I apologize if this question has been posed before (if this is the case, please send me the link). It seems reasonable since precipitation is a point event and groundwater level record is a time series.
Dear colleague, I am not sure to fully understand your question. However, if you wish to obtain recharge information from groundwater records, you will have to know the specific yield, which not easily measured.
Dear Pierre, I am acquainted with the most commonly used methodologies for groundwater recharge estimate. Indeed, Sy estimate is an obscure subject innthis area: filed with uncertainties and methodological hindrances. Let me try to clarify my question for you. Given the fact that both precipitation and gw levels can be understood as time-series, we can (actually we should) use tools from this area in order to quantitatively describe, and hence model or estimate, groundwater recharge. I am not telling anything new. Literature is full of examples. However, I was not able to find the use of an specific methodology for time-series studies called intervention analysis for hydrogeological phenomena. Theoretically it is quite plausible to do so. Since I am no expert in time-series analysis, I would like to know better.
I use this modified ET model and then caluculate net recharge (infiltration) from the climate data ie precipitation and runoff on a daily basis.
i hope it can be of any use to you
http://www.teriin.org/events/terijislcentre/files/GW_paper.pdf
It is a smart thought but I do not think it is as easy as you think. Since not all precipitation turns to groundwater, also you need to know your boundaries and discharge. If you know Kz you can tell how long will it take a rain droplet to turn groundwater but relief matters maybe you can use solve that problem by using DEM map if there is available one.
The intervention analysis for hydrogeological phenomena as used herein is rather abstract since there are a number of hydrogeological phenomenon . More probably I guess your interest could be GW recharge and time-series analysis considering ET, Precipitation, Runoff-Rainfall, Surface Water-GW studies etc with regards to GW recharge . There exist a number of Models including Modflow etc tyhat nay be of help.
Hey Oguz, thanks for your answer. Indeed I agree with you: it is not so straight forward. Especially given that the aquifer I am studying is a relatively deep crystalline fractured hard-rock one under semi-arid conditions (low rain, high evaporation rates, not suitable for equivalent porosity assumptions, poorly interconnected, a hell of a job to get local hydrogeological data...). Therefore I am looking for time-series methods that can give me insights on the recharge processes. We have the vadose zone, boundaries and discharge quite well characterized though, as well as a DEM of the entire watershed. I noticed some examples in literature that it is possible to do time-series analysis (cross-correlation, interference analysis, impulse response functions, trend analysis, etc) between the cumulative precipitation and the water levels time-series. I am facing a real-life situation (not an ideal one) with limited data and limited resources (so we can't generate all the physical parameters necessary for a complex modelling). Any advice will be gladly welcome :D
Dear Professor Basil, Thanks for your answer. This is an abstract approach indeed: it consists in lumping lots of phenomena in a gross estimate of recharge. This is the basic assumptions of the well known WTF methodology. However, this methodology is way too subjective in my opinion and I would like to find some quantitative support for using it. I think time-series analysis can most certainly provide me such basis. I also am using two modeling approaches for this same estimate: FEFLOW and Visual-Balan..
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