The model setup of the updated Central Valley Hydrologic Model (CVHM2) is similar to the original Central Valley Hydrologic Model (CVHM). The differences in the model setup are described here as either model discretization, tidal influence, or drain flow. For model discretization, CVHM2 has 13 layers compared to 10 in CVHM. Tidal data for the San Francisco Bay and its influence on the general head boundary was added in CVHM2. Drain flow was not included in CVHM1 for the west side of the San Joaquin Valley, and was added in CVHM2.