AHW26-01

Room:301A

Time:May 27 09:00-09:15

Impact assessment of the Seto-Inland Sea Water Profile Based on CMIP5 Model Ensemble
MORI, Nobuhito1 ; IMAI, Yuki2∗ ; NINOMIYA, Junichi3 ; YASUDA, Tomohiro1 ; MASE, Hajime1
1

Kyoto University, Disaster Prevention Research Instit, 2 Kyoto University Graduate School of Engineering, 3 Kanazawa University, Science and Technology
1.Introduction
This study uses the Regional Ocean Modeling System (ROMS) to project environmental changes of the Seto-Inland Sea inJapan based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) ensemble. The IPCC-AR5 WGI (referred to asAR5) was published in September 2013 and made great progress in impact assessment for future climate changes. Uncertaintyof these future projections can mostly be attributed to either greenhouse gas emission scenarios or the precision of the projection
model (e.g. GCM). Emission scenarios such as Representative Concentration Pathways (RCP) have been considered and theuncertainty in the model is assessed by the model ensemble mean, which assumes that results are scattered around the true value(IPCC, 2013). Although there are many impact assessments on global or large scale changes in the coastal ocean environment,
there are few studies on smaller scale changes, for example in Japan. Further, examination of local scale change has not been
consistently discussed in the AR5 large scale impact assessment.
This study analyzed CMIP5 for near-sea surface global and local ocean areas. It also examined the projection of physicalenvironmental changes of the Seto-Inland Sea in Japan by numerical downscaling with CMIP5 forcing.
2.Analysis of CMIP5
CMIP5 was analyzed for present climate named historical, future climate named RCP 4.5W/m2 scenario (RCP4.5) and
RCP8.5. It focused on ten ocean areas, including global areas and locations in east Japan (E125 degrees-E136 dgrees, N27
degrees-N35 degrees). The objective variables of CMIP5 are atmospheric temperature, cloud fraction, humidity, wind speed, sealevel pressure, shortwave radiation and longwave radiation, which were analyzed by a 61 GCMs ensemble. Spatial distribution ofsea surface temperature (SST) showed a consistent increase overall, with local non-homogeneity; for example, analysis projects
an increase greater than 4 degrees increase in the northwest Pacific. The monthly mean of SST in west Japan was projected tochange with a maximum increase of 3.5 degrees in June and 2.8 degrees in January. The projected increase is higher than that of
the global annual mean. While a constant cloud fraction is projected on the global scale, the model projects a decrease in cloud
fraction in west Japan.
3.Future Change of Water Profile in the Seto-Inland Sea
This study calculated the long-term analysis as 2093 using ROMS as downscaling model with forcing variables from CMIP5
results to project future environmental changes in west Japan’s Seto-Inland Sea. The projection results in present climate condition were compared with observed results (Tanaka et al., 2013) similarly calculated in 2004. Topography data was taken fromJapan GSI, with 1km resolution. Lateral boundary conditions were obtained from FRA-JCOPE. The atmospheric conditions
were implemented using hourly results of CMIP5 analysis for temperature, SLP, short wave radiation, cloud fraction and windspeed. In the summer, the SST shows a remarkable increase of about 1.6 degrees. An increase of the same kind of water profile
was projected in both shallow and deep areas of Hiuchinada and Kitan straits. A difference between the areas is increasing trend
near the sea surface. Remarkable warming near sea surface in Hiuchinada contrasts with constant warming over all layers in
Kitan straits.
4.Conclusions
CMIP5 analysis projected a decrease in cloud fraction in the western part of Japan despite projecting a constant cloud fraction
on the global scale. Furthermore, although results project an increase in short wave radiation in west Japan. They project a global
average decrease.
Using ROMS with forcing from CMIP5 analysis projected an SST increase of 1.6 degrees in the summer. Finally, the water
profile tends to remarkably increase in shallow water, such as in Hiuchinada.

Keywords: the Seto-Inland Sea, water profile, ROMS, CMIP5, cloud fraction, short wave radiation

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AHW26-02

Room:301A

Time:May 27 09:15-09:30

Study on origin of high- pH spring in Yuzawa Geopark, Akita
HAYASHI, Takeshi1∗ ; HAYASHI, Shintaro1 ; YASUHARA, Masaya2 ; TAKAHASHI, Hiroshi2 ;MORIKAWA, Noritoshi2 ; ASAI, Kazuyoshi3
1

Faculty of Education and Human Studies, Akita Univ., 2 GSJ, AIST, 3 Geo-science Laboratory

