ABSTRACT
Shirakami-Sanchi is a World Heritage Site of the United Nations Educational, Scientific, and Cultural Organization (UNESCO) because of its virgin beech forest and diverse species of animals, insects, and plants. It extends over 169.7 km2 and is located near the coast at the Aomori and Akita Prefectures in northern Japan. The elevation at the summit (Shirakami-dake) is 1,235 m above sea level. This trackless area is protected from human activity. The main research area in the Anmon River watershed is located in the northeastern part of Shirakami-Sanchi. In this study, the water holding capacity and runoff load of the Anmon River watershed were investigated. The water quality and flow rate were measured in a 22.2 km2 water catchment area from 2009 to 2011. Precipitation and water samples were analyzed for Total Nitrogen (TN), Total Phosphorus (TP), Chemical Oxygen Demand (COD), Electrical Conductivity (EC), and turbidity once a week, and these data were evaluated using rainfall and a runoff load equation (R-Ld equation). Moreover, the water holding capacity was determined and the data were compared with water discharge rates at other catchment areas including the Sunako Stream, which is covered more than 50% with planted coniferous forest. Ordinary water discharge was 4.81-5.42 mm/day, low water discharge was 2.82-3.43 mm/day and droughty water discharge was 1.21-1.97 mm/day estimated by H-Q equation at a barrier to prevent landslides. It was obviously great quantity of discharge compare with some nearby sites and other research in Japan.
