Patterns and drivers of water quality changes associated with dams in the Tropical Andes
Autor(a) principal: | |
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Data de Publicação: | 2023 |
Outros Autores: | , , , , , |
Tipo de documento: | preprint |
Idioma: | spa |
Título da fonte: | SciELO Preprints |
Texto Completo: | https://preprints.scielo.org/index.php/scielo/preprint/view/5549 |
Resumo: | The Tropical Andes is a biodiversity hotspot facing pressure from planned and ongoing hydropower development. However, the effects of dams on river ecosystems of the region as mediated by physico-chemical changes to water quality are poorly known. Colombia is unique among its peers in South America for managing central public environmental databases, including surface water quality data sets associated with environmental monitoring of dams. To assess the relationship between hydropower and Colombian river conditions, we analyze monitoring data associated with 15 dams, focusing on oxygen availability, thermal regimes and sediment losses because these properties are influenced directly by river damming and impose fundamental constraints on the structure of downstream aquatic ecosystems. We find that most Colombian dams (7 of 10) seasonally reduce concentrations of total suspended solids by large percentages (50-99%) through sediment trapping. Most dams (8 of 15) also, via discharge of warm reservoir surface waters, seasonally increase river temperatures by 2 to 4˚C with respect to upstream conditions. A subset of four dams generates downstream hypoxia (<4 mg L-1) and water 2 to 5˚C colder than inflows—both processes driven by the turbination and discharge of cold and anoxic hypolimnetic waters during periods of reservoir stratification. Reliance on monitoring data likely leads us to under-detect impacts because many rivers are only sampled once or twice per year and cannot capture temporal shifts across seasons and days (i.e., in response to hydropeaking). Despite these blind spots, the monitoring data point to some opportunities for planners and hydropower companies to mitigate downstream ecological impacts. These findings highlight the importance of implementing environmental monitoring schemes associated with hydrologic infrastructure in developing countries. |
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Patterns and drivers of water quality changes associated with dams in the Tropical Andes Patrones y factores impulsores de cambios en la calidad del agua asociados a embalses en los Andes tropicaleshydropowerandescolombiawater qualitymonitoringHidroelectricasAndesColombiaCalidad de AguaMonitoreoThe Tropical Andes is a biodiversity hotspot facing pressure from planned and ongoing hydropower development. However, the effects of dams on river ecosystems of the region as mediated by physico-chemical changes to water quality are poorly known. Colombia is unique among its peers in South America for managing central public environmental databases, including surface water quality data sets associated with environmental monitoring of dams. To assess the relationship between hydropower and Colombian river conditions, we analyze monitoring data associated with 15 dams, focusing on oxygen availability, thermal regimes and sediment losses because these properties are influenced directly by river damming and impose fundamental constraints on the structure of downstream aquatic ecosystems. We find that most Colombian dams (7 of 10) seasonally reduce concentrations of total suspended solids by large percentages (50-99%) through sediment trapping. Most dams (8 of 15) also, via discharge of warm reservoir surface waters, seasonally increase river temperatures by 2 to 4˚C with respect to upstream conditions. A subset of four dams generates downstream hypoxia (<4 mg L-1) and water 2 to 5˚C colder than inflows—both processes driven by the turbination and discharge of cold and anoxic hypolimnetic waters during periods of reservoir stratification. Reliance on monitoring data likely leads us to under-detect impacts because many rivers are only sampled once or twice per year and cannot capture temporal shifts across seasons and days (i.e., in response to hydropeaking). Despite these blind spots, the monitoring data point to some opportunities for planners and hydropower companies to mitigate downstream ecological impacts. These findings highlight the importance