What is a water budget?

A “water budget” is the accounting of the total groundwater and surface water entering and leaving a basin, including the changes in the amount of groundwater stored in the basin. Basic components of water budgets are:

  • Precipitation (rain)
  • Evapotranspiration (a combination of evaporation from the soil and transpiration by plants)
  • Surface water flow (streams and lakes) infiltrating or leaving the groundwater basin
  • Groundwater flow (aquifers) into and out of the groundwater basin
  • Change in groundwater storage
  • Groundwater pumping and consumed or exported from the basin.

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