@article{CalsamigliaGarciaComendadorFortesaetal.2018, author = {Calsamiglia, Aleix and Garcia-Comendador, Julian and Fortesa, Josep and Lopez-Tarazon, Jos{\´e} Andr{\´e}s and Crema, S. and Cavalli, M. and Calvo-Cases, A. and Estrany, Joan}, title = {Effects of agricultural drainage systems on sediment connectivity in a small Mediterranean lowland catchment}, series = {Geomorphology : an international journal on pure and applied geomorphology}, volume = {318}, journal = {Geomorphology : an international journal on pure and applied geomorphology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0169-555X}, doi = {10.1016/j.geomorph.2018.06.011}, pages = {162 -- 171}, year = {2018}, abstract = {Traditional drainage systems combining man-made channels and subsurface tile drains have been used since Roman times to control water excess in Mediterranean lowland regions, favouring adequate soil water regime for agriculture purposes. However, mechanization of agriculture, abandonment or land use changes lead to a progressive deterioration of these drains in the last decades. The effects of these structures on hydrological and sediment dynamics have been previously analyzed in a small Mediterranean lowland catchment (Can Revull, Mallorca, Spain, 1.4 km2) by establishing an integrated sediment budget with a multi-technique approach. Moreover, the recent advances in morphometric techniques enable the completion of this analysis by the accurate identification of active areas (i.e. sources, pathway links, and sinks) and improve the understanding of (de-)coupling mechanisms of water and sediment linkages. In this study, the Borselli's index of connectivity (IC; Cavalli et al. (2013)'s version) derived from a LiDAR-based high resolution DEM (>1 pt m-2; RMSE < 0.2 m) was used to evaluate the spatial patterns of sediment connectivity of the catchment under two different scenarios: (1) the current scenario, including an accurate representation of the 3800 m of artificial channels and levees (CS - Channelled Scenario), and (2) a hypothetical scenario in which these anthropogenic features were removed (US - Unchannelled Scenario). Design and configuration of the drainage system in Can Revull generated changes favouring lateral decoupling between different compartments, with hillslopes-floodplain and floodplain-channels relationships, showing a general decrease of IC values, and high longitudinal connectivity along the artificial channel network. Field observations corroborated these results: structures enabled rapid drainage of the water excess also promoting low surface runoff within the field crops, proving to be an effective management practice for erosion control in agricultural Mediterranean lowland catchments. By contrast, US demonstrated that the abandonment of the current agricultural practices and the subsequent destruction of the drainage system could lead the higher soil loss rates owning to more intense/effective processes of sediment connectivity.}, language = {en} } @article{GrafMorenodelasHerasRuizetal.2018, author = {Graf, Lukas and Moreno-de-las-Heras, Mariano and Ruiz, Maurici and Calsamiglia, Aleix and Garc{\´i}a-Comendador, Juli{\´a}n and Fortesa, Josep and L{\´o}pez-Taraz{\´o}n, Jos{\´e} A. and Estrany, Joan}, title = {Accuracy assessment of digital terrain model dataset sources for hydrogeomorphological modelling in small mediterranean catchments}, series = {Remote sensing}, volume = {10}, journal = {Remote sensing}, number = {12}, publisher = {MDPI}, address = {Basel}, issn = {2072-4292}, doi = {10.3390/rs10122014}, pages = {26}, year = {2018}, abstract = {Digital terrain models (DTMs) are a fundamental source of information in Earth sciences. DTM-based studies, however, can contain remarkable biases if limitations and inaccuracies in these models are disregarded. In this work, four freely available datasets, including Shuttle Radar Topography Mission C-Band Synthetic Aperture Radar (SRTM C-SAR V3 DEM), Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Map (ASTER GDEM V2), and two nationwide airborne light detection and ranging (LiDAR)-derived DTMs (at 5-m and 1-m spatial resolution, respectively) were analysed in three geomorphologically contrasting, small (3-5 km2) catchments located in Mediterranean landscapes under intensive human influence (Mallorca Island, Spain). Vertical accuracy as well as the influence of each dataset's characteristics on hydrological and geomorphological modelling applicability were assessed by using ground-truth data, classic geometric and morphometric parameters, and a recently proposed index of sediment connectivity. Overall vertical accuracy—expressed as the root mean squared error (RMSE) and normalised median deviation (NMAD)—revealed the highest accuracy for the 1-m (RMSE = 1.55 m; NMAD = 0.44 m) and 5-m LiDAR DTMs (RMSE = 1.73 m; NMAD = 0.84 m). Vertical accuracy of the SRTM data was lower (RMSE = 6.98 m; NMAD = 5.27 m), but considerably higher than for the ASTER data (RMSE = 16.10 m; NMAD = 11.23 m). All datasets were affected by systematic distortions. Propagation of these errors and coarse horizontal resolution caused negative impacts on flow routing, stream network, and catchment delineation, and to a lower extent, on the distribution of slope values. These limitations should be carefully considered when applying DTMs for catchment hydrogeomorphological modelling.}, language = {en} }