Statistical interpretation of the impact of forest growth on streamflow of the sameura Basin, Japan

• Published in: Environmental monitoring and assessment Vol. 104; no. 1-3; pp. 369 - 384
• Main Authors: SHENG YUE, HASHINO, Michio
• Format: Journal Article
• Language: English
• Published: Dordrect Springer 01.05.2005; Springer Nature B.V
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Annual runoff; Biological and medical sciences; Data Interpretation, Statistical; Drought; Earth sciences; Earth, ocean, space; Environmental monitoring; Evapotranspiration; Exact sciences and technology; Forestry; Fundamental and applied biological sciences. Psychology; Hydrology; Hydrology. Hydrogeology; Japan; Low flow; Mountain forests; Rivers; Runoff; Statistical analysis; Stream discharge; Stream flow; Synecology; Temperature; Terrestrial ecosystems; Trees - growth & development; Water supply; Far East; Shikoku; Japan; Japan, Shikoku; impact statements; temporal distribution; atmospheric precipitation; runoff; evapotranspiration; forests; surface water; drainage basins; forest impact; watershed management; Asia; statistical test; temperature; growth; vegetation effects; statistical analysis; trend analysis; streamflow
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-005-1679-4

A forested mountainous basin, the Sameura basin, located in Shikoku Island of Japan, experienced increased forest growth in the period from 1953 to 1994, like which occurred across the country. The impact of the forest growth on streamflow of the basin was assessed using statistical trend analysis. Annual maximum daily flow, annual minimum 5-day flow, and annual total runoff decreased by 55.8, 75.8, and 39.6%, respectively, over the period. However, the annual maximum 6-day, annual minimum 41-day, and annual total precipitation, respectively associated with annual maximum daily flow, annual minimum 5-day streamflow, and annual total runoff did not decrease. Annual and monthly temperature, which evapotranspiration positively related to, did not increase except in January. This demonstrates that the forest growth is responsible for the decrease in all these three flow regimes. The increase in evapotranspiration due to the forest growth resulted in the decrease in both total runoff and low flow. Thus, it seems that forest can hardly function to both reduce flood peaks during flood periods and increase water supply during drought periods.