Yuzawa Geopark, located in the southeastern part of Akita prefecture, is famous for geothermal activity and various types
of hot springs. In addition, there are many springs that are recharged by huge amount of snow in this area. A high-pH spring(pH>9) is located in a Neogene hill. There is no hydrological study on the high-pH spring. Therefore, this study aims to clarify
the origin and groundwater quality evolution process of the high-pH spring. We will show the results of major dissolved ions andstable isotopes of springs that were collected in September and November of 2014.
The high-pH spring discharges from joint of Neogene clay layer, and white deposit (calcite?) was found in the joint aroundof discharge point. pH and EC of the high-pH spring were 9.7 to 9.9 and 460 to 480 µS/cm, respectively. Groundwater quality
showed Na-HCO3 type. As for δ 18 O and δD, the high-pH spring was located along local meteoric water line (d=20). Considering
the correlation between isotopic ratios and elevation of discharge points that were obtained from the springs that were collected
in wide area of the geopark, elevation of the recharge area of the high-pH spring was estimated more than 400 masl. However,this value was much higher than the elevation of topographical recharge area of the high-pH spring. The results of this study
suggest that the high-pH spring may be recharged by regional groundwater flow system and may have long travel time.
Keywords: high-pH spring, multi tracer, environmental isotopes, Yuzawa geopark

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AHW26-03

Room:301A

Time:May 27 09:30-09:45

A prompt report on influence and change on the river of around Mt.Ontake after eruption(140927)
ASAMI, Kazuki1∗ ; KODERA, Koji2
1

Undergraduate student, Hosei University, 2 Department of Geography, Hosei University

1.Introduction
Mt.Ontake located in the boundary of Nagano and Gifu erupted by phreatic explosion at about 11:53 a.m. on September
27, 2014. The volcanic ejecta which occurred by this eruption gets into the lake and the outskirts river of the mountaintop
neighborhood, so naturally influence on water environment is thought about. Therefore our laboratory started a continuation
investigation to check a change of the water environment of a river around Mt.Ontake by the eruption.
2.Survey method
The field work item is AT,WT,pH,RpH,EC. In addition, I performed the water quality measurement of the plumb direction
using ALEC at some spots. Furthermore, I collect water and take a sample home with me and analyze TOC, major dissolved
component in a laboratory.
3.A result and consideration
Volcanic ejecta flowed in Nigori river of the crater south side of Mt.Ontake and Outaki river after the Nigori river junction,and river water was able to observe a cloudy state. From result of a measurement of pH, the around Mt.Ontake river became thevalue before and after 7.0 generally, but showed a value before and after 3.5 and the strong acidity at the cloudy spot. In addition,
the value of the EC is less than 20 mS/cm generally, too, but a value is big at the cloudy spot, and a value called 170 mS/cm isobserved in Nigori river just after the eruption.
There is not a cloudy state, and a value of pH is around 7.0 in the river of the east side of Mt.Ontake. But a value of the EC
is slightly big in a part river. In addition, with the Nobunaga Bridge whom there was near a mountain rising to a great heightropeway, pH was around 4.5 values and the value of the EC was relatively big. So I knew that influence of the eruption appearedon the east side of Mt.Ontake particularly in mountaintop neighborhood
The cloudy river water of Outaki river flows into the Ontake Lake made by a dam. As for the surface water of the Ontake
Lake and a spot more downstream than the Ontake Lake, there was no great difference between pH, EC and the whole around
Mt.Ontake river together at the stage of the investigation of October 8 just after the eruption. But when it was on October 31,
a drop of pH and a rise of the EC were confirmed, and a similar change was seen. The volcanic ejecta which flowed into the
Ontake Lake only deposited in the bottom of a lake at the stage of October 8, but I have lake water cycle in the Ontake Lake fromhere to October 31, and influence of the volcanic ejecta of the bottom of a lake appears in the whole lake, and it can call that sucha water is discharged by the dam, and a change appeared in the downstream water.
4.Conclution
Influence and a change to the quality of the water of the around Mount Ontake river by the eruption became clear. I continue
an investigation and investigate the crater lake of source area and the Mitake mountaintop as much as possible and will examine
influence of the eruption more in future.
Keywords: Mt.Ontake, eruption, volcanic product, Ontake Lake, matter cycle

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AHW26-04

Room:301A

Time:May 27 09:45-10:00

Loading Processes of Chemical Matters in a Forested River Catchment : Observations
and Modeling
MIYAMOTO, Takuto1∗ ; CHIKITA, Kazuhisa2 ; HOSSAIN, Md motaleb1 ; SAKATA, Yoshitaka2 ;OCHIAI, Yasuhiro1
1

Graduate school of science Hokkaido university, 2 Faculty of Science, Hokkaido University

