Naoko Nagumo

Location of a pre-Angkor capital city in relation to geomorphological features of lower reach of the Stung Sen River, central Cambodia

The Sambor Prei Kuk archaeological site in lower reach of the Stung Sen River, central Cambodia, is the site of the capital city of the pre- Angkor state of Chenla. The location of Sambor Prei Kuk is discussed in relation to the geomorphological characteristics of lower reach of the Stung Sen River and the requirements of the inhabitants. The uplands were divided into upland I, which is characterized by hills, and uplands II and III, both of which have flat surfaces, with upland III lower than upland II. The present river follows a meandering course within a conspicuous meander scroll zone, and deposits along the channel are repeatedly eroded and redeposited. Back marsh areas have gradually filled with suspended flood water sediments during the last 4600 years at an accumulation rate of 0.6 mm/yr. The floodplain and lake plain were divided into five zones to evaluate the monsoonal flood risk and accessibility to upland, considering uplands distribution. Sambor Prei Kuk on upland II with the port town adjacent the river is situated on the place where water transport is feasible and the risk of monsoonal flood is low, which means the people accommodated to the highly different dry and monsoonal environment.

Characteristics of extreme monsoon floods and local land use in the Lower Mekong Basin, Cambodia

Rivers in the Lower Mekong Basin, Cambodia, receive additional water and waterborne sediments annually during the monsoon. In the 2011 monsoon season, the region was inundated by extreme flood events. This chapter identifies inundation characteristics and explains fluvial landforms developed over a long-term flood history near Phnom Penh and Kampong Thom in Cambodia, based on land classification and field surveys. Understanding the development of fluvial plains and promoting land use in accordance with river behavior can minimize flood risk and allow local populations to live sustainably in flood-prone areas.

Flood damage of the Pampanga River Basin by Typhoon Lando and Nona in 2015

2. 気象概要 フィリピン海を西進してきた台風 24 号は 10 月 18 日にル ソン島中部に上陸し、3~5 km/h で北西方向に移動して 19 日に南シナ海へと抜けた。10 月 17 日~19 日の降水量は、 パンパンガ川流域北東部の Gabaldon で 554 mm と観測地点 の中で最多を記録したが、下流域の Arayat では 172 mm、 Sulipan で 122 mm と東高西低の傾向が見られ、ほとんどの 地点で 18 日に多くの降水があった。一方、台風 27 号は 12 月 14 日にサマール島の北部を通過したあと、10~20 km/h でルソン島の南を西進し、16 日には南シナ海に抜けて北上 した。台風 24 号時に比べて降水量は多く、12 月 15 日~17 日の降水量は Gabaldon で 730 mm、Arayat で 154 mm を記録 し、Sulipan では 149 mm であった。