• The Takaragawa Experimental Watershed is located in the upstream area of Tone river, in the northern part of Gunma Prefecture, central Japan.
• Hydrological observations were started in order to estimate the relation between forest harvesting and water runoff, when natural forest dominated by beech was harvested in the headwater area in the Oku-Tone region in the upstream part of the Tone river. This area is a source of water for the Tokyo metropolitan area.
• Observations began in 1937 at two watersheds called the Honryu watershed with a 1,905.7ha area and the Shozawa watershed with a 117.9ha area.
• Observations began in 1957 at three smaller watersheds in the Shozawa watershed.
• Observation at the Honryu and Shozawa watersheds is continuing today.

Item	Daily precipitation	Daily runoff
Data source〵Location	Main climatic station	Honryu	Shozawa	Watersheds in Shozawa Watershed
				No.1	No.2	No.3
1	1937-1958	1937-1958	1937-1958
2	1959-1977	1959-1977	1959-1977
3				1957-1981	1957-1981	1957-1981
4	1978-1990	1978-1990	1978-1990
5	1991-2000	1991-2000	1991-2000
6	2001-2010	2001-2010	2001-2010
7	2011-2016	2011-2016	2011

Data sources

1. Government Forest Experiment Station (1961) Statical report of hydrological observation at forested experimental basins (Daily precipitation and discharge volume), p.119-171 (in Japanese).
2. TAKARAGAWA Experimental Site, Flood Flow Control Unit, Forest Influences Division (1979) Statistical Reports of Hydrological Observation at TAKARAGAWA Experimental Watershed HONRYU and SHOZAWA Experimental watersheds (January, 1959 - December, 1977), Bulletin of Forestry and Forest Products Research Institute, 302, 97-154 (in Japanese).
3. TAKARAGAWA Experimental Site and Flood Control Unit, Forest Influences Division (1984) Statistical Report of Hydrological Observation at TAKARAGAWA Experimental Watershed. No. 1, No. 2 and No. 3 Experimental Watersheds in SHOZAWA Experimental Watershed. (January, 1957-December, 1981), Bulletin of Forestry and Forest Products Research Institute, 327, 83-190 (in Japanese).
4. FUJIEDA, M., SHlMIZU, T. (1994) Statistical Summary of Hydrological Data from TAKARAGAWA Experimental Basin-HONRYU and SHOZAWA Watersheds (January, 1978 to December, 1990), Bulletin of Forestry and Forest Products Research Institute, 368, 207-245 (in Japanese).
5. KUBOTA, T., NOGUCHI S., SHIMIZU T., HOSODA, I., MURAKAMI S., KABEYA N., SHIMIZU A., ABE T., TSUBOYAMA Y., TAMAI K. (2020) Statistical report of hydrological data from TAKARAGAWA experimental watershed. - HONRYU and SHOZAWA watershed (January, 1991 to December, 2000), Bulletin of FFPRI, 19(2), 159-184.
6. KUBOTA T., NOGUCHI S., SHIMIZU T., ABE T., SHIMIZU A., KABEYA N., NOBUHIRO T., IIDA S., TAMAI K., MURAKAMI S., SAWANO S., TSUBOYAMA Y. (2020) Statistical report of hydrological data from TAKARAGAWA experimental watershed. - HONRYU and SHOZAWA watershed (January, 2001 to December, 2010) -, Bulletin of FFPRI, 19(4), 373-400.
7. TAMAI K., KUBOTA T., NOGUCHI S., SHIMIZU T., IIDA S., SAWANO S., NOBUHIRO T., ARAKI, M., TSUBOYAMA, Y. (2021) Statistical report of hydrological data from TAKARAGAWA experimental watershed. - HONRYU and SHOZAWA watershed (January, 2011 to December, 2016) -, Bulletin of FFPRI, 20(1), 49-67.

Location	Fujiwara, Minakami Town, Tone County, Gunma Prefecture, Japan	Topography
River system	Tone River system
Latitude	36° 51'N
Longitude	139° 01'E
Altitude (m)	805*

^* at the main climatic station

	Honryu	Shozawa	Watersheds in Shozawa Watershed
			No.1	No.2	No.3
Area (ha)	1905.7	117.9	6.5	4.4	5.2
Altitude (m)	805 - 1945	810 - 1380	816 - 1075	886 - 1102	924 - 1187
Geology	Granite, Tuff, Diorite
Soil	Brown forest soil, Podsol
Vegetation	Natural forest with Fagus crenata, Quercus crispula, Acer pictum Thunb. subsp. mono (Maxim.), Magnolia obovata, Thujopsis dolabrata, Pinus parviflora, etc. and plantation of Larix kaempferi or Cryptomeria japonica.
Annual mean temperature (ﾟC)	8.3**
Annual precipitation (mm)	2134**

^** Averaged value for 1937-1956

Main climatic station	Shozawa	Honryu
Click on a photo to enlarge.

Forest Hydrology Laboratory,
Department of Disaster Prevention, Meteorology and Hydrology,
Forestry and Forest Products Research Institute, Japan