Ground water risk assessment for agricultural pollutants uses a principal component called Net Recharge. DRASTIC models are well known for their easiness of implementation. However, net recharge is everything but an easy to calculate parameter. How can I present an easy to replicate method in Australia that is strong enough and at the same time is replicable by a non expert hydrologist professional?
in Victoria we have the following data:
* Monthly water table elevations (historical ones)
* Monthly Rainfall
* Soil Types
* Hydraulic conductivity of aquifers (not very reliable)
* Specific yield (Almost not reliable)
* Deep Drainage (Quite good estimation)
* Evapo-transpiration
* GW histograms
Basically there are two methods for estimating groundwater recharge in a basin, which are essentially field methods and are based on observations and measurements in the field. They are known as Water Balance Method and Ground Water Level Fluctuation Method. The basic formula for the first method which is based on water balance equation is as follows :
Gross Ground Water Recharge = Total input (Rainfall + Imported water) –
(Runoff + Evaporation + Evapotranspiration + Change in soil moisture storage).
The second method which is based on water level fluctuation and consumptive use is as follows :
Net Ground Water Recharge = Change in groundwater storage + Groundwater Extraction.
Gross recharge can be determined adding base flow component of the run-off to the net recharge.
Out of the two methods mentioned above, the second method is more reliable since the parameters involved can be determined more accurately than that of the parameters such as evaporation and evapotranspiration used in the first method.
The height of water level fluctuation between post-monsoon and pre-monsoon periods is more important than the annual height of water level fluctuation for groundwater development and management purposes, as these values reflect the effective groundwater recharge due to rainfall. Kindly note that specific yield and infiltration rate values are very important for the groundwater estimation.
The following paper may be of help to you.
Well,
Simple calculation for recharge is found in the attached article.
Sincerely
Article Impact of intense exploitation on the groundwater balance an...
Dr. Bayan, I found your paper very interesting & recommended the same. Thank you for sharing the publication.
Hello people,
Thanks for your contribution for this fascinating area of knowledge.
I found an easy way to solve this part of my research, for some of you this is enough complex and deserves an entire research.
My idea is to develop the WTF method spatially through a catchment.
1. From the Victorian Ground water Framework I derived the Ground Water Flow System from this catchment including the values for Sy for each type of aquifer (from literature, reports, papers, reported tests)
2. From the WT levels maps from historical data (in prep. Tim Peterson) over the last 20 years, I derived monthly changes in water levels/grid cell.
3. I computed the monthly GW recharge/grid cell
4. I I created the seasonal changes in ground water recharge according to the Australian seasons.
**** The re is a failure in this method, and that is; that, using this method there is a gap for each fluctuation, regularly this is gap is quantified by hand from the histograms.
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Can you please take a look and make any comment on this method?
Many thanks!!
How to calculate recharge capacity of structure like check dam, percolation tank, recharge pit trench or shaft.
Hi
How do i calculate groundwater recharge
I have the following
* daily rainfall data
* daily water level data
*soil type
*specific yield
Recharge can be computed using the simplified water balance equation:
Recharge = Precipitation – Evapotranspiration – Runoff
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