh Tuong watershed successfully not only for Baseline scenario but also for Scenario 1. In brief, SWAT proves its ability in simulation stream discharge and sediment yield in watershed level. It is a useful tool to assist water quantity and quality management process in Nghinh Tuong watershed. Keywords: Key words: stream discharge, watershed, GIS, SWAT model, scenario Number of pages: 50 Date of Submision : January 15, 2015 iii n ACKNOWLEDGEMENT First and foremost, I wish to express my sincere thanks to the boards of Thai Nguyen University of Agriculture and Forestry, Dean of Faculty Natural Resources Management, Department of Remote sensing and Surveying of Thai Nguyen University of Agriculture and Forestry for providing me all the necessary facilities and all the teachers who built me the scientific knowledge to complete this research.
In particular, I would like to thank my principal research adviser Dr. Phan Dinh Binh who guided me wholeheartedly when I implement this research project. I place on record, my sincere gratitude to all staffs, government and people in Nghinh Tuong commune Vo Nhai district and Van Lang commune Dong Hy district, Thai Nguyen province for their expert, valuable guidance and generous support to our project. Finally yet importantly, I take this opportunity to express our deepest appreciation to our families, relatives, friends and fellow students in class of K42-Advanced Education Program who encouraged and supported me unceasingly and all who, directly or indirectly, have lent their helping hand in this venture.
Thank you very much! Thai Nguyen, January 15, 2015 Student Dinh Ngoc Huan iv n TABLE OF CONTENTS ACKNOWLEDGEMENT. iv TABLE OF CONTENTS. v LIST OF TABLES. viii LIST OF FIGURES.
ix LIST OF ABBREVIATIONS. xi Part 1: INTRODUCTION. Research questions and hypotheses. 3 Part 2: LITERATURE REVIEW.
Soil and Water Assessment Tool (SWAT) Model. Concept of SWAT. SWAT hydrologic component. The land phase of the hydrologic cycle.
Routing phase of the hydrologic cycle. Routing in river. Routing through reservoirs. Component processes in model (Neitsch et al.
Lateral subsurface flow. SWAT sediment component (Neitsch et al. The Modified Universal Soil Loss Equation (MUSLE). Description and topography.
Soil classification and soil physical characteristics. Land cover classification. SWAT model performance evaluation. Overview of Nghinh Tuong basin.
Preparation input data. Land use scenarios. Assessing the impact of land-use changes on stream discharge in Nghinh Tuong watershed, Thai Nguyen Province. Land use scenario 1 (2020).
Land use scenario 2 (2030). 47 Part 5: CONCLUSIONS AND DISCUSSION. 52 vii n LIST OF TABLES Table 4. Summarized climatic characteristics (1983- 2012) of Nghinh Tuong watershed for SWAT simulation.
Total monthly precipitation in Nghinh Tuong watershed from 1983 to 2012. Observed monthly stream discharge at Nghinh Tuong outlet from 2002 - 2012 (m3/s). Sub-watershed characteristics of Nghinh Tuong watershed. Sub-outlet’s characteristics of Nghinh Tuong watershed.
Land use scenarios for Nghinh Tuong watershed. Observed and simulated stream discharge for each period in Nghinh Tuong watershed. Coefficients of monthly NSE and PBIAS as calibrating and validating stream discharge. Stream discharge of Scenarios 1 (2020) and Baseline scenario in Nghinh Tuong watershed (m3/s).
Stream discharge of Scenarios 2 (2030) and Baseline scenario in Nghinh Tuong watershed (m3/s). 47 viii n LIST OF FIGURES Figure 3.1: Map of Vo Nhai District. SWAT soil database builder schematization. Application of SWAT on Nghinh Tuong watershed for simulation stream discharge and sediment load .1: The position of Nghinh Tuong basin.
Monthly maximum, minimum and average temperature in Nghinh Tuong watershed from 1983 to 2012. Monthly relative humidity in Nghinh Tuong watershed from 1983 to 2012. Monthly wind speed in Nghinh Tuong watershed from 1983 to 2012. Total monthly precipitation in Nghinh Tuong watershed from 1983 to 2012.
Observed monthly stream discharge at Nghinh Tuong outlet from 2002 - 2012. Digital elevation model (DEM) and stream network of Nghinh Tuong watershed. Map of land use status Nghinh Tuong River basin in 2012. Soil map of Nghinh Tuong River basin in 2012.
Sub-watershed and stream network of Nghinh Tuong watershed. Map of Baseline Land use scenario (2012) for Nghinh Tuong watershed. Map of Land use scenario 1(2020) for Nghinh Tuong watershed. Map of Land use scenario 2 (2030) for Nghinh Tuong watershed.
