How to understand the "local recharge", "baseflow" and "actual baseflow"?

Software Support
1

Hi,
I was confused about the “local recharge”, “baseflow” and “actual baseflow” and had some questions.

  1. Is “local recharge” means “potential baseflow”?
  2. Is “actual baseflow” means the amount of flow that actually reach the river?
  3. For a given sub-watershed, what does “local recharge” minus “actual baseflow” mean?
  4. For a given month, since the quickflow is not LOCAL, does it mean the quickflow reach to the downstream and could be captured by residents in downstream area?
  5. Why the model doesn’t output monthly “local recharge” and monthly “actual baseflow”?
  6. Could you please given some concrete exmples for which problem is needed the results of “local recharge” and which problem is needed the results of “actual baseflow”?
    Thank you in advance!
    Jiangxuan
2

Hi @oohjiangxuan and welcome!

  1. Yes, local recharge means potential baseflow, before that flow is affected by moving downslope, where it might be taken up by vegetation. Although note that we recommend treating this value more like an index than an absolute value, given the simplicity of the calculation.

  2. Yes. Again, treated more like an index.

  3. This isn’t a calculation that I’ve used, but I suppose (local recharge - actual baseflow) could indicate the amount of flow evapotranspired by intervening vegetation between each pixel and the stream.

  4. Yes, I think the assumption is that quickflow runs off the landscape very quickly, so would reach the stream on the order of hours to days. This is the flow that could cause flooding.

  5. I don’t know, but will see if any of our science leads do.

  6. Personally, I haven’t used local recharge results to inform an analysis, but I have used baseflow. Most often, we use actual baseflow to show which places on the landscape are providing water to downstream users in the dry season. This helps people value these places for water provision, which is especially important in places with long dry seasons, and can be used to direct conservation to those places.

~ Stacie

3

To follow up about #6, I heard from a colleague that they used local recharge as part of a study, to look at changes in subsurface water availability for people using wells for drinking water.

~ Stacie

4

Thank you for the help！

5

Hi, @swolny
I am still confused about the value of “local recharge” minus “actual baseflow” after I ran the seasonal-water-yield. since the user guide indicates that L= P-QF-AET, I think it maybe not appropriate to treat the value of “local recharge” minus “actual baseflow” as the amount of flow evapotranspired by intervening vegetation between each pixel and the stream.
Besides, I multiplied the average value of “B.tif” by the study area to represent the amount of actural baseflow. And I multiplied the average value of “L.tif” by the study area to represent the amount of local recharge. I found that the amount of actual baseflow is larger than the amount of local recharge. It makes me more confused because the local recharge means the potential baseflow (largest baseflow) .
thank you