Analysing water level strategies to reduce soil subsidence in Dutch peat meadows

SummaryThe survival of peat meadows in the Netherlands is threatened by soil subsidence, less favourable conditions for farming and rising costs of water management. To support policy-making, a study examined possible future strategies for these meadows in the west of the Netherlands. Future scenarios with different water level strategies and climate scenarios were modelled with the SIMGRO regional hydrological model. The analysis focused on water level control strategies, in combination with subsurface drains, with the aim of reducing subsidence and minimising the water supply in dry periods. Subsurface drains were found to be a good measure to reduce subsidence, but more water had to be supplied. Based on the simulated water level control strategies an optimal scenario was found; it minimises the negative effects of the increased water supply. A scenario simulating the anticipated climate change appeared to have a great impact on the peat meadows. In the future the subsidence rate will increase and more water will have to be supplied to maintain the target surface water levels.

► The SIMGRO hydrological model was set up for peat meadows, calibrated, and used in a scenario study. ► Scenarios focussed on water level control, to minimise soil subsidence and water supply. ► Subsurface drains combined with raising the surface water level reduce soil subsidence. ► In the optimal scenario, less water is required and the soil subsidence is acceptable. ► Climate change scenarios reveal a great impact: increased water supply and soil subsidence.