Groundwater. Mysteries of underground tunnels

Federal Agency for Education of the Russian Federation

Astrakhan State University

Natural Institute

Faculty of Geology and Geography

Thesis

On topic : “Assessment of operational groundwater reserves in the presence of attracted natural resources”

Work completed:

Art. 5th year ZIG-51

Bashlaev S.P.

Scientific supervisor:

Senior Lecturer

Solovyova A.V.

ASTRAKHAN 2013

Introduction

Chapter I. Resources and reserves of groundwater

1.1 General concept of resources and reserves

1.2 Types of resources

1.3 Groundwater reserves

Chapter II. Groundwater resource assessment

2.1 Types of work and methods for determining regional resources

2.2 Zoning of territories in connection with the regional assessment of projected operational resources

2.3 Types of work carried out in connection with the regional assessment of operational resources

2.4 Methodology for assessing projected regional operational resources

2.4.1 Hydrodynamic calculation of forecast regional resources

2.4.2 Assessment of projected regional operational resources when water flows from the overlying aquifer

2.4.3 Assessment of natural (geological) groundwater reserves

2.4.4 Assessment of attracted resources

Chapter III. Assessment of operational groundwater reserves

3.1 Methods for determining operational reserves

3.1.1 Hydrodynamic method

3.1.1.1 Unlimited aquifer area

3.1.1.2 Semi-confined formation

3.1.1.3 Layer strip with two boundaries

3.1.1.4 Formations with a circular feed circuit

3.1.2 Hydraulic method

3.1.3 Combined use of hydrodynamic and hydraulic methods

3.1.4 Balance sheet method

Chapter IV. Use of computers in assessing groundwater reserves

4.1 Software

4.2 Determination of filtration-capacitive properties of aquifers

4.3 Numerical modeling of hydrodynamic and hydrogeochemical processes

Conclusion

List of used literature

Introduction

Groundwater plays a significant role in the development of various sectors of the national economy of our country. Depending on the needs of sectors of the national economy, all types of groundwater distributed in the hydrosphere can be divided into four groups: fresh, thermal, mineral and industrial.

For these types of groundwater, general principles and methods for their exploration have now been developed. For example, a general scientific and methodological technique is the staged exploration of groundwater deposits, which allows, using successive approximations, to identify deposits based on the results of detailed searches, study the conditions for the formation of operational resources based on preliminary exploration data, and prepare it for industrial development based on the results of detailed exploration of the object. General principles should also include the principle of economic feasibility of field exploration, etc.

At the same time, the study of each identified type of groundwater has specific features, the main one of which is the determination of the main parameters necessary for assessing exploitable reserves. Thus, for mineral groundwater, in addition to identifying their quantity in the deposit (operational reserves), it is necessary, based on the exploration results, to qualitatively and quantitatively evaluate the gas composition, as well as the stability during operation of certain chemical components useful for balneology.

When exploring thermal groundwater deposits, it is necessary to evaluate such a parameter as the heat capacity of groundwater, and when exploring industrial groundwater, the content (reserves) of one or another useful component, the extraction of which is planned during operation. There is a certain specificity in the exploration methodology for fresh, thermal, mineral and industrial groundwater, which consists in the principles of placing exploration wells, carrying out experimental filtration work, as well as in the use of exploration tools. Considering these circumstances, it is quite legitimate to independently consider the methodology for prospecting, exploration and evaluation of operational reserves of various types of underground.

Since fresh groundwater is used primarily for domestic and drinking water supply to cities, towns and agricultural facilities, the systematic provision of these waters to the national economy, taking into account growing water consumption, should be considered as the most important social problem of our society.

The share of groundwater in the water supply of urban settlements is about 35-40%; for rural settlements - about 85%. At the same time, the larger the city, the smaller the share of groundwater use, as a rule: for large cities (more than 100 thousand) it is already only about 29%, and in the largest cities (with a population of more than 250 thousand people) In half of the cases, only surface water is used (Moscow, St. Petersburg, Nizhny Novgorod, Yekaterinburg, Omsk, Rostov-Don, Vladivostok, etc.).

This situation is typical for most large cities in the world and is explained by completely prosaic economic reasons. To obtain the required volume of drinking-quality groundwater (several million cubic meters per day for water supply to a large city), it is necessary to use a whole group of large deposits over large areas. They must be sufficiently far from the urban area to allow effective sanitary protection of water intake structures to be organized. The creation of long (tens of kilometers) main water pipelines of large cross-section to transport produced water to the city requires huge capital and operating costs; In such cases, issues of land allocation for such large linear engineering structures also become important.

The purpose of this work is to assess the operational reserves of groundwater in the presence of attracted natural resources. To achieve this goal, the following tasks were set:

1) Study information on operational groundwater reserves from literary sources;

2) Study information about attracted natural resources;

3) Study methods for determining operational reserves.

Chapter I. Resources and reserves of groundwater

1.1 General concept of resources and reserves

The concept of groundwater resources and reserves includes their various categories, differing both in the conditions of formation and in the features of hydrogeological studies that provide justification for one or another category.

The differences between these concepts were formulated very clearly by N.N. Bindeman. (1970): “It is more correct to speak not about “reserves” of groundwater, but about “resources” of groundwater, meaning by this term the provision of groundwater in the water balance of a given area and, leaving behind the term “reserves” only the definition of those quantities water that is in a given pool or layer, regardless of water supply and flow, but depending on its capacity.” Unlike other minerals, groundwater reserves and resources are usually measured in flow units.

Differences in groundwater reserves and resources are reflected in their fundamentally different changes during exploitation. Natural reserves of groundwater necessarily decrease during exploitation, since pumping always causes a decrease in the water level and, consequently, some reduction in its mass in the aquifer. On the contrary, the natural resources of groundwater during exploitation not only do not decrease, but in some cases increase. A decrease in the pressure of groundwater in the formation during pumping can cause the inflow of water from rivers, reduce evaporation from the surface of groundwater, cause or increase the flow of water from above and below located aquifers through relatively poorly permeable layers and windows. Thus, during the operation of water intakes, groundwater reserves decrease and resources increase.

Groundwater reserves and resources can be divided according to their genesis into the following types: 1) natural reserves and resources; 2) artificial reserves and resources; 3) attracted resources.

1.2 Types of resources

Based on a number of characteristics, resources are divided into certain groups. First of all, their genesis is taken into account, taking into account which natural and artificial ones are distinguished (formed under anthropogenic influence) resources.

Natural resources are the total amount of recharge of the aquifer under natural conditions (hence, the amount of natural discharge). The formation of natural resources is determined by natural factors (precipitation, surface water, neighboring aquifers). These resources provide the flow of underground flows, which vary under the influence of such factors.

Artificial resources are provided by anthropogenic influence through the creation of special reservoirs in the recharge area of ​​aquifers or the injection (storage) of water through wells into aquifers.

