Additional Water Sources Research Articles

203 Effect of a Supplemental Water Source on Performance of Growing-finishing Pigs

Abstract Crossbred pigs (Fast Genetics 276 × PIC 800; n = 2,332; initial BW = 24.5 ± 1.6 kg) were used in two, 84-d growth trials to evaluate effects of an additional water source (fixed double nipple waterer) to a wet/dry feeder on growing-finishing pig performance. Pigs were assigned randomly to 1 of 2 treatments with 27 to 30 pigs per pen and 40 pens per treatment. Pens were equipped with a wet/dry feeder (SDI, drop shelf wet/dry feeder) or with a wet/dry feeder in combination with the additional water source. Marketing began on d 84 of each trial so the highest pig demands on feeders and waterers were assumed to occur from d 0 to 84 when all pigs were present in each pen. Growth data were analyzed using the GLIMMIX procedure of SAS and removals, mortalities, and total removals were analyzed using a Chi-square test in SAS version 9.4 (SAS Institute Inc., Cary, NC). No significant interactions between trial and water treatment were observed, thus data were combined using water treatment as a fixed effect and trial as a random effect. No differences were observed for body weight on d 84, average market weight, or number of removals, mortalities, or total pigs removed (Table). Similarly, no evidence for differences in overall average daily gain, average daily feed intake, or gain efficiency were observed regardless of an additional water source. However, pigs given access to a supplemental water source displayed a numeric increase in water disappearance per pig compared to pigs in pens with only wet/dry feeders. In conclusion, addition of a fixed double nipple waterer to wet/dry feeders did not influence growth performance of growing-finishing pigs.

Assessing Future Water Demand and Associated Energy Input with Plausible Scenarios for Water Service Providers (WSPs) in Sub-Saharan Africa

This study examined the current state of water demand and associated energy input for water supply against a projected increase in water demand in sub-Saharan Africa. Three plausible scenarios, namely, Current State Extends (CSE), Current State Improves (CSI) and Current State Deteriorates (CSD) were developed and applied using nine quantifiable indicators for water demand projections and the associated impact on energy input for water supply for five Water Service Providers (WSPs) in Kenya to demonstrate the feasibility of the approach based on real data in sub-Saharan Africa. Currently, the daily per capita water-use in the service area of four of the five WSPs was below minimum daily requirement of 50 L/p/d. Further, non-revenue water losses were up to three times higher than the regulated benchmark (range 26–63%). Calculations showed a leakage reduction potential of up to 70% and energy savings of up to 12 MWh/a. The projected water demand is expected to increase by at least twelve times the current demand to achieve universal coverage and an average daily per capita consumption of 120 L/p/d for the urban population by 2030. Consequently, the energy input could increase almost twelve-folds with the CSI scenario or up to fifty-folds with the CSE scenario for WSPs where desalination or additional groundwater abstraction is proposed. The approach used can be applied for other WSPs which are experiencing a similar evolution of their water supply and demand drivers in sub-Saharan Africa. WSPs in the sub-region should explore aggressive strategies to jointly address persistent water losses and associated energy input. This would reduce the current water supply-demand gap and minimize the energy input that will be associated with exploring additional water sources that are typically energy intensive.

Factors controlling the asymmetry of soil moisture and vegetation dynamics in a hilly Mediterranean catchment

The interaction between hydrology, terrain, and vegetation, is an essential element in understanding complex landscapes, and in forecasting their evolution under climate change. In Mediterranean Europe, few studies have been performed on the interrelation between them. In this study, soil moisture, vegetation, and water table dynamics were measured on opposing hillslopes of a semi-arid, Mediterranean catchment in southern Spain, to quantify the aspect influence on ecohydrological dynamics of an oak-woodland savanna or “dehesa”.Observations of a network of 32 soil moisture sensors on two opposing hillslopes, a north-facing slope (NFS), and a south-facing one (SFS), detected a similar moisture dynamics, although the influence of the vegetation induces a lagged response where the NFS dries out earlier compared to the SFS. Analysis of successive soil water profiles after storm events suggests that the water moves downwards as an unsaturated preferential flow along the walls of the fractured granite material, with residence times between 16.3 and 36.7 days. Our results show that there is a direct coupling between the hillslope hydrology, the depth of the weathered bedrock, much higher on the NFS, and the vegetation dynamics. Vegetation is much denser on NFS, as LIDAR-derived biomass estimates were 29% higher than on the SFS. The evolution of the normalized difference vegetation index (NDVI), obtained from the Sentinel-2 time series, also shows completely opposing trends with a minimum value at the end of winter for the NFS, whereas the SFS reaches minimum values in summer. A significant correlation between NDVI and soil moisture was found for the SFS (Pearson’s R of 0.81). However, this correlation is very poor on the NFS, but a good correlation with water table was found (R = 0.46). This shows how the deep weathering on the NFS allows for an additional water source, contained in the rock moisture and saturated zone, that represents an important source for the vegetation, whereas on the SFS only soil moisture supports the vegetation. These vegetation differences in turn directly impact surface soil moisture, leading to the observed, relatively similar trends on both hillslopes.

