Method for determining a maximum allowable volume of water that can be removed over time from an underground water source

1. A method for determining over time a maximum permissible volume of water that can be harvested from a groundwater source, said volume of water being harvested at a harvesting point and a hydrogeological status of the groundwater source is qualified by measurements of water tables on a reference piezometer, said method being characterized in that it comprises the following steps:

a) continuously measuring of a water table by a first level sensor at the harvesting point, said sensor having a first data record available for a predetermined period in the past;

b) continuously measuring of the water table by a second level sensor on the reference piezometer, said second sensor having a second data record available for a predetermined period in a past;

said method further comprising the following steps implemented by a computer:

c) processing the data from the first level sensor to create a record of the pseudo-static water tables and a record of dynamic water tables for the predetermined period in the past;

d) determining a record of drawdown at the harvesting point over said predetermined period in the past, a drawdown is defined as a difference, at a given moment, between the pseudo-static and dynamic water tables;

e) determining apparent transmissivity values at the harvesting point, for reproducing a best possible record of determined drawdowns over said predetermined period in the past, using a Cooper-Jacob analytic relationship to associate an apparent transmissivity value with different types of pseudo-static water tables, the association of the apparent transmissivity value with the different types of pseudo-static water tables being a first relationship;

f) determining a critical use level at said harvesting point;

g) selecting a reference piezometer having water table measurements over said predetermined period in the past;

h) calculating averages over time of said pseudo-static water tables and the water tables measured on the reference piezometer over said predetermined period in the past;

i) determining a second relationship between said averages over time of said pseudo-static water tables and the averages over time of said water tables measured on the reference piezometer over said predetermined period;

j) determining a maximum permissible drawdown for each pseudo-static water table value, maximum permissible drawdown being defined as the difference between a pseudo-static water table and said critical use level;

k) determining the maximum permissible harvestable volume of said underground water source at said harvesting point using the Cooper-Jacob relationship and said first and second relationships.

2. The method of claim 1 , wherein said averages over time are monthly averages.

3. A non-transitory machine-readable storage medium configured to store a program comprising instructions for implementing each of the steps for determining over time a maximum permissible volume of water that can be harvested from a groundwater source, said volume of water being harvested at a harvesting point and the hydrogeological status of the groundwater source is qualified by measurements of water tables on a reference piezometer:

a) continuously measuring of a water table by a first level sensor at the harvesting point, said sensor having a first data record available for a predetermined period in a past;

b) continuously measuring of the water table by a second level sensor on the reference piezometer, said second sensor having a second data record available for a predetermined period in the past;

c) processing the data from the first level sensor to create a record of the pseudo-static water tables and a record of dynamic water tables for the predetermined period in the past;

d) determining a record of drawdown at the harvesting point over said predetermined period in the past, a drawdown is defined as a difference, at a given moment, between the pseudo-static and dynamic water tables;

e) determining apparent transmissivity values at the harvesting point, for reproducing a best possible record of determined drawdowns over said predetermined period in the past, using a Cooper-Jacob analytic relationship to associate an apparent transmissivity value with different types of pseudo-static water tables, the association of the apparent transmissivity value with the different types of pseudo-static water tables being a first relationship;

f) determining a critical use level at said harvesting point;

g) selecting a reference piezometer having water table measurements over said predetermined period in the past;

h) calculating averages over time of said pseudo-static water tables and the water tables measured on the reference piezometer over said predetermined period in the past;

i) determining a second relationship between said averages over time of said pseudo-static water tables and the averages over time of said water tables measured on the reference piezometer over said predetermined period;

j) determining a maximum permissible drawdown for each pseudo-static water table value, maximum permissible drawdown being defined as the difference between a pseudo-static water table and said critical use level;

k) determining the maximum permissible harvestable volume of said underground water source at said harvesting point using the Cooper-Jacob relationship and said first and second relationships;

wherein said program is executed on a non-transitory computer readable medium.

4. A system comprising means for implementing each of the steps for determining over time a maximum permissible volume of water that can be harvested from a groundwater source, said volume of water being harvested at a harvesting point and the hydrogeological status of the groundwater source is qualified by measurements of water tables on a reference piezometer:

a) continuously measuring of a water table by a first level sensor at the harvesting point, said sensor having a first data record available for a predetermined period in a past;

b) continuously measuring of the water table by a second level sensor on the reference piezometer, said second sensor having a second data record available for a predetermined period in the past;

said method further comprising the following steps implemented by a computer:

c) processing the data from the first level sensor to create a record of the pseudo-static water tables and a record of dynamic water tables for the predetermined period in the past;

d) determining a record of drawdown at the harvesting point over said predetermined period in the past, a drawdown is defined as a difference, at a given moment, between the pseudo-static and dynamic water tables;

e) determining apparent transmissivity values at the harvesting point, for reproducing a best possible record of determined drawdowns over said predetermined period in the past, using a Cooper-Jacob analytic relationship to associate an apparent transmissivity value with different types of pseudo-static water tables, the association of the apparent transmissivity value with the different types of pseudo-static water tables being a first relationship;

f) determining a critical use level at said harvesting point;

g) selecting a reference piezometer having water table measurements over said predetermined period in the past;

h) calculating averages over time of said pseudo-static water tables and the water tables measured on the reference piezometer over said predetermined period in the past;

i) determining a second relationship between said averages over time of said pseudo-static water tables and the averages over time of said water tables measured on the reference piezometer over said predetermined period;

j) determining a maximum permissible drawdown for each pseudo-static water table value, maximum permissible drawdown being defined as the difference between a pseudo-static water table and said critical use level;

k) determining the maximum permissible harvestable volume of said underground water source at said harvesting point using the Cooper-Jacob relationship and said first and second relationships.