Considering the area of ​​distribution, regional and local resources are allocated. Along with these groups, there is such a variety as operational resources, through which groundwater reserves are ensured during the exploitation of aquifers.

Artificial groundwater resources - feeding of aquifers during filtration from canals and reservoirs, in irrigation areas, with targeted measures to enhance their supply. Artificial resources, like natural ones, have a consumption dimension.

Attracted resources - increased recharge of groundwater caused by the formation of depression cones during the operation of water intakes (the emergence or intensification of filtration from rivers, increased recharge of groundwater by precipitation due to a decrease in evaporation from the surface of groundwater as its surface moves away from the surface of the earth).

When exploiting groundwater, all of the above types of groundwater resources are used to one degree or another.

1.3 Groundwater reserves

Several groups of groundwater reserves are currently distinguished based on various characteristics.

Natural reserves are the mass of gravitational water in a reservoir under natural conditions. That part of this mass that can be extracted from the confined aquifer due to the elastic properties of water and rocks without draining the formation is called elastic reserves. When assessing groundwater reserves for water supply (fresh water), it is more convenient to express reserves not by mass, but by volume of water, since the numerical values ​​of the unit mass and volume of water in this case are quite close. In this approximate interpretation, natural reserves are equal to the sum of the volume of water contained in the formation (these reserves are sometimes called “capacitive reserves”) and the volume of water extracted under pressure conditions without draining the formation (“elastic reserves”). The value of the latter in comparison with the capacitive reserves is usually a fraction of a propet.

Artificial groundwater reserves are their volume in a reservoir, formed as a result of irrigation, back-up by reservoirs, and artificial flooding of the reservoir.

Operating groundwater reserves are the amount of groundwater that can be obtained by technically and economically rational water intake structures under a given operating mode and with water quality that meets the requirements throughout the entire estimated period of water consumption. It is recommended to express the amount of water referred to in the above definition as water consumption. Therefore, strictly speaking, we are not talking about operational reserves, but about the operational resources of the aquifer. We can agree with the term operational reserves from a practical point of view - the State Reserves Committee approves mineral reserves (the vast majority of them are solid minerals, where the term “reserves” is precise), and not resources.

The term “operational resources” is used in forecast assessments in a regional plan, as a characteristic of the potential for the exploitation of groundwater in a particular large region.

Taking into account their replenishment, renewable reserves are distinguished (subject to the receipt of resources) and non-renewable (in the absence of sources of their formation). The latter include the so-called geological reserves of groundwater, equal to the volume of water in the horizon.

Like resources, reserves, taking into account the area of ​​their distribution, are divided into regional and local, and based on genetic characteristics - into natural and artificial (accumulated with the participation of anthropogenic influence). If the reserves of a certain horizon are partially replenished due to the influx of water from other aquifers, then the amount of water coming from them is classified as attracted reserves.

A special group consists of operational reserves that can be extracted or are extracted from exploited aquifers, primarily from groundwater deposits in compliance with environmental measures (7). As a rule, operational reserves are confined to groundwater deposits that ensure economically justified extraction. The degree of complexity of these deposits (or their sections) varies. In this regard, they are divided into three groups.

The first of them includes operational reserves of groundwater deposits with simple conditions. In the area of ​​their distribution, aquifers (subdivisions) are consistent in area and structure, are uniform in filtration properties, are provided with nutrition (resources) and are characterized by a stable standard chemical composition.

The second group of groundwater deposits is characterized by a complex structure, as well as complex hydrogeochemical and geothermal conditions. At the same time, however, it seems possible to assess changes in various components of the natural environment, using special technologies to a limited extent during exploration and development of reserves.

The third group includes operational reserves of fields with very difficult conditions, characterized by an unstable geological structure, extreme variability in the thickness and filtration properties of water-bearing rocks, as well as complex hydrogeochemical and geothermal conditions. Conducting exploration work at such deposits requires the use of special expensive technologies, the implementation of which at the exploration stage may be technically infeasible or economically infeasible.

Exploitable reserves are divided into categories (A, B, C1, C2) according to the degree of knowledge of the conditions of formation, quantity and quality of groundwater, as well as operating conditions and preparedness of groundwater deposits for further study or development.

According to the conditions of development, economic and economic significance, operational reserves are divided into on-balance and off-balance reserves. The first of these groups includes reserves, the feasibility of their use has been established on the basis of all geological, economic and sanitary and hygienic factors taken into account by current instructions. The possibility of their use must be confirmed by the relevant federal or territorial authorities. Off-balance sheet reserves include those whose use during the assessment period cannot be considered appropriate for a number of reasons (technical, economic, technological, environmental).

Chapter II. Groundwater resource assessment

2.1 Types of work and methods for determining regional resources

Identification and assessment of regional groundwater resources are carried out regardless of the deposits of these waters due to the fact that such resources are a necessary component of the hydrogeological characteristics of any region. The basis for their assessment are the results of hydrogeological surveys, most often of medium scale (1:200,000), including government surveys. The results obtained make it possible to determine the modules of underground runoff and their changes in annual cycles. Such modules are very informative for dissected mountain regions.

When assessing regional (natural) resources, one of the main methods is the division of river hydrographs , of which up to 20-30%, and sometimes more, is accounted for by underground runoff. Methods for dividing this graph, which reflects changes in river flow throughout the year, have several modifications. The use of each of them makes it possible to estimate underground flow with varying accuracy (10). River flows during low-water periods characterize the minimum value of natural regional groundwater resources. To bring it closer to the true value, various techniques are used based on the introduction of corrections, including taking into account the results of routine observations of the flow of sources (11).

The balance method also allows one to evaluate natural regional resources. . In this case, groundwater resources are assumed to be equal to the difference in water volumes at the maximum and minimum positions of levels in the horizon under study. The latter are recorded during routine hydrogeological observations in at least three sections (wells). The time for measuring levels during routine observations is selected so as to reveal its minimum and maximum positions in at least one cycle of rise - fall - rise of the level. Processing the obtained data (for example, using the finite difference method) makes it possible to estimate the amount of recharge of the aquifer, which characterizes its natural resources.

2.2 Zoning of territories in connection with the regional assessment of projected operational resources

Issues of territorial zoning related to the assessment of predicted groundwater resources are covered in the works of N.N. Bindeman (1), B.I. Kudelina et al (12). When assessing groundwater resources, their relationship with surface waters is of great importance. In this regard, B.V. Borevsky and L.S. Yazvin proposed an approach to zoning the upper hydrodynamic zone that takes into account this relationship. In addition, the ratio of the areas where groundwater resources feed and the areas where their exploitation is possible is taken into account. On this basis, groups of districts are identified.

Territories of group A are characterized by a wide areal distribution of aquifers containing fresh groundwater. Throughout their entire area, exploitation of aquifers is possible. The areas of probable location of water intakes coincide with the areas of recharge of aquifers.

