Fortunately, there are other options for addressing a failing bank other than rip-rap that work with, instead of fighting against, natural stream processes. These typically involve using woody debris, native plants, and other natural materials to reestablish natural features that stabilize the bank while improving river habitat.
Watch this video about a successful soil lift project on the Beaverhead River in Montana.
Healthy riparian vegetation is the best defense against erosion. Establishing vegetation on previously bare banks will start a trajectory towards a healthy, stable riverbank. This usually involves installing cuttings of native willows and cottonwoods, transplanting native shrubs and trees, and spreading native riparian seed. On eroding banks, revegetation needs to be combined with soil bioengineering to allow the plants to become established before they are eroded away. Vegetation provides important functions for fish and aquatic organisms by providing complex habitat, providing an energy source for macroinvertebrates by shedding leaves and woody debris, and by cooling the river by creating shade.
Soil bioengineering seeks to utilize plants and organic materials in an engineered design, with the goal of reestablishing a self-sustaining natural riverbank. Natural materials such as trees, fiber mats and blankets, bundles of cuttings, and rocks of a similar size to those in the stream are used to stabilize banks while providing ecological benefits for the river.
A key feature of bioengineering is roughness, the frictional resistance experienced by flowing water. Increasing roughness slows water, reducing its ability to erode. Creating roughness using organic materials also creates complex habitats that help native fish thrive.
Some examples of bioengineering methods (USDA):