River water is one of the most important natural resource for our live and has much influence for lake and the earth because of
fast transport velocity. Especially, outflow of chemical matters in river is related with river ecosystem and make lake eutrophication. We targeted Oikamanai river basin, forested catchment in Hokkaido. In this catchment, landuse is 88.3 % forest and 10.6
% farmland. Geology is the Neogene Miocene mud and sand stone, half of which is composed by marine deposit.We got thedata on concentration of chemical matters and time series of discharge, electric conductivity (EC) and MET data. Fresh water’sEC monitoring is new technology, so there are few reports. In this study, we calculated time series of concentration of chemicalmatters and chemical matters load using co-relation of concentration of chemical matters and EC. We analyzed discharge routeusing Tank-model. Using this result, we calculated chemical matters load at each discharge route. We discuss mechanism ofoutflow of chemical matters in forested catchment with these data.
In this study, we targeted Mg2+ , Ca2+ , Na+ , SO4 2− , HCO3 − because they have much influence for EC. As a result of Tankmodel, baseflow is distinguished, 68.3 % and surfaceflow is distinguished in high discharge events. HCO3 − analysis intended
soil water tend to cultivate to underground. HCO3 − was more dissolved in river water in high discharge events, this is insisted
to be caused by river erosion. SO4 2− analysis showed iron pyrites is oxidized in weathered mantle and upper basin and organic
matters is bitten by microbe. Ca2+ , Na+ , Mg2+ analysis suggested ionic exchange with H+ occur in soil.

Keywords: forested river basin, chemical matter, Tank-model, L-Q equation

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AHW26-05

Room:301A

Time:May 27 10:00-10:15

Evaluation of Land cover change and Flow regime change in upper area of Dong Nai river
basin, Vietnam
TRUONG, Nguyen cung que1∗ ; KONDOH, Akihiko2
1

Chiba university, Graduate school of Science, 2 Chiba university, Center for Environmental Remote Sensing

Vietnam is considered as one of the top countries to be severely affected by climate change, particularly in coastal areas. Thatby 1 m sea level rises, Vietnam would lead to flooding of up to 20,000 km2 of the Mekong river delta and more than 1 million
people would be directly affected in there and it is also predicted economic loss up to 10% GDP (Dasgupta et al. , 2007). In
rainy season a combine of SLR and rainfall increase to make a serious impact on low-lying coastal areas. It is also predictedthat 40,000 km2 of coastal delta region, 90% of the Mekong delta will flood (Eastham et al. , 2008) and temperature is moresignificantly rise in the plateau region (MONRE, 2012).
Dong Nai river and Mekong delta downstream are located in and supplied the major water resources to the whole Southern ofVietnam. Continuous changes in water resources due to climate changes and several controversies about the potential impact of
sediment transport and river flows downstream due to either the cascade hydroelectric power plant system or dam construction in
the upper of Mekong delta being continuous. In addition, water resources from Dong Nai river is the resource that only controlled
by Vietnam. On the other hand, solving the problems of water shortage in the dry season and flood control in rainy season are
also important for issues of water management at Dong Nai river basin. Therefore evaluation of flow regime change by the affectof climate change and human activities is an urgent issue in Vietnam.
That forest area decreased as a human activity is the big problem in Vietnam. In the period from 2002 to 2009, 620 km2
of forest land lost on average per year and 250 km2 of forest land was converted to other land use (Vietnam Forest Protection
Agency, 2010). The main reasons of deforestation are unsustainable logging and agricultural land development (Hoang M.
H. et al. , 2010). In most cases the forest vegetation lost, runoff increases conversely forest vegetation growing, runoff often
decreases (Maita and Suzuki, 2008).
The river flow regime was analyzed from 1989 to 2009 runoff data at 3 observation stations in study area. The Landsat images
in 2014 and 2005 were used to classify to 5 majors of land cover such as the dense-forest, spare-forest, crop-land, bare-land andwater body.
Dong Nai river basin area is 14,713.5km2 with the main land cover types are dense-forest 35%, spare-forest 26% and cropland
24% in 2005. From 2005 to 2014, the large area of forest (both in dense and spare) was converted to crop-land and bare-land; apart of spare-forest had became dense-forest. Especially the majority of bare-land (7%) had been converted into the other land
cove types. The ratio land cover was dense-forest 33%, spare-forest 16% and cropland 39%. We can see that deforestation has
occurred in the study area from 2005 to present.
As the inflow of Tri An dam, the flow regime at Tri An (basin outlet) slightly increased in all the flow rates of normal
discharge, low-water flow and drought flow but slightly decreased in hosui flow. Flow regime of Ta Lai point, where affected bydeforestation, hosui flow and normal discharge is slightly increased but change trend of low-water flow and drought flow were
not observed. As the inflow of upper stream dam, the flow regime at Da Nhim increased in all the flow rates of hosui flow, normal
discharge, low-water flow and drought flow.

