In this paper, the writer reports the natural structure and functions of the delta-shindens in YATSUSHIRO Compound Deltaic Coastal Plain in Kumamoto Prefecture. Almost all Japanese deltas were reclaimed in the front margins of deltas where remarkable differences inheight were seen between. the rise and fall of a tide since Edo Era, the late Feudal Age. New Shindens were advanced everytime the salt-grass-marsh grew at the front of the older shindens in the front margins of such river deltas as R. Edo, R. Kiso, R. Asahi, R. Takahashi, R. Chikugo and R. Kuma Deltas. It is very important for the shindenthe reclaimed rice-fields at, the front margins of deltas to be constructed with a Natural organic structure in order to check the invasion of the rise tide, to drain the surplus water of older shindens and to irrigate the new shindens. 1), SIOYOKE-TSUTSUMIA dike checking the rise-tide. It was constructed, by the labours of the peasant of the Feudal Lord who presented the capital and the material for reclamation. These peasants. were given the perpetual lease and levied land-tax in rice. 2), Irrigation of delta-shinden. These peasants acquired the irrigation water, from the drainage-water of older shindens and Hondens, and joined in an, irrigation water utilization association. In the lower part of a river invaded. by the tide, they utilized the well-water, in the upper part of it the riverwater arrested by the rise tide. Where irrigation water is poorly available, new shindens were given less water than older shindens. In case, theyjointed in the irrigation water utilization association, new shinden presented ten times as large area to older shinden by way of compensation for that occupied by there water-course in older shinden, or bought the land for the water-course from the Honden, and paid land-tax to their Feudal Lord. When the drainage area of one river, was divided into two sections, each of which has its own different Land Lord, it was very. difficult for the lower villages to reclaim new shinden or to join old irrigation water utilization association by the objection of the upper part which was ruled by the other Feudal Lord. 3), Drainage of surplus water of Delta-Shinden. Surplus water of older shinden were drained into the new shinden, and accumulated in the pond named Akusui-Damari in all day and night. The surplus water drained from the Akusui-Damari of the newest shinden, for only 4 hours, at two fall tide period in a day. Delta-Shinden had the drainage right on the front salt-marsh of delta. This narrow land remained as IRIKAWA-the artificial river between the older shinden and the newer, when newer shindene were. reclaimed in front of the older shinden. In the Yatsushiro Compoud Deltaic Coastal Plain the newer shindens were reclaimed after 170_??_190 years at the front of the older shindens in the early Edo Era, so that arid delta shindens were changed to the deep muddy rice-fields little by little. It gave very heavy agricultural labours and a decrease of harvests to the peasants who were levied the tax on rice. There were many peasants who escaped the shindens and resulted in decreased. income for their Feudal Lord. These deep muddy rice-fields-old delta-shindens-were due to the difficulty of draining the surplus water in the older delta shinden as a result of growing accumulation of soil and sand which were transported by the rivers embanked in the eary Edo Era. At the front of the older delta-shindens, then, newer shindens were reclaimed and they advanced on in front of the older shindens, in order to keep dry rice field from becoming deep muddy rice-field and to mitigate the high pressure of population in the Feudal Village as well as the poverty of the Feudal Lord.
Read full abstract