Water Salinization Research Articles

Salinization at the mouth of the São Francisco River: impacts on the Potengi community, Alagoas, Brazil

The salinization process at the mouth of the São Francisco River has been caused serious damage to the ecosystem and the quality of life among riverine populations. This study aimed to assess the perception of the riverine populations regarding the effects of water salinization at the mouth of the São Francisco River, and also to analyze the quality of water that is provided to the Potengi community in Piaçabuçu, Alagoas, Brazil. For data collection, semi- tructured interviews were conducted with 22 riverine residents. The analyses of water samples were carried out at four places in the community, in which analyzes of pH, electrical conductivity, determination of salinity, and turbidity of the water were made. It was possible to identify, during the performance of this study, the inefficiency of the public authorities, both concerning the informative and mitigating actions, as the exposure of the population to high levels of sodium and turbid water, leading to changes in the parameters concerning data established by the World Health Organization (WHO). The results revealed that one of the samples analyzed presented a saline level 17 times higher than the limit established by the WHO, and a turbidity index was 15.6 times higher than the technical limit established. Therefore, these changes have affected the health of the community, directly compromising the use of water and the composition of the biota in the region.

Assessment of water quality for industrial and irrigation purposes based on ionic indices in the Sítios Novos Reservoir, Ceará, Brazil

The semi-arid climate contributes to the process of water salinization, one of the main water quality problems faced in reservoirs in arid and semi-arid regions. In this scenario, the ionic quality of the surface waters of the Sitios Novos reservoir, Caucaia, Brazil was analyzed using water stability indices, irrigation indices and salinity indices. The influence of the annual climate cycle, the reserved volume and the temporal variation of the ionic indices for the period from 2004 to 2017 were determined. The results showed sodium chloride type waters. The stability indices indicated that the surface water can be potentially corrosive, limiting industrial applications. As for the suitability for use in irrigation, the waters were of medium salinity, low sodium and safe for irrigation purposes regarding the dangerous effect of CO32− and HCO3−. The salinity indices indicated low restriction waters. Strong and moderate correlations between the fraction of available volume and some ionic indices were obtained. The rainy and dry seasons did not present statistically significant influences on the ionic indices evaluated. The ionic indices are simple and low cost tools to keep a continuous and regular monitoring and control of the surface water in the Semi-Arid Tropic.

Experimental study of deicing chemical redistribution and moisture mass transfer in highway subsoils during the unidirectional freezing

Deicing chemicals, when applied to pavement surfaces, occasionally deposited on the ground beyond the road pavement, thus lead to their accumulation in roadside soils and producing secondary salinisation of the ground water. In order to explore moisture and chemical mass transfer in highway subsoils during the winter period, 9 non-saline soil samples of 1 m length were subject to simultaneously freeze–thaw cycles with freezing rate 2 °C/day. To monitor the dependence of mass transfer from the soil density, each further column was packed with increased dry density than the previous one and supplied with 22 g/L of NaCl solution from the base.The results show that soil columns with loose density were consolidated throughout the sample length with the maximum in its lower part. Whilst in the dense soil samples, only the top 10 cm was loosened and attracted a large amount of water to form ice lenses. Chemical mass transfer to the freezing front was observed along the entire length of the samples regardless of density and void ratio. The concentration of de-icing chemicals in the pore water exceeded the supplied solution by 2–2.5 times at the capillary raise zone. In this study, chemical mass transfer is considered in terms of the driving forces and the system equilibrium. The driving force was explained as a cryosuction force, effected to the hygroscopic water in a liquid state with dissolved de-icing chemical ions in it, which migrated towards the freezing front. The continuous secondary salinisation, lasting in the highway subsoils for years, requires an accurate protection as the use of plastic membrane or silicone gel insulation.