Keywords: Dong Nai river basin, Flow regime, Land cover change

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AHW26-06

Room:301A

Time:May 27 10:15-10:30

Characteristics of groundwater temperature distribution of deep wells in Aizu basin
KANEKO, Shohei1∗ ; SHIBASAKI, Naoaki2 ; UCHIDA, Youhei3
1

Graduate School of SSS, Fukushima University, 2 Faculty of SSS, Fukushima University, 3 National Institute of Advanced Industrial Science and Technology
The Shibasaki Laboratory of Fukushima University has conducted a joint research, ’Analysis on Geological Structure of Quaternary and Hydrological Structure in Aizu basin’ with the Shallow Geothermal and Hydrogeology Team, AIST. The laboratory
has carried out studies on groundwater flow and groundwater temperature. Considering popularization of ground-source heatutilization system, comprehension of groundwater flow will be able to design more efficient system.
In this study, we collected continuous monitoring data of groundwater level and groundwater temperature. We also measured
pumped water temperature and its quality from sprinkling snow-melting wells, and depth-wise temperature at an interval of 2 m
in deep wells.
Groundwater level of deep wells and some shallow wells showed reduction of groundwater levels in winter. This is becausesnow-melting wells were operating. Most of their depths range from 150 to 200 m and their strainers are installed at multiple
layers, so groundwater is pumped from several aquifers. Groundwater temperature of snow-melting wells found to be higher
in the eastern part of Aizu basin. The similar trend was identified in temperature distribution maps prepared by Kaneko et al.
(2014).
There are some snow-melting wells with artesian flow at the periphery of Aizu Basin and their temperatures are higher than
the neighboring snow-melting wells. This is because upward movement of groundwater occurs in artesian wells. In general,
temperature should be higher in the western part of the central Aizu basin which lies in downstream area. However, groundwatertemperature was higher in eastern part.
Moreover, snow-melting wells in the eastern part of the basin showed higher temperature, although there is no artesian flow.
In these places, the thickness of Quaternary system is small and groundwater may be pumped from not only Quaternary systembut also Neogene system.
For further investigation, we will examine chemical composition of groundwater by ion chromatography.

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AHW26-P01

Room:Convention Hall

Time:May 27 18:15-19:30

Modeling of Surface Water and Groundwater Cycle System in a Mountainous Catchment
Underlain by Granite
WATANABE, Yasuto1∗ ; TSUJIMURA, Maki2 ; IKEDA, Koichi1 ; YANO, Shinjiro3 ; ABE, Yutaka3 ;MATSUMOTO, Takehiro3
1

Graduate School of Life and Environmental Sciences, University of Tsukuba, 2 Faculty of Life and Environmental Sciences,
University of Tsukuba, 3 Institute for Water Science, SUNTORY Global Innovation Center LTD
A mountainous watershed plays an important role as a recharge area, and many studies have been conducted regarding the
groundwater flow. However, there have not been enough studies in headwater catchment with large topographical relief. Also,
there have been few studies applying numerical simulation to the groundwater flow in the headwater catchment.Therefore, theaim of this study is to reproduce groundwater flow in a steep mountainous catchment underlain by granite using numericalsimulation.
The study area is the headwater catchment of Jingu River in Yamanashi, which is one of the mountainous catchments underlain
by granite. The highest relative height of the catchment is about 1400 m. The numerical simulator is GETFLOWS, which cananalyze three dimensional surface and groundwater flow. In this study area, residence time and recharge altitude of groundwater
have been estimated using CFCs and stable isotopes tracers previously, and this study aims to reproduce those values by numericalsimulation.
The permeability was examined, and trials of reproduction of the groundwater flow system were performed. The permeability
seems to have an effect on the groundwater flow system such as groundwater level and flow path. Also, in the north of thecatchment, it has been found that several springs have longer residence time estimated by CFCs than the others have, and thesimilar result was shown by numerical simulation. Furthermore, the recharge altitude of springs showed appropriate values
except some springs.
Keywords: groundwater, simulation, GETFLOWS, residence time, recharge altitude

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AHW26-P02

Room:Convention Hall

Time:May 27 18:15-19:30

Spatial analytic reasons of eutrophication in Baiyangdian Basin, China
HUANG, Lin1∗ ; SHEN, Yanjun2 ; KONDOH, Akihiko1
1

