scholarly journals El rol de la exploración geofísica en acuíferos profundos en ambientes semiurbanos y rurales en cuencas de ante arco Andino, caso de estudio en acuífero del río Ñuble, Valle Central de Chile

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Igor Aguirre ◽  
José Maringue ◽  
Isabel Santibáñez ◽  
Gonzalo Yáñez
Keyword(s):  
Climate Models ◽  
Sedimentary Basin ◽  
Groundwater Resources ◽  
Large Population ◽  
Central Valley ◽  
Global Scale ◽  
Deep Aquifers ◽  
Exploration Tool ◽  
Over Exploitation

The hydric resource coming from groundwater has a strategic nature at global scale, within a context of overpopulation and over exploitation of the resource and climate change. Chile doesn’t scape to it, where climate models predict a drought for most of the country, including partially, the agriculture region of the Central Valley between Santiago and Puerto Montt. The adaption process to global change demands the exploration new sources of provisions of this resource, being strategic the one coming from aquifers. To date, the knowledge of these resources is limited to depths below 200 m in each aquifer. However, in the Central Valley between Santiago and Chiloé, the geophysical evidences allow to infer the existence of a thick volcano-sedimentary basin growing in thickness southward well above 500m, with good potential for occurrence of large groundwater resources. The characterization of deep aquifers, 200-1,000 m of depth, demands to have an exploration tool economic, non-invasive, and reliable, able to be applied in semi-urban and rural environments, where the water resource need is higher. The geophysical methodologies meet these characteristics and have been applied in Chile and elsewhere as an exploration tool of ground water resources. However, its application have not been described in Andean environments, of large population and/or agro-industrial activity. In consequence, the present work raises a methodological strategy for the characterization of groundwater resources, in particular for the detection of deep resources. We propose the application of a combination of complementary geophysical techniques, including electrical, electromagnetic, and gravimetric methods (to determine the aquifer geometry) along with complementary techniques, like magnetometry, to reduce interpretation ambiguity and , constrained by hydrogeological information and petrophysics of rocks and sediments of the basin and basement. Complementary, we include an analysis of the potential effects of cultural noise and its effects on geophysical observations, given the focus of exploration in semi-urban and rural places. With the aim to validate the proposed methodology we use as a case study the aquifer of Ñuble river, in the Ñuble region, Chile. This aquifer properly represents an Andean forearc environment in rural and semi-urban condition, and potentially hosting a deep seated aquifer. The results allow the characterization of an aquifer with hydrogeological potential between 50 and 300-500 depth, overlying a sedimentary basin of more than 1,000 m thickness. The application of the proposed methodology for the exploration of groundwater resources will provide, in consequence, the recognition of a vital relevance resource for the sustainability of Chile during the following decades.

scholarly journals Salinity of deep groundwater in California: Water quantity, quality, and protection

2016 ◽  
Vol 113 (28) ◽  
pp. 7768-7773 ◽  
Author(s):  
Mary Kang ◽  
Robert B. Jackson
Keyword(s):  
Oil And Gas ◽  
Saline Water ◽  
Groundwater Resources ◽  
Central Valley ◽  
Deep Groundwater ◽  
Depth Data ◽  
Deep Aquifers ◽  
California's Central Valley ◽  
Oil Gas ◽  
California’S Central Valley

Deep groundwater aquifers are poorly characterized but could yield important sources of water in California and elsewhere. Deep aquifers have been developed for oil and gas extraction, and this activity has created both valuable data and risks to groundwater quality. Assessing groundwater quantity and quality requires baseline data and a monitoring framework for evaluating impacts. We analyze 938 chemical, geological, and depth data points from 360 oil/gas fields across eight counties in California and depth data from 34,392 oil and gas wells. By expanding previous groundwater volume estimates from depths of 305 m to 3,000 m in California’s Central Valley, an important agricultural region with growing groundwater demands, fresh [<3,000 ppm total dissolved solids (TDS)] groundwater volume is almost tripled to 2,700 km3, most of it found shallower than 1,000 m. The 3,000-m depth zone also provides 3,900 km3 of fresh and saline water, not previously estimated, that can be categorized as underground sources of drinking water (USDWs; <10,000 ppm TDS). Up to 19% and 35% of oil/gas activities have occurred directly in freshwater zones and USDWs, respectively, in the eight counties. Deeper activities, such as wastewater injection, may also pose a potential threat to groundwater, especially USDWs. Our findings indicate that California’s Central Valley alone has close to three times the volume of fresh groundwater and four times the volume of USDWs than previous estimates suggest. Therefore, efforts to monitor and protect deeper, saline groundwater resources are needed in California and beyond.

