Effects of evapotranspiration on baseflow in a tropical headwater catchment

Cadol, Daniel; Kampf, Stephanie K.; Wohl, Ellen

doi:10.1016/j.jhydrol.2012.04.060

Cited by 31 publications

(41 citation statements)

References 44 publications

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“…Temporal changes in watershed hydrology occur through varying precipitation regimes and evapotranspiration amounts (Bruijnzeel, ; Cadol, Kampf, & Wohl, ). These changes reflect the impacts of climate change, management, and land use change on other hydrologic components (e.g., overland flow and base flow) and the availability of spring water, according to the size of groundwater reservoirs (Bruijnzeel, ; Tang, Yang, Hu, & Gao, ).…”

Section: Introductionmentioning

confidence: 99%

Isotope hydrology of a tropical coffee agroforestry watershed: Seasonal and event‐based analyses

Welsh

Boll

Sánchez‐Murillo

et al. 2018

Hydrological Processes

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Stable isotope variations are extremely useful for flow partitioning within the hydrologic cycle but remain poorly understood throughout the tropics, particularly in watersheds with rapidly infiltrating soils, such as Andisols in Central America. This study examines the fluctuations of stable isotope ratios (δ18O and δ2H) in the hydrologic components of a tropical coffee agroforestry watershed (~1 km2) with Andisol soils in Costa Rica. Samples were collected in precipitation, groundwater, springs, and stream water over 2 years. The local meteoric water line for the study site was δ2H = 8.5 δ18O + 18.02 (r2 = 0.97, n = 198). The isotope ratios in precipitation exhibited an enriched trend during the dry season and a notable depletion at the beginning of the wet season. The δ18O compositions in groundwater (average = −6.4‰, σ = 0.7) and stream water (average = −6.7‰, σ = 0.6) were relatively stable over time, and both components exhibited more enriched values in 2013, which was the drier year. No strong correlation was observed between the isotope ratios and the precipitation amount at the event or daily time‐step, but a correlation was observed on a monthly scale. Stream water and base flow hydrograph separations based on isotope end‐member estimations showed that pre‐event water originating from base flow was prevalent. However, isotope data indicate that event water originating from springs appears to have been the primary driver of initial rises in stream flow and peak flows. These results indicate that isotope sampling improves the understanding of water balance components, even in a tropical humid location, where significant variations in rainfall challenge current modelling efforts. Further research using fine‐scale hydrometric and isotopic data would enhance understanding the processes driving spring flow generation in watersheds.

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Section: Introductionmentioning

confidence: 99%

Isotope hydrology of a tropical coffee agroforestry watershed: Seasonal and event‐based analyses

Welsh

Boll

Sánchez‐Murillo

et al. 2018

Hydrological Processes

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“…Currently, there is no clear understanding of how transpiration by stream-side trees affects streamflow and interception of subsurface flows to streams. Stream-side trees can consume water from different sources, including soil water, stream water, and groundwater (Dahm et al, 2002;Doody et al, 2015;Doody, Holland, Benyon, & Jolly, 2009;Folch & Ferrer, 2015;Schilling, 2007;Scott-Shaw, Everson, & Clulow, 2017) and can thus play a significant role in catchment water budgets (Cadol, Kampf, & Wohl, 2012).…”

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confidence: 99%

Does transpiration from invasive stream side willows dominate low‐flow conditions? An investigation using hydrometric and isotopic methods in a headwater catchment

et al. 2017

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Understanding seasonal partitioning of water in riparian areas is important for assessing how vegetation affects water resources. A combined hydrological‐isotopic field study was conducted within a headwater catchment to explore the dynamics of stream discharge and the effect of riparian evapotranspiration on summer low‐flow conditions. In addition to collection of meteorological data and depth to unconfined groundwater, streamflows were measured at three locations along the length of the river. Isotope ratios of local precipitation, stream water, groundwater, and willow xylem water were used to estimate pathways and sources of water used by vegetation. Using meteorological variables, leaf area index and stand area measurements, willow transpiration was estimated using the Penman–Monteith method. Combining the data from hydrometric, isotope, and vegetation evapotranspiration analysis revealed that water abstraction by stream‐side willows peaked to 5.6 mm/day and had a distinct impact on summer low‐flow conditions and patterns of stream discharge at the daily time scale. Average annual willow transpiration was 270 mm, whereas average annual precipitation during the study period was 1067 mm. However, willow transpiration reduced streamflow and altered water budgets most strongly during critical summer low‐flow periods. Our analysis of transit times, young water fraction, and depth to groundwater water data showed Waipara headwater areas have limited water storage capacity, making them vulnerable to annual variations in precipitation and any other changes in water usage. Removal of streamside willows could potentially influence water balance during summer months when flows tend to be the lowest.

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“…Daily variations of stream flow can be used 195 as a proxy for ET from near-stream zones (Cadol et al, 2012;Gribovszki et al, 2010) and they correlate well with direct sap flow measurements at the study site (Lupon et al, 2016). Daily stream flow variations measured at one particular point integrates riparian ET upstream from that point.…”

Section: Model Validation and Sensitivity Analysismentioning

confidence: 58%

Riparian evapotranspiration shapes stream flow dynamics and water budgets in a Mediterranean catchment

Lupon

Ledesma

Bernal

2018

Preprint

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15Riparian trees can regulate stream flow dynamics and water budgets by taking up large amounts of water from both soil and groundwater compartments. However, their role has not been fully recognized in the hydrologic literature and the catchment modeling community. In this study, we explored the influence of riparian evapotranspiration (ET) on stream flow by simulating daily stream exports from three nested Mediterranean sub-catchments, both including and excluding the riparian compartment in the structure of 20 the PERSiST rainfall-runoff model. The model goodness of fit significantly improved with the inclusion of the riparian compartment, especially during the vegetative period when, according to our simulations, riparian ET reduced mean daily stream flow by 26%. Moreover, sensitivity analyses suggested that riparian ET was a significant hydrological process contributing to stream flow recession in summer. At the catchment scale, simulated riparian ET accounted for 7% of annual water depletions, its contribution 25 being especially noticeable during summer (8-19%). Simulations considering future climate change scenarios suggest that longer vegetative periods would result in higher contribution of riparian ET to annual water budgets. Annual increases in riparian ET ranged between 2 and 13% from the most conservative to the most extreme drought scenarios. Overall, our results highlight that a good assessment of riparian ET is essential for understanding catchment hydrology and stream flow dynamics in 30 Mediterranean regions. Thus, the inclusion of the riparian compartment in hydrological models is strongly recommended in order to establish proper management strategies in water-limited regions.

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Effects of evapotranspiration on baseflow in a tropical headwater catchment

Cited by 31 publications

References 44 publications

Isotope hydrology of a tropical coffee agroforestry watershed: Seasonal and event‐based analyses

Isotope hydrology of a tropical coffee agroforestry watershed: Seasonal and event‐based analyses

Does transpiration from invasive stream side willows dominate low‐flow conditions? An investigation using hydrometric and isotopic methods in a headwater catchment

Riparian evapotranspiration shapes stream flow dynamics and water budgets in a Mediterranean catchment

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