Location
The Punch Bowl is located in the middle-east region of the Korean peninsula and is administratively part of Haean-myun, Yanggu-gun, Gangwon Province. It is a basin that circular outer boundary is surrounded by mountain that is more than 1,100 m high and inner part is about 400 m that has large altitude difference. The cause of formation of the Punch Bowl is a differential erosion. The circular outer boundary is made of Pre-cambrian meta-sedimentary rocks, but the inner part is Jurassic granites that are very highly weathered. It is oval shape that about 12 km of major axis length, about 6.6 km of minor axis length, circumference is about 30 km and area is 44.7 km2. According to atmospheric data (2008), mean daily temperature is 8.4℃, maximum air temperature is 26℃ in July and minimum air temperature is -15.5℃ in January. All four seasons show differences in air temperature between seasons are large. The annual precipitation is 2,103 mm, due to monsoon climate, 64% of the annual precipitation occurs in July and August. The most of residents are working in agriculture, and over 300 groundwater wells are developed to have adequate water resource. Tributaries and streams are shown in arborization pattern and joined from the eastern boundary of basin and flow eastward. Therefore, the basin has simpler water configuration, it is possible to facilitate estimate precipitation, evapotranspiration, groundwater recharge and stream flow. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean Government(MSIP) (No. NRF-2015R1A4A1041105)