Evidence for high-elevation salar recharge and interbasin groundwater flow in the Western Cordillera of the Peruvian Andes

Abstract. Improving our understanding of hydrogeological processes on the western flank of the central Andes is critical to communities living in this arid region. Groundwater emerging as springs at low elevations provides water for drinking, agriculture, and baseflow. Some springs also have recreation or religious significance. However, the high elevation sources of recharge and specific groundwater flowpaths that support these springs and convey groundwater to lower elevations in southern Peru remain poorly quantified in this geologically complex environment. The objectives of this study were to identify recharge zones and groundwater flowpaths supporting natural springs east of the city of Arequipa in the volcanic mountain terrain, particularly, the potential for recharge within the high-elevation closed-basin Lagunas Salinas salar. We used geochemical and isotopic tracers in springs, surface waters (rivers and lakes), and precipitation (rain and snow) sampled from March 2019 through February 2020. We obtained monthly samples from six springs, bimonthly samples from four rivers, and various samples from high-elevation springs during the dry season. We analyzed stable water isotopes (δ18O and δ2H) and general chemistry of springs, rivers, local rainfall, and snow from Pichu Pichu volcano. The monthly isotopic composition of spring water was invariable over time, suggesting that the springs receive a stable source of groundwater recharge and are not supported by relatively short groundwater flowpaths. The chemistry of springs in the low- and mid-elevations (2500 to 2900 masl) point towards a mix of recharge from the salar (4300 masl) and mountain-block recharge (MBR) in or above a queñuales forest ecosystem at ~4000 masl on the adjacent Pichu Pichu volcano. Springs at higher elevation closer to the salar and in a region with a high degree of faulting had higher chloride concentrations indicating higher proportions of interbasin groundwater flow from the salar. We conclude that while the salar is a closed basin, surface water from the salar recharges through the lacustrine sediments, mixes with mountain-block groundwater, and is incorporated into the regional groundwater flow system. Groundwater flow in the mountain block and the subsequent interbasin groundwater flow is accommodated through extensive faulting and fracturing. Our findings provide valuable information on the flowpaths and zones of recharge that support low-elevation springs in this arid region. In this study, high-elevation forests and a closed-basin salar are important sources of recharge. These features should be carefully managed to prevent impacts to the down-valley springs and streams.

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Supplementary material to "Evidence for high-elevation salar recharge and interbasin groundwater flow in the Western Cordillera of the Peruvian Andes"

10.5194/hess-2021-287-supplement ◽

2021 ◽

Author(s):

Odiney Alvarez-Campos ◽

Elizabeth J. Olson ◽

Marty D. Frisbee ◽

Sebastián A. Zuñiga Medina ◽

José Díaz Rodríguez ◽

...

Keyword(s):

Groundwater Flow ◽

High Elevation ◽

Peruvian Andes ◽

Western Cordillera ◽

Supplementary Material

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Relations between groundwater flow in an unconfined aquifer and seepage patterns in a closed-basin lake in glacial terrain

Hydrology Research ◽

10.2166/nh.2014.197 ◽

2014 ◽

Vol 46 (3) ◽

pp. 325-342 ◽

Cited By ~ 3

Author(s):

Marko Vainu ◽

Jaanus Terasmaa ◽

Marko Häelm

Keyword(s):

Groundwater Flow ◽

Water Depth ◽

Lacustrine Sediments ◽

Thick Layer ◽

Unconfined Aquifer ◽

Sediment Type ◽

Physical Factors ◽

Groundwater Abstraction ◽

Closed Basin ◽

Organic Sediment

Groundwater dynamics affect lake water budgets, but its major factors and mechanisms still need clarification. This study evaluates the effects of surrounding groundwater flow on seepage direction and assesses factors that affect seepage flux in a closed-basin lake in northeastern Estonia – Lake Martiska. A piezometric map was used to determine directions of groundwater flow around the lake. Seepage meters were applied for measuring flux at 44 locations along eight transects in the lake in relation to water depth, distance from the shore, sediment type and thickness of organic sediment. Additionally nearshore ice-free areas were mapped in winter. Seepage patterns followed the estimated directions of groundwater flow in nearshore areas. Outseepage records showed the impacts of nearby groundwater-abstraction wells on groundwater flow. However, the within-lake seepage direction and flux differed from the expected at 6–15 m from the shore and water depth of 1–2 m. Seepage flux and physical factors of the lake were uncorrelated. Even with a 3.2 m thick layer of gyttja, seepage influx was 13 ml m−2 min−1; therefore thick lacustrine sediments do not necessarily prevent inseepage. The results suggest that a local confined aquifer around and underneath the lake may cause the observed inseepage pattern.

