Increased Water Withdrawal Research Articles

Water and Economic Growth in Developed and Developing Countries

Water withdrawals are expected to continue growing, further straining available freshwater resources for economies. This review focuses on two key relationships between water and economic growth for developed and developing countries. Rising freshwater withdrawals and stress are directly related to how our economies use water to develop and grow. There is also concern that increasing water scarcity will impact economic growth across countries and regions. Unless there is a marked improvement in the water intensity of countries, economic growth will be the most important driver of increasing water withdrawals and scarcity. Although analysis of the impact of freshwater stress on the growth of economies is inconclusive, there is mounting evidence of an impact at the river basin and sub-national level. Decoupling rising water use from growth will require major water management reforms. Two of them are discussed here: Ending excessive subsidization of irrigation and reallocating subsidies for water supply and sanitation to expand delivery in developing countries.

Trajectory in water scarcity and potential water savings benefits in the Yellow River basin

Water scarcity caused by the mismatched spatiotemporal characteristics of water demand and supply threatens the sustainable development of many countries around the world. The Yellow River is the second largest river in China but suffers from intense human activity and scarce water resources. Most current studies on water scarcity assessment have coarse spatial and temporal resolution or are based over short periods, which precludes our understanding of the long-term trajectories of water scarcity. Moreover, the water savings potential and implications for water scarcity alleviation have not been well understood. Here, we conducted a comprehensive analysis of water scarcity in the Yellow River basin (YRB) during the period 1965–2013 using a survey-based water withdrawal dataset and water availability simulated by a well-validated hydrological model. Our results showed that regional water stress has continuously increased over the past five decades and has exceeded the threshold above which both ecological and socio-economic water resources are unsustainable since the 1990 s. Regions with high water stress were mostly distributed between the Lanzhou and Toudaoguai hydrological stations where large irrigated districts occur. There were 30.1–34.7 % and 20.2–35.5 % of the total population suffered from seasonal and perennial water scarcity, respectively, during different periods. Increased water withdrawal and population growth were the primary factors that caused changes in the exposure of the population to water scarcity. Meanwhile, we found that in the absence of upstream water consumption, water scarcity could be alleviated or removed for 4–13.2 % of the downstream population, especially during seasons when water is scarce (e.g., spring and winter). Water efficiency improvements could save 10.1 % of the total water usage (3.3 km3), of which a 7.8 % saving could come from irrigation, roughly 3.4 times the potential saving from industry (2.3 %). Irrigation savings can increase industrial added value by 4 %, while industrial water savings can meet the localized domestic water use of 4 % of urban, or 10 % of rural residents in sub-basins without water scarcity. These findings provide a basis for the design of measures to alleviate water scarcity and facilitate sustainable water resource management in the YRB.

Assessing the Impacts of Climate Change and Water Extraction on Thermal Stratification and Water Quality of a Subtropical Lake Using the GLM-AED Model

This study combined a catchment model and one-dimensional lake model (GLM-AED) to simulate the response of hydrodynamics and water quality of subtropical Advancetown Lake (South-East Queensland, Australia) to future changing climates from 2040 to 2069 and 2070 to 2099 under Representative Concentration Pathway (RCP) 4.5 and 8.5 and increased water demand from a 50% increase in population over current levels. The simulation adequately reproduced water temperature (RMSE of 0.6 °C), dissolved oxygen (DO) (RMSE of 2 mg/L), and other water quality variables, such as nitrogen, phosphorus, and chlorophyll a (Chl-a). Warming temperatures dominated the change in thermal structure and hydrodynamic status of the lake under future climate change conditions. Projected changes in precipitation and hydrological response from the upstream catchment might, however, partly offset the warming temperatures under future climate change. Increased water withdrawal due to population growth, which involved water extraction from the epilimnion, showed antagonistic effects on water stability compared to those from climate change. Under a high emission scenario of RCP8.5 during the 2080s, there is an increased likelihood of winter turnover failure in Advancetown Lake. Nutrient concentrations were simulated to decrease from reduced catchment loads under future climate change conditions. However, Chl-a concentrations were simulated to increase, especially during the period after winter turnover, under these future conditions. The depth of the hypoxia front during stratification is expected to decrease and move towards the water surface, attributable to the warming water temperatures and prolonged thermal stratification, which might affect biogeochemical processes and exchange fluxes between the hypolimnion and bottom sediments. These potential changes may present challenges for water resource management under future conditions of climate change and population growth.

