Author(s): Rohan Benjankar; Danile Tonina
Linked Author(s): Rohan Benjankar
Keywords: No Keywords
Abstract: Dam operation and reservoir management cause reduced peak flows and stable stream flow pattern, which prevent successful recruitment of native riparian cottonwood because the success of recruitment depends on infrequent high flows that create moist bare sand bars. Furthermore, it requires specific flood recession pattern for seedlings to establish successfully. Current management practice focus on planting cottonwood seedlings to restore cottonwood forest. However, unfavorable flow recession, location and timing of plantation may prevent successful growth. South Fork Boise River floodplain (located in central Idaho, USA) lacks cottonwood seedling recruitment, which is attributed for regulated flows by the Anderson Ranch Dam. We developed a two-dimensional (2D) hydraulic model coupled with a cottonwood recruitment model to predict favorable areas for natural cottonwood seedling recruitment. The results showed that there are limited floodplain, where successful cottonwood seedling recruitment is possible for post-dam flows. The field mapping of cottonwood seedlings recruitment support model results. In addition, the model is used to predict favorable areas for cottonwood plantation and successful growth for post-dam flow cases.