HR: 1340h
AN: H53C-1395 [Abstracts]
TI: The effect of surface cover on infiltration rate in steep forest plantations
AU: Hiraoka, M
EM: pgwhs065@yahoo.co.jp
AF: School of Life and Environmental, 1-1-1 Tennno-dai, Tsukuba, 3058572, Japan
AU: * Onda, Y
EM: onda@geoenv.tsukuba.ac.jp
AF: School of Life and Environmental, 1-1-1 Tennno-dai, Tsukuba, 3058572, Japan
AU: Kato, H
EM: hiroakis980@ybb.ne.jp
AF: School of Life and Environmental, 1-1-1 Tennno-dai, Tsukuba, 3058572, Japan
AU: Ito, S
EM: melodyflags@yahoo.co.jp
AF: School of Life and Environmental, 1-1-1 Tennno-dai, Tsukuba, 3058572, Japan
AU: Mizugaki, S
EM: gakimizu@geoenv.tsukuba.ac.jp
AF: School of Life and Environmental, 1-1-1 Tennno-dai, Tsukuba, 3058572, Japan
AB:
The Japanese cypress (Hinoki; Chamaecyparis obtusa) is a major commercial tree species in Japan, and
without thinning of high-density stands, canopy closure prevents development of understory vegetation. Therefore
there is a concern for overlandflow and sediment yield due to infiltration rate lowering from steep hillslopes of
Japanese cypress plantation. We developed a light-weight rainfall simulator based on the design of Meyer and
Harmon (1979). A flat fan Veejet 80150 spraying nozzle (Spraying systems Co., USA) is mounted on the manifold
at 2.13 m high from the plot surface. The nozzle oscillates so that the spray fans swept across the targeting 1m x
1m plot. The Veejet 80150 spraying nozzle produces large raindrops larger than 2 mm in diameter, and can
simulate the high raindrop kinetic energy of natural storm. A targeted rainfall rate is 180 mm/h. Total 25 sprinkling
experiments have been conducted on 35-degree hillslopes with varying surface cover. We obtained the minimum
infiltration rate of 14 mm/h where the surface cover is very little. The infiltration rates were plotted against the total
understory vegetation and dry weight of total surface cover including litter. The infiltration rate increased with the
increasing total surface cover, and higher regression coefficient is obtained for the case of the total surface cover.
These results will contribute to the future modeling studies of overlandflow occurrences for the catchment scales.
DE: 1826 Geomorphology: hillslope (1625)
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 1838 Infiltration
DE: 1850 Overland flow
DE: 1851 Plant ecology (0476)
SC: Hydrology [H]
MN: 2007 Fall Meeting