Regions of group B are characterized by a limited distribution of fresh groundwater horizons, and the exploitation of the latter is possible throughout their entire area. The locations of water intakes do not coincide with the areas of groundwater recharge (closed or strip-like flooded structures in depressions). The recharge area most often exceeds the area of ​​distribution of aquifers.

Group B includes areas where there is a frequent alternation of areas with fresh and brackish (salt) waters. Placement of water intakes is possible only where the filtration properties of rocks and the composition of groundwater allow. Groundwater recharge areas mainly correspond to private catchment areas of rivers and streams.

Group D includes territories within which the main productive (fresh) aquifers are confined to river valleys and have a hydraulic relationship with surface waters.

In addition to the described approach, it is possible to zonate Adartesian basins on a geostructural basis, in which, along with large block hydrogeological structures, smaller structures of the plicative type are also identified. A similar approach was implemented, in particular, within the Minusinsk Adartesian basin (13), in which the predicted regional operational resources were assessed in relation to low-order hydrogeological structures.

2.3 Types of work carried out in connection with the regional assessment of operational resources

To obtain materials used in assessing the predicted regional operational resources of groundwater, regional hydrogeological studies are carried out on the basis of general ideas about the conditions of their formation in hydrogeological regions, river basins, and territorial administrative divisions. These resources are the basis for conducting prospecting or prospecting work in individual areas. A regional resource assessment is part of the first phase of such work (8). These resources are also assessed in areas where exploratory hydrogeological work has been carried out. They can be assessed with less accuracy for areas where hydrogeological surveys have been carried out at a scale of 1:500,000 and larger. Assessment of regional forecast operational resources requires solving the following problems:

¦ identify the total amount of groundwater resources in the study area and justify the patterns of their formation (distribution, nutrition conditions, runoff, etc.);

¦ establish the role of surface waters in the possible replenishment of resources;

¦ identify promising areas for further research.

2.4 Methodology for assessing projected regional operational resources

To assess predicted operational resources, hydrodynamic calculations, analysis of the water balance of territories, and mathematical modeling methods are used (11). A very common approach using hydrodynamic equations is the VSEGINGEO method (1), according to which natural groundwater reserves are also taken into account. However, as B.V. rightly points out. Borevsky and L.S. Yazvin (2), the latter play a very insignificant role during long-term exploitation of aquifers and can therefore not be taken into account. Therefore, the components of forecast resources are mainly natural and attracted resources.

2.4.1 Hydrodynamic calculation of forecast regional resources

Most often, predicted operating resources are calculated using the method proposed by N.N. Bindeman and F.A. Bochever (1). It consists in an approximate estimate of the flow rate of conditional enlarged water intakes, evenly distributed over the study area. These water intakes can be of the following types: I - groundwater and II - interstratal (pressure) water. Among water intakes of the first type, subtypes are distinguished: 1a, located on watersheds, and 1b - in river valleys.

It is obvious that, in addition to possible overflows from underlying pressure aquifers, water intakes of type 1a can only be fed by precipitation, and type 1b - by precipitation and rivers.

Using this method, the study area is divided into cells (Fig. 1).

Each cell has an area equal to a circular area of ​​radius R - the radius of influence. The conditional water intake corresponding to the cell is considered as a “large well” of radius r. Usually r is taken equal to 10 m or more.

Rice. 1. Layout of conditional water intakes

When determining the resources under consideration, the following additional conditions are introduced:

¦ aquifers are considered homogeneous;

¦ the boundaries of the selected cells are considered impenetrable;

¦ interaction of cells with each other is excluded.

In addition, it is accepted that in different cells the thickness of the aquifer may be different. To evaluate this type of resource in cells 1a, the following equation is used:

where Re - regional forecast operating resources, m3/day; K - filtration coefficient, m/day; Нср - average thickness of the aquifer, m; Sm - the value of the maximum permissible decrease in the horizon level (usually no more than 0.6 - 0.7 Нср), m; W is the recharge module of the aquifer due to precipitation (precipitation minus evaporation), m/day; fe - period of operation of the conditional water intake, days; µ - gravitational fluid loss, units; R - cell radius obtained from converting a square into a circle, m (radius of influence of conditional water intake R = 0.564- l, Where l- cell side size); r- radius of conditional water intake, m; ау - level conductivity coefficient, m2/day.

After a certain time (several years), the first term in the denominator of the equation will become significantly smaller than the second term and can be neglected. Then this formula will take the form

Let us introduce the following notation: рR2 =F- cell area, m2; WF=QW - flow rate provided by precipitation infiltration, m3/day. In this case we get

therefore the final expression takes the form

The equation determines the total amount of water that can be obtained within one cell when draining the aquifer by the value Sm, taking into account the infiltration of atmospheric precipitation.

Throughout the entire territory, i.e. from all n cells, we get.

The flow of water into type Ib cells will occur due to infiltration from rivers flowing through these cells. Its value can be calculated using the equation of inflow into a drain that has a boundary with a constant pressure (14).

2.4.2 Assessment of projected regional operational resources when water flows from the overlying aquifer

It is not uncommon within hydrogeological sections to find a situation in which a groundwater aquifer (layer A, Fig. 2) is separated by a semi-permeable layer (layer B) from the underlying confined aquifer (B).

(A, B) and semi-permeable thickness (B)

With significant decreases in the water level in layer B, it is possible for water to flow into it from layer A through the semi-permeable layer B. Its flow in this case will be identical to infiltration from the aeration zone, and therefore, to assess such flow, the equation discussed above can be used, where µ should be replaced by µ**:

In this case, Sм=Н0-Н and µ** = µ* + µ, where µ* and µ are the coefficients of gravitational fluid loss of formation A and elastic fluid recovery of formation B; Qw is the amount (total flow rate) of water flowing from layer A to layer B at a constant level in layer A.

2.4.3 Assessment of natural (geological) groundwater reserves

Natural (geological) groundwater reserves are determined by a number of factors: the volume of the formation, its water yield, gas saturation, temperature, compressibility of the water-gas mixture, the amount of pressure on the formation and some others. In this regard, natural water reserves Ve and elastic reserves Vpr are distinguished, the latter being formed due to a decrease in pressure and making up a small part of the natural ones.

To determine natural reserves, the equation Ve = Vµ (free-flow water) or Ve = Vµ* (pressure water) is usually used, where V is the volume of the drained part of the formation, µ is the gravitational (gravity) fluid yield of the formation, and µ* is the elastic fluid yield of the pressure formation.

Geological reserves include the entire volume of water in the reservoir, i.e. they exceed natural reserves due to the fact that the latter are characteristic only of that part of the reservoir that will be drained during its operation.

On average, it is believed that µ for gravel and pebble deposits can be taken equal to approximately 0.2; medium-coarse-grained sands - 0.15; fine-medium-grained sands - 0.125; interlayering of sands and siltstones - 0.05; interlayering of sands, siltstones and clays - 0.03 (15).