scholarly journals Remote Sensing Methods for the Biophysical Characterization of Protected Areas Globally: Challenges and Opportunities

2021 ◽  
Vol 10 (6) ◽  
pp. 384
Author(s):  
Javier Martínez-López ◽  
Bastian Bertzky ◽  
Simon Willcock ◽  
Marine Robuchon ◽  
María Almagro ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Protected Areas ◽  
Large Scale ◽  
Anthropogenic Activities ◽  
Global Scale ◽  
Area Network ◽  
Biophysical Characterization ◽  
Challenges And Opportunities ◽  
Scale Characterization

Protected areas (PAs) are a key strategy to reverse global biodiversity declines, but they are under increasing pressure from anthropogenic activities and concomitant effects. Thus, the heterogeneous landscapes within PAs, containing a number of different habitats and ecosystem types, are in various degrees of disturbance. Characterizing habitats and ecosystems within the global protected area network requires large-scale monitoring over long time scales. This study reviews methods for the biophysical characterization of terrestrial PAs at a global scale by means of remote sensing (RS) and provides further recommendations. To this end, we first discuss the importance of taking into account the structural and functional attributes, as well as integrating a broad spectrum of variables, to account for the different ecosystem and habitat types within PAs, considering examples at local and regional scales. We then discuss potential variables, challenges and limitations of existing global environmental stratifications, as well as the biophysical characterization of PAs, and finally offer some recommendations. Computational and interoperability issues are also discussed, as well as the potential of cloud-based platforms linked to earth observations to support large-scale characterization of PAs. Using RS to characterize PAs globally is a crucial approach to help ensure sustainable development, but it requires further work before such studies are able to inform large-scale conservation actions. This study proposes 14 recommendations in order to improve existing initiatives to biophysically characterize PAs at a global scale.

scholarly journals Global‐scale characterization of turning points in arid and semi‐arid ecosystem functioning

2020 ◽  
Vol 29 (7) ◽  
pp. 1230-1245 ◽  
Author(s):  
Paulo N. Bernardino ◽  
Wanda De Keersmaecker ◽  
Rasmus Fensholt ◽  
Jan Verbesselt ◽  
Ben Somers ◽  
...  
Keyword(s):  
Ecosystem Functioning ◽  
Turning Points ◽  
Global Scale ◽  
Arid Ecosystem ◽  
Scale Characterization ◽  
Semi Arid

scholarly journals Southern ocean warming, sea level and hydrological change during the Paleocene-Eocene thermal maximum

2011 ◽  
Vol 7 (1) ◽  
pp. 47-61 ◽  
Author(s):  
A. Sluijs ◽  
P. K. Bijl ◽  
S. Schouten ◽  
U. Röhl ◽  
G.-J. Reichart ◽  
...  
Keyword(s):  
Climate Models ◽  
Global Scale ◽  
Ocean Drilling Program ◽  
Storm Activity ◽  
Southwest Pacific ◽  
Dinoflagellate Cyst ◽  
Surface Warming ◽  
Run Off ◽  
Thermal Maximum ◽  
Hydrological System

Abstract. A brief (~150 kyr) period of widespread global average surface warming marks the transition between the Paleocene and Eocene epochs, ~56 million years ago. This so-called "Paleocene-Eocene thermal maximum" (PETM) is associated with the massive injection of 13C-depleted carbon, reflected in a negative carbon isotope excursion (CIE). Biotic responses include a global abundance peak (acme) of the subtropical dinoflagellate Apectodinium. Here we identify the PETM in a marine sedimentary sequence deposited on the East Tasman Plateau at Ocean Drilling Program (ODP) Site 1172 and show, based on the organic paleothermometer TEX86, that southwest Pacific sea surface temperatures increased from ~26 °C to ~33°C during the PETM. Such temperatures before, during and after the PETM are >10 °C warmer than predicted by paleoclimate model simulations for this latitude. In part, this discrepancy may be explained by potential seasonal biases in the TEX86 proxy in polar oceans. Additionally, the data suggest that not only Arctic, but also Antarctic temperatures may be underestimated in simulations of ancient greenhouse climates by current generation fully coupled climate models. An early influx of abundant Apectodinium confirms that environmental change preceded the CIE on a global scale. Organic dinoflagellate cyst assemblages suggest a local decrease in the amount of river run off reaching the core site during the PETM, possibly in concert with eustatic rise. Moreover, the assemblages suggest changes in seasonality of the regional hydrological system and storm activity. Finally, significant variation in dinoflagellate cyst assemblages during the PETM indicates that southwest Pacific climates varied significantly over time scales of 103 – 104 years during this event, a finding comparable to similar studies of PETM successions from the New Jersey Shelf.