of implementing environmental monitoring schemes associated with hydrologic infrastructure in developing countries.Los Andes tropicales son una zona de alta biodiversidad, que constantemente se enfrenta a la presión del desarrollo hidroeléctrico. Sin embargo, los efectos de los embalses en los ecosistemas fluviales de la regióninfluenciados por cambios fisicoquímicos en la calidad del agua son poco conocidos. Colombia es el único país en América del Sur que gestiona bases de datos ambientales públicos y centralizados, allí se incluyen conjuntos de datos sobre la calidad de aguas superficiales asociados a la vigilancia medioambiental de las represas. Para evaluar las relaciones entre las condiciones de los ríos en Colombia con relación a las centrales hidroeléctricas, analizamos los datos de monitoreo asociados con 15 represas, enfocándonos en la disponibilidad de oxígeno, el régimen térmico y la pérdida de sedimentos; ya que estas propiedades están influenciadas directamente por la construcción de represas en los ríos, e imponen restricciones fundamentales en la estructura de los ecosistemas acuáticos aguas abajo de la presa. Encontramos que en la mayoría de los embalses en Colombia (7 de 10) se reducen estacionalmente grandes porcentajes de las concentraciones de sólidos suspendidos totales (50-99%) debido a la captura de sedimentos. Adicionalmente, la mayoría de los embalses (8 de 15), a través de la descarga de aguas superficiales a mayor temperatura, aumentan estacionalmente las temperaturas del río (entre 2 y 4 °C) con respecto a las condiciones aguas arriba. Un subconjunto de cuatro represas genera hipoxia aguas abajo (<4 mg L-1), y aguas más frías que la de los flujos entrantes (entre 2 y 5 °C), ambos procesos impulsados por la turbinación y descarga de aguas hipolimnéticas frías y anóxicas durante los períodos de estratificación del embalse. Es probable que la dependencia de los datos de monitoreo nos lleve a subestimar los impactos, porque muchos de los ríos solo se monitorean una o dos veces al año y es posible detectar los cambios temporales entre las estaciones y los días (es decir, en respuesta al hydropeaking). A pesar de estos puntos ciegos, los datos de monitoreo representan algunas oportunidades para que los planificadores y las empresas hidroeléctricas mitiguen los impactos ecológicos río abajo. Estos hallazgos resaltan la importancia de implementar esquemas de seguimientos medioambientales asociados con la infraestructura hidrológica en los países en vía de desarrollo.SciELO PreprintsSciELO PreprintsSciELO Preprints2023-04-06info:eu-repo/semantics/preprintinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://preprints.scielo.org/index.php/scielo/preprint/view/554910.1590/SciELOPreprints.5549spahttps://preprints.scielo.org/index.php/scielo/article/view/5549/11336Copyright (c) 2023 Robert Scott Winton, Silvia López-Casas, Daniel Valencia-Rodríguez, Camilo Bernal-Forero, Juliana Delgado, Bernhard Wehrli, Luz Jiménez-Segurahttps://creativecommons.org/licenses/by/4.0info:eu-repo/semantics/openAccessWinton, Robert ScottLópez-Casas, SilviaValencia-Rodríguez, DanielBernal-Forero, CamiloDelgado, JulianaWehrli, BernhardJiménez-Segura, Luzreponame:SciELO Preprintsinstname:Scientific Electronic Library Online (SCIELO)instacron:SCI2023-04-04T18:53:38Zoai:ops.preprints.scielo.org:preprint/5549Servidor de preprintshttps://preprints.scielo.org/index.php/scieloONGhttps://preprints.scielo.org/index.php/scielo/oaiscielo.submission@scielo.orgopendoar:2023-04-04T18:53:38SciELO Preprints - Scientific Electronic Library Online (SCIELO)false |
dc.title.none.fl_str_mv |
Patterns and drivers of water quality changes associated with dams in the Tropical Andes Patrones y factores impulsores de cambios en la calidad del agua asociados a embalses en los Andes tropicales |
title |
Patterns and drivers of water quality changes associated with dams in the Tropical Andes |
spellingShingle |
Patterns and drivers of water quality changes associated with dams in the Tropical Andes Winton, Robert Scott hydropower andes colombia water quality monitoring Hidroelectricas Andes Colombia Calidad de Agua Monitoreo |
title_short |
Patterns and drivers of water quality changes associated with dams in the Tropical Andes |
title_full |
Patterns and drivers of water quality changes associated with dams in the Tropical Andes |
title_fullStr |