Chiba University, 2 Center for Agricultural Resources Research

Baiyangdian is the closed lake located in North China Plain, about 150 km to the south of Beijing. The lake provides domestic
and industrial water to surrounding area. The lake has functions of flood mitigation, water purification, conservation of biodiversity, that is ecosystem services. However, water shortage and pollution becomes serious problem, and ecosystem services are
deteriorated.
Recent economical development in China leads increase in local industries, and population is increasing in the surroundingarea. Water demand is also increasing, that lead to decreased storage and dry up of Baiyangdian lake.
Baiyangdian collects nine streams from Taihangshan mountains and effluent stream flows into Bohai Bay. Swamp area include
about 3,700 of creeks connecting 146 water areas through channels. Total area is about 366 km2 including 36 villages in theswamp area. The climate is temperate monsoon climate, which has dry and cold winter, and hot and moist summer. Averageannual precipitation is 563.9 mm, and annual average pan evaporation reaches 1369 mm. About 80% of precipitation is concentrated from June to September.
Baiyangdian as natural wetland has many functions, namely ecosystem services. Proper conservation is required to maintainlocal agriculture and industries. The final goal of the study is conservation of ecosystem services of natural wetland. In thispaper, we report the interannual and seasonal changes in water area and wetland vegetation in Baiyangdian by using satellite
remote sensing. Field survey of water quality had conducted in 2010. The relationship between the condition of surface waterand vegetation and water quality is investigated.
China 1km Mesh Grid Land Cover data in 1980 and 2000 shows the residential land and industrial land increased in Baiyangdian, and the arable land in the middle and mountain areas tend to increase, but decrease in plain area. Reduction of arable landarea corresponds to the residential and industrial land increased area.
In addition, Water area and vegetated area in the lake has a decreasing tendency between 1989 and 2001. This is caused byhousing and agricultural developments in the reclaimed land. Especially the upper part of Baiyangdian suffers development
activities. On the other hand, it is proved that large water areas of Baiyangdian had been separated.
Field survey was carried out on April, June and September in 2010. Total nitrogen, total phosphorus, nitrate-nitrogen were
measured at plural sampling points. The concentrations of the items are high at the inlet channel of Baiyangdian lake. It seems
wetland vegetation (mainly reed grass) absorb the nutrients. The concentration in September is the lowest in the season. This isconsidered to be the absorption of the nutrients by vegetation in the growing season. It remains as the next point to discussion.
Moreover, the observation months results are compared. The absorption rate of the nutrients in September is more high than itin April and June. One the reasons is that reed grass absorb the nutrients in the growing season from April to July. In addition,
the transparency at inlet is much lower than center and outlet . The concentration distribution and the seasons change of waterprojects , are based on the pollutants from the upper steam, wetland vegetation purification function and the seasonal distributionof precipitation to illustrate.
Baiyangdian is a enclosed water which is near to the city , and solve the problems about enclosed water is the world common
project . For example , in Japan , they are using Water Pollution Prevention Law and Lake Water Quality Prevention Measure to
improve the water quality . In the future, the research of comparative hydrology based on around the world about enclosed water
subject , to master the lake water environment problems as the earth in environment problems.
Keywords: Ecosystem services, Water pollution, Water area, Wetland vegetation

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AHW26-P03

Room:Convention Hall

Time:May 27 18:15-19:30

Hydrological Environment of Surface Water and Groundwater in Ninh Thuan Region,
South-east Coast, Vietnam
LE, Anh Hoang1∗ ; TSUJIMURA, Maki1 ; NGUYEN, Huyen t.t.2 ; PHAN, Tuyen N.2
1

Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Ten-noudai, Tsukuba, 2 Institute of Energy,
6 Ton That Tung, Khuong Thuong ward, Dong Da district, Hanoi, Vietnam
The Government of Vietnam is planning to construct two nuclear power plants in Ninh Thuan province, a coastal region ofVietnam with semi-arid climate conditions. This research aims to investigate the hydrological environment of surface waterand groundwater in the planned site of Ninh Thuan 2 in order to obtain basic information for the construction of the plant.
Inorganic solute ion concentrations and stable isotopes of oxygen and hydrogen in surface water, groundwater and seawater wereanalyzed to understand their chemical characteristics and hydrological process. The results demonstrate that water resourcesin this region are limited and groundwater is considered to be a main water source. The groundwater flows in Holocene andPleistocene aquifers, with the depths of 10 m and 16-21 m, respectively and the dominant flow is from southwest to northeast,
corresponding to the river flow direction in this area. There seems to be an interaction of surface water and groundwater in thisregion. Streams and wells near the shoreline are affected by brackish water with high Na-Cl concentration. Groundwater in the
Holocene aquifer shows a chemical characteristic of Ca-SO4 and Ca-HCO3 type, whereas Na-HCO3 water type is dominant in
the Pleistocene aquifer. The water chemistry is being influenced by freshwater - brackish water mixing, weathering processes
and human activities. The nitrate concentration of groundwater in the Holocene aquifer is higher than that in the Pleistocene
aquifer, and much higher than WHO drinking water standards. This means that water in this region is affected by agricultural
production activities. Therefore, the project developer should have a careful consideration when consuming water in this region
for Ninh Thuan 2 nuclear power plant project.
Keywords: nuclear power plant, environmental impact assessment, water resources

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AHW26-P04

Room:Convention Hall

Time:May 27 18:15-19:30

The origin and formation mechanism of the water quality of deep hot springs from thenorthern foothills of Mt. Fuji
YAGUCHI, Muga1∗ ; MURAMATSU, Yoichi2 ; CHIBA, Hitoshi3 ; OKUMURA, Fumiaki4
1Gra. Shc., The Univ. Tokyo, 2 Fac. Sci. and Tech., Tokyo Univ. Sci., 3 Fac. Sci., Okayama Univ., 4 Japex R.C.

