1986 Fiscal Year Final Research Report Summary
RAINWATER MOVEMENTS AND RUNOFF PHENOMENA IN A SMALL MOUNTAINOUS BASIN
| Project/Area Number |
59460191
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
農業土木
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
SHIKASHO SHIOMI FACULTY OF AGRICULTURE, KYUSHU UNIVERSITY, 農学部, 助教授 (80038265)
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| Co-Investigator(Kenkyū-buntansha) |
MORI KEN FACULTY OF AGRICULTURE, KYUSHU UNIVERSITY, 農学部, 助手 (50117272)
SEGUCHI MASHIRO FACULTY OF AGRICULTURE, SAGA UNIVERSITY, 農学部, 助教授 (20093974)
TANAKA @kOHEI FACULTY OF AGRICULTURE, KYUSHU UNIVERSITY, RETIRED IN 1986, 農学部, 教授 (00039306)
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| Project Period (FY) |
1984 – 1986
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| Keywords | Small Mountainous Basin / Basin Characteristics / Runoff Analysis / Runoff Characteristics / River Water Quality / Soil Moisture Movement / Variable Source Area / 非線形パラメータの同定法 |
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| Research Abstract |
From the results of field measurement in an experimental basin and numerical simulation by stochastic-conceptual runoff model and stochastic system theory, the characteristics of basin and runoff in a small mountainous basin are as follows:
1) Runoff Characteristics in a Small Mountainous Basin
The hydrograph is influenced by the heterogeneity on the hillslope and soil moisture movement in the A-horizon. It seems that when the surface soil of the slope is dry or in the initial stage of runoff, the wet soil of the slope in the vicinity of a stream or the stream itself contribute considerably to the area producing runoff. It is infered that the area producing runoff expands in the direction of the slope as raining continued.
2) Relationship between Basin Storage and Variable Source Area
It was found that the variations of storage were closely related to generation of fast flows on a hillslope, and that basin storage was related to variable source area.
3) Separation of Baseflow Using Water Quality
The baseflow component was separated using a steady and an unsteady water quality model, and the results of separation were checked with the field observation data. It seems that the unsteady water quality model provides a better baseflow separation than that of the steady one.
4) Stochastic Properties of Hillslope Parameters
The hillslope parameters (thickness of surface layer, hydraulic conductivity and effective porosity) showed log-normal distributions. Futhermore, it was found that thickness of surface layer had a marked linear trend in the direction of slope and that the hydraulic conductivity correlated with the effective porosity.
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