279 The Current Understanding of the Role of Wetland Hydrology in the Cycling of Elements and other Substances: A Technical Session in Memory of Paul H. Glaser

This session addresses how wetland hydrology affects the cycling of carbon and other elements from both a scientific and regulatory perspective. Contributors to this session will address how changing wetland hydrology affects geochemical cycling on a global to local basis.

Wednesday, 22 October 2025
1:30 PM - 5:30 PM
HBGCC, 214A

Quantifying Anomalous Hydraulic Head Oscillations to Monitor Peatland Biogenic Gas Activity.

Paper number: 279-4
Program: Technical Sessions
Time: 2:20 PM – 2:35 PM

Authors

Abstract

We present results exploring the use of hydraulic head to monitor free-phase gas in Caribou Bog, a 2200 hectare peatland system in central Maine. Hydraulic head has been monitored in Caribou Bog over the past decade. Here, we focus on pressure transducer data collected at two to eight minute intervals from 2016 to 2020 in three well clusters. Each well cluster contains five monitoring wells with 30 cm long screens positioned at 1.3 to 6.3 m below the peat surface. Data from the pressure sensors has been concatenated and resampled to one minute intervals. Inspection of hydraulic head data plotted against time reveal minute to hour long intervals where the hydraulic head data contains centimeter scale oscillations. We hypothesize that these oscillations are driven by the upward migration of biogenic free phase gas (CH4 and CO2) through the peat column. To quantify the frequency of these anomalous hydraulic head oscillations, we have developed a volatility index that utilizes a moving window to calculate the standard deviation and 'stability' in hydraulic head. Using this index (window size =25, standard deviation>0.001, stability<3), thousands of anomalous events were identified in each monitoring well over a three year period, with about 15 to 20% occurring in the summer months (Jun to Sep) and 30 to 40% occurring in the winter months (Dec to Feb). Our results suggest that free phase biogenic gas migration is enhanced in the winter months when the peat surface is frozen and plants are dormant.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412685

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