Hydrological dataset of a sub-humid continental plain basin (Buenos Aires, Argentina).

The Chaco-Pampean Plain (Argentina) is the strongest economic region and the most inhabited in the country, comprising approximately 66% of the country's population (26,500 million) [1]. In this region, surface slopes are very low (<0.1%) and due to the current climatological features, floods and droughts alternate over time. Salinity and alkalinity of water and soil increase towards the flattest sector of the basin, as well as the contents of arsenic and fluoride, which restrict their human use. Worldwide, population growth and global warming, in addition to political decisions, are leading to abrupt land use changes. Under this premise, identifying and quantifying the hydrological processes that control water quantity and its chemical quality become an imperative task [2]. This data article provides a long-term hydrological dataset from a sector of the Chaco-Pampean Plain, the Del Azul creek basin. Hydrological data such as flow rates and piezometric levels, and physical-chemical (i.e., major and minor solutes, and trace elements) and isotopic (δ18O, δ2H; and d-excess) data from rainwater, surface (creek and wetland) and groundwater (at two depths) are available. Rainwater samples are derived from three precipitation collectors installed at different altitudes (monitoring period: 2010-2019; n = 57). Surface water samples were collected at three sampling sites located along the Del Azul Creek and six wetlands (monitoring period: 2018-2019; n = 12). Groundwater samples were collected from 17 piezometers with depths ranging between 3 and 10 m, and from 12 piezometers of 30 m depth, all located throughout the entire basin (monitoring period: 2018-2019; n = 115). Sampling campaigns were performed during the austral dry (summer) and wet (spring) seasons. This dataset provides useful information to understand a) how water moves from recharge to discharge areas, b) how water acquires salinity, and c) how particular solutes of concern, such as arsenic and fluoride, are distributed in space and time across in an extensive plain.

Can forests buffer negative impacts of land-use and climate changes on water ecosystem services? The case of a Brazilian megalopolis.

While the role of land-use conversion on water quality is reasonably understood, its role on water quantity is controversial. Climate change is also expected to impact water availability. Here we explore the interplay of hydrology, land-use change and climate change in one of the most populous urban areas in the world. We examined the potential of forests to buffer the negative impacts of land-use and climate changes on water-related ecosystem services in Tietê Basin, Brazil, which supplies water to the São Paulo megalopolis. We modelled six hydrological parameters using the WaterWorld Policy Support System, simulating the current baseline and six future scenarios (with different land-use and climate changes). Our results corroborate the general trend that increased forest cover improves water quality. Our modelling also predicts that increased forest cover increases water quantity in the southern part of the basin. The effects of climate change are observed mainly in urban areas, with a reduction in water quality. Because urban areas are not eligible for reforestation, they cannot benefit from its buffering effect on climate change. The increase in water availability is the greatest benefit of reforestation as a strategy to improve water-related ecosystem services in the region. Reforestation, however, will not suffice to restore all hydrological parameters in the basin, and additional sustainable agricultural practices are needed to mitigate impacts on water quality.

Interception and Runoff of High Andean Forest in the Protective Forest Reserve "El Malmo" / Interceptación y escorrentía del bosque altoandino en la reserva forestal protectora "el malmo"

