From the PPIC Blog:
“When the California Legislature created the “modern” water rights regulatory system more than a century ago, it focused exclusively on surface water, exempting groundwater from the permitting system. Yet in most watersheds, surface water and groundwater are closely linked. Actions that change one often have an impact on the other. The arbitrary legal divide has made it harder to manage the state’s water. But a recent law and a new court decision have done a better job of connecting surface water and groundwater.
When rain falls or snow melts in the foothills and mountains of California, water follows several pathways downhill and into rivers and streams. Some water moves across the land or through deep soils and weathered bedrock, arriving in rivers hours to weeks after rain or snowmelt. And some percolates deep into the ground, becoming groundwater. … “
Read more from the PPIC blog here: The Connection between Groundwater and Surface Water