Caring for water What is virtual water?

It is essential that the care of all natural resources be carried out by each municipality or commune in the country, with supervision of the National State. Because it is the same one that is in direct contact with the environment and the inhabitant or at least it should be. And thus recognize the anthropic impacts and their problems, of course seeking specific solutions in each case in question.

The tools

They are instruments for caring for the environment and must be suitable for different scenarios. In this way it is possible to develop solutions in the field of the atmosphere we breathe, the water (surface and underground) we drink, the soil and subsoil we step on and cultivate. They must be adapted to the specific requirements, such as a conductivity meter that measures the salinity of the water in a certain range and no other value. In the field of both surface and underground water resources, the diligence of tools with their application must be carried out by specialized professionals: hydrogeologists.

These positive actions generate, through a study, diagnosis and remediation, a correction with reduction of contamination, contributing to the preservation of the environment and water resources in particular. Like preventive medicine that works by preventing many diseases and loss of work hours for people, preventive management of the natural resource in all areas of the basin is important because it conserves the environment and the community its resources and water reserves.

The management and application of hydrogeology and environmental hydrogeology determines positive effects on problems generated by both anthropogenic and natural causes, although the former are more frequent in occurring.

A qualified participation allows adjusting the reality affected by a change in any natural and/or anthropic scenario (cities); applying pumping tests to recognize subsoil offers and better management of water demand and the hydraulic properties of the aquifer such as its productivity index, the volume of the resource's containing basin, its natural limits, the stratigraphic sequence and the physical qualities chemicals of the water to be exploited and consumed.

With environmental hydrogeology (characteristics and behavior of groundwater and its relationship with the environment) the use of tools allows measuring and limiting values ​​to contain and/or eliminate negative impacts, necessary to try to move towards a state of balance with nature, Currently restricted by anthropic forces developed daily, from producing raw materials to simple daily actions of life that sometimes lead to impacting the environment, due to carelessness or negligence and even unclear interests.

The basic elements to use, both in terms of instruments and actions to recognize the behavior of the aquifers that must always be experienced for the exploitation of the present underground resource and to protect its future are:

a) Measurement of the flow rate of the well by gauging with a previously known volume (receptacle) and a stopwatch to measure the time.

b) Freatimetric probe (graduated in millimeters), to measure the decreases and/or variations of static and dynamic levels, within the survey. When the well is at rest (static level) or in a pumping test. With this you can know the storage of the well(S) and know if the aquifer is free, semi-confined or confined. If there is a well close (or drilled) to the one being pumped, drawdowns of this so-called observation well can be measured and then values ​​of transmissivity (T) and storage (S) can be recognized by calculation. The first “T” value gives us an answer to the power of the aquifer, whether it is poor or too powerful to continuously extract water for community use.

The value of S (dimensionless) shows us the volume that an aquifer can release when descending one piezometric level unit, thus defining the type of aquifer (free, confined, etc.).

c) The convenience of working with a computer program that calculates “T” and “S”, instead of doing it manually with tables and calculators, is the time and degree of precision that is gained. Also the use of simple two-dimensional models allows us to have more than a conceptual model, recognizing the evolution and development of the aquifer in the basin. Its natural or artificial recharges and artificial discharges by pumping from boreholes.

d) A portable device to measure conductivity: This device is used to recognize the quality of the water at values ​​close or not to the total residue of salts in the well water. It tells us whether or not we are close to the limit of the saline concentration of a drinking water. Around 1.000 mg/l are values ​​within the water quality standards.

Measures with unit values ​​of uS/cm. (microsiemens cm.). It is advisable to calibrate it from time to time, with appropriate conductivity solutions so that it always measures a reliable value.

Resource care

The important procedures to take care of an underground resource in its sustainable exploitation over time are referred to the maintenance of its fitness, that is, its quality and constant quantity over time; its content in salinity, that the STD does not increase within a few hours or days of continued exploitation.

The solutions to this may be by lowering the rate of exploitation, that is, the well output flows, or if possible, increasing the number of extraction wells, lowering flow rates, if the basin is sufficiently extensive, compensating in some way so as not to modify resources. and consumption or demands.

Also if we take care of the piezometric drops in the exploitation levels (dynamic levels), by regulating the output of the submersible electric pumps used in the system.

Consumption and limitation of the resource

Through resource exploitation centers such as municipalities or drinking water cooperatives, the limitations and sufficiencies of said resource can be described. Always under the supervision of the commune and through personnel specialized in said communal area. It is the conscience of the municipality, its representative or drinking water entity, to know how to point out important functions such as searching, providing, preserving from contamination and projecting the underground or surface water resource for the future in case of supplying river, lake, lagoon water. Know that it is a resource that is difficult to renewable due to its consumption and polluting anthropic impact.

Virtual Water

In countries that are very poor in water resources, a concept developed by JA Allan, called “virtual water”, equivalent to the amount of water necessary to generate a product (food or not) that subsequently reaches population consumption.

That is, if products are manufactured where water is abundant and sold where it is scarce, there is an equivalent to saving water where there is none or where resources are very limited. The importance of virtual water must occur first in countries that have a very marked water deficit, then there are those that continue on an ascending scale.

Because the unique resource on our planet is non-renewable under anthropic impact (pollution and consumption) as stated above, being determined by the hydrological cycle, with a natural balance generating differential distributions on the earth's surface in different regions, although Human actions are often the true limitations of balance.

The concept of virtual water should be considered as a palliative, since financial resources are not infinite and importing products, in the absence of trade balances with exports, can be limited or nullified, with the problem of water resources still subsisting.

This is like a political resource to attack the problem, but a greater solution should prevail with exhaustive studies to search for the resource, treatment alternatives (for example desalination), or contemplating water imports, through aqueducts, etc., which already occurs. in some regions.

Fortunately, in South American countries like ours, with much smaller water deficit strips towards the west of the subcontinent, with very favorable margins for consumption. For example, for South America, 26% is a percentage of the volume of water on the continent and 6% represents the percentage of its inhabitants; a big difference compared to other continents. That is to say, in the formula, supply exceeds demand very positively.

This availability to find underground and surface water is seen here to be very broad (UNESCO source). Despite this, it is possible and necessary to conserve and care for said resource, repeating the taking of preventive measures, so as not to waste water as a currently non-renewable resource and not to alter it, despite the natural hydrological cycle free of contaminants, it is a substantial physical component. that our planet Earth offers for the pleasure of its inhabitants, without which terrestrial, aquatic and amphibian life would not be possible.

Conclusions and recommendations:

In all the basin scenarios contemplated, research should be prioritized. Define the water supply, control its quality and suitability. Also be part of the Commune and be involved with executive functions to make decisions to be recorded for the benefit of human health, delegating to responsible professionals in case of not having suitable equipment: hydrogeologists.

Always exercising budgetary control, with a contract from the specialized team, with a correct interpretation of the final conclusions of the study of sources, keeping in mind the final objective, the preservation of the water resource in the present and future time in each location, or if you want more adjusted, bringing knowledge to the level of each particular basin, involving each locality that makes up the communes.

Jorge Carlos Pflüger