This data set provides data of water quality, discharge, driving forces (meteorological and nitrogen surplus), and catchment attributes for a set of 1386 German catchments covering a wide range of natural and anthropogenic conditions. A corresponding paper "Water quality, discharge and catchment attributes for large-sample studies in Germany - QUADICA" by Ebeling et al. describing the data set in detail will be made available in the Journal Earth System Science Data (https://www.earth-system-science-data.net/).

This repository includes:

1.) Water quality data as annual medians of observed concentration data of N, P and C species (c_annual.csv)
2.) Water quantity data as annual medians of observed discharge (q_annual.csv)
3.) Monthly medians over the whole time series of water quality variables and discharge (c_months.csv)
4.) Monthly and annual median concentrations, flow-normalized concentrations, and mean fluxes estimated using Weighted Regressions on Time, Discharge, and Season (WRTDS) for stations with enough data availability (for details see the corresponding paper Ebeling et al.; wrtds_monthly.csv, wrtds_annual.csv).
5.) Meteorological data as monthly median average temperatures and sums of precipitation and potential evapotranspiration (tavg_monthly.csv, pre_monthly.csv, pet_monthly.csv)
6.) N surplus time series on annual basis (n_surplus.csv)
7.) Summary statistics for the stations including number of samples, covered time periods, degree of censoring (concentrations below the detection limit), availability of discharge data, and availability and performance of WRTDS models (metadata.csv).
8.) Description of data tables (Metadata_QUADICA.pdf).

Data on catchment attributes and geodata also part of the QUADICA data set are available at "CCDB - catchment characteristics data base Germany" (https://doi.org/10.4211/hs.82f8094dd61e449a826afdef820a2c19). The metadata of the water quality and quantity data base is available at "WQQDB - water quality and quantity data base Germany" (https://doi.org/10.4211/hs.a42addcbd59a466a9aa56472dfef8721).

Conditions: The data set is freely and easily accessible. Please refer to the corresponding paper Ebeling et al. when using or referring to this data set.