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The Glaciochemistry of Snow-Pits from Quelccaya Ice Cap, Peru, 1982

Annals of Glaciology ◽

10.3189/s0260305500005954 ◽

1985 ◽

Vol 7 ◽

pp. 84-88 ◽

Cited By ~ 1

Author(s):

W. Berry Lyons ◽

A. Paul Mayewski ◽

Lonnie G. Thompson ◽

Boyd Allen

Keyword(s):

Amazon Basin ◽

Atomic Absorption Spectrophotometry ◽

High Elevation ◽

Common Source ◽

Gaseous Emissions ◽

Polar Ice ◽

Peruvian Andes ◽

Reactive Iron ◽

Ice Cap ◽

Quelccaya Ice Cap

We present glaciochemical data from a pilot study of two snow-pits from Quelccaya ice cap, Peruvian Andes. These are the first samples to be analyzed from Quelccaya for nitrate and sulfate by ion chromatography (IC), for nitrate-plus-nitrite, reactive silicate and reactive iron by colorimetry, and for sodium by atomic absorption spectrophotometry. The 3 m pits used in this study represent a one year record of mass accumulation and the 29 samples collected provide the first glaciochemical data from this area which can be compared with glaciochemical studies from other locations.Reactive iron, reactive silicate and sodium, and the profiles of >0.63μm microparticles from Thompson and others (1984) are coincident, suggesting that transport and deposition into this area of each species are controlled by similar processes. The common source is probably local, resulting from crustal weathering. In general, the reactive silicate values are lower than those observed in other alpine glacier ice. The highest sulfate and nitrate values were observed in the upper few centimeters of the snow-pit. Most of the sulfate concentrations were less than 3 μM and are similar to values obtained for fresh surface snows from Bolivia (Stallard and Edmond 1981). Since biological gaseous emissions are thought to be the major source of sulfur and nitrogen to the atmosphere over the Amazon basin, the sulfate and nitrate fluctuations may be due to seasonal biological input and/or seasonal shifts in wind direction bringing material to Quelccaya.With only one exception, the colorimetric nitrate-plus-nitrite data were higher than the IC nitrate data. Unfortunately, the IC analyses were conducted 81 d after the colorimetric analyses. The difference between the two data sets could be attributable to the following: (1) the colorimetric technique may yield erroneously high results as suggested for polar ice by Herron (1982), (2) the IC technique yields erroneously low results due, in part, to the possible exclusion of nitrite concentrations, and/or (3) nitrite was lost via biological removal during the 81 d period before the IC analyses. If the IC data are correct, the mean nitrate value is 0.4μΜ (n = 29). This value is similar to those reported from pre-industrial aged polar ice (Herron 1982). If the colorimetric mean value (1.1 μM) is correct, it is similar to colorimetrically determined values from other high-elevation alpine ice (Lyons and Mayewski 1983).

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The Glaciochemistry of Snow-Pits from Quelccaya Ice Cap, Peru, 1982

Annals of Glaciology ◽

10.1017/s0260305500005954 ◽

1985 ◽

Vol 7 ◽

pp. 84-88 ◽

Cited By ~ 4

Author(s):

W. Berry Lyons ◽

A. Paul Mayewski ◽

Lonnie G. Thompson ◽

Boyd Allen

Keyword(s):

Amazon Basin ◽

Atomic Absorption Spectrophotometry ◽

High Elevation ◽

Common Source ◽

Gaseous Emissions ◽

Polar Ice ◽

Peruvian Andes ◽

Reactive Iron ◽

Ice Cap ◽

Quelccaya Ice Cap

We present glaciochemical data from a pilot study of two snow-pits from Quelccaya ice cap, Peruvian Andes. These are the first samples to be analyzed from Quelccaya for nitrate and sulfate by ion chromatography (IC), for nitrate-plus-nitrite, reactive silicate and reactive iron by colorimetry, and for sodium by atomic absorption spectrophotometry. The 3 m pits used in this study represent a one year record of mass accumulation and the 29 samples collected provide the first glaciochemical data from this area which can be compared with glaciochemical studies from other locations. Reactive iron, reactive silicate and sodium, and the profiles of >0.63μm microparticles from Thompson and others (1984) are coincident, suggesting that transport and deposition into this area of each species are controlled by similar processes. The common source is probably local, resulting from crustal weathering. In general, the reactive silicate values are lower than those observed in other alpine glacier ice. The highest sulfate and nitrate values were observed in the upper few centimeters of the snow-pit. Most of the sulfate concentrations were less than 3 μM and are similar to values obtained for fresh surface snows from Bolivia (Stallard and Edmond 1981). Since biological gaseous emissions are thought to be the major source of sulfur and nitrogen to the atmosphere over the Amazon basin, the sulfate and nitrate fluctuations may be due to seasonal biological input and/or seasonal shifts in wind direction bringing material to Quelccaya. With only one exception, the colorimetric nitrate-plus-nitrite data were higher than the IC nitrate data. Unfortunately, the IC analyses were conducted 81 d after the colorimetric analyses. The difference between the two data sets could be attributable to the following: (1) the colorimetric technique may yield erroneously high results as suggested for polar ice by Herron (1982), (2) the IC technique yields erroneously low results due, in part, to the possible exclusion of nitrite concentrations, and/or (3) nitrite was lost via biological removal during the 81 d period before the IC analyses. If the IC data are correct, the mean nitrate value is 0.4μΜ (n = 29). This value is similar to those reported from pre-industrial aged polar ice (Herron 1982). If the colorimetric mean value (1.1 μM) is correct, it is similar to colorimetrically determined values from other high-elevation alpine ice (Lyons and Mayewski 1983).