Characterization of processes and mechanisms controlling ground water salinization in the Algerian Sahara

This study assesses mechanisms responsible for the aquifer salinization in the Guerrara oasis, in southern Algerian Sahara. Here, underground hydrological resources are indispensable for the local inhabitants. To determine the probable causes of ground water deterioration, 54 water samples were collected from pumping wells and were analyzed in order to characterize their major ion hydrochemistry and to compute indexes on water quality. Additionally, geophysical investigations involved electric resistivity surveys that were applied to investigate the aquifer substrate. Data revealed presence of water at 2m in depth with the presence of, at least, four salt layers that are characterized by very low resistivity values. The aquifer waters are of the Cl-SO4-Ca (Mg) and Cl-SO4-K (Na) types. Due to the prevalence of high saline and sulfurous contents (from 288 to 3134mg/l), water quality is not suitable for agricultural and drinking water uses. Our observations revealed that it would be not only the effect of aridity, but also the dissolution of the underlying ancient evaporates that are suspected to rule groundwater salinization.

The Impact of Dust and Salt Aerosols of the Aral Sea on the Tissues of Rat Testes in the Experiment

BACKGROUND: The Aral Sea crisis is recognized as one of the global environmental problems of our time. The extreme environmental situation in the region is caused by massive chemical pollution of the territory for several decades by high doses of pesticides, herbicides, dumping of industrial waste into the rivers that feed the Aral Sea. As a result of the Aral Sea desiccation, aridization of the territory, climate change, and salinization of soil and water occurred. This led to increased mineralization of precipitation, climate change, the spread and deposition of dust on an area of about 25 million hectares. One of the factors in reducing fertile activity in humans is a decrease in spermatogenesis activity. Based on identified trends, WHO is forced to review the main indicators of spermograms in the direction of their reduction.
 AIM: To study the effect of dust and salt aerosols of the Aral Sea on reproductive function, rat testes were studied after 7 and 24 days of inhalation administration.
 MATERIAL AND METHODS: Some morphometric parameters of the testes were evaluated: The diameter of the convoluted seminiferous tubules and the thickness of the germinal epithelium. The obtained comparative morphological and histological characteristics of the testes of the control and experimental groups indicate the negative effect of the components of dust and salt aerosols of the Aral Sea on the reproductive function of male rats.
 RESULTS: The thickness of the epithelial spermatogenic layer in the second group of rats is on average 64.52 μm, which is significantly less compared to the control group (81.3 μm). The thickness of the epithelial spermatogenous layer in the third group is on average within 73.36 μm, which is significantly less than in the control group (81.3 μm), but more than in the group exposed to dust and salt aerosols for 7 days (64, 52 μm).
 CONCLUSION: The study revealed that the impact of dust and salt aerosols of the Aral Sea leads to a change in the morphological and histological characteristics of the testes of animals. In experimental groups, a decrease in the diameter of the convoluted seminiferous tubule and a decrease in the thickness of the epithelial spermatogenic layer were observed. This indicates the negative effect of the components of dust and salt aerosols of the Aral Sea on the reproductive function of male rats exposed to dust for 7 and 24 days.

Comparing taxon- and trait-environment relationships in stream communities

Abstract Traits define how organisms interact with their surrounding environment and with other organisms. Thus, trait composition of biological communities is expected to change predictably along environmental gradients. Because organisms’ traits, but not taxonomic identity, determine their fitness, trait-environment relationships should provide a better way to elucidate how biodiversity respond to environmental change. Here, we used data on tropical streams embedded in a landscape of intensive agriculture to investigate trait-environment and taxon-environment relationships in a set of 91 mayfly communities from southeastern Brazil. We expected that trait-environment relationships would be stronger than taxon-environment relationships and that the linkage between traits and environmental variables would provide mechanistic insights on environmental filtering. We found that variation in both species composition and traits were correlated to salinity, highlighting the influence of water salinization on mayfly communities due to agricultural practices. Surprisingly, using analogous statistical methods, in general, we found that the strengths of trait-environment relationships were lower than that of taxon-environment relationships. Further, (1) species responses to gradients were not correlated to similarity in their traits and (2) some species with different trait composition responded similarly to environmental variation, indicating that different suite of traits can cope with similar environmental contexts. Besides some cautionary results about trait-based approaches, results from taxon-based approaches indicated that variation in composition was more related to spatial variables, suggesting that dispersal limitation undermine its use for large scale assessments. Our results suggest that both taxon- and trait-based approaches have weakness and strengths and deciding between them for biomonitoring purposes will depend on spatial scales, trait interrelationships, and analytical methods.

