We are currently characterizing aquifer in an area where there is paucity of hydrogeologic data and need some sort of secondary data to combine with our geophysical information and what is available is rainfall data.
You have many methods:
-Groundwater budget
-Water Table Fluctuation
-Numerical modeling of infiltration in the vadose zone
-Isotopic methods
-Analytical methods
-Hydrographs and recession curves
RIF I.e. rainfall infiltration factor method and WLF I.e. water level fluctuation method more suits to your requirements.
The method of Thornthwaite (1946), based on temperature, insulation, rainfall and the nature of the soil, on a monthly scale.
Check Kotchoni et al. (2018) paper for water table Fluctuation. Very useful and simple model for recharge estimation with paucity data
It is a useful complementary method. But it requires expensive and not always available piezometers.
Dear Ebong D. Ebong , I believe you have already done some review by now. Nothwithstanding, if you are still looking for an answer, I'd like to suggest you and anyone who is interest in start studying this topic, to start at the following reference:
Healy, R.W., Scanlon, B.R., 2010. Estimating groundwater recharge. Cambridge University Press. 256p.
There are many methods for estimating groundwater recharge and this little book presents a comprehensive review on most of them. You will be convinced by the authors that using a single method may not be enough in order to achieve reasonable recharge rate estimates.
You must be aware of two things: (1) the nomenclature of the recharge rates and mechanisms; and (2), the specific spatial and temporal scales that limits each method as well as the inherent uncertainties of each method. For example, some methods can give you average multiannual rates in a specific point of your watershed (e.g. Chloride Mass Balance, peak displacement methods), while others will give you event based areal distributed recharge estimates (e.g. water table fluctuation). Some are quite objective (e.g. water budgets), while others can be very prone to subjectivity (e.g. WTF). You must have a sound understanding of the assumptions and limitations of each method in order to chose those that are most suitable for your hydrogeological and climatic system and database.
The suggestion you received from Jean-Pierre Faillat may be quite useful if you only have meteorological data (and a few other easily obtainable parameters). But it will provide you only a gross estimate of the (maximum) potential recharge, i.e., the average water surplus that escapes evapotranspiration and is available to infiltrate further towards reaching the aquifer system. Surely better than nothing.
Best of luck.
Many thanks Guilherme Sobrinho for your contribution and for sharing this reference.
Cheers!
- Badges
- Science topic
- Similar topics
- Agricultural Science
- Soil Science
- Soil Analysis