Lifespan map creation enhances stream restoration design.

Research and engineering efforts are establishing a vast number of stream restoration planning approaches, design testing frameworks, construction techniques, and performance evaluation methods. A primary question arises as to the lifespan of stream restoration features. This study develops a framework to identify relevant parameters, design criteria and survival thresholds for ten multidisciplinary restoration techniques: •Parameterize relevant features, notably, (1) bar and floodplain grading; (2) berm setback; (3) vegetation plantings; (4) riprap placement; (5) sediment replenishment; (6) side cavities; (7) side channel and anabranches; (8) streambed reshaping; (9) structure removal; and (10) placement of wood in the shape of engineered logjams and rootstocks.•Identify survival thresholds for parameters, where the feature life ends when the threshold value is exceeded.•Compare parameter thresholds with spatial data of topographic change and hydrodynamic forces as a result of hydrodynamic modelling of multiple discharges. The discharge or topographic change rate that is related to the lowest (flood) return period spatially determines the feature's lifespan in years.

Hydro-morphological parameters generate lifespan maps for stream restoration management.

Anthropogenic, eco-morphological degradation of lotic waters necessitates laws, directives, and voluntary actions involving stream restoration and habitat enhancement. Research and engineering efforts are establishing a vast number of stream restoration planning approaches, design testing frameworks, construction techniques, and performance evaluation methods. As the practice of restoration scales up from an individual action at a single site to sequences of actions at many sites in a long river segment, a primary question arises as to the lifespan of such a sequence. This study develops a new framework to identify relevant parameters, design criteria and survival thresholds for ten multidisciplinary restoration techniques, adequate for site-scale to segment-scale application, in a comprehensive review: (1) bar and floodplain grading; (2) berm setback; (3) vegetation plantings; (4) riprap placement; (5) sediment replenishment; (6) side cavities; (7) side channel and anabranches; (8) streambed reshaping; (9) structure removal; and (10) placement of wood in the shape of engineered logjams and rootstocks. Survival thresholds are applied to a sequence of proposed habitat enhancement features for the lower Yuba River in California, USA. Spatially explicit hydraulic and sediment data, together with numerical model predictions of the measures, were vetted against the survival thresholds to produce discharge-dependent lifespan maps. Discharges related to specific flood-return periods enabled probabilistic estimates of the longevity of particular design features. Thus, the lifespan maps indicate the temporal stability of particular stream restoration and habitat enhancement features and techniques. Areas with particularly low or high lifespans help planners optimise the design and positioning of restoration features.