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INTRODUCTION
1. Problem statement
Groundwater resources is affected by natural and socio-economic
factors such as: extending of agriculture area, deforestation, socio-
economic development, environmental pollution, natural disasters, and
climate change that prevent the percolation and infiltration process and
quality of groundwater [1]. Nowaday, these factors are rapidly changed
combined with the negative impacts of climate change have an direct
influence on groundwater resources and an indirect influence on
groundwater users [2]. Infact in coastal Center of Vietnam, freshwater
storage that can be extracted from shallow aquifer are declined, thus it
effect to living, agriculture production, industry, transportation, and
construction in urban areas and as well as coastal areas[4]. In both
science and practical terms, study on evaluation of declination and
adaptation of coastal aquifers to the needs of water supply under climate
change-sea level rise scenarios which will help decision makers in
planning of water resources allocation and looking for alternative water
resources (if needed)[5].
Gio Linh plain in Quang Tri province is in coastal Center areas with
a coastlines of 15.5km extends from Cua Viet town to Trung Giang ward.
It has two main aquifers are Pleistocene and Holocene aquifer that are
abstracted for living and production water usage. However, groudwater
resources are declined in recently years. The lacking of water supply and
increasing of saltwater intrusion in dry season of 2012-2013 due to the
changing of rainfall that affect to the storage of water at main water
reservoirs in the province. To identify the science basis for proposed
solutions for rational use and protection of groundwater resources is
important in progress of subtainable development in the region.
Consequently, the disertation of « Study the effects of natural,
environment, and socio-economic condition to groundwater resources in
Gio Linh, Quang Tri taking into account the impact of climate change
and sea level rise » was sellected to study and complete.
2. Objectives and scopes of the study
2.1 Objecttives of the study
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To construct scientific and practical basises in proposed solution for
rational use and protect groundwater resources based on analysis, evaluate
and estimate the impact of natural, environment, and socio-economic
factors, climate change and sea level rise in Gio Linh, Quang Tri.
2.2 Scopes of the study
- Overview and construct science basis on analysis, evaluate and
estimate the impact of natural, environment, and socio-economic factors,
climate change and sea level rise to groundwater resources in coastal plain.
- Study the groundwater resources characterization of Gio Linh, QT.
- Analyze the impact of natural, environment, and socio-economic
factors, climate change and sea level rise to groundwater resources.
- Modelling and prediction groundwater recharge with climate
change sea level rise scenarios using numerical hydrological model.
- Evaluate the recharge of rainwater and surface water to aquifers.
- Determine the hydraulic relation between Pleitocence and Holocence
aquifers and rainwater and surface water.
- Quality evaluation and modeling groundwater level and
groundwater quality change with climate change and sea level rise scenarios
- Propose the solutions in rational use and protect groundwater
resources of Gio Linh area under changing of natural, socio-economic,
and environment taking into account the present impact of climate
change and sea level rise.
3. Study subject and area
- Study subject: Groundwater in Pleistocene and Holocence
aquifers.
- Study area: Gio Linh coastal plain, Quang Tri province wih a
study area of 204 km2.
4. Scientific and practical contributions
4.1 Scientific contribution
The study result supplements the evidences on relationship
between aquifers, the components involved in formation of groundwater
reserve and intergrated impact of natural, socio-economic, environment
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to groundwater in Gio Linh coastal plain, Quang Tri province in context
of climate change and sea level rise
4.2 Practical contribution
The study results provides scientific basis for policy makers in
planning, management, exploitation and use water resources in Gio Linh
coastal plain, Quang Tri province.
5. Defended theses
Thesis 1: Groundwater resources in Quaternary aquifers is main
water supply for living, services, and industrial production in Gio Linh,
Quang Tri. The characteristics of geographical conditions and the
changing of natural, socio-economic, environment factors and potential
impacts of climate change and sea level rise have influence the
declination of this resources.
Thesis 2: Groundwater recharge plays an importation role in
formation of groundwater reserves in Quaternary aquifers in Gio Linh,
Quang Tri. In context of the aquifers are vulnerable due to impact of
external factors, the maintain and developing the recharge are main
solutions in oriented rational use and protect groundwater resources.
