no. +**,p.+/ ,0 · application of soil physics to rainwater dynamics at forested hillslopes...

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腍腓腂腀腁腅腎腋腈腊腉腄腃腏腌腐腒腇腃腆腑 臀膑* Application of Soil Physics to Rainwater Dynamics at Forested Hillslopes Ken’ichirou KOSUGI* * Graduate School of Agriculture, Kyoto University, Kyoto 0*02/*,, Japan Abstract Rainwater dynamics at forested hillslopes are one of the most important themes in forest hydrology, because they have large e#ects on storm and base flow hydrographs, occurrences of slope failures, material transports in forest ecosystem, and stream water chemistry. Rainwater infiltration and discharge processes at forested hillslopes can be e#ectively studied by using methodologies developed in soil physical studies, which includes methods for determining saturated-unsaturated soil hydraulic properties, equipments for measuring matric potential and water content in field soils, and numerical simulation techniques for saturated-unsaturated soil water flow. This paper introduces several previous and new studies which applied the methodologies of soil physics to the analyses of rainwater dynamics at forested hillslopes. Topics includes characteristics of forest soil hydraulic properties in comparison with disturbed sandy and loamy soils, e#ects of pore structure of forest soil on rainwater infiltration, indices of water holding capacity of forest soils, e#ects of soil water-repellency on heterogeneous infiltration and occurrence of surface runo#, experiments and modeling of soil-pipe flow, as well as rainwater infiltration in weathered bedrock. Key words : forest hydrology, forest soil, water retention characteristic, hydraulic conductivity, pipe flow +腉腅腊腇 臺臕腜腊腏腩膔臧腝臤臙膟膦腝臼膥腬臫腓膽膱膞臷腝膑腖腘腇腩臆臧膨腥臧臁腸腮膚腓腩腔腣腝臙腺腮 腸膋腱膇腼腝至腥膣腝臬膎臻臒臊腥臌腝膘腝至腜腞膔臧腝臤臙膟腝膩 膃腶膉膘腌膛膼腘腇腩腢腔腝臬CO, 腲腱膐腜腊腏腩膤臗臔腝臚膧腥臧臔膺臫腛腚 腌膧膴腜膰腡腓膕膶腝膡臭腜腊腈腗腤臺臕 腨腍腝臧臡臵腥臧膏腬臹腩腐腙腌膬臱腙腛腕腗 腈腩臺臕腠腝膔臧腝臤腥臤腒腔膔臧腝腱腐腝膽膱 腜腊腈腗腞腝腯膦腝腞腪腕腉腒腗腍腔臟腝臧自腥臧自腝膻至臖臂膎臻腘腝膁腷膈腴腰膀腵膌 腳膄膉腥膪臧腝膻至臖腥腶腙腥腶腝臨 臸腳膂膅膊腂腳膆膌臖腤腎臠腜臅腘腇腩腐腐 腘腞腝腯膦膽膱腜臢腔腛臐膳腓腩膑臛腙腛 腩腐腙腬膭致腒腗腝腯腬臣膦腝腞腪腜膗腒腔腈腎腖腋腝臑腬臝膠腓腩,腕腟腛腔腈腒腑腝腘腆腎腗腈腏腚腖腜 ,+ 腕腟腛腔腈腖腜腞 + 膘膝膫腬臍腙腓腩臄膾臇臎腝腭膇 腯腳腊腦腟腲腹膇腲腍臟腜腖腈腗膻至腑腪腔腥腶腏臧膸 臨腝膖腂腞腚腘腇腩膙腪腝臺腘腤臥0*1* cm 腨臰腈腛腞腥腶腏臧膸臨腞 ,** mmh 膍臞腘腇腨臠臈腉腧腪腩臉膔膵腦腨腤臶腍腈腐腙腌腫腋腩腖腢 臉膔膵臟腝臤腏腒腬臞膢腩腐腙腜膯膒腓腩 腾腂腷膌膹腗腨腱臬腞膿腧腪腛腈腐腙腬臓腒腗 * 臶膦臶膦膓膦膽膱膜腁腆0*02/*, 臏臋膲膷腧腔腃腞腀 腋腁腍腁腌 : 腲腍臧自臧自腻腮腽J. Jpn. Soc. Soil Phys. 臟腝腝腯No. +**, p. +/,0 ,**/腝腓腐腙

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Page 1: No. +**,p.+/ ,0 · Application of Soil Physics to Rainwater Dynamics at Forested Hillslopes Ken’ichirou KOSUGI* *Graduate School of Agriculture, Kyoto University, Kyoto 0*0 2/*,,

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Application of Soil Physics to Rainwater Dynamics at Forested Hillslopes

Ken’ichirou KOSUGI*

* Graduate School of Agriculture, Kyoto University, Kyoto 0*0�2/*,, Japan

Abstract

Rainwater dynamics at forested hillslopes are one of the most important themes in forest

hydrology, because they have large e#ects on storm and base flow hydrographs, occurrences of

slope failures, material transports in forest ecosystem, and stream water chemistry. Rainwater

infiltration and discharge processes at forested hillslopes can be e#ectively studied by using

methodologies developed in soil physical studies, which includes methods for determining

saturated-unsaturated soil hydraulic properties, equipments for measuring matric potential and

water content in field soils, and numerical simulation techniques for saturated-unsaturated soil

water flow. This paper introduces several previous and new studies which applied the

methodologies of soil physics to the analyses of rainwater dynamics at forested hillslopes.