NUMERICAL MODELLING TOXIC SUBSTANCE TRANSPORT IN MINE WATER FLOWS

The purpose of this work is to develop and test a methodology for modelling the migration of toxic substances left after mining in mine water flows in a system of hydraulically connected mine workings of various sizes and elevations depending on the drainage parameters. Methods of research include the analysis of factors that influence the formation of the hydraulic regime in flooded mines, the accumulation and transport of toxic substances. Parameters of moving toxic substances in mine waters are calculated using hydraulic flow equations written for mining workings, with flooded workings being considered as pipelines with distributed recharge. Modelling of non-stationary 1D transport in water from local sources of toxic substances was performed using the finite difference method. Results. Flow rates and velocities in flooded mine workings on two hydraulically connected horizons of different elevations were calculated. For different locations of sources of toxic substances on the example of polychlorinated biphenyls, their concentrations in mine waters along the migration path and at the water hoisting at different flow rates were calculated. The influence of increased water withdrawal, dilution with additional recharge along the migration path and the position of potential sources of substances in the flooded mine were investigated. It wasshown that for the considered example, increasing the water outflow rate by two times accelerates the stabilisation of mass transport with an increase in the daily removal of substances by 3.4–6.4 times, which is more active from the upper horizon. Scientific novelty. For the first time, the transport of substances in flooded workings was simulated by combining a hydraulic flow model with a numerical transport model. Unlike 2D and 3D numerical transport models based on solid mechanics, which average the concentration in the grid blocks, the proposed approach allows the reproduction of the geometry of the mined-out space more accurately. It provides a more realistic distribution of flow velocities and concentrations depending on the parameters of the mine water withdrawal, depth of mine workings, and the mine water level. Practical significance. Using the tested methodology will make it possible to perform engineering predictions of the quality of groundwater and surface water near closed mines for different periods at different levels of flooding, water withdrawal rates and depths of the pumps for mine water drainage. In addition, the proposed technique can be used to justify the conceptual scheme of the numerical hydrogeochemical model of the post-mining areas. Keywords. Close mines, toxic substances, flooded workings, hydraulic flow, water hoisting, transport model.

Water storages in Tana-Beles sub-basin of Ethiopia: what do we know, and where should we go?

The Tana-Beles sub-basin, a strategic economic growth corridor in Ethiopia, relies on water storage to provide a suite of key services to agriculture, drinking water supply, energy, and ecosystems. While there are a range of storage options (e.g., from large dams to subsurface aquifers) that can be utilized to provide these services, a systematic stock-take of literature on water storage in the Tana-Beles has not been undertaken. This knowledge gap constrains the identification of the relative contribution of different storage types in the Tana-Beles. Accordingly, in this study, we conducted a systematic review of literature on the surface and sub-surface storages to examine key issues of the different storage types and their linkages in the Tana-Beles sub-basin. Peer-reviewed and grey publications from various databases were considered for the systematic review. The results indicate that literature in the Tana-Beles sub-basin is more focused on natural storage like wetlands and Lake Tana than built storage types like human-made reservoirs. Overall, the analysis revealed three key points. First, storage volume and water quality in those storages are declining. Second, the causal factors for storage loss and water quality deterioration are agricultural expansion, land degradation, sedimentation, and increasing water withdrawals. Third, the storage gap will increase because of climate change, population, and economic growth while current management options are fragmented. Therefore, the need for more integrated nexus approaches is paramount to optimize storage resources in water, food, energy, and ecosystems in light of population-driven growth in demand and the ongoing global climate crisis.

