Base-flow by using Curve-number 1

[ibram90]

How can I get the base-flow in a small watershed based on the curve number or the landuse?

 

[francesca]

You google for the SCS method.

 

[bltseattle]

CN method was developed for large surface runoff events, not estimating baseflow. Baseflow comes from other processes, such as groundwater. If you must determine it through modeling, rather than direct measurements, channel modeling, or historical records, you should pick a hydrologic model that includes subsurface flow processes.

 

[alhyasat]

I dont know if this will work or not,

first calculate cum. infiltration for each storm using the CN method and construct infiltration time series. Then look for cross correlation between base flow time series and infiltration time series and come up with a statistical model.

i think this will work for large basins only where regional groundwater movement into basin is somewhat limited.

if the watershed is small i think you should use base flow exponential models.

 

[blueoak]

For base flow I use USGS data if it is monitored or compare to a similar basin. If it's small? (<a couple square miles) and there isn't irrigation it is rare to have base flow. In our mountain regions we can get pretty good base flow, but there I go to the field and check the stream. You can normally tell by the rocks and vegetation about where your annual high base flow is. I use somewhere about 20% of the 2 yr bank elevation in mountain areas I have worked.
I just moved near a creek and I can tell by the salts exactly where the normal base flow (we are in year 7 of a drought) should be. Base flow is so variable that just about any guess is good so long as you use something as a basis. I like using plants because they photograph well for the file and environmentalists seem to feel at ease.