Efficient Use Of Collector-Drainage Networks (On The Example Of Bukhara Region)

The article presents opinions and comments on the use of collector-drainage networks and water sources in Bukhara region. Their hydromorphological data on the main collectors located in the region are also given. The changes in the flow and mineralization rate of collector-drainage networks were studied. Suggestions and recommendations were also provided in order to increase the efficiency of secondary use of some types of agricultural crops as an additional source of water from the collector-drainage water in Bukhara region.

A New Method of Fighting Wildfires

It is proposed that in addition to the current method of fighting wildfires that are based on firefighters on the ground, and airdrops, there is the need for a supplemental approach based on using catapults to hurl containers of water at the fires. This additional source of water would serve to extinguish wildfires more rapidly, and thereby reduce the devastation and loss of life they cause, and also reduce the huge amounts of CO2 they pour into the atmosphere that contributes significantly to global warming. Importantly, the use of catapults would result in much greater safety for firefighters on the ground, as well as those serving in the air.

Water Audit Study for East Tambaram

Water auditing is a system to overwhelm the drought related issues, water losses, leakage etc. It plays the significant role in conservation measures to minimize the water loss which increase the efficiency of Urban Local Bodies and reduce the need to search for additional water sources. The main aim of the water audit study is to compute the amount of water that is being supplied by a water system, that is not being distributed or billed to customers. However, for the effective use of this system is to identify losses in the sums, the ULBs must first employ water auditing as a routine business practice. The various associations, such as IWA and AWWA which initiated a large-scale effort to assess the reduction of water related problems with the help of audit. Hence, a detail study on water audit is explored on the areas were water is being used in a system, identifying the sources of lost water, and an action plan is also developed to control or reduce water losses.

A New Water Source for Southern California: The Regional Recycled Water Program

Key TakeawaysThe Metropolitan Water District of Southern California and Los Angeles County Sanitation Districts are working together on a large‐scale program to develop recycled water as a new, much‐needed potable source to the region.With planning in the works since 2009, an undertaking as extensive as the Regional Recycled Water Program involves equally extensive coordination and evaluation, which includes a local demonstration facility.Beyond providing an additional water source for Southern California, the program will ensure reliability, sustainability, and flexibility in future expansion of the water supply through raw water augmentation.

High Mediterranean water-level during the Lago-Mare phase of the Messinian Salinity Crisis: insights from the Sr isotope records of Spanish marginal basins (SE Spain)

The Messinian Salinity Crisis (MSC) successions record extreme fluctuations in the Mediterranean's environmental conditions. However, some of the scenarios that are thought to have caused these extreme environments are contentious. One prominent example of this is the Mediterranean water level during the Lago-Mare stage of the MSC, which is interpreted either as being very low during a largely desiccated Mediterranean punctuated by endorheic lakes (lacustrine scenario) or sufficiently high to enable basin-wide connectivity across the Mediterranean and with the Atlantic and the Eastern Paratethys (lagoonal scenario). In SE Spain, adjoining marginal basins of Sorbas, Nijar and Vera exhibit sedimentary records of the Lago-Mare stage. Here we present 11 new 87Sr/86Sr isotope ratios measured on ostracod (Cyprideis sp.) valves from these successions, which add to the 11 already published data from these basins and whose significance, in terms of water provenance, has not been fully explored. In parallel, we construct a mass balance model that provides quantitative insights into the Sr isotopic composition of the water in which the ostracods dwelt. Overall, measured and published 87Sr/86Sr isotope ratios from Sorbas (0.709066–0.709131), Nijar (0.708814–0.709099) and Vera (0.708764–0.708813) all show lower values than modelled ratios for endorheic lakes (>0.7100). These Spanish basins therefore require an additional source of water with a lower Sr isotope signature which is likely to have been derived from the main Mediterranean waterbody (0.7086–0.7087). This interpretation implies that at least the Western Mediterranean had a relatively high and fluctuating water level during the Lago-Mare stage of the MSC.

