Tools for assessing hydrologic challenges and restoration potential of reservoir deltas: case studies from Southern California

Data from 23 River Partners restoration project sites in 8 counties across California were included in this dataset (Figure 4), representing a range of soil types and environmental conditions. Projects had been planted in 11 different years ranging from 2003 to 2018, representing a variety of precipitation and climate conditions. Plant propagules were either seed (ex., Quercus spp.), 18-inch cuttings buried to 12-inches (ex., Salix spp.), or one-gallon container plants. During the establishment phase, plants were maintained using horticultural restoration methods including highly aggressive mechanical or chemical weed control, and frequent supplemental watering using drip or flood irrigation based on soil conditions and evapotranspiration demand. Height measurements were taken in 12 different years from 2005 to 2020, within 12 to 43 months after planting. To select plants for measurement, we randomly established 20m x 50m monitoring plots in each restoration project at a rate of one plot per 5-20 acres. Plots were at least 10 meters from the project boundary, and oriented with the long axis (50m) facing north. All trees and shrubs within the plot were measured. Height was measured by placing a Stadia rod at the plant base and recording the tallest branch height.