Estimating the collapse of aggregated fine soil structure in a mountainous forested catchment.
This paper describes the relationship of forest soil dryness and antecedent rainfall with suspended sediment (SS) yield due to extreme rainfall events and how this relationship affects the survival of forest plants. Several phenomena contribute to this relationship: increasing evaporation (amount of water vapour discharged from soil) due to increasing air temperature, decreasing moisture content in the soil, the collapse of aggregates of fine soil particles, and the resulting effects on forest plants. To clarify the relationships among climate variation, the collapse of soil particle aggregates, and rainfall-runoff processes, a numerical model was developed to reproduce such aggregate collapse in detail. The validity of the numerical model was confirmed by its application to the granitic mountainous catchment of the Nagara River basin in Japan and by comparison with observational data. The simulation suggests that important problems, such as the collapse of forest plants in response to decreases in soil moisture content and antecedent rainfall, will arise if air temperature continues to increase.
Institute of Industrial Science (IIS), The University of Tokyo, Be505, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan. Electronic address: mouri@rainbow.iis.u-tokyo.ac.jp.
Goro
G
Mouri
Information and Multimedia Center (IMC), Gifu University, 1-1 Yanagido, Gifu City 501-1193, Japan.
Seirou
S
Shinoda
Faculty of Geography, Lomonosov Moscow State University, 119991 Russia, Moscow, GSP-1, Vorob'evy Gory, MSU Moscow, Russia.
Valentin
V
Golosov
Faculty of Geography, Lomonosov Moscow State University, 119992 Russia, Moscow, GSP-1, Vorob'evy Gory, MSU Moscow, Russia.
Sergey
S
Chalov
Department of Urban and Environmental Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan.
Michiharu
M
Shiiba
Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
Tomoharu
T
Hori
Institute of Industrial Science (IIS), The University of Tokyo, Be607, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
Taikan
T
Oki
D002980:Climate; D004777:Environment; D007564:Japan; D008962:Models, Theoretical; D011891:Rain; D045483:Rivers / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D013696:Temperature; D014197:Trees; D014867:Water / Q000032:analysis
D012987:Soil; D014867:Water
Aggregated structure; Antecedent rainfall; Collapse; Ground dryness; Hydrological model; Suspended sediment; Warmer climate