Using Stable Isotope Analysis (δD and δ18O) and Tracing Tests to Characterize the Regional Hydrogeological Characteristics of Kazeroon County, Iran

Unpredictable climate changes are affecting water resources, especially in karst arid and semiarid areas. In such locations, the need for additional sources of water always arises. The paper gives insight into hydrogeological characteristics of Kazeroo County and resolves some unknowns around the catchment area of the springs important for water supply of the wider urban area of the city of Kazeroon, Iran, by using stable isotope analysis (δD and δ18O) and tracer test. Multiple tracer test and stable isotope analysis were conducted for research purposes. The uranine injected at Tale Milek 1 borehole was detected in the Chenar Shahijan spring in less than 2 and in the Seyed Hossein spring after 6 days. Small amounts of uranine were detected in the Sasan and Pirsabz springs. Based on the high apparent flow velocity (approximately 1750–2000 m/day), the underground system has a quick response to the precipitation during dry seasons. The assumed hydraulic connection between Shahneshin North (Asmari) and Dashtak Northzones has been confirmed by tracer test since the dye injected in Northern Asmari Shahneshin anticline appeared in the springs in Dashtak North zone. The results of water stable isotope measurements show that the catchment area of karst springs in the vicinity of Kazeroo is probably over 2000 m at the area of Shahneshin anticline and is positioned lower than the catchment area of Arjan spring.

Climatology and Dynamical Evolution of Extreme Rainfall Events in the Sinai Peninsula—Egypt

The whole Mediterranean is suffering today because of climate changes, with projections of more severe impacts predicted for the coming decades. Egypt, on the southeastern flank of the Mediterranean Sea, is facing many challenges for water and food security, further exacerbated by the arid climate conditions. The Nile River represents the largest freshwater resource for the country, with a minor contribution coming from rainfall and from non-renewable groundwater aquifers. In more recent years, another important source is represented by non-conventional sources, such as treated wastewater reuse and desalination; these water resources are increasingly becoming valuable additional contributors to water availability. Moreover, although rainfall is scarce in Egypt, studies have shown that rainfall and flash floods can become an additional available source of water in the future. While presently rare, heavy rainfalls and flash floods are responsible for huge losses of lives and infrastructure especially in parts of the country, such as in the Sinai Peninsula. Despite the harsh climate, water from these events, when opportunely conveyed and treated, can represent a precious source of freshwater for small communities of Bedouins. In this work, rainfall climatology and flash flood events are presented, together with a discussion about the dynamics of some selected episodes and indications about future climate scenarios. Results can be used to evaluate the water harvesting potential in a region where water is scarce, also providing indications for improving the weather forecast. Basic information needed for identifying possible risks for population and infrastructures, when fed into hydrological models, could help to evaluate the flash flood water volumes at the outlets of the effective watershed(s). This valuable information will help policymakers and local governments to define strategies and measures for water harvesting and/or protection works.

Transpiration Rates, Climate and Soil Water Balance of Eucalyptus Grandis Afforestation on Temperate Grasslands in ne Argentina

ABSTRACT Fast-growing Eucalyptus plantations evidence high rates of evapotranspiration. The increasing afforestation rates may affect local soil water balances. In this study, we measured transpiration rates in E. grandis at individual and stand level and we modeled it based on climate variables and soil water storage through a climate time series 1981–2010. We also estimated the aboveground net primary productivity and the water use efficiency based on regional empirical models. Transpiration rates were measured by the constant heat measurement method in 6 to 12 trees in three 100 m2 plots in an 11-year-old plantation. The model fitted suggested that stand transpiration of E. grandis plantation near harvest age is limited by soil water storage and that the water table does not constitute an additional water source. The transpiration of E. grandis plantation was about 800 mm year−1 which approximates 90% and 40% of the annual precipitation in dry and wet years, respectively. Our estimations compared well to other regional studies and suggest that stand transpiration, aboveground net primary productivity, and water use efficiency can be made based on simple climatic variables. A deeper discussion is needed to evaluate the impact of E. grandis transpiration rates at the regional scale.