Impact of salinization and pollution of groundwater on the adaptation of mosquito vectors in the Jaffna peninsula, Sri Lanka

Mosquito-borne diseases are a major health concern in many tropical and sub-tropical countries. In the absence of specific treatment for many mosquito-borne diseases, vector control in the form of eliminating preimaginal development sites and insecticide application has an important role in controlling these diseases. Anthropogenic environmental changes have become important driving forces causing the adaptation of many major mosquito vectors to such changes. Anthropogenic activities are major contributors to global warming that is causing arise in sea levels. Sea level rise along with over exploitation of groundwater results in sea water intrusion to fresh water aquifers causing fresh water salinization in coastal zones. Human activities, including the extensive use of fertilizers and agrochemicals, also cause groundwater pollution. Mosquito vectors that normally lay eggs and undergo preimaginal development in fresh water are now seen to be adapting to develop in brackish and polluted water habitats. This article reviews recent findings that show the adaptation of mosquito vectors of human diseases to lay eggs and undergo preimaginal development in groundwater that is undergoing rapid salinization and pollution in the Jaffna peninsula.

Spatial and temporal analysis of shallow groundwater quality using GIS, Grombalia aquifer, Northern Tunisia

This study aimed to analyze the spatial and temporal variations of water quality from 2000 to 2015 in the Grombalia basin aquifer, northern Tunisia. Some physicochemical parameters of collected samples were measured and processed in a GIS environment. Quantitative assessments of their distribution patterns and spatio-temporal variability were performed.Inverse distance weighting (IDW) interpolator and map algebra procedures were the used GIS tools. During 2000, 2015 campaigns 21 groundwater samples were collected from georeferenced boreholes and analyzed for Ca2+, Na+, Mg2+, K+, SO42−, HCO3−, Cl−, EC, pH, T°, O2, and Salinity. Hydrochemical indices were also estimated such as sodium adsorption ratio, total dissolved solids, and soluble-sodium percentage. Findings were examined in terms of water quality, salinization degree and deterioration rate. During the considered interval, a mixed facies of Cl–SO4–Na–Ca, which remained roughly unchanged, characterizes the aquifer. While the spatial distribution of almost all ions is the same, the obtained spatio-temporal maps (2000–2015) for each ion indicate different patterns. Significant variations of concentration were observed in the pediplain area. This region is susceptible to contain most suitable sources for irrigation purposes; it represents 23.8% of groundwater samples that are among the good and safe category. Also, there is no significant variations of water quality indices are observed in the aquifer, except for some northern samples (coastal area). Therefore, a slow hydrochemical process maintains the aquifer quality with a moderate variability while an ongoing salinization hazard locally induces the deterioration level.

The role of Sarcocornia perennis in the interstitial water salinization process

In salt marshes, there seems to be a trade-off between the presence of plants and some abiotic factors. In particular, it was observed that while groundwater salinity conditions the plant distribution pattern in certain salt marshes, it does not do so in others. In the salt marsh of Fracasso beach (Península Valdés, Argentina) the groundwater has a higher salinity than the seawater. Previous studies have proposed that salinization is a consequence of the concentration and/or precipitation of salts as a result of partial evaporation/evapotranspiration of the tidal water that floods the salt marsh. However, the role of vegetation in the salinization process has not been thoroughly studied so far; therefore, this research work aims to explore this relationship. To this end, 10 soils samples with plants and 10 soil samples without plants were taken from the unsaturated zone in Fracasso marsh. At the laboratory, the soil samples were centrifuged to obtain the interstitial water to determine the electrical conductivity, the concentration of chloride, and the isotopic composition. Also, texture and moisture content were determined. The results indicate that fine fraction and moisture contents were higher in the patches with plants than in those without plants. Conversely, electrical conductivity, chloride concentration and δ18O and δ2H values were higher in the interstitial water of the non-vegetated samples. These results indicate that in patches without plants, the evaporation process is higher than in patches with plants. The presence of low permeability soils reduces infiltration favouring the evaporation of tidal water. Under these conditions, the distribution of vegetation within the salt marsh plays an essential role in attenuating evaporation. S. perennis has a shadow effect that locally attenuates water evaporation causing the soil beneath the vegetation canopy to have less salinity than the adjacent soil without vegetation.

