Assessing the effects of seismic line disturbance on boreal peatland water balance using CoupModel

The slow recovery of trees in peatlands disturbed by seismic lines has spurred scholarly investigation into the underlying factors. This study aimed to quantify the impact of seismic lines on water balance components using the process-based model CoupModel. Simulated values were compared with field measurements from a seismic line located near Fort McMurray, Alberta, Canada. The simulations indicated higher soil moisture and temperature on the seismic line compared to undisturbed conditions, which aligned with the field measurements. Furthermore, the predicted shallower water table depth on the line was consistent with the field observations. The simulated actual evapotranspiration (AET) on the line was 6% higher than offline, which is less of an increase than previously documented. It was also found that understory evaporation dominated the AET from the seismic line and the adjacent natural area, and thus loss of overstory transpiration due to online canopy removal was more than balanced by higher ground layer evaporation. However, greater available water from higher effective precipitation and lateral flow outweighed the high AET on the seismic line, resulting in the seismic line having higher water storage than offline by 5 mm. Using a sensitivity analysis, we observed that a small change in soil compaction caused a substantial increase in drainage, runoff, soil moisture, and water storage. Furthermore, environmental condition (e.g., soil temperature) changed proportionally in response to seismic line creation in dense-canopy peatlands, particularly with an increase in transpiration and a decrease in soil temperature.