Evaluation of water demand and supply under varying meteorological conditions in Eastern India and mitigation strategies for sustainable agricultural production

Spatio-temporal variability of water demand and supplies under different meteorological conditions and their linkage with dynamic groundwater (annually utilizable groundwater) reserve was investigated in a Canal Command (area irrigated by a canal system) of Eastern India. Annual irrigation water supply from surface water sources (i.e., canal, river lift and tanks) and groundwater sources (i.e., shallow and deep tubewells) was estimated for different meteorological conditions. Annual water demands as crop irrigation requirements (CIRs) for the prevailing cropping patterns in the study area were also assessed under different meteorological conditions using crop evapotranspiration and effective rainfall data. Thereafter, the estimated irrigation water supply and irrigation water demand were subjected to spatio-temporal and statistical analyses. The mean annual CIR in the study area was estimated at 7002 ± 852 MCM during 2004–2013 period. Boro paddy was found to be the most water-consuming crop, accounting for about 50% of the total crop water requirements. The mean annual dynamic groundwater reserve (DGWR) in the study area was estimated to be 5169 ± 782 MCM. Considering DGWR as an additional source of irrigation water, 28, 25 and 35 blocks were characterized as ‘water surplus’ during ‘normal,’ ‘dry’ and ‘wet’ years, respectively. Also, DGWR substantially reduced demand–supply gaps in the remaining blocks. The surplus water available in the blocks due to DGWR availability could be used to mitigate water-deficit condition in neighboring blocks. Thus, this study suggests cost-effective alternatives for the efficient management of available water resources and identifies management strategies for sustainable agricultural production under diverse climatic conditions.

Establishing irrigation potential of a hillside aquifer in the African highlands

AbstractFeeding 9 billion people in 2050 will require sustainable development of all water resources, both surface and subsurface. Yet, little is known about the irrigation potential of hillside shallow aquifers in many highland settings in sub‐Saharan Africa that are being considered for providing irrigation water during the dry monsoon phase for smallholder farmers. Information on the shallow groundwater being available in space and time on sloping lands might aid in increasing food production in the dry monsoon phase. Therefore, the research objective of this work is to estimate potential groundwater storage as a potential source of irrigation water for hillside aquifers where lateral subsurface flow is dominant. The research was carried out in the Robit Bata experimental watershed in the Lake Tana basin which is typical of many undulating watersheds in the Ethiopian highlands. Farmers have excavated more than 300 hand dug wells for irrigation. We used 42 of these wells to monitor water table fluctuation from April 16, 2014 to December 2015. Precipitation and runoff data were recorded for the same period. The temporal groundwater storage was estimated using two methods: one based on the water balance with rainfall as input and baseflow and evaporative losses leaving the watershed as outputs; the second based on the observed rise and fall of water levels in wells. We found that maximum groundwater storage was at the end of the rain phase in September after which it decreased linearly until the middle of December due to short groundwater retention times. In the remaining part of the dry season period, only wells located close to faults contained water. Thus, without additional water sources, sloping lands can only be used for significant irrigation inputs during the first 3 months out of the 8 months long dry season.

Quantitative assessment of the changes in regional water flow systems caused by the 2016 Kumamoto Earthquake using numerical modeling

Coseismic changes in water levels and discharges are well-known phenomena worldwide. Reliable hypotheses to explain these hydrological changes qualitatively have been proposed using various data and analyses. However, there are few quantitative assessments of these changes, which require hydrological simulators. A dense monitoring network revealed coseismic river and groundwater level changes induced by the 2016 Mw 7.0 Kumamoto crustal earthquake associated with many post-seismic fracture systems. In this study, we reproduced these changes using a physically based, fully distributed, integrated watershed modeling tool (GETFLOWS). In particular, the formation of new fracture systems is key to understanding the hydrological changes observed after the earthquake, which were incorporated into our model by changing parameters. Previous studies suggested that the observed water level drop immediately after the earthquake is explained by the drawdown of surface and aquifer waters to fill open spaces in the upper crust along the fracture systems generated under extensional stress field. After the initial water drop, water levels rose in the long-term because additional water sources were released from surrounding mountains due to the coseismic increase in the permeability of the soils and rocks around the compressional fracture systems. These hypotheses were validated in our model by adjusting the depths of fracture systems. Consequently, we constructed the three-dimensional distribution of these property changes over the study area. Furthermore, the model calculation yielded the volumes of missing and released mountain waters in the studied watershed (ca. 106 and 108 m3, respectively). This study demonstrates the utility of an integrated watershed modeling tool for investigating coseismic hydrological changes in active hydrological systems quantitatively.