COMPUTER MODELLING OF GROUNDWATER OVEREXPLOITATION: CASE STUDY FROM THE PLAIN OF SIDI BEL ABBÈS (NORTHWESTERN ALGERIA)

In the plain of Sidi Bel Abbes, the Plio-Quaternary aquifer is the most important groundwater reservoir. Its computer modelling shows that it resembles a toboggan, formed by a succession of connected underground pools. The simulation conducted between 1971 and 2014 reproduced well the average water-table drop of about 11m across the entire aquifer, emphasizing its clear overexploitation, resulting mainly from withdrawals increase parallel to considerable precipitation diminution, especially between 1982 and 2006. The prediction phase simulated between 2015 and 2030 translated significant aquifer drawdowns, especially for scenarios 2 and 3, particularly East and South of the plain. The computer modelling of the aquifer illustrated its continual destocking and reflected its dangerous overexploitation, which if maintained at this rate, could have devastating consequences (complete drying of boreholes, subsidence, water and soil salinization, etc) on the plain of Sidi Bel Abbes.

Study of basic characteristics of quinoa seeds

Quinoa crop is considered as a source of healthy nutrition due to its energy and nutritional value. The nutritional parameters of quinoa seeds exceed the characteristics of traditional cereals. The high protein content distinguishes quinoa seeds from other plant food. Quinoa contains all the important amino acids, it is rich in minerals and vitamins. The special chemical composition of grain can ensure the production of gluten-free food products. Quinoa due to its unique chemical composition and lack of gluten, can be used as a valuable raw material for the creation of specialized (gluten-free) products for people suffering from celiac disease and for products of high nutritional value. This crop may be an alternative one in areas with water deficiency, droughts and salinization, where other crops are unprofitable. Problematic aspects of the crop production are level of seed germination in the field condition, low and unstable yields.
 The main condition for the quinoa spread, like other plant species, is the success of the initial phases of plant development. The ability to form in new growing conditions a crop with certain parameters of standing density provides the possibility of further steps in the beeding process and technological optimization of crop indicators.
 The evolutionary way of the trait formation such as the absence of the seed dormancy period are analyzed, the mechanisms and dynamics of the decrease in the viability of seeds in the modern crop of quinoa are revealed. Significant differences in the seed characteristics of 2019 and 2018 harvest years (storage period of 14 and 28 months, respectively) indicate the difficulty of maintaining the economic indicators of seeds for the 2-nd and subsequent storage years.
 Based on the experiment result to determine the dynamics of water absorption of seeds, their reactions to soaking and heating, the basic characteristics of quinoa breeding samples (perspective for introduction in the zone of the north-eastern forest-steppe of Ukraine) were determined.
 It was found that the level of passive water absorption was in the range of 79.7–81.5 % of the mass of dry seeds. The maximum intensity of water absorption was fixed within 1-st hour. Seeds with a longer storage period are characterized by more intense initial water absorption. At temperature of 18 °C, the total duration of the seed swelling period is 7‒8 hours.
 The highest efficiency of seed soaking was noted for seed samples of the 2019 harvest year, compared with which the growth of indicators of germination energy and laboratory germination was + 9.5 and + 5.8 %. The same seed sample had the best parameters according to the results of heating: + 6.9 and + 2.4 % respectively.

Groundwater chemistry and demarcation of seawater intrusion zones in the Thamirabarani delta of south India based on geochemical signatures.

