Effects of bedrock groundwater dynamics on runoff generation: a case study on granodiorite headwater catchments, western Tanzawa Mountains, Japan

Abe, Yutaka; Uchiyama, Y.; Saito, Masahiko; Ohira, Mitsuru; Yokoyama, Takahide

doi:10.3178/hrl.14.62

Cited by 3 publications

(1 citation statement)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is reasonable for total event rainfall and maximum ΔP to be related because ground surface sealing under saturated or near‐saturated conditions is fundamentally necessary for pore‐air entrapment (e.g., Danjo et al, 2015; Sako et al, 2011); such conditions become more likely to occur with increasing rainfall. Also the response of groundwater level change will be likely to be larger with larger amount of rainfall (e.g., Abe et al, 2020). A higher number of pore‐air entrapment events was recorded at HA1 than at TC1; moreover, the slope of relationship between the amount of total event rainfall and maximum ΔP was greater at HA1 (0.17) than at TC1 (0.068).…”

Section: Discussionmentioning

confidence: 99%

Field measurement of entrapped pore‐air pressure and the effect of rising groundwater level in the soil layer

Iwagami,

Noguchi,

Shimizu

et al. 2024

Hydrological Processes

View full text Add to dashboard Cite

Unsaturated soil contains pore air, some of which becomes entrapped in the soil layer during the infiltration process. Such entrapped pore air in the soil layer inhibits infiltration, decreases hydraulic conductivity, and causes erroneous estimates of groundwater response. Experimental studies suggest an effect of compressed entrapped pore air on stream discharge. However, few studies have investigated the behaviour of pore air in the field, and no method for measurement of pore‐air behaviour has been established. We measured pore‐air pressure (Pair) with a simple handmade probe, combined with atmospheric pressure (Patm) and groundwater level. The entrapment and compression of pore air were detected based on the pressure difference (ΔP = Pair – Patm). Observations were conducted for approximately 1 year in two small headwater catchments (TC and HA, which have differences in soil depth and groundwater level dynamics) in Ibaraki Prefecture, Japan. Positive responses of ΔP during some rainfall events were confirmed at both TC and HA. Pore‐air entrapment occurred even during weak rainfall events with rainfall intensity of <10 mm/h. During a typhoon event in October 2019, a maximum ΔP of 3.9 kPa was observed at HA. The pore pressure increase recorded by the tensiometer was mostly explained by the increase in ΔP, which was supported by the soil moisture data. Therefore, we concluded that our handmade measurement system could successfully measure Pair and detect pore‐air entrapment in the field. This showed that Pair is not negligible. Total event rainfall was related to the maximum ΔP. It also showed that the rise in the groundwater level plays a significant role in pressurization of the entrapped pore air. We present the first field data demonstrating the effect of groundwater level rise on the pressurization of entrapped Pair.

show abstract

Section: Discussionmentioning

confidence: 99%

Field measurement of entrapped pore‐air pressure and the effect of rising groundwater level in the soil layer

Iwagami,

Noguchi,

Shimizu

et al. 2024

Hydrological Processes

View full text Add to dashboard Cite

show abstract

Estimating water balance components and their uncertainty bounds in highly groundwater-dependent and data-scarce area: An example for the Upper Citarum basin

Rusli

Weerts

Taufiq³

et al. 2021

Journal of Hydrology: Regional Studies

View full text Add to dashboard Cite

Scale‐Dependent Inter‐Catchment Groundwater Flow in Forested Catchments: Analysis of Multi‐Catchment Water Balance Observations in Japan

Oda,

Iwasaki,

Egusa

et al. 2024

Water Resources Research

View full text Add to dashboard Cite

Inter‐catchment groundwater flow (IGF) plays an essential role in streamflow generation and water quality in forested headwaters. Multiple factors are thought to contribute to IGF, including climate, topographical, and geological factors. However, studies have not clarified the relationships between IGF and catchment properties in the headwater catchments due to the lack of observational data at scales smaller than 100 ha. This study examined possible factors influencing IGF using random forest analysis based on annual water balance data from 152 forested catchments ranging from 0.09 to 9400 ha in Japan. The results showed that catchment scale had the greatest influence on IGF, and IGF tended to decrease with increasing catchment area at scales of less than 10 ha. The average IGF stabilized around zero in catchments greater than 10 ha. The averaged IGF trend with catchment scale indicated more outward groundwater flow in catchments smaller than 10 ha, but no relationship between IGF and catchment size in catchments larger than 10 ha. The variability in IGF decreased with catchment size and was lowest at 10–100 ha. The decrease in variability in catchments less than 100 ha was mainly due to river confluence and the increased variability in catchments larger than 100 ha indicated potential observation errors increase in catchments of this size.

show abstract

Effects of bedrock groundwater dynamics on runoff generation: a case study on granodiorite headwater catchments, western Tanzawa Mountains, Japan

Cited by 3 publications

References 18 publications

Field measurement of entrapped pore‐air pressure and the effect of rising groundwater level in the soil layer

Field measurement of entrapped pore‐air pressure and the effect of rising groundwater level in the soil layer

Estimating water balance components and their uncertainty bounds in highly groundwater-dependent and data-scarce area: An example for the Upper Citarum basin

Scale‐Dependent Inter‐Catchment Groundwater Flow in Forested Catchments: Analysis of Multi‐Catchment Water Balance Observations in Japan

Contact Info

Product

Resources

About