Using collector-drainage water in saline and arid irrigation areas for adaptation to climate change

The paper presents data of scientific research on the conditions of the Bukhara oasis of Uzbekistan reducing the salinity of collector-drainage water through water plants Lemna minor, Azolla caroliniana, Eichhornia crassipes and scientific and practical recommendations for the irrigation of cotton biologically purified collector-drainage waters. A decrease in the salinity of collector-drainage water with a salinity of 3-5 g/l was achieved with the help of aquatic plants Lemna minor and Azolla caroliniana, using them as an additional source of water for irrigation of cotton variety Bukhara-102, a high harvest of raw cotton, as well as saved river water and prevented environmental pollution.

The Storage and Water Quality Characteristics of Rungiri Quarry Reservoir in Kiambu, Kenya, as a Potential Source of Urban Water

Urbanization has caused limitations on water resources, while climate change has reduced amounts of surface water in some parts of the world. Kikuyu, a suburban area in Kiambu county, Kenya, is facing this challenge. The major challenge in the study is scarcity of potable water, resulting in inadequate water supply to Kikuyu residents. Currently, only 63.6% of the population is being supplied with water by Kikuyu Water Company, the company mandated to supply water to the area. Water demand was 2972 m3/day in 2015 and was projected to be 3834 m3/day by 2025. This has put pressure on the already exploited clean water resources, making it necessary to seek additional sources of domestic water. Storage capacity and water quality of surface water bodies, especially small reservoirs whose water can be used to ease the demand, need to be assessed for supplemental water supply. This study aimed at assessing the suitability of the abandoned quarry reservoir as a source of potable urban water by determining its storage capacity characteristics and water quality status. Volume characteristics were determined using bathymetry survey in January 2019. Water samples were collected in January and August 2019 and analyzed for chemical, physical, and bacteriological quality, as per the American Public Health Association (APHA) standard methods for water and wastewater. Parameters were evaluated based on World Health Organization (WHO) and Kenya Bureau of Standards (KEBS) guidelines for drinking water, and rated based on the drinking water quality index (WQI). The reservoir’s maximum storage capacity was found to be 128,385 m3, the surface area was 17,699 m2, and the maximum depth was 15.11 m. Nineteen of the twenty-five investigated parameters were within the acceptable standards. However, the concentrations of manganese (Mn), cadmium (Cd), iron (Fe), turbidity, total coliforms, and Escherichia coli (E. coli) were above the acceptable limits. Manganese and iron levels increased with depth. The overall WQI of the reservoir was 82.51 and 85.85 in January and August, respectively. Therefore, based on WQI rating, the water scored a good quality rating and could be used for domestic supply upon treatment. The original achievement of this study is establishment of the volume of the water in the quarry as an additional source of water to the nearby community, along with water quality status.

Sustainable management of the groundwater resource of Jaffna, Sri Lanka with the participation of households: Insights from a study on household water consumption and management

Groundwater is the only source of water for drinking, domestic, and agricultural needs in Jaffna, a district in northern Sri Lanka. While the sustainability challenges to this groundwater resource in terms of water availability and quality have been highlighted and studied extensively through existing research, household water consumption and management practices have been overlooked. Hence, this study tried to investigate on household water consumption pattern and management practices along with comparing the effectiveness of different water management measures on reducing water deficit of the district. The primary data was collected through a questionnaire survey from 142 households belonging to a water rich rural area, a water scarce rural area, a coastal area and an urban area. The data was analyzed both quantitatively and qualitatively. Based on the results there was no statistically significant difference in average per capita consumption among the different areas studied and on average a person in Jaffna, Sri Lanka consumes 200 L per day. Also, household size and households having their own water source are the two most important predictors of total water consumed in a household. In addition, more than half of the respondent households do not engage in water conservation at their households at present due to continuous access to water through their own water source. Further analysis on the effectiveness of management interventions by using Water Evaluation and Planning System (WEAP) modeling on reducing deficit showed that if the current consumption patterns continue, there will be an unmet demand of 51.7 million cubic meters (MCM) of water in the year 2030. On the other hand, by implementing the management interventions, such as increasing recharge, reducing per capita consumption, having additional water sources, reducing non-revenue water, and installing a water treatment plant, together all the water demand for the year 2030 can be met.

