Effect of Peri‐urban Development and Lithology on Streamflow in a Mediterranean Catchment

Abstract

Predicting the impact of urbanization on the hydrology of peri‐urban catchments remains a challenge. Using data from nine streamflow gauges installed in a small Portuguese catchment, this study investigates the streamflow responses over a 3‐year period. The catchment comprises unique nested sub‐catchments, characterized by varying proportions of non‐urban land‐use (17–97%) and impermeable surfaces (6–36%), distances between the urban areas and the stream network and storm drainage systems (piped versus dispersed) and overlying distinct lithologies consisting of sandstone and limestone. The results show that in the peri‐urban catchment (39% urban and 22% impervious surfaces) most water infiltrated and annual storm runoff varied between 9% and 13% of rainfall. In urban sub‐catchments (≈50% urban), 29% of rainfall became storm runoff on sandstone and 17% on limestone. In sub‐catchments with more than 80% forest, storm runoff coefficients were averaged 6% independent of the lithology. Sub‐catchments with storm runoff drainage systems and downslope urban areas had shorter response times (<20 min) than dispersed urban sub‐catchments, in which part of the runoff infiltrated, and the response time was up to 1 h. Baseflow contributed between 25–33% upstream and 37–38% downstream of the sandstone total runoff, but was less than 5% in limestone areas independent of location. Hydrological impacts of urbanization may be minimized in planning through disconnecting the urban areas from the stream network, thereby enabling runoff from impervious areas to infiltrate into the soil in downstream forest patches before reaching the stream. Copyright © 2017 John Wiley & Sons, Ltd.

Impact of Soil Depth and Topography on the Effectiveness of Conservation Practices on Discharge and Soil Loss in the Ethiopian Highlands

“…The greater discharge in the shallower watershed agrees with saturation excess runoff theory, where the portion of saturated soil increases for a given storm with decreasing soil depth. This results in more direct runoff generated, shortening the residence time in the watershed and consequently leading to less evapotranspiration from the rainwater [38,39].…”

Impact of Land-Use Changes on Spatiotemporal Suspended Sediment Dynamics within a Peri-Urban Catchment

“…In Espírito Santo, runoff from upslope detached housing is mostly dissipated in surrounding pervious soil, enhancing water retention and infiltration opportunities. In contrast, in Porto Bordalo, runoff from its urban surfaces is partially piped to the stream network, thereby enhancing flow and sediment connectivity between the urban areas and the stream network [34]. This may explain the similar TSC and SSC of Porto Bordalo and Espírito Santo during the urbanization period, considering the unplanned retention basin downslope the road construction area in Porto BordaloB.…”

“…Table 1. Main topographical, lithological, land-use (in 2016) and hydrological characteristics of the catchment and sub-catchments investigated in Ribeira dos Covões (adapted from [34]). The four selected sites form part of a hydrological monitoring network installed in Ribeira dos Covões catchment in 2010 [34].…”

“…Main topographical, lithological, land-use (in 2016) and hydrological characteristics of the catchment and sub-catchments investigated in Ribeira dos Covões (adapted from [34]). The four selected sites form part of a hydrological monitoring network installed in Ribeira dos Covões catchment in 2010 [34]. Chemical aspects of stream water quality (notably nutrients and heavy metals) at the sites between October 2011 and March 2013 were reported in Ferreira et al [35].…”

“…Water level data recorded on dataloggers at 5-min intervals at each site were converted to discharge data using previously derived stage-discharge rating curves [34]. Then, 5-min rainfall data were provided by two rain gauges.…”