Figure 5

Physical drivers of daily water level in the Delta. (a) Map of the Delta showing gauge transects plotted in b-e along the bays and straits seaward of the Sacramento-San Joaquin Rivers confluence (blue), Sacramento River (red), San Joaquin River (green), Middle River (light blue), and Old River (black). (b–e) Spatially-varying influence of each regression term on water level for low, moderate, and high forcing conditions (Table 1). Along-channel distances are measured inland from the San Francisco gauge (westernmost blue dot in a). Lines show water level forcing for median values of river discharge, exports, tide range, the absolute value of non-tidal coastal water level (which has a symmetric distribution around 0), and wind speed. Shaded regions show forcing for the 25th to 75th quantiles. Note that for the tidal-fluvial term, the lower edge of the shaded region shows 25th-quantile tide range and 75th-quantile river discharge (minimizing Stokes drift), and the upper edge shows the reverse.