Browsing by Author "Garcia-Chevesich, Pablo A."

Now showing 1 - 7 of 7
  • No Thumbnail Available
    Item
    Climate Change and Overuse: Water Resource Challenges during Economic Growth in Coquimbo, Chile
    (2022) Pizarro, Roberto; Garcia-Chevesich, Pablo A.; McCray, John E.; Sharp, Jonathan O.; Valdes-Pineda, Rodrigo; Sanguesa, Claudia; Jaque-Becerra, Dayana; Alvarez, Pablo; Norambuena, Sebastian; Ibanez, Alfredo; Vallejos, Carlos; Mendoza, Romina
    The arid Coquimbo region of Chile has experienced a significant economic growth in recent decades, fueled in large part by water-intensive activities such as mining and agriculture. Under this context, a monthly and annual trend analysis of precipitation, streamflow, and piezometric levels was carried out. Thus, 43 pluviometric stations, 11 fluviometric stations, and 11 wells were selected. These stations were evaluated for their temporal trends using the Mann-Kendall test. Results revealed a significant decrease in river flows, with negative and significant trends concentrated in the mean and maximum flows, both at annual and monthly levels. Likewise, positive trends were found in the depth to water table on wells, with significant trends in 81.8% of the monthly cases, and in 72.7% of the annual cases. While also decreasing over the same period, rainfall trends exhibit high variability and lacked significance. Although the amounts of precipitation have decreased, this does not seem to be the main factor responsible for the scarcity of water in the region, but rather an excessive consumption of this resource. This is endorsed by the increase in GDP (Gross Domestic Product), which is explained by activities that consume water (mining and agriculture). Similarly, an increase in the granting of underground water rights was verified, which speaks of the high demands for the resource. However, future modeling is advised to better understand the regional hydrology of the area and quantify the anthropic effects on water resources more precisely.
  • No Thumbnail Available
    Item
    Constructed wetlands to treat polluted waters in Latin America and the Caribbean
    (2024) Garcia-Chevesich, Pablo A.; Morales-Paredes, Lino; Romero-Mariscal, Giuliana; Arenazas-Rodriguez, Armando; Ticona-Quea, Juana; Pizarro, Roberto; Vanzin, Gary; Sharp, Jonathan O.
    A collaborative analysis of constructed wetlands in Latin America and the Caribbean, published in Spanish, brought together insights from 10 different countries in the region. The collective reports focused on both subsurface and surface flow wetlands. Treatment targets included industrial and agricultural discharges, yet the emphasis was on the treatment of domestic wastewater as a pollutant, and a lack of sufficient municipal wastewater treatment infrastructure. Common macrophyte genera as well as unique species were highlighted for their potential contributions to treatment and ecological diversity. Finally, a growing body of legal frameworks for establishment and protection were reported.
  • No Thumbnail Available
    Item
    Increases in the Amounts of Agricultural Surfaces and Their Impact on the Sustainability of Groundwater Resources in North-Central Chile
    (2024) Pizarro, Roberto; Borcoski, Francisca; Ingram, Ben; Bustamante-Ortega, Ramon; Sanguesa, Claudia; Ibanez, Alfredo; Toledo, Cristobal; Vidal, Cristian; Garcia-Chevesich, Pablo A.
    Water is a fundamental resource for Chile's productive structure, which is more important in arid areas, and especially with agricultural uses. This study was based on two basins (Cogot & iacute; and Illapel) located in the Coquimbo Region of north-central Chile. In this region, surface water rights were closed in 2002 and the only current option is the use of groundwater. These basins have high water demands due to the use of surface and groundwater for agricultural purposes, a fact that should influence the sustainability of groundwater reserves over time. The objective of this study was to determine how much agricultural use has affected the availability of groundwater in two basins. Under the previous context, the evolution of agricultural irrigation surfaces was evaluated using Landsat images and forest classifications. Similarly, groundwater reserves were evaluated using the recessive curves of hydrographs associated with the beginning of each hydrological year. The results show an increase in the agricultural area between 1996 and 2016, with a subsequent decrease, while groundwater reserves denoted significant decreases over time. In conclusion, a significant decrease in the volumes of groundwater reserves in both basins was observed, a decrease that is consistent with the increase in irrigated areas.
  • No Thumbnail Available
    Item
    Open-Source Design of Infiltration Trenches for Sustainable Soil and Water Conservation in Rural Areas of Central Chile
    (2024) Pizarro, Roberto; Vidal-Silva, Cristian; Jaque, Dayana; Cordova, Alfredo Ibanez; Sanguesa, Claudia; Toledo, Cristobal; Garcia-Chevesich, Pablo A.
