The influence of plantation forest legacy on blanket bog hydrology

Abstract

Human activities in headwater blanket bogs can lead to downstream flooding due to changes in land cover; however, the effects of the geographic distribution of these land cover modifications, especially the role of legacy of plantation forestry on hydrological regime, remains poorly characterized. Therefore, the focus of this research is to estimate the impact of legacy of plantation forestry on streamflow in small (21 ha) blanket bog catchment of Ireland. A network of groundwater monitoring and hydro-meteorological stations were installed to collect high-resolution (15 min to 1 h) hydro-meteorological and groundwater level data. Generalized Multistep Dynamic (GMD) TOPMODEL was calibrated using high resolution (1 m × 1 m) Light Detection and Ranging (LiDAR) and hydro-meteorological data in intact blanket bog watershed. The calibrated model was validated before simulating in degraded (legacy of plantation forestry) catchment. The effect of legacy of plantation forestry on streamflow was examined by comparing observed and simulated streamflow series at various timescales (monthly, seasonal, and yearly). The results indicated that streamflow increased by 106 % annually due to legacy of plantation forestry, with the highest monthly increase recorded in February (275 %) and the lowest in September (16 %) when compared to intact blanket bog. Seasonal analysis revealed an increase in streamflow attributed to legacy of plantation forestry, with the highest increase observed in winter (237 %) and the lowest in summer (24 %). Minimal interception losses, reduced evapotranspiration, and compact bog contribute to elevated runoff relative to undisturbed conditions. The results of this study assist water managers, stakeholders, and policymakers in facilitating effective planning and decision-making.