Observed versus simulated monthly stream discharge and precipitation of Nghinh Tuong watershed during calibration and validation periods .Observed versus simulated average monthly stream discharge during calibration and validation periods of Nghinh Tuong watershed. Locations of land use change for scenario 1 (2020) for Nghinh Tuong watershed. Locations of land use change for scenario 2 (2030) for Nghinh Tuong watershed. 47 x n LIST OF ABBREVIATIONS SWAT : Soi water assessment tool CEAP : Conservation Effects Assessment Projects GIS : Geographic information system ARS : Agricultural Research Service DEM : Digital Elevation Model SWt : The sum of water vapor at the end of measurement (mm); SWo : The sum of initial water volume at day I (mm); T : Time (day); Rday : The total rainfall at the day i (mm) Qsurf : The sum of surface water of the day i (mm); Ea : Water vapor amount at the day i (mm) Wseep : The amount of water penetrating underground layer; Qgw : The amount of recurrent water at the day i (mm) SCS : Soil Conservation Service Ia : The initial abstractions which includes surface storage, interception and infiltration prior to runoff (mm H2O), S : The retention parameter (mm H2O).
CN : Curve number HRU : Hydrologic Response Unit HSG : Hydrologic Soil Group USGS : United States Geologic Survey NSE : Nash-Sutcliffe efficiency USDA : The United States Department of Agriculture xi n PART I. Research rationale Nghinh Tuong is the upland stream of Cau river in which supplies water for domestic, agriculture and industrial sectors in Thai Nguyen. It is a vital resource for any human activities and living. However, the river basin has been affected seriously by the economic growth caused the pollution and depletion clean water resources, and extremely climate events as drought and flooding.
If we do not have appreciated solution for protecting the resources, we have to pay an expensive cost in the near future. On the other hand, the intensive agriculture, overexploitation heavy metals as well as deforestation have lately been raising many problems in this basin. The farmers cultivate agricultural crops, (especially in slope land) and overuse of pesticides and fertilizers for crops, which makes not only soil erosion but also pollutants load on stream into downstream. Nevertheless, there have been no comprehensive assessments of land use change impact in this river basin.
Hence, a modeling effort to simulate these problems in Nghinh Tuong watershed should be implemented. Under these circumstances, we proposed the research project “Application of SWAT model to assess the impact of land-use changes on stream discharge in Nghinh Tuong watershed, Thai Nguyen Province” 1. Research’s objectives The rapid economic growth has affirmed that Thai Nguyen is a major social and economic center of the Northern midland and mountainous area of Vietnam. On the flip side however, the environment has suffered the degradation, exposed the population to serious air and water pollution, including watershed 1 n degradation.
The cause of the watershed degradation is mainly due to overexploitation of natural resources and land use change. Nghinh Tuong watershed located in Vo Nhai district, Thai Nguyen province is a sub-basin of Cau river basin, which is the biggest river basin in Viet Nam. Its estimated length is 46 km, and it drains an area of 397 km2, discharging thousands of ha irrigation demand annually for people in Nghinh Tuong commune (NTPC, 2010). Approximately 40% of the river's length travels the limestone walls, valleys and steep cliffs, especially, passes through Than Sa protected areas which has been containing diverse of rare plant and animal species.
Since the economic renewal campaign (Doi Moi), most of areas in the river basin have been converted to other farming land types and levels, which bring more economic benefits. On the other hand, deforestation and intensive agricultural land practices put a high pressure on land. In addition, recently the illegal extraction of sand, gravel, gold and forest production have impacted broadly on environment, water quantity and quality which leads to soil erosion, degradation, sediment and nutrient deposition in this river basin. The recent studies showed that water discharge depends not only on the precipitation, but also on land use types.
Gassman et al, (2007) stated that water discharge based on proportion of arable land and forested land in the basin. Once the water discharge increases, it leads to the step-up of soil erosion rate, reduction of soil fertility and downstream flooding during the rainy season. Furthermore, the soil loss can transport pollutants in land as pesticides, heavy metals, waste to downstream basin causing seriously impact on the living environment of aquatic species and human health (Ella, 2005), especially in dry season. 2 n This study are (1) to apply (SWAT) model in a small watershed in Thai Nguyen to assess the long-term impact of land-use changes on stream discharge; (2) to understand the behavior of the river based on land use types; and (3) to provide appropriate suggestions to sustain the soil and water resources.
Research questions and hypotheses How do the intensive agriculture, overexploitation heavy metals as well as deforestation have lately been raising many problems in Nghinh Tuong basin ? What is the modeling effort to simulate these problems in Nghinh Tuong watershed? The application of SWAT model-Soil and Water Assessment Tools understand the effect of land-use changes on stream discharge and prove its ability in simulation stream discharge in watershed level and then provide appropriate suggestions to sustain the soil and water resources. Limitations The Application of SWAT model is very large. However, the input data requirements for models and need much time to process the data, the input data requirements for models and need much time to process the data.