The value of µ is also often found using the formula µ=, and µ* using a similar equality µ* =, where Km is water conductivity, aw- level conductivity coefficient, and a- piezoelectric conductivity coefficient (all three parameters in m2/day).

2.4.4 Assessment of attracted resources

Attracted resources are a specific balance category that arises only during the operation of a water intake. This is the total consumption of additional nutrition of the exploited horizon in addition to the natural intensity of nutrition. Two possibilities for the emergence of attracted resources:

In areas of natural nutrition, it may increase when operational levels decrease;

In areas of natural unloading, there is an inversion at first, and after a complete inversion, an inverse pressure ratio and a flow in the opposite direction appear at the boundary, which did not exist under natural conditions.

The most important point: the structure of the water intake balance is capable of significant transformation over time, and the possible direction of these transformations largely depends on the position of the water intake in relation to the current balance-hydrogeodynamic boundaries of the formation.

A typical illustration (Fig. 3): if the water intake is located close to the river (or to another drainage boundary), then quite quickly, with small depressions, it already appears first, and then and. Therefore, a hospital can be quickly established. If the water intake is far from the drainage boundary, then the funnel will reach it after a very significant time, or, in principle, will not be able to reach it within the limits of permissible decreases in the water intake. The magnitude of the natural flow under these conditions has no significance for the formation of the water withdrawal balance; the main source of formation of operational reserves will be only the natural reserves of the reservoir and the rate of development of the funnel will be the same as in the conditions of the groundwater basin; accordingly, it is not a permanent hospital.

Rice. 3. The nature of the development of depression funnels when the water intake is located at a distance and near the river

In this regard, let us remember the hydrogeological (hydrodynamic) rationality water intake It turns out that there are places where it is more profitable to locate a water intake than somewhere nearby: the parameters are better, the favorable balance effect of boundary conditions is more easily manifested. Such areas can primarily be considered as “groundwater deposits”.

The assessment of attracted resources is an increase in natural nutrition due to the intensification of “old” processes and the emergence of “new” ones. The balance sheet valuation must "calculate" such possibilities; further, we can only estimate their maximum possible intensity, based on the nature of the processes that provide the resources involved.

The clearest example: the formation of attracted resources due to the caused influx from the river. In this case, the balance assessment of the possible amount of attracted resources should be especially scrupulous in the basins of small rivers, the flow of which is comparable to the future groundwater withdrawal.

Let's consider two options.

1 . The river is a transit river for the deposit, i.e. the depression funnel does not completely cover the upstream part of the river basin (Fig. 4. 1). How to assess the potential amount of river flow attraction? It seems that the “incoming” river flow is at the upper limit of the expected depression area? No, you need to understand that complete interception of river flow in the field area is not always acceptable; As a rule, the amount of residual “sanitary” flow (the minimum necessary to maintain the landscape and other functions of the river) must be agreed upon with the basin supervision authorities. Accordingly, the balance sheet assessment of attracted resources

2 . The river is “truly small”, i.e. the depression from the water intake completely covers its catchment area upstream (Fig. 4. 2). Apparently, in such a situation, it is more correct to assume that there are no balance-sheet attraction possibilities (), since after a completely possible complete inversion of groundwater discharge, the river flow within the field zone will be zero. You just need to understand that such a model can only be used for balance calculations, since in real water withdrawal the inversion of discharge on the flanks is partial and, therefore, the remaining part of the river flow can still form an influx from the river in the area closest to the water intake.

As already emphasized, the balance assessment does not consider the water intake system (i.e. the location, layout and design of the water intake structure). However, when assessing operational reserves for a real stated need, it must be determined (justified, calculated).

Therefore, actual EZ calculations are performed using one of two main methods: hydrodynamic or hydraulic (each of them has modifications).

resource reserve underground water

Chapter III. Assessment of operational groundwater reserves

3.1 Methods for determining operational reserves

As already noted, operational reserves include groundwater reserves that are involved or at a certain time may be involved in exploitation. It is obvious that operational reserves studied in detail corresponding to categories P, C, B or A are of practical interest, first of all. Each category is subject to certain requirements, for example, those developed by the State Reserves Commission (GKZ).

It should also be noted that the methodology for determining reserves significantly influences the justification and choice of methods for searching and exploring groundwater deposits, especially the latter. In this regard, the choice of methodology for assessing groundwater reserves according to various categories of knowledge is very responsible.

As noted by N.I. Plotnikov (16), for a reasonable assessment of groundwater reserves, it is advisable to divide them into two groups. The first of them includes deposits within which water intakes are located in areas of groundwater recharge (river valleys, etc.). These are mainly infiltration-type deposits.

The second group includes deposits confined to drainage areas. Such deposits are often exploited under conditions of unsteady flows, in particular, with a higher water intake rate than the amount of resources used (filtration deposits).

When assessing the operational reserves of groundwater, especially high categories, it is necessary to take into account the boundary conditions in plan (unbounded or semi-bounded layer, layer layer with different boundaries, circular contour, etc.) and in section (free-flow layer with infiltration feeding, pressure when flowing from above or below, etc.), as well as initial conditions (with a weak level fluctuation, a significant level fluctuation, etc.).

When calculating reserves, the initial level mark is usually taken to be its minimum value, revealed during routine observations.

3.1.1 Hydrodynamic method

This method is used for schematized natural conditions, taking into account the interaction of wells, their operating time, as well as boundary conditions in plan and section (i.e., the calculation is carried out in relation to standard design schemes). The main disadvantages are the inability to sufficiently take into account the design features of wells and the heterogeneity of horizons. When using the method, the formation is considered homogeneous, i.e., the average value of the main parameters (Km, A etc.). Essentially, calculating reserves using the hydrodynamic method comes down to determining the productivity of the designed water intake for the required period (most often - 10,000 days, i.e. 27 years).

The amount of level decrease in the exploited aquifer should not exceed the value of the maximum permissible decrease (Sm). The latter for a non-confined formation should not exceed 0.5 - 0.6 m, where m is the thickness of the horizon. If the formation is very thick (about 50 m or more), it can be increased to 2/3 of the value m. Low-pressure formations, having a head of about 5 m or less, are usually considered as unconfined. For pressure formations, Sm usually does not exceed the pressure value, excluding thick formations that can be exploited in pressure-free mode (i.e. with drainage by 2/3 of m).

The hydrodynamic method for calculating groundwater reserves is applicable in many cases, however, in a number of hydrogeological situations its use is inappropriate, in particular in cases where it is not possible to accurately schematize natural conditions or take into account the significant heterogeneity of the aquifer using hydrodynamic formulas. The capabilities of the hydrodynamic method are significantly expanded in terms of taking into account the complexity and heterogeneity of aquifers, if it is used not as a traditional analytical solution, which requires a very strict schematization of natural conditions, but in the version of grid modeling of the operation of a design water intake using finite difference or element methods using special computer programs .

