ProdukHukum Pendidikan

Maki TSUJIMURA,

Maki TSUJIMURA,

Ph.D.

Ph.D.

Associate Professor in Hydrology and Hydrogeology, Doctoral Prog

Associate Professor in Hydrology and Hydrogeology, Doctoral Program in Sustainable ram in Sustainable Environmental Studies, Graduate School of Life and Environmental

Environmental Studies, Graduate School of Life and Environmental Sciences; Sciences; Executive Leader, EDL Education Program, University of Tsukuba

Executive Leader, EDL Education Program, University of Tsukuba

Co

Co--ChairholderChairholder, UNESCO, UNESCO--Chair on Sustainable Management of Groundwater in MongoliaChair on Sustainable Management of Groundwater in Mongolia Environmental Diplomatic Leader (EDL)

Environmental Diplomatic Leader (EDL)

Education Program, University of Tsukuba

Contents

Introduction - rainfall runoff process in watershed Transformation from rainfall into runoff

Infiltration

Runoff characteristics

Runoff components: End Members Mixing Analysis Subsurface flow process in hillslope and runoff

Role of bedrock groundwater in runoff

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Infiltration

%

2! - 3 (! 3

--

-Measurement of infiltration capacity

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Contrasting of forest situation and

infiltration capacity

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, ! < !8

= < ,

Measurement of infiltration capacity

Calculation of IC using data of sprinkler

I = P – Q

I: IC, P: rainfall intensity, Q: overland flow intensity

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" , -" , , 5 ) 5 ) !

Exercise 1

$

% &' % ( )' % * '

+,- )+ -,. )+ .,) -+ ),/ .+ /,0 .0 0,1 -0 1,2 0 2,3 -+ 3,4 -0 4,-+ 0 -+,-. -0 -.,-/ -. -/,-1 -1 -1,-3 -3 -3,.+ .1 .+,.0 .. .0,)+ .. )+,)0 .1 )0,/+ .2 /+,/0 ./ /0,0+ .) + ) , , ,

= + ) 8 "

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Exercise 1 -Answer

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+ 0 -+ -0 .+

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日付 %.++-' 流 量 % * ' + .+ /+ 1+ 3+ -++ -.+ -/+ -1+ 雨 量 % * ' 流量 雨量 &&$! , , . ! , , . !

Hydrograph and hyetograph

Runoff characteristics reflecting hydrological processes

$B

= &8> ! , 1 $&&C , . ! , . ! , . ! , . ! , . ! , . ! :B ! 1 8;C / $B !

1 < &C

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I II III IV V VI VII

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I II III IV V VI VII

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Where does water come from?

Mass balance

End Members Mixing Analysis (EMMA)

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Exercise 2

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< !

The data in the left table shows temporal change of δ18_{O in stream water (runoff:}

L/s/km2_{) during a rainstorm in a small}

headwater basin, Seto, Aichi, Japan. Calculate contribution rate of pre-event water to runoff water using EMMA and show the results by graph.

Exercise 2 -Answer

6

+

Case in a headwater

Contrasting runoff components separation using 18_O

between the watersheds underlain by shale and granite

Shale watershed: >98% coming from pre-event water Granite watershed: 64% coming from pre-event water

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$ Stream

Saturation Divide Weir

Overland flow

Spring Stream Saturation Divide Weir

Rain gauge

Observation line

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+&+ .&+ /&+ 1&+ 3&+ % *0 ' .30 + &+ . &+ / &+ 1 &+ , & % *(

+ &) *(

+ .+ /+ 1+ 3+ -++ , %8 ' + .+++ /+++ 1+++ 3+++ + ++ -- -. ++ --+ --+--+ -. -. ++ -. + ++ -) -. ++ -) %( * *$ . ' , .+++

% ' , .10 '

降 水 量 % ' ,濃 度 % ( ,-' 地 下 水 成 分 割 合 %8 ' 比 流 量 %( ,-$ ,.' 地下水成分 降水濃度+&) +&+ +&0 -&+ -&0 .&+ % *0 ' -1 +&+ .&+ /&+ 1&+ , & % *( ' +&2 *( + .+ /+ 1+ 3+ -++ , %8 ' + . + / + 1 + 3 +

