Urban groundwater baseflow influence upon inorganic river-water quality: The River Tame headwaters catchment in the City of Birmingham, UK

摘要: Summary Understanding the linkage between urban land, groundwater, baseflow and river contamination at city scale is lacking. This study evaluates influence of inorganic (major/minor ions metals) groundwater in Triassic sandstone–Quaternary deposits aquifer system underlying City Birmingham, UK upon water quality Tame. Baseflow water-quality data have been collected from a riverbed piezometer network installed 7.4 km reach crossing effluent unconfined sandstone compared to data. Overall, chemical was not as poor potentially surmised urbanisation present. impact river-water also low. These conclusions were underpinned by evidences of: limited changes along reach; some concentrations being diluted better baseflow; only occasional breaching criteria; river-reach local elevated dicharges; natural attenuation occurrence within riverbed; and, modest, albeit somewhat uncertain, mass fluxes. fluxes ranges 100–3500 t/yr for major ions, 1–50 t/yr minor 1–500 kg/yr toxic metals with zinc nickel most prominent. The sporadic ascribed discrete plume discharges. More detailed sub-reach studies would be required fully resolve contributions improve flux estimates. Not uncommonly, studied already contaminated hence persistent may assume more importance if became cleaner through other control measures. Future research should consider emergent significance baseflows. There are needs to: conduct similar investigate city-scale impacts comparable elsewhere; spatially temporally dynamic develop improved estimation methods.