When estimating reserves using the hydrodynamic method, the amount of decline in the aquifer level at the most unfavorably located point (for example, in the center of the water intake, where it will be greatest) at the end of the service life is usually calculated. The value of reduction in the level S obtained by calculation is compared with the value of Sm If S ? Sm, reserves at a given water intake capacity are considered secure. This calculation determines the total reserves, usually in category C. Their more accurate indexing depends mainly on the type of well (its diameter, etc.), the number of pumping wells, the magnitude and duration of the level decline, etc. To resolve this issue, first of all, the requirements of the GKZ instructions are used.

3.1.1.1 Unlimited aquifer area

The best known use for solving this problem is the “big well” method, which is based on the equation:

S = SВН + Sс,

where S is the complete decrease in the water level in the well located in the center of the design water intake area, reduced to the “large well”; SВН - decrease in the level of the aquifer due to the operation of all wells affecting the central (external) one; Sc is an additional decrease in the level in the central well, resulting from its own operation, taking into account the perfection and location in the system of interacting wells (own).

The external decrease in SВН is found by equality (here and below for pressure waters):

where is Q? - total flow rate of the system of designed wells, m3/day; R0 is the radius of the “large well”, and Rп is the reduced radius of influence of the water intake, m (system of interacting wells; determined by the equality:

R p = 1.5uvaf - here f is the operating time of the water intake, days; f is usually taken equal to 10,000 days).

This equation is applicable in cases where the condition is met: for a linear series of wells or for a ring system of wells.

The amount of level decrease in the central well due to its own work is found by the equation:

where Q is the well flow rate, m3/day; rп - reduced radius of the area of ​​influence of the well and rc - radius of the well, m; O , - filtration resistance, taking into account the imperfection of the well, non-dimensional (dimensionless is found in the reference table).

For linear water intake rп = и R0 = 0.2 L, where b is the distance between the wells of the linear row, and L is the length of the row of water intake wells, m.

Rice. 5 Layout of wells in a linear series in an unlimited reservoir

Thus, the water reserves of a linear water intake within an area with a supply radius Rп in an unlimited reservoir will be determined by the flow rate QU, ensuring a decrease in S, which is found by the equation:

3.1.1.2 Semi-confined formation

Semi-bounded aquifers are considered to be those that have a remote boundary on one or more sides that is not reached by a depression funnel that forms during the operation of the water intake.

The remaining boundaries (or boundary) often have either a constant pressure (river, reservoir) or a constant - up to zero values ​​- flow. In the first case, the influx of water to the water wells will flow in greater quantities compared to the second option.

The initial relationship for calculating reserves has the same form as the first equation. The numerical value of Sin largely depends on the boundary conditions. In particular, for a boundary with constant pressure it can be determined by the dependence:

Where l- distance from the water intake line to the circuit with constant pressure, m (other designations are the same).

The value of Sc is found using the equation:

used to determine reserves in an unbounded reservoir. If there is a boundary with an impermeable contour (the flow rate across the boundary is 0), the equation is used

Where l- distance to the impermeable contour, m. Depressions in the central well are also found by the equality S = SВН + Sс.

3.1.1.3 Layer strip with two boundaries

Aquifers of this type (according to boundary conditions) have different contours, the diversity of which can often be reduced to two types - with constant pressure and with constant flow - and their combination (3 options). In this case, the boundary conditions will mainly affect only the value of Sin.

1st option - both boundaries with constant pressure. In relation to this option

where z is the width of the strip (i.e., the aquifer), m; z1 - distance from the water intake to the nearest circuit, m.

2nd option - both circuits are waterproof. In this case, the equation is used

where z2 is the distance to a more distant contour, m.

3rd option - one circuit with constant pressure, the second - impermeable. In this case, the reduction is determined by the equality

and, in this case z 1 - distance to the circuit with constant pressure.

3.1.1.4 Formations with a circular feed circuit

The most typical cases are the cases of an impenetrable circuit and a circuit through which power occurs everywhere. The equation S = SВН + Sс is also used for the calculation. To determine Sin for a pressure formation with a circular impermeable contour, the equality is used:

where Rк is the radius of the circular contour, m. The use of this equation is possible if the operating time of the water intake (f) is more than 360 days.

In the case of a circuit with circular power supply, this equation has the form

The main condition for the application of most of the formulas given when highlighting the hydrodynamic method of estimating reserves is the distance of the outermost wells of the water intake row from the nearest reservoir boundary. For a linear arrangement of wells, it must exceed 2.5 R0, and for a ring row - 1.6 R0.

It should also be noted that if the exploited aquifers are unconfined, then in the above formulas it is necessary to replace the expression 2mS with H2-h2, where H is the thickness of the unconfined horizon, and h is the height of the residual water column in the wells after the water level in them has decreased, m .

3.1.2 Hydraulic method

The basis of the hydraulic method for determining groundwater reserves is data (empirical dependencies) obtained as a result of experimental and experimental pumping, or pilot exploitation of the aquifer.

In addition to the flow rates obtained in the process of these works, interpolation of flow rate curves (dependences of Q on S), constructed based on the results of experimental work, is also used. The most reliable results are obtained in the case of at least threefold decreases in the level at various flow rates. This method makes it possible to take into account the design features of wells, their relative position and the structure of water-bearing sediments. Its disadvantages are the inability to take into account changes in the flow rate of water intakes over time and, in addition, the inability to predict the influence of boundary conditions of formations on the productivity of water intakes.

It is also necessary to take into account that more accurate results can be obtained from single-operating wells under steady-state filtration conditions. However, to approximately solve problems, the method can also be used when using data from interacting wells. Moreover, in this case, it is necessary to achieve stabilization of the level (or quasi-stationary regime) in the entire zone of influence of the pilot work. In such cases, the level reduction due to the operation of interacting wells (S) can be determined by the equation

where S0 is the decrease in level in the central well of the group water intake when it operates with the design flow rate, often determined from the flow rate curve within the limits of permissible interpolation; DSi - level cuts in this well due to the operation of each well i of n other design wells (determined during single, paired or group pumping); Qi are the flow rates of the corresponding wells during pilot work, which caused the cutting of DSi levels in the central well; Qi are the design flow rates of the same wells.

The most accurate results of determining S using the equation are obtained for infiltration fields with constant feeding. The resulting value of S is compared with Sm. In addition to the considered methodology, the hydraulic method of estimating operational reserves also includes the method of depression funnels, proposed by N.I. Plotnikov (17).

3.1.3 Combined use of hydrodynamic and hydraulic methods

The advantages and disadvantages of the hydraulic and hydrodynamic methods for assessing the operational reserves of groundwater deposits, noted in the previous sections, show that in many cases it is advisable to use them together. In this case, it is possible to take into account the design features of water intake wells, their interaction and the heterogeneity of hydrogeological sections, as well as the operating time of the wells and the features of the boundary conditions of the formations.

