Ponded Surface Water Research Articles

Submarine Groundwater Discharge From Non-Tidal Coastal Peatlands Along the Baltic Sea

Submarine groundwater discharge (SGD) is an important pathway for water and materials within the land-ocean transition zone that can impact coastal environments and marine life. Although research from sandy shorelines has rapidly advanced in recent years, there is very little understanding of coastal areas characterized by a low hydraulic conductivity, such as carbon-rich coastal peatlands. The objective of this study was to determine the magnitude and location of terrestrial SGD to be expected from a non-tidal low-lying coastal peatland located along the Baltic Sea and to understand the controlling factors using numerical modeling. We employed the HYDRUS-2D modeling package to simulate water movement under steady-state conditions in a transect that extends from the dune dike-separated rewetted fen to the shallow sea. Soil physical properties, hydraulic gradients, geological stratifications, and topography were varied to depict the range of properties encountered in coastal peatlands. Our results show that terrestrial SGD occurs at the study site at a flux of 0.080 m2 d−1, with seepage rates of 1.05 cm d−1 (upper discharge region) and 0.16 cm d−1 (lower discharge region above submerged peat layer). These calculated seepage rates compare to observations from other wetland environments and SGD sites in the Baltic Sea. The groundwater originates mainly from the dune dike—recharged by precipitation and infiltration from ponded peatland surface water—and to a lesser extent from the sand aquifer. The scenario simulations yielded a range of potential SGD fluxes of 0.008–0.293 m2 d−1. They revealed that the location of terrestrial SGD is determined by the barrier function of the peat layer extending under the sea. However, it has little impact on volume flux as most SGD occurs near the shoreline. Magnitude of SGD is mainly driven by hydraulic gradient and the hydraulic conductivity of peat and beach/dune sands. Anisotropy in the horizontal direction, aquifer and peat thickness, and peatland elevation have little impacts on SGD. We conclude that SGD is most probable from coastal peatlands with high water levels, large Ks and/or a dune dike or belt, which could be an essential source for carbon and other materials via the SGD pathway.

Sediment oxygen demand enhancement at the sediment/water interface of a shallow pond induced by pressure fluctuations from raindrop impact at the water surface

The increase of Sediment Oxygen Demand (SOD) by raindrop impact at the water surface of shallow ponds was investigated. A model was built to simulate pressure fluctuations at the sediment/water interface driven by raindrops striking the water surface of the pond continuously at constant intervals of a few seconds when the water depth h in the pond is on the order of 5 to 100 cm. Simulated pressure fluctuations at the sediment/water interface were translated into bed shear velocity describing the intensity of near – bed turbulence. Modeled shear velocity increases as the depth of water in the pond increases. Also, shear velocity becomes larger with increased terminal velocity of raindrops which was varied from 400 to 600 cms−1. The DO flux from the water column to the sediment surface, i.e. SOD, was calculated using the obtained shear velocity. Modeled SOD can be solely dependent on the microbial oxygen uptake rate (μ) in the sediment when μ < 500 mg L−1 d−1. While, SOD depends on the shear velocity, which in turn depends on the water depth (h) in the pond when h < 20 cm, the microbial oxygen uptake rate (μ) becomes solely limiting and SOD is no longer water – side controlled when h > 20 cm and μ > 1000 mg L−1 d−1. This simulation result suggests that raindrops impinging on the water surface of the pond can increase the SOD as can increase in height of bed roughness and/or the velocity of water flowing over the sediment surface as a turbulent flow. SOD induced by raindrop impact at the water surface can be equal to that for turbulent flow, or even larger depending on the water depth and microbial oxygen uptake rate.

Bacterial Community Changes in Penaeus vannamei Boone, 1931 Surface and Rearing Water During Enterocytozoon hepatopenaei Infection

White faeces syndrome is one of the major disease problems in shrimp aquaculture, resulting in enormous economic losses to farmers. Although white faeces syndrome is usually associated with Enterocytozoon hepatopenaei (EHP) infections, it may not be the sole cause for the occurrence of white faecal strings on the pond water surface. There is limited information on the microbial dynamics in a pond affected by white faeces syndrome. Hence, this study aimed at the bacterial community changes occurring on the surface of shrimp Penaeus vannamei Boone, 1931 afflicted by the white faeces syndrome and the pond water in which it was reared. The pond water and the shrimp surface shared &gt;45 % of the operational taxonomic units (OTUs), reflecting the influence of water quality on the bacterial community composition on the shrimp surface. Among these, the Proteobacteria formed the principal phyla and remained unaltered throughout the culture period. Bacteroidetes formed the second largest group across samples, followed by Cyanobacteria, Actinobacteria, Planctomycetes, Verrucomicrobia and Chloroflexi. The relative abundance levels of health indicator bacterial families such as Thiotrichaceae,Microbacteriaceae and Chitinophagaceae showed significant fluctuations on the shrimp surface. Disease indicators such as Rickettsiaceae, Mycobacteriaceae showed an increase in numbers on the shrimp surface. PICRUSt functional predictions revealed higher abundances of genes involved in metabolism and genetic information processing. The study provides valuable findings on the bacterial communities of rearing water and shrimp surface associated with white faeces syndrome.