Sub-surface water samples from the delta of Thamirabarani River of south India were evaluated for human health risks and seawater intrusion using the geochemical signatures. Electrical conductivity (EC), total dissolved solids (TDS), pH and the concentrations of major cations and anions in 40 samples collected during the winter (January) and summer (July) of 2018 show comparable values. Subsequently, the results were verified with respect to the international drinking water quality standards. The piper trilinear diagram shows mixed Ca-Mg-Cl, Na-Cl, Ca-HCO3 and mixed Ca-Na-HCO3 facies in the samples. Similarly, the plenteous of cations are sequenced as Na+ > Ca2+ > Mg2+ > K+ and the plenteous of anions are sequenced as Cl- > SO42- > HCO3->Br- > NO3- > PO4-. Gibbs plots illustrate that rock-water interaction and evaporation control the geochemistry of sub-surface water. More than 40% of the samples are unsuitable for drinking, and their higher EC and TDS values reflected the seawater intrusion, in addition to the anthropogenic activities (salt panning). Interrelationship between ions of sub-surface water was used to get a better insight into the saline water intrusion in the study area. To mitigate the river water salinization and seawater incursion in the aquifers, engineering solution such as weir construction across the Thamirabarani River near Mukkani village has been proposed. After construction of the weir, freshwater in the river can be diverted to the salt-affected and seawater-intruded areas to improve the scenario.

Hydro-environmental changes assessment after Guadalhorce River mouth channelization. An example of hydromodification in southern Spain

The Guadalhorce River mouth (Málaga, Southern Spain) was channelized between 1997 and 2003 to reduce flooding potential in adjacent densely populated sections of Málaga. The channel was bifurcated near the Mediterranean Sea, surrounding an isolated wetland complex composed of eight different ponds. Groundwater-level and wetland-stage data, combined with water-chemistry data from wells and wetlands, collected since 1977, have documented the hydrological and ecological responses to channelization. The results show that channelization has extended the tidal influence inland from the Mediterranean Sea through the Guadalhorce River and the subjacent coastal aquifers, producing a change in groundwater hydrodynamics. The isolation of the wetlands resulting from channelization has provoked a significant salinization of both surface water and groundwater, the extent of which varies among wetlands. These decadal-scale changes in water chemistry have promoted the appearance or increase of halophilic vegetation and have caused a shift from diving birds to predominantly shorebirds in some wetlands. Documentation of these unexpected ecosystem responses is a necessary first step for land managers who need to consider groundwater and surface water as a single resource, particularly in groundwater-dependent ecosystems along the densely populated and ecologically sensitive Mediterranean coastal areas.

ACTUAL WATER USE OF YOUNG DATE PALM TREES AS AFFECTED BY AMINOLEVULINIC ACID APPLICATION AND DIFFERENT IRRIGATION WATER SALINITIES

AbstractThe Arabian Gulf countries are facing unprecedented water management challenges owing to limited water resources and salinization of the soil. Date palm trees represent a crucial socio‐economic asset in the region. Improving water productivity and tolerance to salinity are the most viable options. A split plot experiment was conducted on 4‐year‐old date palm trees in concrete lysimeters. The objective was to study the effects of aminolevulinic acid (ALA) and different irrigation water salinities (EC) on actual water use (ET) and irrigation efficiency (IE). Low: < 1, medium: 12–15 and high: 18–20 (dS m‾¹) EC were used as main plots while zero and 5 ml per tree of ALA represent the subplots. Data were collected during the period between June 2016 and September 2017. Results indicated that ALA application significantly increased tree ET by about 7%. Medium and high EC levels masked the effect of ALA on ET. EC significantly reduced ET by about 70 and 83% for high and medium EC respectively. The highest ET was obtained under low EC with ALA. Highest IE (63%) was obtained under low EC with ALA, followed by 48% for low EC without ALA. All ALA treatments resulted in higher IE compared with no ALA. © 2020 The Authors. Irrigation and Drainage published by John Wiley & Sons Ltd on behalf of International Commission for Irrigation and Drainage

