Isotope hydrology and water sources in a heavily urbanized stream

Complex networks of both natural and engineered flow paths control the hydrology streams in major cities through spatio-temporal variations connection disconnection diverse water sources. We used spatially extensive temporally intensive sampling stable isotopes to disentangle hydrological sources heavily urbanized Panke catchment (~220 km2) north Berlin, Germany. The isotopic data enabled us partition stream across using a Bayesian mixing analysis. upper part streamflow is dominated by groundwater (~75%) from gravel aquifers. In dry summer periods, becomes intermittent catchment, possibly as result local abstractions. Storm drainage dominates responses precipitation events. Although such events can dramatically change composition network, storm only accounts for 10%–15% annual streamflow. Moving downstream, subtle changes isotope signatures occur characteristics vary affected different tributaries. However, effluents wastewater treatment plant (WWTP), serving 700,000 people, dominate lower (~90% runoff) where urbanization effects are more dramatic. associated increase sealed surfaces downstream also reduces relative contribution volume runoff again urban drainage, though still about 10% comes drains. study shows potential inexpensive tracers catchments that provide integrated understanding complex cities. This offers an important evidence base guiding plans develop re-develop protect, restore, enhance their ecological amenity value.