1 + + ! . 2

- . + + ! . 2

- 3 + + ! . 2

+ + + ! . 3

1 + + ! . 3

- . + + ! . 3

%(

*

*$

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% ' ', , -1 '

降 水 量 % ' ,濃 度 % ( ,-' 地 下 水 成 分 割 合 %8 ' 比 流 量 %( ,-$ ,.' 地下水成分 降水濃度+&2 , , ! , , ! " < , .F ! " < , .F ! C ! C ! F . .) , ! F . .) , ! , ,

1 &8 1 &86

>

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<

比流量%( ,-$ ,.'

降水量

% '

比流量 %( ,-_$ ,._'

降水量 ( )

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2 &&$!

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%

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Role of bedrock groundwater in

runoff

>&

Role of bedrock groundwater in

runoff

Role of bedrock groundwater in

runoff

>

Role of bedrock groundwater

in runoff

>

Aquitard

不 透

水 層

Confined aquifer _{Confined aquifer} Acuitard Unconfined aquifer Unconfined aquifer GW table River Spring Recharge area Well Residence time 1940 1990 C F C s co n ce n tr a ti o n

CFCs in atmosphere

Age in spring / GW

Present

Residence time in spring / GW

Age Present

A q_u

CFCs (chlorofluorocarbons)

CFCs (chlorofluorocarbons)

CFC-11

　

(CCl

₃

F, trichlorofluoromethane)

CFC-12 (CCl

₂

F

₂

, dichlorodifluoromethane)

CFC-113 (C

₂

Cl

₃

F

₃

, trichlorotrifluoroethane)

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9 + ! _"/"<$ "/"<$$ "/"<$$ '/;J$&&

CFCs is stable in the atmosphere.

CFCs concentration in the atmosphere is

increasing since 1950.

Atmosphere (F_a)

Groundwater (F_g)

Soil surface

Water table

Air in soil (F_s)

F_a

F_s

= %-'

: ; <

(

−

_.

)

=

_%.'

:

%5 5 -430'

              +       + +       +       + = . ) . -) . --++ -++ -++ -++ %)' % 8'&

-， .， )， -， .， ) $ 5 5

Excess air through

fissurs of bedrock Decomposition by microorganism

Aquitard

不 透

水 層

Confined aquifer Aquitard

Unconfined aquifer Unconfined GW

CFCs contamination

River Spring

Recharge altitude Recharge temperature

Well

Urban air

Thickness of unsaturated zone

A q_u

Age of spring and GW in Mt. Tsukuba

Age of spring and GW in Mt. Tsukuba

(Matsumoto, T., 2009)

(Matsumoto, T., 2009)

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CFC-11 pg/kg 100 500

1000

CFC-11 concentration

Spatial distribution of CFCs and chemical components

Spatial distribution of CFCs and chemical components

Chemical characteristics

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Age of spring and GW

Age of spring and GW

4 ,

Age of spring and GW in a mountainous watershed facing ocean

Age of spring and GW in a mountainous watershed facing ocean

(

) 5

9 , 8

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&& ：：：：降水降水降水降水

： ：：

：大気大気大気 サンプル大気サンプルサンプルサンプル

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17 18 14 20 17 14 10 14 14 7 12 8 13 10 ( 4 , ' 2km 松山沢川 神宮川 田沢川 尾白川 釜無川 ：湧水 ：河川水 本流 ：河川水 支流 ：流域界

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10 19 ' ： ( 1 4 ,1

= 5

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Summary

Rainfall-runoff characteristics suggest subsurface flow processes occurring in hillslope.

Groundwater is dominant in runoff during rainstorms in warm humid regions.

Role of bedrock groundwater is important in runoff during rainstorms in headwater catchments.

Residence time of groundwater and spring water varies dynamically according with hydrological regime in headwaters.