Linking soil water balance with flood spatial arrangement in an extremely flat landscape

Abstract

In areas with very mild relief, water drains in a disordered way due to the lack of a developed drainage network, as it occurs in extremely flat sedimentary regions like the Argentine Pampas. The study analysed the flood spatial arrangements in 2014 by calculating landscape metrics and relating them to soil water balance. The study area is located at Del Azul creek lower basin (Pampa Ecoregion, Argentina). Daily soil water balances were obtained, and seven landscape metrics were calculated in 15 windows in five LandSat images, all along 2014, to explore the relationship between hydrological scenarios and spatial pattern summarized with principal component analysis. Water excess concentrated in winter (June and August); deficits were in late spring and summer (January and November), whereas the beginning of autumn (March) was an intermediate situation. Principal component 1 (44.7%) reflected area and shape metrics and correlated positively with water table level; principal component 2 (32.3%) summarized aggregation ones and was negatively associated with accumulated water excesses or deficits in previous 30 days and useful reserve. Both exhibited possible threshold-driven behaviour. Internal heterogeneity between NW and SE zones within the study area coincided with the existence of ancient alluvial fans. The results highlight the peculiarities of the flood spatial patterns in regions with very mild relief, where landforms usually determine water flows. K E Y W O R D SArgentine Pampas, floods, landscape metrics, large plains, soil water balance, spatial patterns

Ecosystem stability of temperate grasslands in response to variability of hydrological conditions

“…The alternation of periodic floods and droughts is a distinctive feature of the region that determines very different spatial patterns of surface water arrangement depending on water availability in the system (Aliaga et al, 2016; Fajardo et al, 2022; Salese & Lara, 2022; Vercelli et al, 2019). In particular, waterlogging in the Flooding Pampa is a disturbance process that impacts plant community structure (Chaneton et al, 1988; Entraigas et al, 2017; Entraigas et al, 2019).…”

Surface soil moisture variability in a sector of a humid basin characterized by extremely flat relief

“…The location of these wells coincides with 12 of the soil moisture sampling sites, as is detailed in Figure 1, and the sampling of both variables was carried out simultaneously. Soil water storage . Estimation was obtained by a daily water balance implemented as it was described by Vercelli et al (2019). The balance considers daily rainfall (P) and potential evapotranspiration (PET) which is calculated using the Penman–Monteith method recommended by the Food and Agriculture Organization, whose validity has been demonstrated for both wet and dry climates (Allen et al, 1998).…”

Completamiento de series temporales de niveles freáticos en un área deprimida de la llanura bonaerense

“…La primera distante unos 27 km del sector pero considerada estación de confianza y la segunda ubicada prácticamente en el sector. Se contó con información de evapotranspiración estimada y con un balance hidrológico en el área de La Baguala (Varni y Custodio, 2013;Vercelli et al, 2019), ubicada en el interior del dominio de modelación.…”