Uzbekistan’s Aquatic Environment and Water Management as an Area of Interest for Hydrology and Thematic Tourism

2021 ◽  
Vol 12 (3) ◽  
pp. 642
Author(s):  
Jacek RÓŻKOWSKI ◽  
Mariusz RZĘTAŁA
Keyword(s):  
Water Management ◽  
Agricultural Land ◽  
Groundwater Resources ◽  
Global Scale ◽  
Aral Sea ◽  
Irrigated Agriculture ◽  
Human Consumption ◽  
Irrigation Systems ◽  
Natural Lakes ◽  
Area Of Interest

The functioning of Uzbekistan’s economy is closely linked to the water resources of its huge cross-border rivers: the Amu Darya and the Syr Darya, as well as to the groundwater present within their basins. Both natural lakes and artificial reservoirs (e.g. the Aydar-Arnasay system of lakes, the Kayrakkum Reservoir, the Chardarya Reservoir) are present there, which retain significant amounts of water, and large canals with lengths of up to several hundred kilometres which involve complex hydraulic structures are used for irrigation purposes. All these are components of a water management system which needs optimisation; as much as 80% of agricultural land is irrigated, with 70% of the water being lost due to inefficient irrigation systems. The consequence of this allocation of river flows and the overuse of water in irrigation systems has been the disappearance of the Aral Sea (1960 year – 68,900 km2, 2017 year – 8,600 km2) and the inflow of water into the Sarygamysh Lake as well as the reduction of Uzbekistan’s groundwater resources by about 40%. The intensive development of irrigated agriculture is associated with changes in surface and groundwater quality caused, inter alia, by the increased use of chemicals in agriculture and the discharge of collector-drainage waters into river systems as well as their reuse. The extent of environmental degradation in some areas (especially in the Aral Sea region) is unique on a global scale. The origins of Uzbekistan’s other hydrological tourist attractions are related to attempts to ensure the availability of water for both human consumption and industrial use under conditions of water scarcity in the country’s arid and semi-arid climates. Not just the spectacular watercourses and water bodies present there (e.g. rivers, lakes, canals), but also small water retention facilities and minor infrastructure elements (e.g. wells, springs and retention basins, canals, ditches and flow control structures) are of potential tourist importance.

scholarly journals The use of groundwater crustacean communities as indicators for aquifers quality in the semi-arid region of north-central Chile

2018 ◽  
Vol 1 ◽  
Author(s):  
Sanda Iepure ◽  
Nicolas Gouin ◽  
Angeline Bertin ◽  
Ana Camacho ◽  
Antonio González-Ramón ◽  
...  
Keyword(s):  
Negative Impact ◽  
Groundwater Resources ◽  
Economic Benefits ◽  
Nutrient Loads ◽  
Groundwater Temperature ◽  
Groundwater Levels ◽  
Water Abstraction ◽  
Over Exploitation ◽  
The Impact ◽  
Semi Arid

Chile has large extensions of arid and semi-arid regions throughout the whole country, where the intensive demands and use of water resources, especially groundwater for irrigations and mining activities, increased dramatically over the last decades. The aquifer depletions due to water abstraction for irrigation and nutrient loads, exert major alterations of water quality, groundwater recharge and the natural renewal rate. All these factors diminish the aquifer value for the users and contribute to the degradation of groundwater as environment and habitat for fauna. This intensive use of groundwater resources in Chile brought to significant social and economic benefits, but their inadequate management resulted in negative environmental, legal and socioeconomic consequences. In this study, we aimed at providing a first assessment of environmental alterations of groundwater ecosystems from agricultural watersheds in northern Chile by specifically evaluating the effects of nitrogen and pesticide loads on groundwater communities and identifing the ecosystem service alterations due to agricultural activities. The study has been performed in a glacial aquifer from Coquimbo region; 250 km north of Santiago de Chile, the floodplain of which is dominated by agriculture (fruits tress, vineyards). Due to low regional precipitations (100-240 mm/year) the aquifer is primarily recharged by snowmelt from the Andean chain and surface runoff. The relative groundwater levels, groundwater temperature, chemical analysis of nitrogen and total phosphorus and pesticide concentrations were examined, along with the evaluation of crustacean biodiversity and spatial distribution pattern. Stygofauna taxonomic richness and the presence of stygobites have been related more to groundwater level stability than to chemical water parameters indicating that over-exploitation has a negative impact on habitat suitability for groundwater invertebrates. Groundwater biota assessment is essential in understanding the impact produced by agriculture activities on groundwater as a resource and as ecosystem, a nexus that becomes more and more widely recognized. The rationale and the preliminary results of this study are summarized in the Suppl. material 1.