RESUMEN Los bosques tropicales son importantes a nivel mundial por su biodiversidad y los servicios ecosistémicos que proveen, son claves en el ciclo global del agua. Los cambios y presiones de origen antrópico que afectan a los bosques tropicales inciden en el papel fundamental de estos en la provisión de agua. En este trabajo se evalúa la relación de las coberturas vegetales presentes en el Bosque altoandino de la Reserva Forestal Protectora "El Malmo" con la calidad y cantidad de interceptación y escorrentía; la zona de vida analizada comprende cuatro tipos de coberturas: bosque denso altoandino, vegetación secundaria baja, plantación de latifoliadas y mosaico de pastos con espacios naturales. Se instalaron ocho montajes (dos por cobertura) compuestos cada uno de una parcela de escorrentía y un medidor de precipitación bajo el dosel; el levantamiento de datos se efectúo cada ocho días durante 24 semanas. Los resultados indican que la interceptación de la precipitación no difiere en cada cubierta, mientras que si se ve afectada la escorrentía superficial y su calidad respecto a sedimentos, cambios que obedecen fuertemente a las diferencias en las condiciones físicas del suelo. La cobertura que permite las mejores dimensiones de calidad y cantidad de agua es el bosque denso altoandino. La influencia de la intervención antrópica en el área y la presencia de invasoras afectan negativamente estas variables. Este trabajo aporta conocimiento sobre el comportamiento hidrológico de la Reserva, para su uso en la gestión forestal. Así mismo, genera información, hasta el momento inexistente, sobre la relación interceptación/escorrentía en bosques de la región Cundiboyacense, convirtiéndose en punto inicial de comparación para nuevas investigaciones en ecosistemas altoandinos.

ABSTRACT Tropical forests are important globally for their biodiversity and the ecosystem services they provide are key to the global water cycle. The changes and pressures of anthropic origin that affect tropical forests affect the fundamental role of these in the provision of water. In this work the relationship between the vegetation cover in the High Andean Forest of the Protective Forest Reserve "El Malmo" with the quality and quantity of interception and runoff is evaluated; the life zone analyzed includes four types of cover: dense high Andean forest, low secondary vegetation, broadleaf planting and mosaic of pastures with natural spaces. Eight assemblies were installed (two per cover) each composed of a runoff plot and a pluviometer under the canopy; the data was collected every eight days for 24 weeks. The results indicate that the interception of precipitation does not differ in each cover, whereas if surface runoff and its quality with respect to sediments are affected, changes that are strongly related to differences in soil physical conditions. The coverage that allows the best dimensions of quality and quantity of water is the high Andean dense forest. The influence of anthropic intervention on the area and the presence of invasive species adversely affect these variables. This work provides knowledge about the hydrological behavior ofthe Reserve, for its use in forest management. Also, it generates information, until the moment nonexistent, on the interception / runoff relationship in forests of the Cundiboyacense region, becoming an initial point of comparison for new research in High Andean ecosystems.

Impactos potenciais das alterações do Código Florestal nos recursos hídricos / Potencial impacts of changes in the Forest Law in relation to water resources

Florestas ripárias, mosaicos de vegetação e áreas alagadas têm papel fundamental na proteção dos recursos hídricos mantendo a qualidade da água em excelentes condições para abastecimento e recarregado aquíferos repondo, portanto, volumes substanciais de águas para o componente subterrâneo. A remoção de florestas ripárias e áreas alagadas têm um efeito extremamente negativo degradando a qualidade das águas superficiais e subterrâneas, acelerando a sedimentação de lagoas, represas e rios, e diminuindo o estoque de água nas nascentes e aquíferos. Todos os serviços ambientais dos ecossistemas aquáticos ficam comprometidos com o desmatamento e remoção de áreas naturalmente alagadas, portanto a preservação destas áreas é essencial para regular tanto o ciclo hidrológicos como os ciclos biogeoquímicos. A remoção destas áreas torna insustentável a agricultura em curto prazo.

Mosaics of vegetation, riparian forests, and wetlands have an important quantitative and qualitative role on the hydrological cycle. Riparian forests protect the water quality of rivers, lakes and reservoirs. Wetlands control floods, sedimentation and regulate the water quality by enhancing processes such as denitrification, phosphorus and heavy metal retention. Both ecosystems of transition are fundamental. The removal of wetlands and forests (riparian and mosaics of vegetation) affects environmental services of these ecosystems, causing loss of economic assets of the capital natural and accelerating degradation of rivers, lakes, reservoirs and the watersheds. Protection of these ecosystems of transition is thus fundamental for the development of agriculture. The loss of services affects society, human health, increasing costs of recovery and deteriorating human-ecological relationships.