We found that double peak hydrographs occurred only after a certain amount of catchment storage was exceeded.
Both ANC and TP were positively correlated with the amount of catchment classified as pasture and arable.
The second RDA axis represented gradients in the amount of catchment classified as mire (or bog), in particular the importance of local factors such as substrate type, water temperature, and riparian mire and fine wooded debris (FWD).
For streams, the five best single predictors of water chemistry were the amount of arable land in the catchment (68%), followed by the amount of alpine treeless areas in the catchment, altitude (2.7%), stream width (2.7%), and mean annual discharge Q (1.3%).
Despite high sensitivity of FCO2 to river hydraulics, CO2 flux normalized to unit channel length (FlCO2) depended primarily on channel discharge, which determines ultimately the amount of CO2 exported from the catchment and emitted to the atmosphere, regardless of the complex interplays among channel hydraulic characteristics.
Atmospheric deposition was calculated from eq 2, where Qprecip was the amount of precipitation to the Oder catchment (cubic meters per year), which was taken from the data supporting the Nest decision support system (Erik Smedberg, personal communication).
Hence, our finding that the amount of arable land in a catchment explained nearly 70% of the variability in stream water chemistry was not expected using these data, and implies that even a small-scale agricultural land use within a catchment may affect phosphorus concentration.
After estimating the environmental availability (i.e., a large part of human feces is collected in sanitary facilities and disposed outside the catchment) the amount of fecal material potentially available in the environment was calculated and converted to the total number of standard FIB E. coli introduced per day (Table 2).
The main drivers among the PCDs considered were a topographical wetness index, road density in the catchment, soil properties in the catchment (mainly the amount of gravel substrate) and local channel slope at the site of a road-stream intersection.
The amount of SOC and TSN in three sub-catchments showed a significant positive correlation with the controlled watershed area (P < 0.05).
River water was more contaminated compared to the reservoir water, which may be attributed to discharge of household and industrial waste in the rivers and lack of adequate water to dilute the concentration of contaminants, whereas, in the reservoirs, the concentration of contaminants reduced due to accumulation of sufficient amount of water draining from their catchments.
