Drainage Retention Capacity (DREC) of Krisak Mountain Meadows Agricultural Area (Jizera Mountains, Czech Republic) for Mitigation of Negative Impacts of Climate Change

Installing drainage systems in saturated soils decreases the level of the subsurface water table and enables the creation of groundwater reservoirs without gravity water – i.e. drainage retention capacity (DREC). DREC, developed by the hydraulic functions of a drainage system, can be defined as a groundwater reservoir, which is limited by soil surface and which occupies an intermediate position in the water table. It is shaped in a parabola form, above the drains. DREC mitigates the negative impact of hydrological extremes, e.g. floods or rainstorms. The purpose of this paper is, to present a methodology for determining DREC on the basis of the height of the water level, in the midway between the drains; with description of the use of DREC for estimation of the rate of potential flooding of the landscape surface; and to describe the application of DREC in a drainage engineering project commissioned by the Ministry of Agriculture of the Czech Republic for water regime protection in the Krisak mountain meadow agricultural area, Jizera Mountains, Czech Republic. The results obtained from in-situ experimental testing confirmed that the equations that are presented in this paper can serve as a reliable tool for DREC approximation.