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Who owns the rainfall? A legal frontier?

The 2011 report by the Association of California Water Agencies (ACWA),  Sustainability from the Ground Up: A Framework for Groundwater Management in California (pages 13-14) encapsulates the following:

Under California law, water is characterized as being surface water or groundwater. Groundwater is further classified as either a subterranean stream or as percolating groundwater. Surface water and groundwater classified as a subterranean stream are subject to the permitting authority of the State Water Resources Control Board, while groundwater classified as percolating groundwater is not subject to that authority.  (ACWA 2011)

California’s Sustainable Groundwater Management Act (SGMA – 2014, amended 2015) Definitions states,

“Groundwater” means water beneath the surface of the earth within the zone below the water table in which the soil is completely saturated with water, but does not include water that flows in known and definite channels.

According to that distinction, rainfall that infiltrates and percolates right where it lands is not subject to prior appropriation.  Correct???  Comments welcome, please. 

As Rainfall to Groundwater emerges online, autumn 2017,  all published proposals for recharge to meet the challenges of SGMA have relied on diversion of surface waters.  

California’s State Water Resources Control Board administers vested water rights and issued the following press release January 15, 2016::

State Water Board Issues its First Temporary Groundwater Storage Permit to Capture Rain Season High Flows  

The below web page summarizes the existing regulatory situation:

Applications for Groundwater Recharge/Storage 

Essentially, diversion of even flood flows for habitat benefits and recharge is nevertheless considered diversion, despite that such flood flows would not likely have been captured for “beneficial uses” otherwise.  Thus, diversion of surface waters, even with the best intentions for recycling it back into the overall system, requires a Temporary Groundwater Storage Permit.

Rainfall to Groundwater proposes restoring infiltration and percolation capacities on lands with degraded detention functions, so that more rainfall enters the groundwater system right where it lands.

Among the state water boards’  recently updated FAQs regarding water rights is, “How do I know if I need a water right permit?” The response there clarifies the boards’ permitting authority with respect to groundwater.

Final resolution of potential regulatory issues may prove more straightforward for groundwater basins whose watersheds are less subject to water exports.  California Groundwater Sustainability Agencies in such cases may work out the details of sustaining groundwater and appropriation among themselves.

Elsewhere, water exporters with senior appropriative rights could conceivably balk at conversion of what would otherwise become storm runoff, into groundwater.  However, some points to keep in mind:

  • We aim here to restore historically degraded detention functions.  So we are not really proposing new storage – just restoring original functions, before we humans unwittingly impacted the natural “sponges” inherent to the watersheds we’ve most profitably exploited.  
  • The Rainfall to Groundwater approach simultaneously offers (natural, infrastructure-free, low-cost) flood reduction and *holistic* groundwater recharge.  
  • Even in the case of vested rights, such as along riparian zones, arrangements among stakeholders should be feasible, since this approach clearly benefits all concerned.


Further Reading

Association of California Water Agencies (ACWA) 2011 .  Sustainability from the Ground Up: A Framework for Groundwater Management in California.