Figure 3
Measurements of temperatures, specific conductivity, pH, oxygen concentrations, and H 2 S concentrations pre- and post-flood. Temperature, specific conductivity, pH, and oxygen content were measured using a Hydrolab Multisonde 4A (Hach Environmental). Measurements and calibration of probes were conducted according to the manufacturer's recommendations. For the measurement of H2S concentrations, 1 ml of water was injected into a vial containing 1 ml of zinc acetate (0.12 M with 0.5 ml NaOH 1.5 M in a N2-atmosphere) using a syringe. The vials were stored at room temperature and photometric measurements were conducted in the laboratory according to [76]. Pre-flood data were previously published in [26] and available from visits in three (AB, AT, EAII) or four (RO, EAI, V, X, XIII) different years. Values of each variable were averaged for each year (at least three Hydrolab readings and one H2S sample was taken at each site and visit) and mean and standard deviation among years are shown. Post-flood data were collected in January 2008. Depicted are mean values based on at least two Hydrolab readings and two H2S samples taken at each site and visit.