One of the main conditions for the successful use of this method is that in the process of determining reserves, the same boundaries of aquifers are preserved, primarily in plan, that were available during the period of experimental work carried out in connection with the assessment of the hydrogeological parameters of these horizons. Therefore, it is applicable primarily in conditions of unconfined aquifers or strata-strips with impermeable boundaries.

Calculation of reserves when using this technique, as well as other methods, comes down to finding the amount of level reduction S in the most unfavorably located well (usually central in a system of interacting wells) and comparing it with Sm.

At the first stage of calculations, an additional decrease (cut) in the level in an unfavorably located well of the design water intake is determined when it operates as a single well at the end of its service life:

where S0 is the decrease in the level in the well at the design flow rate (determined from the curve of the dependence of flow rate on the decrease, constructed according to experimental pumping data), m; Qop is the well flow rate during trial pumping and Qe is the well design flow rate, m3/day; z1 - decrease in the level in the well for time f1 from the start of experimental pumping; z2 - decrease in the level in the well after time f2 (most often at the end of the experimental pumping); f e - operating life of the water intake.

At the second stage of calculations, the level cutoff in the same design well is determined when it interacts with other wells at the end of the life of the water intake (according to group pumping data):

where Dz1, is the level cut in the design well during group experimental pumping after time f, from its beginning; Dz2 - cutting off the level in the same well after a time f 2 from the start of pumping (most often at the end of pumping).

The total reduction S is found, as usual, using the equation and compared with the maximum permissible reduction (Sm).

If group pumping was not carried out from neighboring wells, but single pumpings were performed alternately from each and due to them, level cuts were obtained, recalculated at the end of the life of the water intake: DS1, DS2, ..., DSn, then the general decrease in the unfavorably located well is located as

The cut-off values ​​DSi at the end of the life of the water intake are found (for each of them separately) based on single pumping data using the equation given above. Similarly, if necessary, the level reduction in any of the interacting wells of a given water intake system can be calculated.

3.1.4 Balance sheet method

When using the balance method for assessing reserves, the incoming and outgoing components of the balance of groundwater deposits are taken into account. The incoming part is the infiltration of atmospheric precipitation, surface water, as well as the influx of water from neighboring aquifers. The consumption part is evaporation (for groundwater), outflow into surface reservoirs, watercourses and other places of discharge on the day surface, overflows into neighboring aquifers.

The balance method determines, first of all, the general possibilities for exploiting groundwater in the areas of deposits. They must satisfy the equation

where Qр - regional natural groundwater resources, numerically equal to the flow rate of the underground flow; Ve - natural groundwater reserves; b - coefficient of practical extraction of natural groundwater reserves (usually from 0.3 to 0.6).

Balance calculations are used, as a rule, only in combination with hydraulic and hydrodynamic methods for assessing operational reserves, since they do not make it possible to calculate declines in water intake wells and are regional.

The most significant when using this method is the income part of the balance sheet, which consists of the amount of natural reserves and regional natural resources.

When determining natural reserves, the greatest difficulties arise in the process of obtaining the water yield value µ. It is most appropriate to determine the latter for groundwater aquifers, according to N.N. Bindeman, based on experimental pumping from wells according to the equation:

where b is the coefficient found from the graph given in work (1), depending on S1 and S2 for a given ratio; Q - flow rate of the central well, m3/day; f is the time of experimental pumping, days; r1 - distance to the near and r2 - to the far observation wells, m; S1 - decrease in level during pumping in the near (towards the central) and S2 - in the far observation wells, m.

It is possible to determine water yield based on the results of routine observations, although with less accuracy. In this case, you can use, for example, the equation of G.N. Kamensky in finite differences (18).

Finding regional natural resources in the process of using the balance method should be carried out, according to the recommendation of N.N. Bindeman, based on an assessment of the amount of recharge of the aquifer by precipitation according to the equation:

where W is the infiltration of atmospheric precipitation per unit area of ​​the water surface of the aquifer, m/day; F is the area of ​​the aquifer recharge area, determined from the hydrogeological map, m2.

Quite labor-intensive studies must be performed to determine the amount of precipitation infiltration. For this N.N. Bindeman recommends, in particular, the equation of G.N. Kamensky in finite differences with unsteady movement of groundwater. Using this technique, the average annual infiltration rate can be calculated using the equation

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In the hydrogeological practice of assessing the amount of groundwater, natural groundwater reserves, natural groundwater resources and operational reserves of groundwater deposits are distinguished.
There are deposits of groundwater containing large amounts of water, but the nutrition is negligible. When water is withdrawn, such a deposit will quickly be depleted. On the other hand, there are deposits of groundwater that contain a small amount of water, but have abundant nutrition. Water extraction from such a deposit will be significantly greater than from the first type of deposit. Therefore, to take into account such features of groundwater deposits, the concepts are introduced - natural resources of groundwater deposits, natural reserves of groundwater deposits.
The natural resources of a groundwater deposit are the volume of water filtered into the aquifer due to various sources: infiltration, water flow from adjacent aquifers (lying above and below the exploited one), water inflow from rivers and lakes. The natural resources of groundwater deposits are measured as volume divided by the time of entry into the aquifer. The most commonly used value is m3/day. The natural resources of groundwater deposits are calculated by water flow into rivers and lakes, flow into adjacent aquifers, and evaporation. The amount of natural resources varies throughout the year. Usually in spring and autumn the value is higher than in summer and winter. It has been noticed that when groundwater is exploited, its nutrition often improves.
Natural reserves of deposits and groundwater horizons are the volume of groundwater that is located in a given IW deposit or aquifer, fills pores and cracks, and does not depend on the balance and flow of water, but on the capacitive properties of this aquifer or deposit. The units of measurement for natural reserves are volumetric. Usually m3 or thousand m3 are used, depending on the size of the deposit and aquifers. In the pressure filtration mode, it is necessary to take into account the elastic natural reserves of groundwater deposits, the additional amount of water that appears when the aquifer is opened, due to a decrease in intra-formational pressure as a result of expansion of the volume of water and a decrease in the pore space of the aquifer itself.
Natural reserves decrease when groundwater is withdrawn from PV deposits. In unconfined aquifers at water intakes there is always a decrease in the water level and, as a consequence, a decrease in the capacity of the aquifer. Under pressure conditions, there is a decrease in the level of pressure water, as a result of which there is a loss of elastic reserves of groundwater as a result of a decrease in pressure inside the formation.

