Архив метки: groundwater

ASSESSMENT OF GROUNDWATER PROTECTION AND VULNERABILITY IN THE LENA RIVER BASIN, THE REPUBLIC OF SAKHA (YAKUTIA)

Ecology and dynamics Опубликовано автором

Belousova A.P., Oboturov A.S., Rudenko E.E. Assessment of Groundwater Protection and Vulnerability in the Lena River Basin, the Republic of Sakha (Yakutia) // Ecosystems: ecology and dynamics. No 1. 2025. P. 59-81. | Abstract | PDF | Reference

 

For the first time, the methodology of small-scale (1:5 000 000) assessment of the protection and vulnerability of groundwater was applied in the Lena River Basin in the Republic of Sakha (Yakutia). The already developed approach has been improved in order to apply it to an understudied and both geologically and landscape difficult area that mostly consisted of a cryolithozone.

To create a map of protection level, the following temporary maps were compiled: map of aeration zone, map of soil sorption capacity, map of protection zone, and map of active soil layer capacity. To create a map of the resulting vulnerability for the most industrially developed part of the Neryungrinsky District, we assessed a potential hazard to environment posed by the polluted groundwater of 4 wells that were part of the state monitoring network. Using mercury as an example, we showed that this indicator could change significantly and reach its highest values due to a large weight coefficient and inaccurate determination of water elements that characterize the 1st class of hazard. Despite our studies being observational and lacking quantitative assessments, its results indicate that the groundwater of the Lena River basin requires protection due to the increasing anthropogenic pressure associated with mining.

Funding. This work was carried out as part of the scientific program of the Water Problems Institute of the Russian Academy of Sciences, project No. FMWZ-2025-0002.

Keywords: groundwater, protection, vulnerability, protection zone, aeration zone, active layer.

DOI: 10.24412/2542-2006-2025-1-59-81

EDN: MZBZRS

WATER RESOURCES OF THE REPUBLIC OF KALMYKIA: THEIR CURRENT STATE AND USAGE

Ecology and dynamics Опубликовано автором

Ulanova S.S. Water Resources of the Republic of Kalmykia: Their Current State and Usage // Ecosystems: ecology and dynamics. No 4. 2023. P. 29-58. | Abstract | PDF | Reference

 

 

The Republic of Kalmykia is the driest region in the south-east of the European part of Russia. It has the lowest water resources among the other subjects of Russia. In this paper, we characterize its water resources, their distribution over the territory through the natural and artificial hydrographic network of channels and irrigation systems, and we also consider the use of artificial river runoff and their water quality. The framework for this research is the database to the “Water Management Map of the Republic of Kalmykia” (2003) that the author of this article has compiled and continues to update with the materials of remote sensing and statistical books on Russian water resources and water management (2000-2019), as well as with the long-term geo-ecological monitoring of key water bodies of Kalmykia, carried out in the Department of Environmental Studies of the Kalmykian Institute for Complex Studies of Arid Territories.

Analysis of the Water Management Map revealed that the hydrographic network of the republic that consists of 137 rivers with a total length of 4007.9 km and a density of 0.05 km/km2 is poorly developed. They are part of the basins of Azov and Caspian Seas, and most of them are low rivers (0.5-1.0 l/s), belonging to the drainless areas of the West Caspian basin. The total area of the drainless territory is 49.2 thousand km². As of now, there are 314 water bodies in Kalmykia, of which 256 are artificially created (121 ponds, 135 reservoirs), 43 are small rivers and 15 are lakes. The artificial origin of most water bodies can be explained by the need for seasonal and long-term regulation of the river runoff for agricultural use. Although each water body has its own unique features, all of them suffer under instability of hydrological and hydrochemical regimes, sharp changes in water salinity due to the amount of incoming runoff every year/season, severe siltation, poor flora and fauna.

