Assessing the Ecological Potential of Wetlands Surrounding Reclaimed Pads Field Pilot

There may be many instances where functioning forest ecosystems develop on pads and the surrounding ecosystem is not impacted, or is impacted minimally. If this can be predicted, pad removal efforts can be focused on pads where off-pad impacts are most likely to occur and lead to better understanding of reclamation techniques needed to reclaim pads left in place to minimize off-pad impacts. Findings from this trial will be used to a) support development of a decision matrix of ecological criteria and pad characteristics to use to provide guidance into whether or not the pad should be removed or b) determine if more plots should be added in a future study. Potential outcomes: (1) decreased reclamation costs by leaving select pads in place; (2) increased availability of funds and effort for reclamation of peatland areas where pads are removed with potential for improved ecological outcomes; and (3) increased knowledge for reclaiming pads in place. Site selection for the study was completed in 2019 (Project LE0052), a pilot study was completed in 2021 and a full study was completed in 2023. Few in situ pads have been reclaimed, so conventional oil and gas pads were used in this study as a proxy for in situ pads. Twenty sites were included in the study.

Wellsite pads < 1 ha and lacking padded access roads, or with thin padding below surface water levels, influenced peatland water chemistry directly downstream of the pad (~10m away), but changes were generally too low to induce noticeable vegetation changes. This suggests padded wellsites in peatlands without padded access roads could be reclaimed in place with minimal risk of impact to vegetation and water quality. Greater impacts could occur if pad material’s electrical conductivity (EC) exceeds 2 dS/m, or if pad is in a peatland with higher lateral flow of water; no sites in the study exhibited severe impacts, so no thresholds for EC and water flow rate can be provided. Pads in this study were 0.6 – 1.2 ha, and size was not a predictive factor for impacts to adjacent peatlands. In-situ pads may exceed 4 ha, which could cause greater impacts due to increased ‘wake’ effect, increased area/material for leaching and greater potential for acting as a barrier to water flow. This could be reduced by modifying pad shape or incorporating water flow channels. Establishing vegetation cover could reduce leaching or transport of sediment. Without additional information, caution should be taken in extrapolating these results to pads greater than 1 ha.