Ultraviolet radiation and water salinization on recirculating aquaculture systems

Abstract: The objective of this work was to evaluate the effects of ultraviolet radiation (UV) and water salinity on nitrification, water quality, bacterial load, and juvenile tilapia growth in recirculating aquaculture systems (RASs). The experimental period was divided into two phases. The first one lasted 20 days and evaluated the effects of salinity (0 and 2 g L-1) and UV (with or without) on water quality during the period of substrate colonization by nitrifying bacteria. In the second phase, after the storage of juvenile tilapia, the effects of the same experimental factors were evaluated on water quality, bacterial load, and fish growth performance. The RASs employed were efficient for ammonia removal, regardless of the treatments used. During the experimental period, the nitrite concentrations increased linearly, with a more pronounced increase after fish storage until 30 days of the experiment. There were no significant effects of UV, salinity, or the interaction of both on total ammonia, nitrite, and alkalinity. The low levels of salinity (2 g L-1) and UV did not affect the nitrification process and fish performance. The use of UV is efficient to reduce the bacterial load of recirculating aquaculture systems.

The technology of improving almond planting material tolerance to the salt stresses of soils based on experience in phytotron

There was studied impact of the bitter almond seeds preliminary steeping on the development of plants at the first stages of development in conditions of saline waters irrigation in the greenhouse experiment ambient in phytotron. It was established that steeping the seeds in excessive salt solution results in enhanced plants tolerance to the soil salinization and saline waters irrigation. This is evidenced by the obtained regularities of influence on the development of plants of biochemical character (content of proline, chlorophyll and carotinoids, total carbon); chemical (content of basic chemical elements); morphological (rate of the plants height and stalk diameter growth, leaf-area duration). The introduction of developed technology into nursery science will permit to improve the tolerance of seedlings to salinization of soils and irrigation waters.

Decadal patterns of anthropogenic salinisation in typical mountain streams in northeastern China: Increased rates and sources

Salt pollution and anthropogenic-accelerated weathering is globally shifting the ionic composition and increasing salinisation of fresh water. We analyzed a 40-year data set (1970s-2010s) to characterize the drastic change of dissolved ionic composition, conductivity and pH levels. We also identified causative factors in these highly polluted mountain streams in northeastern China. Dissolved salt ions (Ca2+, Mg2+ and SO42-) increased by 3.02-5.21 fold and conductivity (a proxy for salinisation) increased by 3.09 fold. The average pH values increased from 7.08 to 8.49. The dominant ions, Ca2+, Mg2+, SO42- and HCO3-+CO32-, accounted for ∼90% of ionic composition based on mass concentration. Between the 1970s and 2010s, the dominant anion shifted from HCO3-+CO32- to a mixture of SO42- and HCO3-+CO32-. Increasing mining and land development appear to be the primary driving factors for the change of Ca2+, Mg2+, SO42- and HCO3-+CO32- concentrations; whereas, agricultural land was the main driving factor for the variation in K+, Na+ and Cl- concentrations. The source of ions has shifted from a more natural weathering of carbonate rocks to one of mineral dissolution that is affected by anthropogenic activities. Our study shows that freshwater mountain streams are at risk of long lasting anthropogenic salinisation and should be considered in future management and conservation plans.

The thermohaline structure of the North Atlantic waters in different phases of the Atlantic multidecadal oscillation