    Specific algorithms are developed to solve the equations that define the physical dimensions under various conditions. In this sense, the storm index method was incorporated for the variable precipitation intensity, expanding the number of rainfall stations with the intensity duration frequency (IDF) curves from 9 to 31 within the considered territory (the Biobio Region of Central Chile). Likewise, the infiltration values and runoff coefficients necessary for calculating the dimensions of the trenches were obtained using the Python programming language. The results show that an open-source Python solution allows high reliability and efficiency based on the tests developed. For this reason, this prototype is expected to add new mathematical expressions that may arise to better account for an efficient design of soil and water conservation works or infiltration trenches. In this way, it is concluded that it is possible to develop simulation models for the efficient design of trenches based on well-defined and limited theoretical modeling, adding to computer language tools. This allows for a virtuous synergy that can help address efficient public policies to conserve soil and water in Chile and elsewhere.
  • No Thumbnail Available
    Item
    Spatio-Temporal Behavior of Land Surface Temperatures (LSTs) in Central Chile, Using Terra MODIS Images
    (2024) Munoz-Aguayo, Pedro; Morales-Salinas, Luis; Pizarro, Roberto; Ibanez, Alfredo; Sanguesa, Claudia; Fuentes-Jaque, Guillermo; Toledo, Cristobal; Garcia-Chevesich, Pablo A.
    Land surface temperature (LST) is one of the most important variables in the physical processes of surface energy and water balance. The temporal behavior of LST was analyzed between the latitudes 32 degrees 00 ' S and 34 degrees 24 ' S (Valpara & iacute;so and Metropolitana regions of Chile) for three summer months (December, January, and February) in the 2000-2017 period, using the Terra MODIS image information and applying the Mann-Kendall test. The results show an increase in LST in the study area, particularly in the Andes mountain range in January (5240 km2), which mainly comprises areas devoid of vegetation and eternal snow and glaciers, and are zones that act as water reserves for the capital city of Santiago. Similarly, vegetated areas such as forests, grasslands, and shrublands also show increasing trends in LST but over smaller surfaces. Because this study is regional, it is recommended to improve the spatial and temporal resolutions of the images to obtain conclusions on more local scales.
  • No Thumbnail Available
    Item
    The Impact of a Lack of Government Strategies for Sustainable Water Management and Land Use Planning on the Hydrology of Water Bodies: Lessons Learned from the Disappearance of the Aculeo Lagoon in Central Chile
    (2022) Valdes-Pineda, Rodrigo; Garcia-Chevesich, Pablo A.; Alaniz, Alberto J.; Venegas-Quinones, Hector L.; Valdes, Juan B.; Pizarro, Roberto
    Several studies have focused on why the Aculeo Lagoon in central Chile disappeared, with a recent one concluding that a lack of precipitation was the main cause, bringing tremendous political consequences as it supported the argument that the government is not responsible for this environmental, economic, and social disaster. In this study, we evaluated in detail the socio-economic history of the watershed, the past climate and its effects on the lagoon's water levels (including precipitation recycling effects), anthropogenic modifications to the lagoon's water balance, the evolution of water rights and demands, and inaccurate estimates of sustainable groundwater extraction volumes from regional aquifers. This analysis has revealed novel and undisputable evidence that this natural body of water disappeared primarily because of anthropogenic factors (mostly river deviations and aquifer pumping) that, combined with the effects of less than a decade with below-normal precipitation, had a severe impact on this natural lagoon-aquifer system.
  • No Thumbnail Available
    Item
    The Large-Scale Effect of Forest Cover on Long-Term Streamflow Variations in Mediterranean Catchments of Central Chile
    (2022) Pizarro, Roberto; Valdes-Pineda, Rodrigo; Garcia-Chevesich, Pablo A.; Ibanez, Alfredo; Pino, Juan; Scott, David F.; Neary, Daniel G.; McCray, John E.; Castillo, Miguel; Ubilla, Patricio
    Forest ecosystems play an important role in hydrological processes as surface and subsurface runoff, as well as the storage of water at the catchment scale. Therefore, it is important to have a greater understanding of the effects of forests in the long-term water balance of Mediterranean catchments. In this sense, this study evaluates the effect of native forests, forest plantations, and the combination of both, on long-term streamflow variations in central Chile, an unusual area of Mediterranean climate characterized by a well-marked annual cycle with dry summers and wet winters. Thus, the temporal pattern of monthly streamflow was evaluated for mean flow (Qmean), maximum flow (Qmax), and minimum flow (Qmin) in 42 large-scale (>200 km(2)) Mediterranean catchments. Each series of monthly streamflow data was QA/QC, and then evaluated using the Mann-Kendall's non-parametric statistical test to detect temporal variations between 1994 and 2015. In addition to the previous analysis, the monthly series were grouped into wet seasons (April-September) and dry seasons (October-April), to determine if there were any significant differences within the annual hydrological cycle. The areas covered with native and forest plantations and their relative changes were evaluated for each catchment through streamflow variations and forest cover indicators. Results revealed that streamflow variations are positive and significant when more forest cover exists. The intra-catchment relationships assessed for both species revealed the significant role of native forests and mixed masses as key ecosystems for the long-term conservation of summer streamflow in Mediterranean catchments of central Chile. These findings encourage an urgent need to create highland afforestation programs on degraded areas of central Chile, to maximize water storage in a region that is quickly drying out due to unsustainable water and land use management practices and the effects of global warming.