Operating groundwater reserves

The main criterion for the maximum possible extraction of groundwater is operational reserves. The essence of the operational reserves of groundwater deposits is the volume of water per unit of time that can be extracted from the aquifer by water intake structures (wells, catchments, wells) under a certain operating mode of the aquifer and water quality, according to design requirements. Operable fresh water reserves are assessed only for the water intake area. The unit of measurement for operational groundwater reserves is volumetric values. M3 are usually used.
There are analytical methods for calculating the operational reserves of groundwater deposits and numerical modeling of conditions and determination of groundwater reserves. The main analytical method for assessing operational resources is the hydrodynamic method. The method is based on analytical dependencies and schematization of hydrogeological conditions. Several water intake structures - captages, wells - are approximated as one source of water reduction - a “big well”. The maximum permissible reduction in groundwater levels is calculated for the center of the “large well”. Hydrogeological conditions are schematized, boundary conditions are identified, and a preliminary design for the location of water intake wells is drawn up. This method is primarily used for simple hydrogeological conditions and is used in conjunction with other assessment methods.
The hydraulic assessment method is based on experimental filtration studies of the aquifer. This method is usually used for fields with difficult conditions. Characterization using this method requires a significant investment of money.
The essence of the balance method is to determine the flow of groundwater at the designed water intake. The balance takes into account the items of water inflow and consumption. The balance method is convenient for assessing the role of each individual element of the overall balance. The disadvantage of the method is the inability to determine the productivity of the well. The balance method gives the average predicted value of the decline in groundwater levels.
Numerical modeling methods are currently used as the main tool for determining the operational reserves of the PV field. Using numerical software systems based on the flow continuity equation, a schematic model of the field is constructed taking into account geological and hydrogeological conditions based on previously conducted and experimental testing. Numerical complexes count water flows between elementary cells and schematic layers that break up the entire studied massif. Data characterizing filtration characteristics are entered into the model and boundary conditions are indicated. A model of a stationary hard filtration regime is constructed, and the model displays the existing natural conditions. After this, data characterizing the capacitive properties of the aquifer are entered into the model. The model becomes stationary elastic filtration mode. After this, the filtration model indicates the well or the expected water withdrawal from a given aquifer. The model calculates the position of levels and the structure of the flow during disturbed, non-stationary filtration, taking into account the capacity of the aquifer. By varying the well flow rate, you can select the optimal combination of well flow rates and lowering the groundwater level.

It is best to use different assessment methods in combination. Make an assessment using numerical methods, check or calibrate a model, or use analytical methods.
Based on calculations, water intake structures are designed that will supply water to villages, cities, and enterprises. Therefore, the task of assessing and determining the resources and reserves of groundwater deposits is a very important one.

CLASSIFICATION OF GROUNDWATER RESOURCES AND RESERVES AND BASIC PROVISIONS OF THE METHODS FOR THEIR EVALUATION CONCEPT OF TYPES OF GROUNDWATER RESERVES AND RESOURCES AND THEIR CLASSIFICATION

Groundwater, suitable for use in the national economy, should be considered as a mineral resource. However, unlike other minerals (solid, oil and gas), groundwater has a number of specific features that must be taken into account when assessing the prospects for their use in the national economy.

A distinctive and main feature of groundwater reserves compared to reserves of other minerals is their renewability. Groundwater is the only mineral resource, during the exploitation of which in many cases not only its consumption occurs, but also additional formation caused by increased recharge of groundwater. The sources of such additional recharge can be both surface water and groundwater from aquifers adjacent to the exploited one, and a decrease in the evaporation of groundwater when its level decreases. The formation of groundwater reserves can also occur as a result of various water management activities (hydraulic construction, irrigation), and the creation of special groundwater “factories”*.

Another significant feature of groundwater is related to its mobility and close relationship with the environment. This relationship is reflected in the boundary conditions (relationship of groundwater and surface waters, conditions of recharge and discharge of groundwater). Boundary conditions appear during the operation of water intakes and largely determine the possibility of using groundwater, while the influence of the external environment on solid mineral deposits manifests itself over geological time.

One more important feature of groundwater should be noted, related to the assessment of the prospects for its use. It lies in the fact that the rational selection of groundwater under certain conditions depends not so much on the amount of water in the formation, and on the amount of water entering the formation under natural conditions, but on the filtration properties of the water-bearing rocks, which determine the resistance to the movement of groundwater to water intake structures.

The listed main features of groundwater, which distinguish it from other minerals, predetermined the need to identify several concepts characterizing: a) the amount of water located in the aquifer; b) the amount of water entering the aquifer under natural conditions during water management activities, as well as in connection with operation; c) the amount of water that can be selected by rational water intakes for the national economy.

In other words, if when assessing the prospects for the use of solid minerals, oil and gas, one concept is enough - “mineral reserves”, then for groundwater this concept alone cannot fully characterize the possibility of their rational exploitation.

Let us recall that by reserves of a mineral we mean its weight, the quantity contained in the bowels of the earth.

For groundwater, in addition to reserves, as noted above, their nutrition should be taken into account. This was pointed out by one of the founders of Russian hydrogeology, F.P. Savarensky, back in the early 1930s, who proposed to distinguish between “reserves” of groundwater and their “resources,” understanding the latter as “providing groundwater in the water balance of a given area.” Extensive hydrogeological literature is devoted to the classification of groundwater reserves and resources. The most complete information on these issues is contained in the works of F. M. Bochever (1957, 1961), B. I. Kudelin (1960).

In this work we will not discuss the classifications proposed by various authors, especially since the difference between many of them is mainly terminological in nature. Let us dwell only on the characteristics of the most important concepts, taking as a basis the terminology proposed by N.N. Bindeman (1963) and used in compiling individual volumes of the monograph “Hydrogeology of the USSR”.

Groundwater reserves and resources can be divided into: 1) natural reserves and resources;

2) artificial reserves and resources;

3) attracted resources;

4) operational reserves and resources*.

NATURAL SUPPLIES -. mass of gravitational water in the formation under natural conditions. That part of this mass that can be extracted from the formation when the pressure decreases due to the elastic expansion of water and compression of the rock (reducing porosity) is usually called elastic reserves.

When assessing groundwater reserves for water supply, it is advisable to express natural reserves in units of volume.

Natural resources - the amount of water entering the aquifer under natural conditions as a result of infiltration of atmospheric precipitation, filtration from rivers and lakes, overflow from overlying and underlying horizons, inflow from adjacent territories. The natural resources of an aquifer are equal to the sum of all incoming elements of the balance of a given horizon. They are expressed in flow units and can also be determined by the sum of all flow elements of the balance (evaporation, transpiration by vegetation, spring flow, filtration into rivers, lakes and flow into adjacent horizons).

* The terms used in this work are not accepted by all hydrogeologists. Often the term “natural reserves” corresponds in the literature to the terms “static”, “secular”, “geological”, “reserves”, and “natural resources” - “dynamic reserves”, “underground flow rate”.

Artificial reserves are the volume of groundwater in a reservoir accumulated as a result of irrigation, back-up by reservoirs or filtration from them, artificial replenishment of groundwater (storage).

And with To s u c t a l r e s o u r s - the amount of water entering the aquifer as a result of filtration from canals and reservoirs, irrigation, as well as measures to artificially recharge groundwater.

P r i v l e To a m e n t r e s o u r s - an increase in groundwater recharge during the operation of water intakes due to the occurrence or intensification of filtration from rivers, lakes, and overflow from adjacent, usually higher-lying aquifers.