Since the mid-1990s, drilling wells for hot spring bathing purpose was performed on a deep aquifer at depths reaching 1,500m
below the surface in the northern foothills of Mt. Fuji. Meanwhile, the origins of the water and the formation mechanisms of thewater qualities have not always been investigated thoroughly. Clarification of the forming environment of the hot spring waters
is indispensable for the protection and sustainable development of hot spring sources.
In this study, water samples were collected from wells for hot spring bathing purposes and from natural springs in the northernfoothills of Mt. Fuji and the adjacent Misaka and Tanzawa Mountains area, and were subjected to chemical and isotopic analysis
of hydrogen, oxygen, and sulfur (δD, δ 18 O, δ 34 S). Based on the analytical results, the origin of the water and water-rock interactions, which affect the water quality of the deep hot springs, were discussed.
The water in samples were thought to be originated through mixing of meteoric water with very small amounts of alteredseawater, which had been trapped in the pore space in the basement rock, so-called green tuff formation. After subtraction of
the seawater-derived components, concentrations of major components of the water samples were thought to be controlled by
the dissolution of gypsum and/or anhydrite, calcite precipitation, and the formation of Na-smectite by weathering of albitizedplagioclase. Around the distribution areas of volcanic products of Mt. Fuji, the weathering process of olivine may also influence
the concentrations of Mg2+ ions. The δ 34 S values of SO4 2− ions of hot spring waters were higher on the Misaka and Tanzawa
Mountains side, whereas they were lower on the foot of Mt. Fuji side (down to +8.2 ‰), indicating the presence of different
SO4 2− ion sources; the former SO4 2− ions with high SO4 2− values are derived from marine anhydrite and/or gypsum, whereas
the latter SO4 2− ions with low δ 34 S values are involved in volcanic anhydrite and/or gypsum.

Keywords: northern foothills of Mt. Fuji, deep hot spring, water quality, water-rock interaction, stable isotope ratio

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AHW26-P05

Room:Convention Hall

Time:May 27 18:15-19:30

Historical Rainfall, Runoff and Flood of Wadi Siham Basin, Yemen
AL WARD, Majed ahmed2 ; ISMAIL, Wan ruslan1∗
1

Geography Department, Thamar University, Dhamar, Yemen, 2 Geography Section, School of Humanities, Universiti Sains
Malaysia, 11800 Pulau Pinang
Wadi Siham Basin (WSB) is one of the most important agricultural areas, and one of the seven largest wadis in the westernregion of the Republic of Yemen. This study aims to evaluate the quantity and spatial and temporal variation of rainfall andrunoff. The rainfall (1979-2008) as well as runoff and floods (1990-2009) data were collected and treated statistically in order toevaluate the rainfall and runoff trends. The areal catchment rainfall was estimated by using the Thiessen polygon method, while
the recurrence interval and probability analysis were carried out using the Hazen method. The Mann?Kendall and Sen’s slope
analyses results showed that the Wallan and Al-Amir stations produced significant negative values (-4.72 and -6.11 mm/year
respectively). However, the rainfall trend in Dhamar had a significant positive value of 50.20 mm/year. The average annual
rainfall in WSB was 346.39 mm/year. The total amount of rainfall was 1711.26 Mm3 . The mean annual water runoff was 82.92
Mm3 . A total of 570 events of flood occurred with a total volume of 53.10 Mm3 . The total water runoff was 4.85% of total rain
precipitated on WSB indicating that the total amount of water loss was 95.15% varied between evapotranspiration and infiltration.
In conclusion, the study results suggested the need for an urgent and sustainable water resource management in WSB.
Keywords: Rainfall, Runoff, Flood, Mann Kendal Test, Wadi Siham, Yemen

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AHW26-P06

Room:Convention Hall

Time:May 27 18:15-19:30

The characteristics of mercury deposition on to forest ecosystem observed in YakushimaIslandYOSHIDA, Akifumi1∗ ; NAGAFUCHI, Osamu2 ; YOKOTA, Kuriko4 ; NAKAZAWA, Koyomi3 ; OSAKA, Ken’ichi2 ;TETUKA, Kenshi5 ; TETUKA, Tatuko5 ; KITABUCHI, Hiroyuki1
1

