| Isotope hydrological investigations in large scale river basins provide insights into processes
(evaporation, transpiration), storage behavior (groundwater recharge, residence times), and
catchment characteristics (altitude effect, summer - winter patterns, mixing). Time series of
isotopes in precipitation are usually available in monthly resolution and river water is
generally monitored extensively only during short periods. In this contribution a report is
given on interpretations of stable isotope (deuterium and oxygen-18) hydrological time series
from seven sub catchments of the Weser River in Germany (5,410 km2 to 46,240 km2,
altitudes ranging from 0 to 1,100 m asl). Isotope data is available in monthly resolution from
2003 to 2010 (95 months) and for two stations (Höxter with 15,320 km2 and Rinteln with
17,260 km2) additionally samples were collected in weekly resolution during 2010.
Precipitation was collected in Hannover on a weekly basis since 2007 and allows a
direct comparison with the river water series. A comparison of isotope signals of
different time resolutions as well as patterns that are related to precipitation input are
discussed and an overall isotope characterization for large catchments will be presented. |