The meridional structure of climatic trends and anomalies of potential temperature and salinity in the North Atlantic waters in different periods of the Atlantic Multidecadal Oscillation (AMO) in 19482017 are studied based on the EN4 and WOA2013 objective analyses data. An analysis of these different data sets allowed us to reveal almost identical patterns of variability of the thermohaline fields of the North Atlantic, which increases the reliability of the results. Long-term temperature and salinity trends simulated over the period 19482017 show that warming and salinization of water occur in the upper ~1 km layer of the North Atlantic. On the contrary, cooling and freshening of deep waters are observed, which is associated with the melting of the Greenland ice sheet, transport of fresher waters from the Arctic Ocean, and deepening of these cold and fresher waters into the deeper layers. Composite analysis of the zonally averaged temperature and salinity anomalies of the North Atlantic waters after removing the trends showed that in the warm AMO periods warming and salinization of waters are observed in the upper 1-km layer of the North Atlantic when compared to the cold periods based both on the EN4 and WOA2013 data. Below the 1-km layer, significant regions of cooling and freshening are observed; this distribution is more pronounced in the EN4 data. Analysis of the dynamics of zonally averaged temperature and salinity anomalies in the successive periods associated with the temporal variability of the AMO index revealed that these anomalies propagate along the zonally averaged meridional thermohaline circulation. To show this using the Institute of Numerical Mathematics Ocean Model (INMOM), the stream function of the Atlantic Meridional Overturning Circulation (AMOC) was simulated. It is shown that positive and negative anomalies of both temperature and salinity circulate along the water motion in the AMOC around its core, descending down into the deep ocean layers approximately at 60 N and ascending to the surface at 25 N, replacing each other with a period of about 60 years. It can be assumed that due to this process both the warm and cold phases of the AMO are formed.

Exploring the Effects of Hydraulic Connectivity Scenarios on the Spatial-Temporal Salinity Changes in Bosten Lake through a Model

Lake water salinization in arid areas is a common problem and should be controlled for the better use of freshwater of lakes and for the protection of the environment around lakes. It is well known that the increasing of hydraulic connectivity improves water quality, but for a lake, understanding how hydraulic connectivity changes its water quality in terms of spatial aspects is of great significance for the protection and utilization of different regions of the lake water body. In this paper, the impacts of three connectivity scenarios on the spatial-temporal salinity changes in Bosten Lake were modeled through the three-dimensional (3D) hydrodynamic model, Environmental Fluid Dynamics Code (EFDC). The constructed Bosten Lake EFDC model was calibrated for water level, temperature, and salinity with acceptable results. As for the Bosten Lake, three connectivity scenarios were selected: (1) the increasing of the discharge water amount into the lake from the Kaidu River, (2) the transferring of 1 million cubic meter freshwater to the southwestern part of the lake (the Huangshuigou region of the lake), and (3) the changing of the outflow position from the southwestern part of the lake (the Kongque river) to the southeastern of the lake (the Caohu region). Through the simulations, we found that the region of the lake mainly influenced by the three scenarios presented here were different, and of the three scenarios, scenario 3 was the best means of controlling the overall lake salinity. On the basis of the salinity distribution results gained from the simulations, decision-makers can choose the ways to mitigate the salinity of the lake according to which region they want to improve the most in terms of economic efficiency and preserve in terms of ecological balance.

A reduction in spring mixing due to road salt runoff entering Mirror Lake (Lake Placid, NY)

Wiltse B, Yerger EC, Laxson CL. 2019. A reduction in spring mixing due to road salt runoff entering Mirror Lake (Lake Placid, NY). Lake Reserv Manage. 36:109–121. Road salt has resulted in the salinization of surface waters across temperate North America. Increasingly, road salt is recognized as a significant regional pollutant in the Adirondack Park. Here we analyze biweekly limnological data from Mirror Lake (Lake Placid, NY) to understand the role of road salt runoff in an apparent lack of spring mixing in 2017. Water column profile data show notable spatial and temporal variability in chloride concentrations within the lake. Concentrations are highest at the lake bottom during the winter, with increases associated with the onset of road salt application to the watershed. High chloride concentrations in the hypolimnion persisted through the summer of 2017 due to a lack of complete spring mixing as the result of road salt induced density differences within the water column. Water density calculations and Schmidt stability point to an increase in water column stability due to the accumulation of salt at the lake bottom. The incomplete spring mixing resulted in greater spatial and temporal extent of anoxic conditions in the hypolimnion, reducing habitat availability for lake trout. Restoration of lake mixing would occur rapidly upon significant reduction of road salt application to the watershed and improvements in stormwater management.