Environmental Science Graduate school, University of Shiga Prefecture, 2 University of Shiga Prefecture, 3 Division of Environmental Science, University of Shiga prefecture, 4 Toyohashi University of Technology, 5 Society of Yakushimaology
Mercury (Hg) is a global pollutant that affects human and ecosystem health. Atmospheric Hg can be removed from the atmosphere by wet or dry deposition. Many studies suggest that the interactions between atmospheric Hg and the forest canopy may
be a key process influencing Hg input to forested watersheds. These studies are mainly conducted in Europe, however, only afew studies were reported in Asian monsoonal area. The characteristics of the seasonal variation of a precipitation is different
between Asian monsoonal area and Europe region, i.e., there is a rainy season (June-July) and typhoon season (July-September)in Asian monsoonal area. It has been reported that the most of atmospheric mercury is supplied as a wet deposition. Therefore,
it is important to evaluate the characteristics of Hg atmospheric deposition in Asian monsoonal area. Yakushima island has morethan 8,000 mm of annual precipitation. Therefore, it is suitable site to evaluate the mercury dynamics in the forest ecosystem.
Study sites are located at a height of 200 m and 1600 m above sea level of the broad-leaved evergreen forest in the western areaof Yakushima Island, respectively. In 200 m experimental site, the experiment was conducted at a 100 m x 100 m experimentalsite around the observation tower. We installed automatic rain samplers which can collect rain water every 10 mm precipitation, bulk deposit samplers (within canopy and without canopy) and groundwater collecting devise, respectively. In addition,
we sampled stream water which flow down near the observation tower. In 1600 m experimental site, we installed automaticrain samplers. These experiments are conducted during 2011-2014 sampling campaign and each samples are collected once amonth basis. Hg, major ions, and DOC were analyzed. From these result we will discuss the characteristics of Hg deposition inYakushima Island.

Keywords: Yakusima, mercury, forest ecosystem, Asia monsoon, precipitation

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AHW26-P07

Room:Convention Hall

Time:May 27 18:15-19:30

Study on a numerical model for fluid flow and heat transport through permeable porous
media
YOSHIOKA, Mayumi1∗
1

National Institute of Advanced Industrial Science and Technology (AIST)

Interaction between the atmosphere, the surface and the subsurface is one of the most important keys in understanding, managing and utilizing the water environment. Recently, technologies for estimating the shallow subsurface thermal environment
adequately are required along with the popularization of the ground-coupled heat pump system and the heating and cooling system by direct use of groundwater. A numerical simulation model for being able to estimate processes of fluid flow and thermaltransport in unsaturated and high permeable porous media is required in order to develop the technique of shallow geothermalenergy utilization.
In this study, the one-dimensional infiltration experiments using a cylinder column and improving the numerical simulation
model were carried out. In the experiment, highly permeable porous media 3 and 5 millimeters in diameter were used. The flow
velocity and the temperature changes in the column were measured. The experimental results were represented by the numericalmodel.
As the results, the high-velocity flow in the permeable porous media was simulated by the model using multi-phases system.
In addition, in the model the temperature of soil, liquid (water) and air were able to be simulated individually and the calculated
results were agreement with the experimental results.

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AHW26-P08

Room:Convention Hall

Time:May 27 18:15-19:30

Potential map of Borehole Heat Exchanger system for the central part of Kanto Plain andthe Obama Plain
HAMAMOTO, Hideki1∗ ; HACHINOHE, Shoichi1 ; SHIRAISHI, Hidetaka1 ; ISHIYAMA, Takashi1 ;MIYAKOSHI, Akinobu2 ; MIYASHITA, Yuji3 ; TAHARA, Daisuke4
1

