The effect of river regulation on groundwater flow patterns and the hydrological conditions of an aapa mire in northern Finland

Northern Finland. This study examined long-term (decade-scale) hydrological and ecological consequences of dam construction subsequent river regulation on the environmentally protected Viiankiaapa mire. Pre-regulation floods affected hydrology riverbanks mire, which contain habitats flood-dependent or groundwater-influenced ecosystems. Groundwater discharge flow patterns pre-regulation flood coverage were simulated to investigate impact mire area. The models indicate that regular flooding covered westernmost part before regulation. modelling suggests has raised locations springs in shore, reduced hydraulic gradient towards river, groundwater table banks western increased stable isotopic composition water constructed changed directions close dam. effects mixed: studied plant species declined due reduction after Conversely, occurrence Hamatocaulis vernicosus lapponicus appears be related high areas suggesting suitable habitat for these may have expanded