A new method for restoring ditches in peatlands: ditch filling with fiber bales

Abstract

Ditching is a common practice to dewater wetlands, including peatlands, and ditch blocking is a common method for restoring wetlands because substrate is often unavailable for filling the ditches. However, filling has many advantages compared to blocking ditches. Our goal was to test whether ditches could be filled in a Colorado sloping fen (Chattanooga Fen) using bales created from shredded aspen (Populus tremuloides) tree‐fiber. We monitored water table levels before and after we filled two ditches (combined length of approximately 165\u2009m\u2009×\u20093\xa0m wide) as well as an undisturbed reference portion of Chattanooga fen. The reference site had stable water tables that rarely dropped more than 20\u2009cm below the soil surface. The ditches had been dewatering large areas of the fen for at least 100\u2009years. Filling the ditches with fiber bales resulted in a water table increase between 2 and 22\u2009cm in an area up to 150\u2009m below the ditch. Native sedges now cover the area where we filled the ditches, with no erosion or compression/settling of the ground observed and no water backing up behind the filled ditches. Filling the ditches with shredded fiber bales is a good option for restoration in wilderness areas, or areas lacking peat or mineral soil fill because it is a natural material that is easily transported and placed in the ditches.