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Urban waterlogging occurs when precipitation events cause urban runoff to exceed the capacity of stormwater systems, causing water accumulation on the land surface. Valparaiso City is one of the main metropolitan centers in Chile. Rapid urban growth forced the city to invest substantial resources to upgrade its stormwater system. The most recent is the Argentina stormwater canal. However, soon after the stormwater canal was operational, solids (sandy clay, fine sand) washed-off from upland watersheds accumulated in the lower elevation sectors of the canal, close to the conduit outfall to Valparaiso Bay. This has degraded the water conveying capacity of the canal and increased waterlogging hazards if extreme storms and high tide events combine. This research explores management scenarios for reducing the hazard of waterlogging in the canal. Hydrological and in-stream hydrodynamic modeling is used to propose watershed management scenarios aimed to reduce flows and suspended solids wash-off. The impact of those scenarios for reducing waterlogging hazard is assessed. [ABSTRACT FROM AUTHOR]

Background and aims: The Elqui river basin is located north of the Coquimbo Region, in the semiarid zone of Chile. This body of water is particularly important due to the economic activities it supports and its high environmental vulnerability. The objective of this study was to determine the diversity and floristic composition of macrophytes of the Elqui river basin. M&M: Twenty sampling stations with plots of 1 m2 were distributed in the three sub-basins that make up the study area. Inside each plot, all plant species were recorded along with their respective abundances. In addition, in each station some environmental variables were measured, which were analyzed together with the biological data. Results: A total of 51 macrophyte species and one alga were identified, with dominance of native elements with emergent habit. Statistical analyses indicate moderate differences regarding the floristic composition of the three sub-basins compared; these are mainly concentrated in the Turbio river. The analysis of the environmental data indicates that the variables that most influence the composition of species in the study area are: altitude, total suspended solids, redox potential and water depth. Discussion: Studies on macrophytes at the hydrographic basin level are practically null in Chile. This type of information increases knowledge on biodiversity and allows a more efficient management of continental aquatic systems. [ABSTRACT FROM AUTHOR]

LED spectrophotometry is a robust technique for the indirect characterization of wastewater pollutant load through correlation modeling. To tackle this issue, a dataset with 1300 samples was collected, from both raw and treated wastewater from 45 wastewater treatment plants in Spain and Chile collected over 4 years. The type of regressor, scaling, and dimensionality reduction technique and nature of the data play crucial roles in the performance of the processing pipeline. Eighty-four pipelines were tested through exhaustive experimentation resulting from the combination of 7 regression techniques, 3 scaling methods, and 4 possible dimensional reductions. Those combinations were tested on the prediction of chemical oxygen demand (COD) and total suspended solids (TSS). Each pipeline underwent a tenfold cross-validation on 15 sub-datasets derived from the original dataset, accounting for variations in plants and wastewater types. The results point to the normalization of the data followed by a conversion through the PCA to finally apply a Random Forest Regressor as the combination which stood out These results highlight the importance of modeling strategies in wastewater management using techniques such as LED spectrophotometry., (© 2024. The Author(s).)

The effects of a sudden rainfall (40 mm d-1) event on the surface waters covering muddy tidal flats were studied during April 2016 at the estuarine Cruces River wetland in south-central Chile (~40°S). The study area included flooded vestigial tree trunks, which is evidence of coseismic subsidence associated with the 1960 Valdivia earthquake as a source of environmental variability. The tidal flat with vestigial tree trunks registered the fastest and highest depth of inundation. In contrast, the tidal currents velocity and total suspended solids' concentrations were higher at the flat without trunks. Sudden rainfall events can significantly modify the characteristics of surface waters above sedimentary intertidal surfaces, where structures such as flooded trunks are present. [ABSTRACT FROM AUTHOR]

Although explosive volcanic eruptions are natural disturbances that cause significant environmental repercussions and impose multiple changes on ecosystems, post‐eruption studies of rivers and streams are not common. The most recent eruption of the Puyehue‐Cordón Caulle volcanic complex (PCCVC) began on 4 June 2011 with a large explosion and the emission of a column of gas and volcanic ash (particle size <0.001–2 mm) followed by the release of silica magma, and lasted approximately until June 2012. The wind‐dispersed volcanic ash affected the area surrounding the PCCVC in southern Chile and, subsequently, most of South America, but local effects on streams and rivers in the vicinity were more drastic. We collected water, ash, and benthic macroinvertebrate samples four months after the eruption from four rivers: Two were visibly impacted (Gol‐Gol and Nilahue) in areas where volcanic ash thickness ranged between 1 and 5 cm, in the vicinity of the PCCVC fissure (8–15 km), and two adjacent rivers (Calcurrupe and Chanleufu) were located 20–40 km from the PCCVC fissure where ash thickness was <1 cm and did not present visible impacts. Results were then compared with data obtained from previous research projects. This study reports that this natural disaster induced an increase in concentrations of total suspended solids and of phosphorous in the rivers Gol‐Gol and Nilahue, as well as habitat destruction, deterioration of environmental quality, and the consequent devastation of macroinvertebrate assemblages inhabiting these rivers directly following the eruption. We conclude that volcanic eruptions can generate local extinctions of benthic macroinvertebrates in the short term, compared with rivers that were not affected by volcanic ash. [ABSTRACT FROM AUTHOR]

The article discusses a study on the effects of volcanic-related natural sedimentation on Trichoptera or caddisfly species found in Chubut province, Argentina. The researchers proposed that the mobility and swimming abilities of Trichoptera enabled their resistance to sediment deposition caused by the eruption of the Chaitén volcano. Species tolerance to sedimentation was found to be associated with traits such as respiration mode, filter-feeding habits, and rounded body shape.