URBANIZATION DEVELOPMENT UNDER CLIMATE CHANGE: HYDROLOGICAL RESPONSES IN A PERI-URBAN MEDITERRANEAN CATCHMENT

Relatively few studies have so far investigated the hydrological impacts of urbanization in Mediterranean catchments, and particularly in peri-urban catchments experiencing relatively rapid and large changes in their land-use mosaic. This study uses data-based model simulations to investigate such impacts, with the Ribeira dos Covoes catchment in Portugal as a concrete Mediterranean peri-urban catchment example. We distinguish the impacts of urbanization from those of climatic change on the water flux partitioning and connectivity in the catchment over the period 1958-2013. Decrease in precipitation over this period has primarily driven decreases in annual runoff and actual evapotranspiration, while the urbanization development has primarily changed the relative flux partitioning and connectivity pattern in the catchment. The relative contribution of overland flow to annual and seasonal runoff has increased, keeping the absolute overland flow more or less intact, while the baseflow contribution to the stream network has decreased. Methodologically, the present simulation approach provides a relevant means for distinguishing main drivers of change in hydrological flux partitioning and connectivity under concurrent urbanization and climatic changes. (c) 2017 The Authors. Land Degradation & Development Published by John Wiley & Sons Ltd.