Depending on their geographical location, artificial water bodies can be divided into 3 groups: group in the Caspian Lowland, in the Yergeni Upland, and in the Kumo-Manych Depression. The reservoirs with the smallest water table (0.011 to 5.84 km2) are located in the Yergeni Upland, while in the Caspian Lowland, their size varies from 0.087 to 51.54 km2. The largest artificial reservoirs are located in the Kumo-Manych Depression, with the maximum values equal to 782.99 km2 and the minimum values reaching 0.02 km2.

Qualitative analysis showed that water of almost every Kalmykian water body is either salty or very salty, and average long-term values of surface water mineralization varies from 1.7 to 10.5 g/l. Regarding their hydrological regime, for the most part they suffer due to unstable water volume, water table, water level and mineralization, as well as high evaporation, slow water exchange, poor flowage and, as a result of hot climate conditions, high accumulation of chemical and toxic substances.

Taking into account the limited and unstable, still forming water resources of Kalmykia, our calculations showed that the average annual runoff volume is 1.64 km3/year, while the potential water supply of one resident is 5.61 thousand m3/year. The local surface water is available, but is far from being suitable for water supply; the local groundwater is highly mineralized for the most part, and people use it for drinking and cooking without any additional treatment. To date, the existing capacities and technologies of water treatment facilities in the republic cannot provide a so much needed protection from water pollution, which is constantly growing, while the adequate measures for water treatment remain insufficient and lacking. Annual water consumption from private sources reaches 50 million m3. The water shortage in the Kalmykian economy is somewhat covered by the outside sources: 700-750 million m3/year of drinking water for people, livestock and irrigation are brought into the republic from the neighboring territories and the basins of the Volga, Kuma and Terek rivers.

In order to provide water for production, agricultural and social needs and to prevent its negative effects, Kalmykia had been constructing a water management complex from 1937 to 1972, which now includes:

  • 3 pasture pipelines with a total length of 1,200 km;
  • Chograi reservoir and Chograi discharge canal;
  • protective dam guarding the town of Lagan;
  • more than 300 ponds and small reservoirs for utilization of local runoff, which were built mainly by economic means;
  • more than 2,000 groundwater wells;
  • 5 irrigation systems that cover 124.5 thousand ha of land.

We analyzed some literary sources (Borodychev et al., 2016; Ovchinnikov et al., 2015, 2016; Shumova, 2021) to find out that the total length of the main irrigation network in Kalmykia is 1,137 km, and the length of the discharge network is 633 km. From 2010 to 2018, the area of irrigated agricultural lands there remained unchanged, equal to 48.3 thousand ha. However, their condition over 2005-2018 was assessed as good in 2-4% of cases, as satisfactory in 24-29%, and as unsatisfactory in 68-73%. The level of water mineralization in the irrigation and drainage systems varies from 0.3 to 2.0 g/l depending on the chemical composition. The total annual fresh water withdrawal limits are 1253.5 million m3, but at present only 600 million m3 is actually being withdrawn. In the mid-1990s, up to 60% of this volume was used for irrigation in the total area of 170 thousand ha; these days, the irrigated area has decreased to 42 thousand, which, in its turn, lowered water consumption from 700 to 150-200 million m3.

A major fault of the existing network of water canals is its unprotected riverbed that was formed in the bare ground which causes significant water losses, especially when the riverbed is formed on light soils. In addition, it provokes a secondary salinization, alkalinization, flooding and waterlogging. Moreover, conditions of strong evaporation cause even more losses during transportation; e.g., in 2020 it amounted to 106.19 million m3. At the same time, modern technologies in water use are barely applied in the republic: the volume of water in the recycling and re-sequential systems is insignificant, amounting to 0.17 million m3.

