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Introduction Background and RationalePeatlands are organic-rich wetlands that provide important ecosystem services at a range of spatial scales (Kimmel & Mander, 2010). Local hydrological setting is of central importance in determining the characteristics and functions of these ecosystems (Siegel & Glaser, 2006). Peatlands are characterized by waterlogged, anoxic conditions that suppress microbial decomposition, causing carbon to accumulate slowly but persistently over thousands of years in the form of partially decomposed plant detritus (Yu et al., 2010). Peatlands cover less than 3% of the Earth's land surface (Xu et al., 2018b) yet they are thought to store between approximately 500 and 600 Gt (5-6 × 10 17 g) of carbon (Müller & Joos, 2020;Page et al., 2011;Yu, 2011Yu, , 2012, equivalent to between approximately one sixth and one third of global soil carbon (Scharlemann et al., 2014). As well as being long-term carbon sinks, peatlands also emit greenhouse gases, particularly carbon dioxide (CO 2 ) and methane. Peatland greenhouse gas budgets are highly sensitive to surface wetness, and even modest changes in water-table depths can cause peatlands to switch between being net sinks and sources of greenhouse gases when measured in CO 2 -equivalent units (Evans et al., 2021;Günther et al., 2020). In some locations, water that drains from peat

Artificial drainage networks established throughout peatlands during the peat extraction process often remain active following abandonment, maintaining a water table relatively far from the surface of the peat, and hindering the survival and reestablishment of Sphagnum mosses. As an initial restoration effort, the primary drainage network of an abandoned cutover peatland was blocked with a series of peat dams, consequently reducing the runoff efficiency and causing the site-average water table to rise by 32 cm. Higher water tables and a blocked drainage network resulted in increased runoff variability, dependent upon antecedent conditions (capacity to retain additional water on-site), and event-based precipitation dynamics. Evapotranspiration (ET) rates were 25% higher following rewetting (3.6 mm day −1 ) compared to prerestoration ET rates of 2.7 mm day −1 . Total storage changes were restricted following rewetting, as a factor of the reduced runoff losses limiting water table drawdown, thereby constraining peat compression and preventing undue drying of the unsaturated zone. An average surface level rebound of 3 cm was observed, increasing the mean hydraulic conductivity by an order of magnitude. Changes to the system hydrology following restoration efforts produced hydrological conditions more favourable for the recolonization of Sphagnum mosses.