Laguna–San Diego Coastal water resource basin explained

Laguna–San Diego Coastal water resource basin (HUC 180703) is one of three hydrologic basins within the Southern California Coastal water resource subregion and is one of approximately 2,200 water resource basins in the United States hydrologic unit system.

The Laguna–San Diego Coastal water resource basin is a third-level subdivision of the United States hydrologic unit system. The tiers of the classification system, in order from largest to smallest, are regions, subregions, basins (formerly accounting units), subbasins (formerly cataloging units), watersheds, and subwatersheds. These geographic areas contain either the drainage area of a major river, or the combined drainage areas of a group of rivers.^{[1] [2]}

The Laguna–San Diego Coastal basin is approximately and includes the drainage into the Pacific Ocean from Moro Canyon near Laguna Beach to the international border between the United States and Mexico.^[3] The Laguna–San Diego Coastal basin is composed of five fourth-level hydrological units called water resource subbasins (formerly known as water resource cataloging units), each with its own 8-digit hydrologic unit code.

List of subbasins of the Laguna–San Diego Coastal basin

Basin HUC[4]	Basin name	Basin description	Basin location	Basin size	Basin map
18070301		San Juan Creek, Aliso Creek, Laguna Beach coastal streams, Dana Point coastal streams, San Clemente coastal streams[5] [6]	Orange County
18070302	Santa Margarita subbasin	Santa Margarita River, drains Fallbrook and Marine Corps Base Camp Pendleton[7]	San Diego County, Riverside
18070303	San Luis Rey–Escondido subbasin	Sometimes called the San Luis–Carlsbad Watershed; includes San Luis Rey River,[8] Escondido Creek, Buena Vista Lagoon, Agua Hedionda Lagoon, Batiquitos Lagoon, San Elijo Lagoon, Loma Alta Creek and the associated slough[9]	San Diego County
18070304	San Diego subbasin	San Dieguito Creek, Peñasquitos Creek, San Diego River, Pueblo Watershed coastal streams including Chollas Creek, Sweetwater River and reservoirs, Otay River	San Diego County
18070305	Cottonwood–Tijuana subbasin	Tijuana River (international watershed, subbasin boundary is at the border)	San Diego County

See also

• South Coast hydrologic region
• Groundwater recharge
• Water in California
• Principal aquifers of California

Notes and References

1. Web site: Science in Your Watershed - Locate Your Watershed . 2016-10-12 . USGS.
2. Web site: Hydrologic Unit Maps . 2016-10-12 . USGS.
3. Web site: USGS Water Resources: About USGS Water Resources . 2023-03-18 . water.usgs.gov.
4. Web site: National Hydropower Asset Assessment Environmental Attribution . 2016-10-12 . . 2013 . McManamay RA, Bevelhimer MS, Kao SC, Yaxing W, Martinez-Gonzalez M, Samu N.
5. Web site: Watersheds of Interest in Orange County . waterboards.ca.gov.
6. Web site: Appendix D, Watershed Chapters OC Watersheds California . 2023-04-16 . ocerws.ocpublicworks.com . en.
7. Web site: Santa Margarita – Project Clean Water . 2023-04-16 . en-US.
8. Web site: Our San Luis Rey River Watershed . sandiegocounty.gov.
9. Web site: 2019 San Diego Integrated Water Management Plan .