Monitoring and Modeling Drainage Network Contraction and Dry Down in
Mediterranean Headwater Catchments
Abstract
Enhancing an understanding of expansion/contraction dynamics of active
drainage networks is fundamental for both scientific purposes and
environmental planning and management. This study analyzes for the first
time the network shrinking and dry down in two seasonally dry
Mediterranean catchments (overall area 1.15 km2) using
a comprehensive approach based on monitoring and modeling of the active
network. A seasonal field campaign consisting of 19 subweekly visual
surveys was carried out at the beginning of the summer of 2019.
Observations were then used to calibrate and validate an integrated
model aimed at estimating the time evolution of the total active
drainage network length based on meteorological drivers and defining the
position of the active stretches based on topographic and geological
information. Statistical modeling of the active length showed that
weather can successfully describe the observed variability of network
dynamics during the summer recession. In particular, the study
emphasizes the role of evapotranspiration in the seasonal contraction of
the stream network. The modeling of the spatial patterns of the active
network achieved good performance when topographic data were used as
explanatory variables. Nevertheless, the model performance further
increased when site-specific geological information was integrated into
the model, with accuracies higher than 90% in cell-by-cell comparisons.
The proposed methodology, which combines meteorological, topographic and
geological information in a sequential manner, was able to accurately
represent the space/time dynamics of the active drainage network in the
study area, proving to be an effective and flexible tool for the study
of network dynamics.