Groundwater sustainability under land-use and land-cover changes

In recent decades, agricultural activities have increased water withdrawals from the Shazand plain in the Markazi Province (Iran). In this study, the Soil & Water Assessment Tool (SWAT) model was used to estimate recharge content as an essential component of groundwater models. MODFLOW2000 in the GMS10.5 software was used for groundwater modeling, and the extent of land use change in the Shazand plain was investigated. The results showed that the agricultural sector allocated the largest change with an 18% increase. During 2009–2016, the water table declined by 5 m due to the decrease in recharge and the increase in exploitation. Therefore, the management scenarios of removal of irrigated crops, optimization of cultivated area, and reduction of the cultivated area by 10, 20, and 30% were applied. The results showed 3, 0.28, 0.49, 1, and 1.5 m increases in the water table at the end of the 7-year study period. Every year, reduction of the cultivated area by 10, 20, and 30%, almost 31, 20.5, and 10.3 million m3 less will be extracted from the aquifer.

Growing control of climate change on water scarcity alleviation over northern part of China

Study regionNorthern part of China (NPC) Study focusAlong with rapid economic development and population growth, the NPC has been identified as a water scarcity hotspot. Previous studies attributed the intensified water scarcity primarily to increasing human water withdrawal over the NPC in the 20th century. However, water withdrawal has stagnated since the beginning of 21st century, which raises a question of whether the trend of water scarcity changes, particularly when considering the contribution of water availability that is subject to climate variability. Based on the water stress index (WSI), we detected the trends of water scarcity by a piecewise linear regression approach and investigated their associated drivers in the NPC by using survey-based datasets and hydro-climate model simulations. New hydrological insights for the regionResults show that the trends of WSI changed from positive to negative after 2001. Increased water withdrawal was the dominant factor for the aggravated water scarcity before 2001. However, as the rising precipitation offsets the effect of increasing evapotranspiration, climate change has increased water availability and become the major contributor to the alleviated water scarcity during 2001–2020. Furthermore, future projections suggest that climate change would further alleviate future water scarcity over the NPC by increasing water availability. The results suggest the growing role of climate change in affecting water scarcity, which are significant for guiding regional water policy-making.

Attribution Analysis of Runoff Variation in the Second Songhua River Based on the Non-Steady Budyko Framework

Understanding the role of climate change and catchment characteristics in hydrological activity is important for the efficient use of water resources. In this study, a Budyko framework suitable for non-steady conditions was used to assess the impacts of climate change and catchment characteristics on the long-term changes in annual and seasonal runoff in the Second Songhua River (SSR) basin during the last 30 years. Based on the analysis of the hydro-meteorological series of the SSR, the runoff in the SSR basin showed a non-significant increasing trend. The hydro-meteorological elements changed abruptly in 2009, and the study period was divided into a baseline period (1989–2009) and a disturbed period (2010–2018). Runoff increased during the disturbed period compared to the baseline period, with a significant increase in spring runoff in the upstream area and summer runoff in the downstream area. The attribution analysis results indicated that the annual runoff was mainly affected by climatic factors, and 66.8–99.6% of yearly runoff changes were caused by climate change. Catchment characteristics had little effect on yearly runoff but significantly affected seasonal runoff. The catchment characteristics affecting runoff were mainly increased water withdrawal, changes in snowfall, degradation of permafrost, and changes in reservoir operation. This study provides a basis for further understanding the intra-annual runoff variability for SSR and other similar rivers.

