MODELACIÓN HIDROLÓGICA BAJO ESCENARIOS DE CAMBIO CLIMÁTICO PARA UN EMBALSE DE ABASTECIMIENTO DE AGUA EN LA PAZ, BOLIVIA
Abstract
El embalse Milluni Grande depende principalmente de la precipitación, siendo vulnerable ante periodos de sequía, de forma que puede afectar a la seguridad hídrica de las ciudades de La Paz y El Alto. Por lo tanto, el presente estudio busca determinar la variación de la cantidad de agua disponible en el embalse bajo el set de escenarios de cambio climático establecidos en el quinto informe del Panel Intergubernamental sobre el Cambio Climático (IPCC) para el periodo 2022-2090. El área de estudio se limitó a la microcuenca Milluni, tomando el embalse Milluni Grande como punto de desemboque. La modelación hidrológica se realizó mediante la herramienta Water Evaluation and Planning System (WEAP) utilizando el ensamble de datos diarios de precipitación y temperatura generado a través de la herramienta Gridded Meteorological Ensemble Tool (GMET). Se incorporaron los escenarios de cambio climático empleando el Modelo 1 del Sistema Terrestre de Noruega NorESM1-M, reduciendo su escala mediante el método no paramétrico de vecinos más cercanos (knn-bootstrap). Se obtuvieron las siguientes tendencias para el periodo y área de estudio: incremento general de temperatura, incremento de precipitación en época seca y reducción de precipitación en época húmeda, lo cual puede generar situaciones de sequía. Por otra parte, el caudal de entrada al embalse Milluni Grande tiene tendencia a variar de forma directamente proporcional a la precipitación, mientras que su volumen tiene tendencia a reducirse. Asimismo, puede existir un déficit en la cobertura de los requerimientos de los sitios de demanda, llegando a valores mínimos de 45% para el sistema de distribución Achachicala y 27% para el sistema Meseta. Todos los resultados son acentuados en el escenario pesimista RCP 8.5.
The Milluni Grande reservoir depends mainly on precipitation, being vulnerable to drought periods, which may affect the water security among La Paz and El Alto cities. Therefore, the present study sought to determine the variation of water available in the reservoir under the set of climate change scenarios stablished on the fifth report of the Intergovernmental Panel on Climate Change (IPCC) for the period 2022-2090. The study area was limited to the Milluni microbasin, taking the Milluni Grande reservoir as the outlet point. The hidrological modelling was performed through the Water Evaluation and Planning System (WEAP) using the temperature and precipitation daily data ensemble generated with the Gridded Meteorological Ensemble Tool (GMET). Climate change scenarios were incorporated using the Model 1 of Norway Land System NorESM1-M, reducing its scale through the nearest neighbor non-parametric method (knn-bootstrap). The following tendencies were obtained for the study period and area: overall temperature rise, precipitation rise during the dry seasons and precipitation reduction during the wet seasons, which might cause drought situations. On the other hand, the Milluni Grande inlet flow tends to vary proportionally to the precipitation, while its volume tends to decrease. In addition, a deficit in the coverage of the requirements of demand sites might exist, reaching minimum values of 45% for the Achachicala distribution system and 27% for the Meseta system. All results are accentuated in the pessimistic scenario RCP 8.5.
The Milluni Grande reservoir depends mainly on precipitation, being vulnerable to drought periods, which may affect the water security among La Paz and El Alto cities. Therefore, the present study sought to determine the variation of water available in the reservoir under the set of climate change scenarios stablished on the fifth report of the Intergovernmental Panel on Climate Change (IPCC) for the period 2022-2090. The study area was limited to the Milluni microbasin, taking the Milluni Grande reservoir as the outlet point. The hidrological modelling was performed through the Water Evaluation and Planning System (WEAP) using the temperature and precipitation daily data ensemble generated with the Gridded Meteorological Ensemble Tool (GMET). Climate change scenarios were incorporated using the Model 1 of Norway Land System NorESM1-M, reducing its scale through the nearest neighbor non-parametric method (knn-bootstrap). The following tendencies were obtained for the study period and area: overall temperature rise, precipitation rise during the dry seasons and precipitation reduction during the wet seasons, which might cause drought situations. On the other hand, the Milluni Grande inlet flow tends to vary proportionally to the precipitation, while its volume tends to decrease. In addition, a deficit in the coverage of the requirements of demand sites might exist, reaching minimum values of 45% for the Achachicala distribution system and 27% for the Meseta system. All results are accentuated in the pessimistic scenario RCP 8.5.
Description
Vol. 21, No. 1