The main problem of irrigation and amelioration of Kalmykian pastures is technical deterioration of the overall systems that haven’t been rebuilt since their launch in 1960-1980s, as well as the lack of sufficient financial support to cover electricity of the pumping stations. Therefore, we present the following solutions as the priority measures for water supply and economic development of the Republic of Kalmykia. These solutions should be carried out step by step, systematically and differently depending on the peculiarities of each region of Kalmykia. For example, to ameliorate its northern regions, such as Oktyabrsky, Maloderbetovsky and Ketchenerovsky Administrative Districts, it is necessary to resume water supply from the Volga River using waterways. However, to make it possible, the dam near Charlakta settlement must be restored since it was completely destroyed in violation of all laws during construction of the gas pipeline between Evdyk and Tsagan-Nur settlements. This would fill the southern part of Sarpinsky reservoirs, i.e. the Sarpa Reservoir. In the south-east, it is possible to use the North-West Caspian Sea, the low mineralization of which can be treated to supply water to the Lagansky and Chernozemelsky Districts.  In the south, it is necessary to finally complete the slacking reconstruction of the Levokumsk Hydraulic System and the repair of the dam, and then fill the Chograi Reservoir and launch the Chernozemelsk Irrigation System.

It is also necessary to reconstruct irrigation systems in order to reduce water losses during its transportation and use on fields. The large-scale geological exploration of groundwater (searches, explorations and reserves re-evaluation) should be resumed as well within the North Caspian and the Yergeni groundwater basins in order to restore the operation of groundwater wells.

Keywords: surface water, groundwater, irrigation system, Republic of Kalmykia, water reserves, water volume, water quality, current state of water resources, water management.

Funding. This work was supported by the Russian Science Foundation, grant No. 23-27-10017 “Geo-ecological Assessment of Water Bodies of the Republic of Kalmykia and Adjacent Territories.”

DOI: 10.24412/2542-2006-2023-4-29-58

EDN: JPJWCD

USE OF A NUMERICAL EXPERIMENT IN STUDYING MIGRATION OF DIFFERENT POLLUTANTS IN THE GROUNDWATER OF THE KALUGA REGION IN THE AREA OF RADIOACTIVE ZONE

Ecology and dynamics Опубликовано автором

Belousova A.P.,  Rudenko E.E.,  Vlasov K.G. Use of a Numerical Experiment in Studying the Migration of Different Pollutants in the Groundwater of the Kaluga Region in the Area of the Radioactive Trace // Ecosystems: ecology and dynamics. No 2. 2023. P. 40-72. | Abstract | PDF | Reference

 

 

The purpose of this article was to use a mathematical modeling in order to study the migration of various pollutants, including radionuclides, from poorly sorbed to highly sorbed ones that travel from groundwater to pressure groundwater through a separating layer, an aquiclude, and has varying permeability. Among others, the field of hydrogeological researches performs search and exploration of groundwater deposits. Search is the first stage which is carried out in unexplored territories, followed by exploration, the second stage, which is performed in the promising territories that were revealed during the first stage.

Our studies follow the first stage, because the territories of our choice, located in the Kaluga Region and affected by the Chernobyl accident, were unexplored. We focused on studying the migration of pollutants from groundwater through the aquiclude of the pressure waters. The direction of our search was determined by the aquiclude’s ability to let the pollutants through, which is considered the most unfavorable conditions for groundwater, or its ability to keep the pollutants out, which is considered a favorable condition. However, both of these stages do not exist separately in natural and artificial conditions, because they simply merge together, but, in order to study that, a thorough geological and hydrogeological knowledge of the territory is needed, which we do not possess for the study area. Therefore, our research was carried for both stages: in the first one, the aquiclude was assumed to be permeable, while in the second one it was assumed impermeable.

For each stage, exploratory numerical experiments were carried out using mathematical modeling. The object of those studies was the part of the Kaluga Region, most affected by the accident at the Chernobyl nuclear power plant. Studies concerning the first stage have been already completed and published by our crew (Belousova, Rudenko, 2021a, 2021b), while the results of the second stage and generalizing results of both studies are presented in this article. We studied the migration of various pollutants, including radionuclides, from groundwater through an impermeable aquiclude to the confined aquifer. We used the same profiles that were studied in the first stage, but applied slightly modified scenarios and used different coefficients of pollutant sorption distribution (Kd).