scholarly journals What can we learn from long-term groundwater data to improve climate change impact studies?

2011 ◽  
Vol 8 (4) ◽  
pp. 7621-7655 ◽  
Author(s):  
S. Stoll ◽  
H. J. Hendricks Franssen ◽  
R. Barthel ◽  
W. Kinzelbach
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Climate Change Impact ◽  
Large Scale ◽  
Climate Models ◽  
Groundwater Resources ◽  
Groundwater Dynamics ◽  
Impact Studies ◽  
Change Impact

Abstract. Future risks for groundwater resources, due to global change are usually analyzed by driving hydrological models with the outputs of climate models. However, this model chain is subject to considerable uncertainties. Given the high uncertainties it is essential to identify the processes governing the groundwater dynamics, as these processes are likely to affect groundwater resources in the future, too. Information about the dominant mechanisms can be achieved by the analysis of long-term data, which are assumed to provide insight in the reaction of groundwater resources to changing conditions (weather, land use, water demand). Referring to this, a dataset of 30 long-term time series of precipitation dominated groundwater systems in northern Switzerland and southern Germany is collected. In order to receive additional information the analysis of the data is carried out together with hydrological model simulations. High spatio-temporal correlations, even over large distances could be detected and are assumed to be related to large-scale atmospheric circulation patterns. As a result it is suggested to prefer innovative weather-type-based downscaling methods to other stochastic downscaling approaches. In addition, with the help of a qualitative procedure to distinguish between meteorological and anthropogenic causes it was possible to identify processes which dominated the groundwater dynamics in the past. It could be shown that besides the meteorological conditions, land use changes, pumping activity and feedback mechanisms governed the groundwater dynamics. Based on these findings, recommendations to improve climate change impact studies are suggested.

scholarly journals A Review of Case Studies on Climate Change Impact on Hydrologic Cycle: An Indian Perspective

2021 ◽  
pp. 249-266
Author(s):  
P K Bhunya ◽  
Sanjay Kumar ◽  
Sunil Gurrapu ◽  
M K Bhuyan
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Hydrological Cycle ◽  
Groundwater Resources ◽  
Rainfall Events ◽  
Groundwater Levels ◽  
Groundwater Level Fluctuations ◽  
Change Impact ◽  
Heavy Rainfall Events ◽  
Flood Characteristics

In recent times, several studies focused on the global warming that may affect the hydrological cycle due to intensification of temporal and spatial variations in precipitation. Such climatic change is likely to impact significantly upon freshwater resources availability. In India, demand for water has already increased manifold over the years due to urbanization, agriculture expansion, increasing population, rapid industrialization and economic development. Numerous scientific studies also report increases in the intensity, duration, and spatial extents of floods, higher atmospheric temperatures, warmer sea, changes in precipitation patterns, and changing groundwater levels. This work briefly discusses about the present scenario regarding impact of climate change on water resources in India. Due to the insufficient resolution of climate models and their generally crude representation of sub-grid scale and convective processes, little confidence can be placed in any definite predictions of such effects, although a tendency for more heavy rainfall events seems likely, and a modest increase in frequency in floods. Thus to analyses this effect, this work considers real problems about the changing flood characteristics pattern in two river regions, and the effect of spatial and temporal pattern in rainfall. In addition to these, the work also examines the trend of groundwater level fluctuations in few blocks of Ganga–Yamuna and Sutlej-Yamuna Link interfluves region. As a whole, it examines the potential for sustainable development of surface water and groundwater resources within the constraints imposed by climate change.

Sign in / Sign up

Export Citation Format

Share Document