Redox Values, Hydrology, and Iron Cycling within a Riparian Zone in Guilford, CT.

Redox measurements, groundwater levels, and chemical data were collected during two consecutive growing seasons at six locations along an approximately 100-m transect in the riparian zone of the West River located in Guilford, CT. Instrument clusters were placed in the wetland, the ridge and swale area, the adjoining upland area, and near the river in a non-wetland area. Redox probes were placed at depths of 30 cm and 60 cm based on morphological features observed in the soil profiles. Shallow wells were placed at a depth of 50 cm below ground surface and piezometers were placed at depths of 40 cm and 55 cm, respectively. The toeslope wetland and meander scar positions maintained reducing conditions throughout the monitoring period. Dry summers did not appear to influence redox values. In the microtopography area, redox values indicated reducing conditions in both the ridge and swale areas, despite unsaturated conditions in the ridge areas. Organic matter content varied with landscape position. Total iron showed concentrations ranging between 1 and 13 mg/g, with the highest concentrations in the upper portion of the profile and decreasing with depth. Iron mineralogy varied between goethite and hematite depending on differences in parent material.