Topics includes characteristics of forest soil hydraulic properties in comparison with disturbed

sandy and loamy soils, e#ects of pore structure of forest soil on rainwater infiltration, indices of

water holding capacity of forest soils, e#ects of soil water-repellency on heterogeneous infiltration

and occurrence of surface runo#, experiments and modeling of soil-pipe flow, as well as rainwater

infiltration in weathered bedrock.

Key words : forest hydrology, forest soil, water retention characteristic, hydraulic conductivity,

pipe flow

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Brooks, R.H. and Corey, A.T. (+30.) : Hydraulic pro-

perties of porous media. Hydrol. Pap. no. -. Colo-

rado State Univ., Ft. Collins.

Chan, T.P. and Govindaraju, R.S. (,**-) : A new model

for soil hydraulic properties based on a stochas-

tic conceptualization of porous media. Water

Resour. Res., -3 : ++3/, doi : +*.+*,3 / ,**, WR

**+3/..

�v§± �+33+� : rf¨�Y²,&���³e´�Qc�0CD`c�,©´µ �Q��ª¶c·«� .

�.� : ,-�-*.

Katsura, S, Kosugi, K., Yamamoto, N. and Mizuyama,

T. (,**/) : Saturated and unsaturated hydraulic

conductivities and water-retention characteris-

tics of weathered granitic bedrock �¬���­P®e �+333� : hij\D�0C�¯�`r�0C��°`��no]?µ ±P�²¸³·¹´µº¶©·»¸¹wP�^)�0Cº\>�]?°µ _`=O� --/ : -/�.,.

Kosugi, K. (+33.) : Three-parameter lognormal distri-

bution model for soil water retention. Water

Resour. Res., -* : 23+�3*+.

Kosugi, K. (+330) : Lognormal distribution model for

unsaturated soil hydraulic properties. Water

Resour. Res., -, : ,031�,1*-.

Kosugi, K. (+331 a) : A new model to analyze water

retention characteristics of forest soils based on

soil pore radius distribution. J. For. Res., , : +�2.

Kosugi, K. (+331 b) : New diagrams to evaluate soil

°»�]l : OP�^)��¼«_`¼�0CDEc�<c 25

Page 12: No. +**,p.+/ ,0 · Application of Soil Physics to Rainwater Dynamics at Forested Hillslopes Ken’ichirou KOSUGI* *Graduate School of Agriculture, Kyoto University, Kyoto 0*0 2/*,,

pore radius distribution and saturated hydraulic

conductivity of forest soil. J. For. Res., , : 3/�+*+.

����� �+333� : ���������� ����������� ��� 2+ : ,,0�,-/.

����� �,**.� : �� ����� ��� !." #$�%&'��(����� )*+,� ��-.�� /1 �-� : 1+�13.

Kosugi, K., Mori, K. and Yasuda, H. (,**+) : An inverse

modeling approach for the characterization of

unsaturated water flow in an organic forest floor.

J. Hydrol., ,.0 : 30�+*2.

Kosugi, K., Uchida, T. and Mizuyama, T. (,**.) : Nu-

merical calculation of soil pipe flow and its e#ect

on water dynamics in a slope. Hydrol. Process.,

+2 : 111�123.

Kutílek, M. and Nielsen, D.R. (+33.) : Soil hydrology.

p. /-, Catena Verlag, Cremlingen, Germany.

Noguchi, S., Tsuboyama, Y., Sidle, R. C. and Hosoda, I.

(+333) : Morphological characteristics of macro-

pores and the distribution of preferential flow

pathways in a forested slope segment. Soil Sci.

Soc. Am. J., 0- : +.+-�+.,-.

�� /�012������� �+321� : �34�����5%6��78 ��� �9:��9:�;<���=�(���� ��� 03 :

-0,�-01.

>?@A �+330� : $���B���� C����DE��� �!"�#$FG �%� �&'H-� pp.

+/�,-� IJKL� (M�� ) �+32,� : �NOP*+,-(�%QRS T���1U�V� ��� 0. : .*3�.+2.

� ) �+32/� : W'�X���V�Y.Z��NOP*+,-(��[/� ��� 01 : ..3�.0*.

01�2 �+33,� : ���&-� p. -1� &\3� (M�Tsutsumi, D., Sidle, R.C. and Kosugi, K. (,**/) : A

simple model of lateral preferential flow in

hillslope soils. �4]��5�67 �,**.� : �� ����� ��� ! -"

#^8%&'�W'��_9`a%bbc�$��&defg78h:� ��-.�� /1 �,� : /2�0..

Uchida, T., Kosugi, K. and Mizuyama, T. (+333) :

Runo# characteristics of pipeflow and e#ects of

pipeflow on rainfall-runo# phenomena in a

mountainous watershed. J. Hydrol., ,,, : +2�-0.

5�67��������ijk��Wlm �+33/� :$���5nodp'q��H%rs�tu%6��vw;78� �<� +*0 : /*/�/*2.

van Genuchten, M. Th. (+32*) : A closed-form equa-

tion for predicting the hydraulic conductivity of

unsaturated soils. Soil Sci. Soc. Am. J., .. : 23,�232.

=�>x�C��� �+33/� : yz{�%&|Sq�} p��(��%rs�tu ��� #~��(��%Q�?�vw#� ��� 11 : ,,.�,-+.

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