Center for Environmental Science in Saitama, 2 National Institute of Advanced Industrial Science and Technology, 3 Hot Springs
Research Institute of Kanagawa Prefecture, 4 Fukui Prefectural University
A Borehole heat exchanger (BHE) is an economically and environmentally friendly technology that is widely used in Europe
and North America, but rarely used in Japan. One of the reasons for this is the relatively complex topography and geologicalstructure in Japan compared with those in Europe and North America.
Complex structures produce regional differences in subsurface thermal properties and temperature structures, leading to regional variation in the efficiency of BHEs. Thus, it is important to evaluate the available subsurface heat energy through thermal
response tests and/or numerical simulations and to design appropriate systems (depth and number of boreholes for heat exchange).
Geological structures, groundwater properties, and subsurface temperatures are essential input data for numerical simulations.
We performed BHE numerical simulations using measured data and present a new method for constructing a BHE potential
map from regional geological structure models for typical Japanese plains. Our target areas are the central part of the Kanto
Plain and the Obama Plain. The Kanto Plain contains the capital city of Japan and has a population of more than 40 million.
On the other hand, the Obama Plain is located in the central part of Japan and faces the Sea of Japan. And population densityof the Obama Plain than that of the Kanto Plain. It is important to evaluate the energy potential of BHE in a part of this area
for socio-economic studies. We have performed measurements of subsurface temperatures at 23 stations in the central part of
the Kanto Plain (Saitama region). Subsurface temperatures and thermal conductivities at four stations at Obama Plain. In ourpresentation, we discuss that the difference of subsurface thermal environment and efficiency of BHEs.
Results of the numerical simulations show that the BHE efficiency increases by 20% when the subsurface temperature increases by 5 degC and the efficiency also increases by 30% when the groundwater flow varies from 0 m/year to 15 m/year.
In addition, the results of the subsurface temperature profiles show long-term subsurface warming in the Kanto plain during
the last century. The influence of subsurface warming effects on the BHE efficiency through numerical simulations is discussed.
We show that subsurface warming effects cause the BHE efficiency of heating to increase.
Keywords: Borehole Heat Exchanger system, groundwater, Kanto Plain, Obama Plain

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AHW26-P09

Room:Convention Hall

Time:May 27 18:15-19:30

Analysis of groundwater flow system for potential assessment of ground-source heatpump system in regional scale
SHRESTHA, Gaurav1∗ ; UCHIDA, Youhei1 ; YOSHIOKA, Mayumi1
1National Institute of Advanced Industrial Science and Technology

Ground-source heat pump system is an energy efficient and environment friendly technology that utilizes natural heat stored ina subsurface of shallow depth up to about 100m. It is used for space-heating, space-cooling, hot water supply and snow-melting
purposes. Development rate of GSHP system is gradually increasing in Japan. However, the pace is still lacking behind America
and European countries because of higher initial cost resulted by oversized design of ground heat exchangers (GHE) and lack of
information on its advantages. To promote the development of GSHP system, evaluation of suitable locations for its installation
is essential.
Regarding geology, Quaternary System usually exists in the shallow subsurface which mainly consists of sand and gravel. In
this Quaternary System, groundwater is actively flowing. For this reason, hydrological and geological information are necessary
because they largely influence the subsurface temperature distribution, and consequently affects heat exchange rate of GHE as
well as overall operation of GSHP system.
In this study, groundwater flow system of the Tsugaru Plain in Aomori Prefecture was comprehended in order to assess thepotentiality of GSHP system. A regional scale 3D groundwater flow ? heat transport model was developed for this purpose. Horizontal dimensions of the model were 64km in east-west and 78km in north-south direction. In the model, layers 1 ? 4 belonged
to Quaternary System, layers 5 ? 7 to Neogene and layers 8 ? 12 to Paleogene. Saturated steady state simulation of groundwaterflow and heat transport was conducted with this model. In Tsugaru Plain, hydrological field data such as groundwater level could
not be measured as groundwater observation wells were not sufficient. Therefore, the analysis model was verified by comparing
the computed hydraulic heads and water table with past studies and literature values. Additionally, computed results were validated by inspecting the path of simulated groundwater flow at natural springs, confirming if groundwater was flowing in upward
direction.
Based on the simulation results of the analysis model, distribution maps of groundwater flow velocity, water table depth fromsubsurface and subsurface temperature were prepared using geographic information system (GIS). Groundwater flow velocity
was found higher at peripheral areas. It can be due to higher hydraulic gradient near the mountainous areas. At areas with higher
groundwater flow velocity, improved heat exchange rates of GHEs can be expected because of advection effect. Water table depth
from surface was found to be shallow in most of the areas of the plain, which indicates the sustainable operation of GSHP systemfrom the view point of groundwater availability and saturation of geological layers. Aomori Prefecture (2011) and Machida
and Yasukawa (2008) showed similar results of water table. Subsurface temperature computed from heat transport simulation
was found higher at the central area of plain, which is thought to be due to the heat transfer by groundwater advection. For
space-heating with GSHP system, the central area can be suitable from temperature perspective. In this way, the comprehensionof regional scale groundwater flow system accompanied with subsurface temperature distribution can provide useful information
to assess suitable locations for the installation of GSHP system.
References:
Aomori Prefecture (2011) Survey report on potential use of ground-coupled heat pump system and hot spring temperature in
Aomori Prefecture. Aomori, Japan, 210 pp (in Japanese).
Machida, I., Yasukawa, K. (2008) Regional groundwater survey for the use of GSHP system in Aomori Prefecture. Vision forthe promotion of GSHP system in Aomori Prefecture, Aomori, Japan, pp. 91-126 (in Japanese).

Keywords: ground-source heat pump system, groundwater flow, heat transport, potential assessment

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