Development of novel mixed matrix membranes (MMMs) for oil sands wastewater treatment: A critical review

AbstractWhile oil sands production plays a significant role in Canada's economy, the rise in oil sands production leads to increasing water withdrawal, consumption, storage and contamination that threaten the sustainability of water sources, biodiversity, ecosystem and public health. Effective treatment and reuse of oil sands process‐affected water (OSPW) can be a strategic solution for these issues. Membrane technology has emerged as a favourite choice for OSPW treatment with high removal and energy efficiency, small footprint and facile operation, installation and scale‐up. However, challenges also exist for membrane technologies related to fouling that causes a rapid decline in membrane performance. Mixed matrix membranes (MMMs) prepared by mixing superhydrophilic zwitterionic materials and inorganic nanoparticles into host membranes are anticipated as next‐generation membrane designs with significant potential for OSPW treatment by achieving multifunctionalities including fouling resistance, improved water permeability, selectivity and mechanical strength. Reproducibility and feasibility for large‐scale industrial applications remain important research questions for the production of MMMs for OSPW treatment. This study provides new insight on the performance, stability and durability of MMMs, outlooking to the commercialization prospect of MMMs. The research outcomes therefore can provide valuable knowledge for the design and development of high‐quality membranes with the required characteristics for OSPW treatment applications.

Modeling the Economic and Environmental Impacts of Land Scarcity Under Deep Uncertainty

AbstractLand scarcity is increasing over time, driven by complex multisector dynamics. The impacts of land scarcity on the economy and environment are multi‐faceted and regional, so any action to convert land will contain inherent tradeoffs. These impacts are complicated by the deeply uncertain evolution of the various sectors influencing land scarcity. A need therefore exists to provide multi‐metric and multi‐sector assessments that are robust to myriad uncertainties. Land conservation effectively limits the supply of productive land, while biofuel consumption increases the demand and competition for that land, and how these dynamics individually and jointly propagate to economic and environmental impacts is an important open question. To address this, we adopt the Global Change Analysis Model (GCAM) that has representations of various important systems including the climate, macroeconomic, energy, agriculture and land, and water resources systems. Various scenarios of increased land demand (from biofuels) and decreased land supply (from conservation) under various socioeconomic scenarios drawn from the SSPs were simulated using GCAM. We find that while biofuel consumption and land conservation reduce carbon emissions, this comes at the cost of higher food prices, reduced crop production, and increased water withdrawals. Additionally, some regions experience these tradeoffs more severely than others and are more heavily impacted from the same biofuel mandate or by an additional percent of protected land. These and other findings highlight the importance of multisector modeling frameworks that capture many cross‐sector linkages, and acknowledge the important uncertainties confronting the human‐Earth system when making any analysis of land scarcity impacts.

SDG indicator 6.4.1 “change in water use efficiency over time”: Methodological flaws and suggestions for improvement

Sustainable Development Goal indicator 6.4.1 is defined as the change in water use efficiency over time and measured as the change in the ratio of gross economic value added by irrigated agriculture, industry and the services sector to the volume of water withdrawn over time. The rationale behind this indicator is to decouple a country's economic growth from its water use. Yet, this unwittingly results in an economic distortion of the water balance, favouring increased water withdrawal in service of higher water-use efficiency, at the expense of environmental sustainability. This paper discusses three methodological flaws. First, aggregation of only economic values across all sectors ignores social and environmental values and is very sensitive to changes in the relative water use by agriculture versus industry and services. Second, the economic value derived from agriculture and from imports cannot in fact be decoupled from agricultural water use. Third, the indicator completely ignores the effects of diminished return flows to the environment due to increased re-use of water. A novel alternative, disaggregated WUE approach is therefore proposed, which links water consumption to the water balance. It is defined as the economic value of irrigated and rainfed agriculture combined with water consumption (ETa) by rainfed and irrigated agriculture per area based on earth observation data. It is measured as the change in the ratio of gross economic value added by irrigated and rainfed agriculture to the volume of water consumed by rainfed and irrigated agriculture over time. This approach is more consistent and objective, while being methodologically, hydrologically and environmentally sound. It acknowledges the coupling of economic growth and water depletion, and the need to strike a balance between opportunities for economic growth and environmental sustainability. This better serves the full breadth of the water and sanitation goal as defined in SDG 6.