Patterns and drivers of water quality changes associated with dams in the Tropical Andes |
title_full_unstemmed |
Patterns and drivers of water quality changes associated with dams in the Tropical Andes |
title_sort |
Patterns and drivers of water quality changes associated with dams in the Tropical Andes |
author |
Winton, Robert Scott |
author_facet |
Winton, Robert Scott López-Casas, Silvia Valencia-Rodríguez, Daniel Bernal-Forero, Camilo Delgado, Juliana Wehrli, Bernhard Jiménez-Segura, Luz |
author_role |
author |
author2 |
López-Casas, Silvia Valencia-Rodríguez, Daniel Bernal-Forero, Camilo Delgado, Juliana Wehrli, Bernhard Jiménez-Segura, Luz |
author2_role |
author author author author author author |
dc.contributor.author.fl_str_mv |
Winton, Robert Scott López-Casas, Silvia Valencia-Rodríguez, Daniel Bernal-Forero, Camilo Delgado, Juliana Wehrli, Bernhard Jiménez-Segura, Luz |
dc.subject.por.fl_str_mv |
hydropower andes colombia water quality monitoring Hidroelectricas Andes Colombia Calidad de Agua Monitoreo |
topic |
hydropower andes colombia water quality monitoring Hidroelectricas Andes Colombia Calidad de Agua Monitoreo |
description |
The Tropical Andes is a biodiversity hotspot facing pressure from planned and ongoing hydropower development. However, the effects of dams on river ecosystems of the region as mediated by physico-chemical changes to water quality are poorly known. Colombia is unique among its peers in South America for managing central public environmental databases, including surface water quality data sets associated with environmental monitoring of dams. To assess the relationship between hydropower and Colombian river conditions, we analyze monitoring data associated with 15 dams, focusing on oxygen availability, thermal regimes and sediment losses because these properties are influenced directly by river damming and impose fundamental constraints on the structure of downstream aquatic ecosystems. We find that most Colombian dams (7 of 10) seasonally reduce concentrations of total suspended solids by large percentages (50-99%) through sediment trapping. Most dams (8 of 15) also, via discharge of warm reservoir surface waters, seasonally increase river temperatures by 2 to 4˚C with respect to upstream conditions. A subset of four dams generates downstream hypoxia (<4 mg L-1) and water 2 to 5˚C colder than inflows—both processes driven by the turbination and discharge of cold and anoxic hypolimnetic waters during periods of reservoir stratification. Reliance on monitoring data likely leads us to under-detect impacts because many rivers are only sampled once or twice per year and cannot capture temporal shifts across seasons and days (i.e., in response to hydropeaking). Despite these blind spots, the monitoring data point to some opportunities for planners and hydropower companies to mitigate downstream ecological impacts. These findings highlight the importance of implementing environmental monitoring schemes associated with hydrologic infrastructure in developing countries. |
publishDate |
2023 |
dc.date.none.fl_str_mv |
2023-04-06 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/preprint info:eu-repo/semantics/publishedVersion |
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preprint |
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publishedVersion |
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https://preprints.scielo.org/index.php/scielo/preprint/view/5549 10.1590/SciELOPreprints.5549 |
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https://preprints.scielo.org/index.php/scielo/preprint/view/5549 |
identifier_str_mv |
10.1590/SciELOPreprints.5549 |
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spa |
language |
spa |
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https://preprints.scielo.org/index.php/scielo/article/view/5549/11336 |
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https://creativecommons.org/licenses/by/4.0 info:eu-repo/semantics/openAccess |
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https://creativecommons.org/licenses/by/4.0 |
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openAccess |
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SciELO Preprints SciELO Preprints SciELO Preprints |
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SciELO Preprints SciELO Preprints SciELO Preprints |
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