A myriad of downstream communities and industries rely on streams fed by both groundwater discharge and glacier meltwater draining the Cordillera Blanca, Northern Peruvian Andes, which contains the highest density of glaciers in the tropics. During the dry season, approximately half the discharge in the region's proglacial streams comes from groundwater. However, because of the remote and difficult access to the region, there are few field methods that are effective at the reach scale to identify the spatial distribution of groundwater discharge. An energy balance model, Rhodamine WT dye tracing, and high‐definition kite‐borne imagery were used to determine gross and net groundwater inputs to a 4‐km reach of the Quilcay River in Huascaran National Park, Peru. The HFLUX computer programme (http://hydrology.syr.edu/hflux.html) was used to simulate the Quilcay River's energy balance using stream temperature observations, meteorological measurements, and kite‐borne areal photography. Inference from the model indicates 29% of stream discharge at the reach outlet was contributed by groundwater discharge over the study section. Rhodamine WT dye tracing results, coupled with the energy balance, show that approximately 49% of stream water is exchanged (no net gain) with the subsurface as gross gains and losses. The results suggest that gross gains from groundwater are largest in a moraine subreach but because of large gross losses, net gains are larger in the meadow subreaches. These insights into pathways of groundwater–surface water interaction can be applied to improve hydrological modelling in proglacial catchments throughout South America. Copyright © 2016 John Wiley & Sons, Ltd.
Mountain water resources are of particular importance for downstream populations but are threatened by decreasing water storage in snowpack and glaciers. Groundwater contribution to mountain streamflow, once assumed to be relatively small, is now understood to represent an important water source to streams. This review presents an overview of research on groundwater in high mountain environments (As classified by Meybeck et al. (2001) as very high, high, and mid-altitude mountains). Coarse geomorphic units, like talus, alluvium, and moraines, are important stores and conduits for high mountain groundwater. Bedrock aquifers contribute to catchment streamflow through shallow, weathered bedrock but also to higher order streams and central valley aquifers through deep fracture flow and mountain-block recharge. Tracer and water balance studies have shown that groundwater contributes substantially to streamflow in many high mountain catchments, particularly during lowflow periods. The percentage of streamflow attributable to groundwater varies greatly through time and between watersheds depending on the geology, topography, climate, and spatial scale. Recharge to high mountain aquifers is spatially variable and comes from a combination of infiltration from rain, snowmelt, and glacier melt, as well as concentrated recharge beneath losing streams, or through fractures and swallow holes. Recent advances suggest that high mountain groundwater may provide some resilience-at least temporarily-to climate-driven glacier and snowpack recession. A paucity of field data and the heterogeneity of alpine landscapes remain important challenges, but new data sources, tracers, and modeling methods continue to expand our understanding of high mountain groundwater flow.
Accelerating mountain glacier recession in a warming climate threatens the sustainability of mountain water resources. The extent to which groundwater will provide resilience to these water resources is unknown, in part due to a lack of data and poorly understood interactions between groundwater and surface water. Here we address this knowledge gap by linking climate, glaciers, surface water, and groundwater into an integrated model of the Shullcas Watershed, Peru, in the tropical Andes, the region experiencing the most rapid mountain‐glacier retreat on Earth. For a range of climate scenarios, our model projects that glaciers will disappear by 2100. The loss of glacial meltwater will be buffered by relatively consistent groundwater discharge, which only receives minor recharge (~2%) from glacier melt. However, increasing temperature and associated evapotranspiration, alongside potential decreases in precipitation, will decrease groundwater recharge and streamflow, particularly for the RCP 8.5 emission scenario.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.