Shrinking lakes, air pollution, and human health: Evidence from California's Salton Sea

Due to increased water withdrawals and ongoing climate change, many inland lakes around the world are shrinking and dry lake beds can be significant sources of particulate matter air pollution. Using a natural experiment provided by the shrinking Salton Sea in California, this paper shows that each one-foot drop in lake elevation is associated with a 0.28 μg/m3 (2.6%) increase in PM2.5 concentrations. IV model results then show that Salton Sea-induced changes in PM2.5 over 1998–2014 led to increases in respiratory mortality of 1.4/yr.–15.6/yr. in the counties surrounding the lake, generating $13.2–$147.3 million in annual health costs.

Exploring changes in water use patterns, demand and stress along the Nile River Basin through the lens of Kenya and Egypt

Noting the geopolitical implications of water demand and stress issues on water resources worldwide, this study investigated water demand, changes in water use patterns and water stress developments in the Nile Basin transboundary water resource by comparing Egypt and Kenya. Using an integrative literature review, the study summarises past research, drawing overall conclusions and highlighting unresolved issues. The findings demonstrate increased water withdrawals and a growing unmet demand in both countries. In addition to changing water use patterns towards municipal and industrial use, hydropower development in Kenya and navigation in Egypt are being driven by factors such as heightened upstream use, population growth and settlement patterns, economic development and climate change. In addition, spatial distribution of water stress was demonstrated, whereby downstream countries such as Egypt remain critically vulnerable, although upper riparian countries such as Kenya are gradually also facing emerging water stress problems. This water stress and its spatial distribution are being driven by supply–demand imbalances related to population growth and economic development, escalating upstream water use, deteriorating water quality, inefficient and ineffective water use and climate change. The findings inform a discussion of the crucial socioeconomic, geopolitical and policy implications for riparian countries in the Nile Basin and other transboundary water resources worldwide.

Compounding effects of human activities and climatic changes on surface water availability in Iran

By combining long-term ground-based data on water withdrawal with climate model projections, this study quantifies the compounding effects of human activities and climate change on surface water availability in Iran over the twenty-first century. Our findings show that increasing water withdrawal in Iran, due to population growth and increased agricultural activities, has been the main source of historical water stress. Increased levels of water stress across Iran are expected to continue or even worsen over the next decades due to projected variability and change in precipitation combined with heightened water withdrawals due to increasing population and socio-economic activities. The greatest rate of decreased water storage is expected in the Urmia Basin, northwest of Iran, (varying from ~ − 8.3 mm/year in 2010–2039 to ~ − 61.6 mm/year in 2070–2099 compared with an observed rate of 4 mm/year in 1976–2005). Human activities, however, strongly dominate the effects of precipitation variability and change. Major shifts toward sustainable land and water management are needed to reduce the impacts of water scarcity in the future, particularly in Iran’s heavily stressed basins like Urmia Basin, which feeds the shrinking Lake Urmia.

Energy-water nexus in China's energy bases: From the Paris agreement to the Well Below 2 Degrees target

China's energy bases suffer from serious water shortages. To analyse the energy-water nexus under China's Nationally Determined Contribution (NDC) and the Well Below 2 Degrees (WBD2) target with a more detailed spatial resolution, a five-region China TIMES-W model incorporating water issues is developed. The results show the following: 1) Strict climate targets will require significant increases in non-fossil energy use. 2) Water withdrawal for energy use in the energy bases is expected to be 9.8 billion m3 in 2050 in the WBD2 scenarios. The increased water withdrawal will mainly be caused by the deployment of water-intensive carbon mitigation technologies, such as coal/gas-fired power plants with CCS, concentrating solar power plants and biomass power plants, the water withdrawal for which will be 5.5 billion m3. 3) The carbon intensities for the power sector will be in the range of 0.04–0.15 kg CO2/kWh while the water withdrawal intensities 0.33–1.38 m3/kWh by 2050 in the WBD2 scenario in different energy bases. Not only renewable energy potential but also available water resources should be considered in the development plan for energy bases. In addition, more R&D efforts on CCS with air cooling and concentrating solar power with air cooling should be encouraged.

