Since surface water and groundwater are connected, isn’t groundwater pumping dewatering the Napa River and threatening our remaining native fish populations?

The Basin Analysis Report finds that overall, groundwater levels in the Napa Valley Subbasin have been stable for decades, demonstrating that current groundwater pumping has not contributed to chronic depletions of groundwater storage and that pumping has likely been below the sustainable yield for the Subbasin. Surface water and groundwater are connected; therefore, seasonal and year to year variability in precipitation and other factors have affected both surface water and groundwater. Since at least the 1930s, periods of no flow days have been observed in the Napa River system, particularly during drier years. Based on the analyses of surface water and groundwater interconnections, including the relationship of this connection to seasonal and annual groundwater elevation fluctuations, the Basin Analysis Report uses 16 wells (and other data including stream gage data) in the Subbasin to monitor groundwater level impact on the Napa River. As long as the fall water levels in these 16 wells remains above the determined level, (the “minimum threshold”), the contribution of groundwater to flow in the Napa River is determined to be no less than has occurred historically in the fall. On average, it is preferable for fall water levels in these wells to approximate their individual measureable objective, which is a level higher than the minimum threshold.

Show All Answers

1. Is groundwater quality currently being monitored?
2. Is there a link between groundwater and surface water, and if so, how will it be managed?
3. What is a water budget?
4. What is irrigation system efficiency and what factors affect the efficiency?
5. What is the current status of the Napa River for impairment under the Clean Water Act?
6. How is climate change taken into account in considering and planning for groundwater sustainability?
7. How does the groundwater basin affect flows within the Napa River?
8. If groundwater conditions are so good, why did my well go dry?
9. If depth to groundwater is so shallow, why do wells seem to be getting deeper to find water?
10. Why are streams that used to flow in the summer now dry?
11. Since surface water and groundwater are connected, isn’t groundwater pumping dewatering the Napa River and threatening our remaining native fish populations?
12. Are you doing anything about well problems in the county like the Petra Dr / Soda Canyon area?
13. Return to the Groundwater FAQ page