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Dissolved noble gas and isotopic tracers reveal vulnerability of groundwater in a small, high‐elevation catchment to predicted climate changes

Water Resources Research ◽

10.1029/2009wr008718 ◽

2010 ◽

Vol 46 (10) ◽

Cited By ~ 23

Author(s):

Michael J. Singleton ◽

Jean E. Moran

Keyword(s):

Climate Changes ◽

Noble Gas ◽

High Elevation ◽

Isotopic Tracers

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Development, verification and validation of a three-dimensional groundwater flow model for ESM

10.5194/egusphere-egu2020-12117 ◽

2020 ◽

Author(s):

Yosuke Miura ◽

Kei Yoshimura

Keyword(s):

Surface Water ◽

Groundwater Flow ◽

Arid Region ◽

Flow Model ◽

Three Dimensional ◽

Central Valley ◽

Groundwater Flow Model ◽

The World ◽

Semi Arid Region ◽

Semi Arid

<p>&#160; Groundwater is one of the important water resources in the world and Groundwater flow is linked with surface water strongly. Many studies on groundwater are conducted in a local scale or focused on affect-ing surface water in a global scale. In current Earth System Model, fixed and constant one-dimensional vertical grid is used in unsaturated zone. In real world, the thickness of unsatu-rated zone depends on the climate and it is considered that there are limitations of runoff process expression especially in humid mountainous area. In this study, we developed three-dimensional groundwater flow model as ESM which can represent the variably saturated flow and groundwa-ter storativity. Since, this model is eventually coupled with Land Surface Model, it is possible to track the underground water flow using boundary conditions of recharge and surface water level.</p><p>&#160; We verified accuracy of the code using one & two-dimensional infiltration problem, three-dimensional groundwater pumping problem, and hillslope problem. Our model was com-pared with other researchers results, experimental data, analytical solutions. In consequence, our model was able to get accurate results. Subsequently, we conducted validation in Central valley, California, USA. The reason of chose this region is that this region is a semi-arid region, ground-water is used for irrigation and well pumping data is accessible. Over the world, groundwater use is more important in arid or semi-arid region than in humid area, and also highly utilized as agri-cultural water. Central valley has representativeness of groundwater use. In addition, the famous groundwater model, MODFLOW, was used to evaluate water resource management in this region. As well as MODFLOW, we calibrated hydraulic conductivity with 24 observation sites during 1961 - 2003 to validate. 156 observation points excluded 24 calibration points were used as vali-dation in same period. In the near future, we will confirm the difference between one-dimension and three dimensions setting of the unsaturated zone with respect to runoff process.</p>

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Storage and routing of water in the deep critical zone of a snow dominated volcanic catchment

10.5194/hess-2019-140 ◽

2019 ◽

Author(s):

Alissa White ◽

Bryan Moravec ◽

Jennifer McIntosh ◽

Yaniv Olshansky ◽

Ben Paras ◽

...

Keyword(s):

High Elevation ◽

Critical Zone ◽

Precipitation Pattern ◽

Fracture Density ◽

Stable Water Isotopes ◽

Ion Chemistry ◽

Major Ion ◽

Welded Tuff ◽

Isotopic Analyses ◽

Perched Aquifer

Abstract. This study combines major ion and isotope chemistry, age tracers, fracture density characterizations, and physical hydrology measurements to understand how the structure of the critical zone (CZ) influences its function, including water routing, storage, mean water residence times, and hydrologic response. In a high elevation rhyolitic tuff catchment in the Jemez River Basin Critical Zone Observatory (JRB-CZO) within the Valles Caldera National Preserve of northern New Mexico, a periodic precipitation pattern creates different hydrologic flow regimes during spring snowmelt, summer monsoon rain, and fall storms. Hydrometric, geochemical, and isotopic analyses of surface water and groundwater from distinct stores, most notably a perched aquifer in consolidated collapse breccia and deeper groundwater in a fractured tuff aquifer, enabled us to untangle the interactions of these groundwater stores and their contribution to streamflow across one complete water year. Despite seasonal differences in groundwater response due to water partitioning, major ion chemistry indicates that deep groundwater from the highly fractured site is more representative of groundwater contributing to streamflow across the entire water year. Additionally, comparison of streamflow and groundwater hydrographs indicates hydraulic connection between the fractured welded tuff aquifer and streamflow while the perched aquifer within the collapse breccia deposit does not show this same connection. Furthermore, analysis of age tracers and stable water isotopes indicates that groundwater is a mix of modern and older waters recharged from snowmelt and downhole neutron probe surveys suggest that water moves through the vadose zone both as vertical infiltration and subsurface lateral flow, depending on lithology. We find that in complex geologic terrain like that of the JRB-CZO, differences in CZ architecture of two hillslopes within a headwater catchment control water storage and routing through the subsurface and suggest that the perched aquifer does not contribute significantly to streams while deep fractured aquifers contribute most to streamflow.

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