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Estimate of Ecological Condition in CMW Region

#4096


Appraisal of Eco-Condition of Lithosphere’s Upper Hydrodynamic Zone of Guarded Eco-Resort Region of Caucasian Mineral Waters around Radioactive Dumping of Mining Object in Lermontov Town

Tech Area / Field

  • ENV-MIN/Monitoring and Instrumentation/Environment
  • ENV-WPC/Water Pollution and Control/Environment

Status
3 Approved without Funding

Registration date
05.04.2011

Leading Institute
VNIITF, Russia, Chelyabinsk reg., Snezhinsk

Supporting institutes

  • Pyatigorsk’s State Technological University, Russia, Stavropol reg., Pyatigorsk

Project summary

The project proposal falls in the field «ecology of hydrolithosphere» and suggests a solution for prediction and contamination prevention measures in the most vulnerable layer of the Earth, that is hydrolithosphere, which is a unified hydraulically connected system.

The subject of the investigation is located within a northern slope of the Head Caucasian Range, administratively included in the area of the Caucasian Mineral Waters (CMW). This area has a status of especially guarded ecology-resort region. Its economy is oriented onto resort - recreational business and mineral water bottling. The region includes such well-known mineral springs as Narzan, Essentuky, Kislovodskiy, Lermontovskiy and others. For the recent decade, a production volume of mineral waters has increased more than three times. Anthropogenic impact on hydrolithosphere increased significantly and resulted in redistribution of natural vertical hydraulic gradients in water-bearing horizons, and as well changed not only their quantity, but also a sign. This difficult ecological situation is seriously aggravated by the fact that within the upper hydrodynamic zone of the CMW area there is a tailings dump of radioactive waste (Lermontov town). Taking into account a hydro-geological and ecological situation changed not to the best, at present problems on radiation safety in the region are becoming extremely important. Planning protecting environment measures, as a rule, is rather expensive and also requires a precise appraisal of current contamination condition and prediction of its spreading.

Developing a mathematical model for the subject that most adequately reflects physical processes of contaminant migration, and substantiating measures on prevention of contamination spreading generally and radioactive one in particular can solve the problem. In this connection, the main problems of the project are the following.

1. Development and substantiation of a mathematical model for the subject.

This model structure and methods for implementation of solutions is supposed to allow including a geological-hydrogeological structure of the subject as much as possible. First of all, it concerns problems among which: modeling collectors with a double porosity (pore-cracked type), complicated tectonic boundaries (interior and exterior), hydraulic interrelation of water-bearing horizons of various hydrodynamic floors involved in the zone of anthropogenic impact. The model must provide an opportunity to forecast a situation with a prediction period up to several hundreds years. Taking into account existing state of the scientific and technical basis, spatial and flat-space models realized by numerical methods with a computer by various schemes are more preferable.

To describe a contamination spreading process in underground waters, it is supposed to use the numerical technique “MIF”, created in the Russian Federal Nuclear Center, which can be modified when the model of the subject is defined more exactly. The technique is intended to solve two and three-dimensional equations of migration and filtration on random quadrangular and hexahedral lattices. It has a set of conservative difference schemes permitting to receive monotone solutions for various classes of tasks at different initial and boundary conditions.

2. Development of the technique for the mathematical model verification

The natural-geological subjects are systems with distributed parameters. Their capacitive and fluid loss properties are unknown exactly. Regularities of their spreading in space are also unknown. Existing methods of parameter estimation are based on single or multiple pumping-out (artificial disturbance of a stratum), performed by special techniques of experimental - filtration researches (Tays, Jacob, Huntush, Walton). These are expensive and labor-consuming methods, which enable to estimate parameters in a point or limited local area. They are based on not quite correct assumptions and require special conditions to conduct experimental work. It is not always possible to maintain these conditions in practice (constancy of disturbance, specially located system of points of observation etc.). These methods practically are not used in complicated hydro-geological subjects (subjects belonging to complexity rate III, among which the subject being considered in the Project Proposal), and prediction solutions are developed on the basis of hydraulic methods. The last are based on long actually observed regularity of time history for elements of modes we are interested in. However, hydraulics does not reveal physics of the process, and it is not useful when anthropogenic impact changes or at a large prediction period.

The problem of the Project Proposal is to develop a definition procedure for a coefficient of the model based on the test modeling. To accomplish this, values for the group of model parameters are specified, calculations for each group are performed, and as well model solutions and actual appraisals from data for the whole period of observations are compared. The criterion of choice for parameters is a minimum discrepancy between model and actual data.

The advantage of the method is the suggested technique of the guided search excludes parametrical errors and, as a result, ensures maximum adequacy of the model resulting in an adequate accuracy and timeliness of the monitoring system as a whole.

3. Substantiation of the monitoring and control system for migration of radioactive and contaminants. Prediction of the situation.

At present, as for really operating monitoring of hydrolithosphere, one can say just about collection and generalization of some information. As to control, main problems are development of constantly operating mathematical models (COM). The necessity in COM is quite clear. Natural geological subjects are complicated stratified systems with distributed parameters heavily changeable along spatial coordinates, unclear boundary conditions (at least, at the first stages of research), which, in addition to that, by virtue of high price are described by rather limited amount of points of observation (that are boreholes). For these reasons, prediction and verification procedures should be done in turn, and monitoring itself should be formed on feedback control. Such schemes are widely used in controlled engineering objects and quite enough completely described in the automatic control theory (ACT).


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