Effects of Subsurface Water Infiltration Systems on Groundwater Table Dynamics in Drained Peat Soils

Drainage of wet soils is a widely used method to enable use of these soils, for example, agriculture. Artificial drainage may, however, cause multiple adverse effects, especially in the case of peat soils where drainage can result in oxidation of peat and associated greenhouse gas emissions, as well as soil subsidence. Shallower water table depths (WTDs), especially in summer, may counter these problems. Here, we assess the effects of two methods aimed at raising the summer WTD using passive or active water infiltration via subsurface drainage systems, on five sites in the coastal plains of the Netherlands. WTDs were monitored for 4 years with high‐frequency measurements in a control and treatment plot, allowing for a statistical comparison of the WTD time series between the two. Using linear mixed effect models, we obtained a combination of six parameters characterising the influence of water infiltration systems (WISs) on the average WTD and on its fluctuations, including the spatial aspect of distance to the subsurface drain. The parameters show that WISs are effective in reducing the WTD fluctuations at four out of five sites, whilst the effect on the average WTD clearly depends on the applied water levels in the WIS. The local site conditions as well as the installation characteristics and management of the WIS are used to explain the (differences in) parameters, highlighting the importance of a correct implementation and management of the WIS.