Effect of bedrock flow on catchment rainfall‐runoff characteristics and the water balance in forested catchments in Tanzawa Mountains, Japan

Abstract

In this paper, we examined the role of bedrock groundwater discharge and recharge on the water balance and runoff characteristics in forested headwater catchments. Using rigorous observations of catchment precipitation, discharge and streamwater chemistry, we quantified net bedrock flow rates and contributions to streamwater runoff and the water balance in three forested catchments (second‐order to third‐order catchments) underlain by uniform bedrock in Japan. We found that annual rainfall in 2010 was 3130 mm. In the same period, annual discharge in the three catchments varied from 1800 to 3900 mm/year. Annual net bedrock flow rates estimated by the chloride mass balance method at each catchment ranged from −1600 to 700 mm/year. The net bedrock flow rates were substantially different in the second‐order and third‐order catchments. During baseflow, discharge from the three catchments was significantly different; conversely, peak flows during large storm events and direct runoff ratios were not significantly different. These results suggest that differences in baseflow discharge rates, which are affected by bedrock flow and intercatchment groundwater transfer, result in the differences in water balance among the catchments. This study also suggests that in these second‐order to third‐order catchments, the drainage area during baseflow varies because of differences between the bedrock drainage area and surface drainage area, but that the effective drainage area during storm flow approaches the surface drainage area. Copyright © 2012 John Wiley & Sons, Ltd.

Bedrock geology controls on catchment storage, mixing, and release: A comparative analysis of 16 nested catchments

“…Their seasonal interplay relative to streamflow generation imparts single‐ or double‐peaked (delayed) storm hydrographs. Along similar lines, catchments with reportedly similar bedrock geology may well exhibit distinct precipitation–discharge transformation processes and patterns across variable scales (e.g., Katsuyama, Tani, & Nishimoto, ; Oda, Suzuki, Egusa, & Uchiyama, ; Uchida & Asano, )—a feature that we have not yet been able to explore.…”

Circumferential sap flow variation in the trunks of Japanese cedar and cypress trees growing on a steep slope

“…Annual precipitation at this site averages approximately 3000 mm (Shiraki et al, 2007), and snow is usually present on the ground between January and March. The catchments are mainly covered with a mixed stand of 20-30 year old coniferous trees (mainly Japanese cedar and Japanese cypress; Oda et al, 2012). Meteorological measurements were conducted at the study plot, which was in an open space on a ridge of the Oborazawa Watershed.…”

Spatial variability in specific discharge and streamwater chemistry during low flows: Results from snapshot sampling campaigns in eleven Swiss catchments

“…Catchments consist of different stores of water with a range of ages and specific chemical compositions that contribute to streamflow (Kirchner, 2003). Streamflow during low-flow periods largely originates from groundwater (e.g., Costelloe, Peterson, Halbert, Western, & McDonnell, 2015;Soulsby et al, 2007), including bedrock groundwater (e.g., Oda, Suzuki, Egusa, & Uchiyama, 2013;Sayama, McDonnell, Dhakal, & Sullivan, 2011;Tague & Grant, 2004). The properties of these groundwater stores, and thus their responses to extended dry periods, vary markedly from place to place, so that the magnitude of low flows can also be highly variable in space (e.g., Floriancic et al, 2018;Smakhtin, 2001;Sun, Kasahara, Otsuki, Saito, & Onda, 2017).…”