6. New findings
Using intergrated methods (Experiment, statistic, numerical
model,…) to evaluate natural water recharge to Quaternary aquifer in Gio
Linh coastal plain, Quang Tri province.
To prove the changing of salt-fresh water boundary of Holocence
aquifer are still going on due to climate change and sea level rise.
7. References and data of dissertation
- References were collected having related contents to the
dissertation
- Project researches and studies that I had involved in are related to
my dissertation.
- Documents and data were directly updated and calculated
8. Dissertation structure
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The dissertation is reported in 140 pages. Beside introduction,
conclusion, references, and appendices, the dissertation consists of 3 chapters:
Chapter 1. Scientific basis and methodology of the study on the
effect of natural and environment conditions and climate change-sea
level rise to groundwater resources.
Chapter 2. Groundwater resources characteristics and effect of
natural and environment conditions and climate change-sea level rise to
groundwater resources in Gio Linh, Quang Tri.
Chapter 3. Evaluate the effect of factors to groundwater and
propose rational solutions in use and protect groundwater resources in
Gio Linh, Quang Tri.
9. Acknowledgment .
The dissertation is completed at geographical department, Institute of
Science and Technology, Vietnam Academy of Science and Technology
in the effort of PhD candidate under the supervision of Associate
Professor Pham Quy Nhan (Hanoi University of Natural Resources and
Environment), and Associate Professor Dang Xuan Phong (Vietnam
Academy of Science and Technology ).
I would like to express my sincerely thanks to Geographical
department, Graduated training section, Nafosted fund of Vietnam, FWO
fund of Belgium, Water resources faculty- Hanoi university of HUNRE,
NAWAPI, and colleagues.
CHAPTER 1. SCIENTIFIC BASIS AND METHODOLOGY OF
THE STUDY ON THE EFFECT OF NATURAL AND
ENVIRONMENT CONDITIONS AND CLIMATE CHANGE-SEA
LEVEL RISE TO GROUNDWATER RESOURCES
1.1 Overview on related studies
1.2.1. In the world
There are numbers of research on groundwater resources flutuation
due to effect of natural and environment conditions and climate change-
sea level rise around the world and as well as in Vietnam [29]. The major
group studies and directions related to this topic as follows :
a. Group study on the effects of saltwater intrusion
b. Group study on the factors that effect to groundwater recharge
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c. Group study on the factors that effect to groundwater using
combination of climate model and groundwater model.
General comment:
- The studies on saltwater intrusion in aquifers due to impacts of
natural, socio-economic, environment conditions and climate change and
sea level rise show that the main reasons cause saltwater intrusion in
coastal aquifers are: geological structure, hydrogeology, over groundwater
extraction, changing of recharge, changing of discharge area. This study
direction was implemented in Netherlands, Australia, India,…
- The studies on groundwater recharge due to effect of
geographical, socio-economic, environment conditions and climate
change and sea level rise focus on research on soil classification,
vegetation cover, rainfall, temperature, water evapotranspiration,water
budget, GIS and DEM. Evaluate water recharge in aquifers based on the
result of model with climate change scenarios has been applied in
Belgium, Netherlands, England, and India.
- The studies on combination of groundwater model and climate
model have been studied in details by using “weather machine” models,
rainfall model, recharge combines with GIS, hydraulic model of HELP,
WetSpass, groundwater model of Modflow and GMS, weather model of
GCMs. The combination of models brings high efficiency on evaluate the
changing of groundwater through climate change and sea level rise scenarios.
General assessment: Three mentioned approaches on effects of
geographical, socio-economic, environment conditions and climate
change and sea level rise to groundwater are all the evaluation of factors
that effect to groundwater in order to find groundwater protection
solutions under negative impacts of climate change and sea level rise.
These approaches are distinguish on properties, impact source, and
impact level of each factors.
1.2.2 In Vietnam
- In general, there are few studies on evaluation of climate
change impact to groundwater in Vietnam, most of the studies focus on
environment, socio-economic, and surface water resources.