Numerical experiments of the second stage were carried out according to the following scenarios: 1 – (1-3-1), 2 – (1-6-1), 3 – (1-10-1), 4 – (6-60-6), 5 – (26-260-26), 6 – (100-1000-100). The first digit is the Kd value (l/kg) in the 1st layer, the second digit – 2nd layer, the third digit – 3rd layer. This selection of coefficients was determined by the fact that their values were assigned to be higher in the aquiclude than in the upper and lower aquifers.

Each scenario was applied for two conditions: with and without radioactive decay. The starting condition was the contamination degree of groundwater, just like the contamination degree of the ground in the radioactive trace zone of the study area. However, such a spread of contamination by either radionuclides or other pollutants is not actually (in natural conditions) observed in the groundwater of this territory. Pollutant concentrations can be specified in g/l, maximum permissible concentration (MPC) and background concentrations, but we used MPC. Kd of various pollutants were selected from the known values for the Bryansk Region (Belousova, Rudenko, 2021a, 2021b); regarding radionuclides, the Kd values mainly refer to the unsaturated zone of contamination.

We established that the main factors forming the pollutant migration are the radioactive decay of the said pollutants, their sorption properties, and the hydrodynamic dispersion of groundwater flow, which, in turn, depends on the geological and hydrogeological conditions of the study area and the aquiclude permeability. The studied situation proves that aquicludes cannot ensure a full protection of pressure groundwater from pollution.

Keywords: groundwater, underground confined waters, modeling of migration processes, pollutant, radionuclides, sorption, radioactive decay.

Acknowledgments. We would like to thank Yu.V. Minyaeva who prepared materials for this article before her saddening demise.

Funding. This work was carried out for the Water Problems Institute of the Russian Academy of Sciences, No. FMWZ-2022-0002 “Research of Geoecological Processes in Hydrological Systems of Land, Formation of the Quality of Surface and Ground Waters, Problems of Water Resources Management and Water Use under Conditions of Climate Change and Anthropogenic Impacts”.

DOI: 10.24412/2542-2006-2023-2-40-72

EDN: UEXKOC

INTEGRATED METHODOLOGY AND ITS APPLICATION FOR ASSESSING THE PROTECTION OF GROUND AND CONFINED SUBTERRANEAN WATERS FROM VARIOUS POLLUTANTS AND THEIR VULNERABILITY TO POLLUTION IN THE KALUGA REGION IN THE RADIOACTIVE TRACE FROM THE ACCIDENT AT THE CHERNOBYL NPP

Ecology and dynamics Опубликовано автором

Belousova A.P., Rudenko E.E. Integrated Methodology for Assessing the Protection Degree of Ground and Confined Subterranean Water from Different Pollutants as Well as Their Vulnerability to Pollution and Its Application in the Kaluga Region in the Radioactive Trace from the Accident at the Chernobyl NPP // Ecosystems: Ecology and Dynamic. No. 2. 2022. P. 99-122. | Abstract | PDF | Reference |

 

 

The object of our research is groundwater and confined subterranean waters in the territory of the Kaluga Region, most affected by the accident at the Chernobyl Nuclear Power Plant. Our aim was to develop a complex methodology to assess the level of protection and vulnerability of groundwater and confined subterranean water against various pollutants, including radionuclides.

The methodology was tested in the territory of the Kaluga Region, in its zone of the radioactive contamination zone from the Chernobyl Accident.

Our earlier studies that assessed protection and vulnerability of subterranean waters began almost immediately after the accident and were carried out according to the original methodology, developed by the authors of this article. They were fully focused on groundwater only or, more specifically, on the first aquifer under the ground surface. However, this research studies both groundwater and confined subterranean water, located below the groundwater aquifer.

Depending on the location of pollution source, two approaches are considered to solve our main aim. The first option involves a pollution source placed on the ground surface, the way it was observed right after the Chernobyl Accident. The second option involves a pollution source located directly in the groundwater or spreading over a large area, in which case the number of study objects decreases, and it becomes a specific case of the first option.