Water governance and justice in Cape Town: An overview

AbstractThe drought that drew the world's attention to Cape Town in early 2018 was the worst on record, threatening to cut off household taps for 4 million people. Even before the drought, the city's relation to water was complex; South Africa still struggles with the legacy of racial inequality including its implications for water justice. Spatial and economic segregation of people initiated when Europeans first settled in the Cape culminated during the apartheid era 1948–1994. It forcibly moved hundreds of thousands of “colored” and “black” Capetonians to inferior housing in low‐lying areas prone to flooding and with limited access to water, sanitation, and other services. Post‐1994 policies have aimed to promote water justice for all citizens, but municipalities have struggled with implementation especially in rapidly growing informal settlements. During the recent drought, the City of Cape Town ramped up its program for water demand management, including pressure reduction, leak repairs, and public awareness‐raising campaigns. However, poor communication and a lack of trust contributed to a near‐panic situation at the threat of “Day Zero” as dams almost ran dry in the first half of 2018. Saved by winter rains, Cape Town is now exploring additional water sources and developing a new Water Strategy. Taken together, the City's experiences demonstrate that sustainable water governance needs to acknowledge the interrelated threats of drought and flooding, and the range of impacts these threats as well as the City's responses have on a population still defined by extreme inequality.This article is categorized under: Engineering Water > Planning Water Human Water > Water Governance Science of Water > Water Extremes

Groundwater level reduction and pollution in relation to household water management in Kabul, Afghanistan

Availability and sustainable management of water and sanitation, one of the sustainable developmental goals, is closely related to other issues such as poverty, war, urbanization, rapid population growth, and lack of infrastructures. Afghanistan, as a post-conflict country, is facing difficulties in securing a reliable drinking water. This study aimed to assess the household water resource in Kabul and to understand the relationship with other issues such as sewage system, income level, lifestyle changes, rapid population growth for developing a sustainable water-resource management. An extensive questionnaire survey, interview, and water-quality survey were conducted. Groundwater was the main drinking-water source. Merely 12% of Kabul’s residents had access to public water supply system. Fifty percent of households, especially those with low income, relied on private wells. The groundwater level dropped during the past decade in most areas of Kabul due to rapid population growth and lifestyle changes forcing some households to find new water source. Groundwater showed high concentration of nitrate in some places. Sewage system was also poor. Only 20% of households, especially those with higher income, were connected to wastewater treatment system or used toilets with storage tank. Others used cesspit and dry toilets. Cesspits replaced dry toilets in the past decade due to lifestyle changes, rapid population growth, and unplanned urbanization. Lack of wastewater treatment and the change in toilet type may have caused groundwater pollution. Kabul urgently must find additional water sources and protect its drinking water from pollution by establishing a wastewater treatment system considering socio-economic factors.

WATER EXCHANGE IN THE ESTUARY OF THE RAZDOLNAYA RIVER (AMUR BAY, JAPAN SEA) IN THE ICE COVERED PERIOD

Environmental conditions in the Razdolnaya/Suifen Estuary and adjacent marine area were monitored from 2008 to 2018, by seasons, including winter observations in January 2014 and January 2018. The river discharge in winter was low: 6 m3 /s (mean annual discharge is 73 m3 /s). The estuary was covered by ice. The cline of salt water at the bottom was traced upstream up to 28 km from the river mouth. The currents in the estuary changed in tidal cycle. Increasing of salinity and temperature (> 2о ) at the bottom was observed in the distance 20–24 km from the river bar (this area was distinguished by relatively thin ice, 20 cm, against 40–70 cm in the rest of estuary). Modeling of the water balance in the estuary showed an additional source of salt water in the internal estuary, beyond the direct exchange with the sea over the river bar, that was presumably the water flow through the aquifer. This groundwater discharge was responsible for supporting of the salted bottom layer and for temperature and salinity increasing in the internal estuary during the ebb phase in conditions of limited water exchange by two-layered estuarine circulation because of ice cover at the river mouth.