Short, medium and long-term effects of density on the demographic traits of a threatened newt

Mediterranean streams undergo seasonal reductions in water availability that may affect amphibian demography due to habitat loss and the concentration of individuals in the shrinking aquatic habitats. However, there are few empirical examples of how increased population density experienced by larval stages produces long-term effects on growth and fitness at postmetamorphic stages. We tested the effect of four different larval densities on the demography and growth of the endangered stream-dwelling newt Euproctus platycephalus. By manipulating larval populations in experimental aquaria, we analyzed the short-term effects of density in terms of growth and mortality rates as well as of social behavior. To assess medium- and long-term effects we tested the metamorph individuals after 1 and 3 years, respectively, and adults for maternal effect by assessing the relationship between mean larval size and fecundity. Larval body size and growth rate appeared inversely proportional to larval density. Density affected the incidence of aggressive behavior by increasing the rate of mutilation to arms and tail. One-year-old salamanders raised at the highest larval density grew significantly less. All 3-year-old individuals reached comparable body size and body condition irrespective of initial larval density. Salamanders presented a positive relationship between maternal size and (1) fecundity and (2) larval size. In natural conditions, increased density may cause slower growth and a reduction in the percentage of individuals reaching metamorphosis. Prolonged dry periods and increased water withdrawals for agricultural and industrial practices have almost certainly affected the population dynamics of Sardinian newt populations in the long term.

Agricultural water policy reforms in China: a representative look at Zhangye City, Gansu Province, China

Water resources are essential for agricultural production in the grain-producing region of China, and water shortage could significantly affect the production and international trade of agricultural products. China is placing effort in new policies to effectively respond to changes in water resources due to changes in land use/land cover as well as climatic variations. This research investigates the changes in land, water, and the awareness of farmer vis-à-vis the implementation of water-saving policies in Zhangye City, an experimental site for pilot programs of water resources management in China. This research indicates that the water saved through water-saving programs and changes in cropping structure (2.2 × 108 m3 a−1) is perhaps lower than the newly increased water withdrawal through corporate-led land reclamation (3.7 × 108 m3 a−1). Most critically, the groundwater withdrawal has increased. In addition, our survey suggests that local government is facing a dilemma of water conservation and agricultural development. Therefore, the enforcement of the ban on farmland reclamation and irrigation water quotas in our study area is revealed to be relatively loose. In this vein, the engagement of local stakeholders in water governance is essential for the future sustainable management of water resources.

Using regional scale flow–ecology modeling to identify catchments where fish assemblages are most vulnerable to changes in water availability

Abstract Streamflow is essential for maintaining healthy aquatic ecosystems and for supporting human water supply needs. Changes in climate, land use and water use practices may alter water availability. Understanding the potential effect of these changes on aquatic ecosystems is critical for long‐term water management to maintain a balance between water for human consumption and ecosystem needs. Fish species data and streamflow estimates from a rainfall‐runoff and flow routing model were used to develop boosted regression tree models to predict the relationship between streamflow and fish species richness (FSR) under plausible scenarios of (1) water withdrawal, (2) climate change and (3) increases in impervious surfaces in the Piedmont ecoregion of North Carolina, U.S.A. Maximum monthly flow, the fraction of total flow originating from impervious surface runoff, coefficient of monthly streamflow variability, and the specific river basin accounted for 50% of the variability in FSR. This model was used to predict FSR values for all twelve‐digit Hydrological Unit Code catchments (HUC‐12s) in the North Carolina Piedmont under current flow conditions and under water withdrawal, climate change and impervious surface scenarios. Flow–ecology modeling results indicate that predicted FSR declined significantly with increased water withdrawals. However, the magnitude of decline varied geographically. A “hot‐spot” analysis was conducted based on predicted changes in FSR under each scenario to understand which HUC‐12s were most likely to be affected by changes in water withdrawals, climate and impervious surfaces. Under the 20% withdrawal increase scenario, 413 of 886 (47%) HUC‐12s in the study area were predicted to lose one or more species. HUC‐12s in the Broad, Catawba, Yadkin and Cape Fear river basins were most susceptible to species loss. These findings may help decision making efforts by identifying catchments most vulnerable to changing water availability. Additionally, FSR‐discharge modeling results can assist resource agencies, water managers and stakeholders in assessing the effect of water withdrawals in catchments to better support the protection and long‐term conservation of species.

