Groundwater Basin Boundary Descriptions - South Coast Region (4-XXX Basins)
This dataset includes the official groundwater basin boundary descriptions for California's 515 groundwater basins. To make locating descriptions easier, they have been organized by region. This resource contains descriptions for basins that start with the number eight (4-XXX) indicating they are located in the South Coast Region.
Data files
Supporting files
| Data title and description | Access data | File details | Last updated |
|---|---|---|---|
4-001_Upper Ojai Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Upper Ojai Valley (4-001) groundwater basin. | Download | PDF | 07/18/25 |
4-002_Ojai Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Ojai Valley (4-002) groundwater basin. | Download | PDF | 07/18/25 |
4-003.01_Ventura River Valley_Upper Ventura River_BasinBoundaryDescription This file contains the official basin boundary description for the Ventura River Valley - Upper Ventura River (4-003.01) groundwater basin. | Download | PDF | 07/18/25 |
4-003.02_Ventura River Valley_Lower Ventura River_BasinBoundaryDescription This file contains the official basin boundary description for the Ventura River Valley - Lower Ventura River (4-003.02) groundwater basin. | Download | PDF | 07/18/25 |
4-004.02_Santa Clara River Valley_Oxnard_BasinBoundaryDescription This file contains the official basin boundary description for the Santa Clara River Valley - Oxnard (4-004.02) groundwater basin. | Download | PDF | 07/18/25 |
4-004.03_Santa Clara River Valley_Mound_BasinBoundaryDescription This file contains the official basin boundary description for the Santa Clara River Valley - Mound (4-004.03) groundwater basin. | Download | PDF | 07/18/25 |
4-004.04_Santa Clara River Valley_Santa Paula_BasinBoundaryDescription This file contains the official basin boundary description for the Santa Clara River Valley - Santa Paula (4-004.04) groundwater basin. | Download | PDF | 07/18/25 |
4-004.05_Santa Clara River Valley_Fillmore_BasinBoundaryDescription This file contains the official basin boundary description for the Santa Clara River Valley - Fillmore (4-004.05) groundwater basin. | Download | PDF | 07/18/25 |
4-004.06_Santa Clara River Valley_Piru_BasinBoundaryDescription This file contains the official basin boundary description for the Santa Clara River Valley - Piru (4-004.06) groundwater basin. | Download | PDF | 07/18/25 |
4-004.07_Santa Clara River Valley_Santa Clara River Valley East_BasinBoundaryDescription This file contains the official basin boundary description for the Santa Clara River Valley - Santa Clara River Valley East (4-004.07) groundwater basin. | Download | PDF | 07/18/25 |
4-005_Acton Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Acton Valley (4-005) groundwater basin. | Download | PDF | 07/18/25 |
4-006_Pleasant Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Pleasant Valley (4-006) groundwater basin. | Download | PDF | 07/18/25 |
4-007_Arroyo Santa Rosa Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Arroyo Santa Rosa Valley (4-007) groundwater basin. | Download | PDF | 07/18/25 |
4-008_Las Posas Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Las Posas Valley (4-008) groundwater basin. | Download | PDF | 07/18/25 |
4-009_Simi Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Simi Valley (4-009) groundwater basin. | Download | PDF | 07/18/25 |
4-010_Conejo_BasinBoundaryDescription This file contains the official basin boundary description for the Conejo (4-010) groundwater basin. | Download | PDF | 07/18/25 |
4-011.01_Coastal Plain Of Los Angeles_Santa Monica_BasinBoundaryDescription This file contains the official basin boundary description for the Coastal Plain Of Los Angeles - Santa Monica (4-011.01) groundwater basin. | Download | PDF | 07/18/25 |
4-011.02_Coastal Plain Of Los Angeles_Hollywood_BasinBoundaryDescription This file contains the official basin boundary description for the Coastal Plain Of Los Angeles - Hollywood (4-011.02) groundwater basin. | Download | PDF | 07/18/25 |
4-011.03_Coastal Plain Of Los Angeles_West Coast_BasinBoundaryDescription This file contains the official basin boundary description for the Coastal Plain Of Los Angeles - West Coast (4-011.03) groundwater basin. | Download | PDF | 07/18/25 |
4-011.04_Coastal Plain Of Los Angeles_Central_BasinBoundaryDescription This file contains the official basin boundary description for the Coastal Plain Of Los Angeles - Central (4-011.04) groundwater basin. | Download | PDF | 07/18/25 |
4-012_San Fernando Valley_BasinBoundaryDescription This file contains the official basin boundary description for the San Fernando Valley (4-012) groundwater basin. | Download | PDF | 07/18/25 |
4-013_San Gabriel Valley_BasinBoundaryDescription This file contains the official basin boundary description for the San Gabriel Valley (4-013) groundwater basin. | Download | PDF | 07/18/25 |
4-015_Tierra Rejada_BasinBoundaryDescription This file contains the official basin boundary description for the Tierra Rejada (4-015) groundwater basin. | Download | PDF | 07/18/25 |
4-016_Hidden Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Hidden Valley (4-016) groundwater basin. | Download | PDF | 07/18/25 |
4-017_Lockwood Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Lockwood Valley (4-017) groundwater basin. | Download | PDF | 07/18/25 |
4-018_Hungry Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Hungry Valley (4-018) groundwater basin. | Download | PDF | 07/18/25 |
4-019_Thousand Oaks Area_BasinBoundaryDescription This file contains the official basin boundary description for the Thousand Oaks Area (4-019) groundwater basin. | Download | PDF | 07/18/25 |
4-020_Russell Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Russell Valley (4-020) groundwater basin. | Download | PDF | 07/18/25 |
4-022_Malibu Valley_BasinBoundaryDescription This file contains the official basin boundary description for the Malibu Valley (4-022) groundwater basin. | Download | PDF | 07/18/25 |
4-023_Raymond_BasinBoundaryDescription This file contains the official basin boundary description for the Raymond (4-023) groundwater basin. | Download | PDF | 07/18/25 |