The concepts of “exploitable reserves” and “exploitable resources” of groundwater are essentially synonymous. They mean “the amount of groundwater that can be obtained by technically and economically rational water intake structures under a given operating mode and water quality that meets the requirements throughout the entire estimated period of consumption” (“Instructions...”, 1962). This value, therefore, represents the productivity of water intake and is expressed in units of flow (usually in m "/day). Therefore, it would be more logical to use only the term “operational resources”. But since the term “reserves” is accepted for all other minerals , and they are approved by the State Commission for Mineral Reserves (GKZ), when considering the possibilities of using groundwater in the national economy, the term “operational reserves” is usually used. It is adopted in official documents (classification of operational reserves and instructions from the State Reserves Committee for its use). At the same time, in a regional assessment of groundwater reserves and resources, the term “operational resources” is more accurate, since in this case groundwater resources are considered as part of general water resources.

The operational resources of groundwater in a particular region are determined not only by hydrogeological conditions, but also by the operation scheme (location of water intakes, distances between them, flow rates of individual water intakes). In this regard, N.N. Bindeman (1972) proposed to distinguish two concepts: “potential operational resources” and “forecast operational resources”. Potential operational resources should be understood as groundwater resources that can be obtained by placing water intakes over the entire area of ​​distribution of the aquifer and at distances between water intakes that ensure full use of natural, attracted and artificial groundwater reserves and resources, taking into account a given decrease in level and accepted duration operation. In contrast to potential, predicted operational resources correspond to a certain layout of water intake structures. Potential resources characterize the maximum amount of water that can be withdrawn from an aquifer. Since water-bearing rocks have filtration resistance, the predicted resources corresponding to a certain layout of water intakes are usually less than the potential ones, and only in some cases the predicted resources can reach the potential value. N. N. Bindeman (1973) proposed to call the share of possible use of potential resources with a particular layout of water intakes the predicted coefficient of groundwater use.

Of course, under different hydrogeological conditions, certain types of reserves or resources will prevail in the formation of operational resources (reserves) of groundwater, which will be discussed in detail in the next section.

Exploitable resources (reserves) of groundwater can be provided by sources of formation either for a certain limited period of operation or for an unlimited time. In the latter case, the source of formation of operational resources are natural and artificial resources, as well as attracted resources (if they, in turn, are provided for an unlimited period of operation), since when t~oo the second and fourth terms on the right side of the equation tend to zero.

There is no doubt that when solving various economic problems related to the use of groundwater, the assessment of operational resources (reserves) of groundwater is of paramount importance. Only the amount of operational resources (reserves) allows one to judge the possibility and feasibility of using groundwater. However, the calculation of other types of groundwater reserves and resources is of some interest. This is necessary both for the assessment of individual sources of formation of operational groundwater resources, and for the quantitative characteristics of aquifers and structures in natural conditions.

quantity, volume (mass) of groundwater contained in an aquifer. There are static (natural, capacitive, secular) water reserves, which characterize the total amount of water in the aquifer and are expressed in volumetric units, and elastic water reserves, which mean the amount of water released when the aquifer is opened. and a decrease in reservoir pressure in it (during pumping or self-outflow) due to the volumetric expansion of water and a decrease in the porosity of the reservoir itself.

In the practice of hydrogeological research for water supply purposes, natural and operational groundwater resources are usually assessed. Natural resources (dynamic reserves) are understood (according to B.I. Kudelin) as the fueled flow of underground flow. Natural resources of groundwater are continuously renewed in the process of moisture circulation on Earth and in the average long-term context are equivalent to underground runoff. They characterize the natural productivity of aquifers. Operating resources correspond to the amount of water that can be extracted per unit time from an aquifer using water intake that is rational in technical and economic terms, without a progressive decrease in productivity and dynamic levels and deterioration in water quality throughout the entire period of operation. When assessing operational resources, the possibility of using static and elastic reserves, inflow of water from outside, and other factors are taken into account.

In the USSR, the determination of operational groundwater resources for specific consumers (city, plant, etc.) and the assessment of natural and operational groundwater resources of large territories and the country as a whole are carried out (regional assessment).

Z.p.v. are assessed according to categories A, B, C 1 and C 2, approved by the State Commission for Mineral Reserves (GKZ). Category A includes terrestrial waters that have been explored and studied in detail to ensure a complete elucidation of the geological structure, the conditions of occurrence and recharge of aquifers, pressures, filtration properties, the connection of used waters with the waters of other aquifers and surface waters, as well as possibility of replenishing operational reserves. Category B includes reserves that have been explored and studied in detail to ensure that only the main features of the occurrence, structure and recharge of aquifers are clarified. When determining Z.p.v. category C 1, only the general features of the structure, conditions of occurrence and distribution of the aquifer are determined. Category 02 reserves are established on the basis of general geological and hydrogeological data, confirmed by sampling of aquifers at individual points, or by analogy with studied or explored areas.

Lit.: Bindeman N.N., Assessment of operational reserves of groundwater, M., 1963; Bochever F. M., Theory and practical methods of hydrogeological calculations of operational reserves of groundwater, M., 1968; Map of modules of forecast operational resources of fresh and brackish groundwater in the USSR, scale 1: 5,000,000, M., 1964; Map of underground flow of the USSR, scale 1: 5,000,000, M., 1964; Kudelin B.I., Principles of regional assessment of natural groundwater resources, M., 1960; Hydrogeologist's Reference Guide, ed. V. M. Maksimova, 2nd ed., vol. 1, L., 1967.

I. S. Zektser.

• - natural flow rate of underground...

  Dictionary of geological terms

• - see Underground resources...
• - see Dynamic inventories...

  Dictionary of hydrogeology and engineering geology

• - see Static reserves...

  Dictionary of hydrogeology and engineering geology

• - ".....

  Official terminology

• - the ability of groundwater to cause and accelerate corrosion of materials due to chemical and electrochemical influences - aggressiveness to underground water - agresivita podzemní vody - Grundwasseraggressivität - talajvizek agresszivitása - gasar...

  Construction dictionary

• - the ratio of the amount of water that replenishes the underground water reserves of the aquifer in question with the amount of water consumed from these reserves during the reporting period - the balance of underground water - vodní bilance -...

  Construction dictionary

• - the ratio of the amount of water that replenished the groundwater reserves of the considered volume of the aquifer with the amount of water consumed from these reserves over a certain period of time...

  Geological encyclopedia

• - syn. the term hydrogeological basin...

  Geological encyclopedia

• - a set of aquifers and low-permeability strata, characterized by a closed balance of groundwater...

  Ecological dictionary

• - the amount of groundwater that can be obtained at the field using geologically and technically sound water intake structures under a given mode, operating conditions and...

  Ecological dictionary

• - A set of aquifers and low-permeability strata, characterized by a closed balance of groundwater...

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• - ".....

  Official terminology

• - ".....

  Official terminology

• - quantity, volume of groundwater contained in the aquifer...

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In underground caves