The results of our research and the methodology we offer for the further use can be applied for assessment of the ecological state of subterranean waters in different country territories, at different scales; for design and construction of fresh subterranean water intakes for drinking purposes; for design and organization of subterranean water monitoring in the areas affected by the Chernobyl Accident. The results of our research are new and significant for further studies.

Keywords: groundwater, subterranean confined water, pollutant, subterranean water protection from pollution, subterranean water vulnerability to pollution, radionuclides, sorption, migration period.

DOI: 10.24412/2542-2006-2022-2-99–122

EDN: CFVOIW

MODELING OF THE POLLUTED GROUNDWATER FLOW INTO CONFINED WATER IN THE FOREST ECOSYSTEMS BY THE EXAMPLE OF THE KALUGA REGION IN THE RADIOACTIVE CONTAMINATION ZONE

Ecology and dynamics Опубликовано автором

Belousova A.P., Rudenko E.E. MODELING OF THE POLLUTED GROUNDWATER FLOW INTO CONFINED WATER IN THE FOREST ECOSYSTEMS BY THE EXAMPLE OF THE KALUGA REGION IN THE RADIOACTIVE CONTAMINATION ZONE // Ecosystems: ecology and dynamics. 2021. Vol. 5. No 3. P. 192-224. | Abstract | PDF | Reference |

 

 

The purpose of this article is to study the migration processes of various pollutants, including radionuclides, from poorly sorbed to highly sorbed ones, in the groundwater and confined water, using the method of mathematical modeling. The object of the study is the part of the Kaluga Region that was affected by the accident at the Chernobyl Nuclear Power Plant the most.

The modeling of contamination processes in the groundwater and confined water in the radioactive contamination zone was carried out according to 3 scenarios of the development of such processes. We took into account various pollutants and mass transfer processes, using the mathematical MT3D program, and made a series of numerical experiments. Scenario 1) groundwater contamination with highly sorbed pollutants; scenario 2) contamination with highly sorbed pollutants and radioactive pollutants; scenario 3) contamination with poorly sorbed pollutants.

Besides, an unfavorable option for the ecological condition of confined waters was considered, due to the impervious horizon being insufficiently impermeable to the polluted waters, flowing from the aquifer. This situation was probably caused by the natural lithological structure (interlayers, sand lenses, sandy loams, insufficient depth) and industrial factors (poorly insulated holes, wells and other structures that open the aquifer). All the factors listed above are the “fast migration routes” that make it possible for a lot of pollutants to penetrate the confined aquifers, where the fresh water is contained.

To study the pollutants migration in the previously created MT3D model, we selected two profiles. They were located along the lines of groundwater flow, stretching from the watershed to the area of discharge, i.e. the rivers. The ecological situation was analyzed for 4 calculation periods of 30, 60, 100 and 300 years (to link it to the half-lives of radionuclides), for 4 coefficients of sorption distribution (Cd) of pollutants: 6, 26, 200 and 1000 l/kg for radionuclides with decay and other toxic, strongly sorbed pollutants without it; 0.5, 1.0 and 3.0 l/kg for poorly sorbed pollutants. We assessed the ecological situation in the first layer (groundwater), the second one (watershed layer and pore solutions) and the third one (confined water).

In addition, several spots were selected for the analysis of the ecological situation.

The modeling resulted in a comparison of all development scenarios of the pollution processes and analysis of the factors that determined them. In addition, we studied the capabilities of the process of pollutant diffusion and its impact on pollutant migration. Therefore, the main factors to form the processes of pollutant migration are their radioactive decay, their sorption characteristics, and the hydrodispersion of groundwater flows, which depends on the geological and hydrogeological conditions of the studied territory. Aside from this, diffusion plays an insignificant role in their migration as well.

Keywords: groundwater, confined water, migration processes modeling, pollutants, radionuclides, sorption, molecular diffusion, radioactive decay.

DOI: 10.24412/2542-2006-2021-3-192-224