The Impact of Climate Change on Water Resource of Agricultural Landscape and its Adaptation Strategies: A Case Study of Chari Basin, Chad

The study of the impact of climate change on water resource of the agricultural landscape is of great importance for the management and planning of water resources and agricultural production. This article examines the impact of climate change on agriculture and water resources in the Chari Basin in Chad. The study is usually based on the values of the standardized precipitation index calculated over the study period (1950-2010), i.e., 50 years of observations. The results obtained show a great variability of the SPI values. However, Buishand's statistical tests, Hubert's segmentation, linear regression and the Mann Kendall slope used confirm this rainfall variability. The most remarkable periods of drought in terms of intensity in 1961, 1915, 1977, 1980 and 2005 are extremely severe during which they are felt on all stations in southern Chad. 90% of Lake Chad, the largest in the country, has disappeared in the last 50 years under the combined effect of droughts and increased water withdrawals for irrigation. Studies predict an intensification of this dry and arid climate throughout the 21st century, which means fewer agricultural changes, degraded pastures, and a difficult daily life for those dependent on agriculture. The total national cereals, whose production was estimated at about 1,620,000 tons last year, experienced a deficit of 455,000 MT, a decrease of 50 percent compared with the previous year and an average of 23 percent of the last five year's. A sector support policy would provide answers to the structural problems it faces in order to improve its performance.

Modern state of the Small (Northern) Aral Sea fauna

AbstractThe Aral Sea is a terminal lake lying within the deserts of Central Asia in Kazakhstan and Uzbekistan, draining the Amu Darya and Syr Darya rivers. Before the 1960s, it was a large brackish water lake with an average salinity of 10.3 g L−1. The anthropogenic regression and salinization of the Aral Sea at that time resulted from increasing water withdrawals from the Amu Darya and Syr Darya for irrigation purposes. The salinization resulted in the disappearance of most of its invertebrates and all freshwater fish. As a result of the water level decrease, the Aral Sea divided into a northern Small Aral and a southern Large Aral at the end of the 1980s, with the two having different hydrological regimes. After construction the first Kokaral Dam in 1992, the water level of the Small Aral Sea increased by >1 m, with a gradual decline in the salinity beginning. To date, the Small Aral has again become brackish. Its average salinity reached 5.3 g L−1 by April–May 2013, with the highest salinity of 9.9 g L−1 in Butakov Bay, whereas the salinity was very low at 1.2–2.0 g L−1 in the estuary zone of the Syr Darya. There is an ongoing process of restoration of the former biodiversity, with many fresh water and brackish water invertebrate species reappearing due to the decreasing salinity. Freshwater fish species (bream, roach, carp, asp, zander, wels, etc.) returned into the Small Aral from the Syr Darya River and lakes in its lower reaches where they survived. Fisheries are recovering and catches are growing. Continuing salinity decreases, however, may cause decreases in the numbers, or even disappearance, of marine and halophilic invertebrate species. This study summarizes the results of studies of the Small Aral zooplankton, zoobenthos and ichthyofauna carried out in the spring of 2013. An historical review of changes in the Aral Sea and its fauna also is presented.