Resource use in whiteleg shrimp Litopenaeus vannamei farming in Ecuador

AbstractA survey of 101 shrimp farms in Ecuador revealed that the average annual shrimp yield based on production pond water surface area was 7.03 ± 0.93 (SE) t/ha/year. The range in annual yield among the five provinces with shrimp farms was 3.67 ± 0.71 to 11.95 ± 5.56 t/ha year, respectively. Averages for total land, water, and energy use were 0.54 ± 0.01 ha/t shrimp, 76,817 ± 6,330 m3/t shrimp, and 61.2 ± 4.2 GJ/t shrimp, respectively. Average wild fish use for fish meal and fish oil included in feed was 0.65 ± 0.02 t/t shrimp. One‐fourth of land use was land embodied in feed. Nearly 80% of total water use was incurred for exchanging water. Eighty‐seven of the farms practiced daily water exchange at an average rate of 8.5% pond volume per day (range 0.7–30%). Pumping water at all farms and mechanical aeration at 47 of the farms were the major direct energy uses. About half of the total energy use was embodied, and roughly half of the embodied energy was in feed.

Replenishment of urban landscape ponds with reclaimed water: Spatiotemporal variations of water quality and mechanism of algal inhibition with alum sludge

Algal blooms caused by high concentrations of nutrients (especially phosphorus) limit the use of recycled water (RW) for replenishing landscape ponds in the context of global water scarcity. Previous studies have demonstrated that alum sludge is a low cost phosphorus sorption medium, which could potentially be applied in constructed wetlands and sewage treatment plants. However, whether alum sludge can be used for algae inhibition in reclaimed water urban landscape ponds (RWULPs) should be explored. In this study, phosphorus removal and algae inhibition by alum sludge were investigated in a RWULP in China. The results highlight that there is a serious risk of algal blooms in RWULPs. The algal density was found to be 1.58 × 105 cell·mL−1, which is 6.84 times higher than that of the surface water ponds. The algal blooms presented a Cyanophyta–Chlorophyta–Bacillariophyta-type, and the dominant algae species were Microcystis flos-aquae (Wittr.) Kirchner, Chlorella vulgaris, and Scenedesmus quadricauda. Moreover, the removal rate of phosphorus by alum sludge was as high as 98% and eventually leads to phosphorus stress, which has an important effect on algae growth and algae inhibition rate of 80%. In addition, the proportion of phosphorus and nitrogen in the adsorbed alum sludge increased by 3.12% and 0.32%, respectively, and Al3+ was reduced by only 2.18%. Alum sludge is a potential inhibitor of algae in RWULPs that does not negatively impact the environment. These results are of great importance in algal bloom control of RWULPs and may help alleviate the problem of urban water resource scarcity.

Characterization of an AFFF impacted freshwater environment using total fluorine, extractable organofluorine and suspect per- and polyfluoroalkyl substance screening analysis

The vast number of per- and polyfluoroalkyl substances (PFASs) that are in global commerce (n > 4700) pose immense challenges for environmental monitoring. The large discrepancy between this large number and the few PFASs usually monitored suggest that environmental exposure might be substantially underestimated. This study applied a workflow, which included analysis of total fluorine (TF), extractable organofluorine (EOF), 24 target PFASs and suspect screening. The workflow aimed to close the organofluorine mass balance and to tentatively identify overlooked PFASs in various matrices from an aqueous film forming foam (AFFF) contaminated pond and its adjacent riparian zone. PFAS target analysis revealed that water, aquatic invertebrates as well as emergent aquatic insects had high concentrations with up to 2870 ng L−1, 9230 ng g−1 dry weight (dw) and 1470 ng g−1 dw ∑24PFASs, respectively. The EOF mass balance could be explained by target PFAS analysis for most biota samples such as aquatic invertebrates, emergent aquatic insects and terrestrial spiders and earthworms (i.e. EOF ≈ ∑24PFASs). In the pond surface water, 42–58% of the EOF was not explained by target PFASs. However most new tentatively identified PFASs (n = 25) were detected in water, which could contribute to the unknown EOF. Nine suspects could be further identified, which where perfluoroalkyl sulfonamide-based compounds and derivatives that all have been found in historical AFFFs produced by electrochemical fluorination. One suspect, F5S-PFOS, was also detected for the first time in aquatic and terrestrial invertebrates.

Modeling water consumption, N fates, and rice yield for water-saving and conventional rice production systems

Quantifying water consumption, nitrogen (N) fates, and crop yield is crucial in developing the best management practices for rice production systems. A 2-year field experiment was conducted in Taihu Lake region, China. The experiment consisted of water-saving controlled and conventional flooding irrigation regimes that are factorially combined with two N management practices (farmers’ N fertilization and site-specific N management). A simple surface ponding water layer component was incorporated into the original WHCNS (soil water heat carbon nitrogen simulator) model to simulate and comprehensively evaluate water consumption, N fates, and rice yield for water-saving and conventional rice production systems. Field experiment data, including surface water ponding depth, soil water content, runoff, runoff N loss, crop N uptake, and yield, was measured to test the improved model. Results showed agreement between the measured and simulated values of surface ponding water depth, soil water content, runoff, N runoff loss, ammonia volatilization, crop N uptake, and yield and simulated values agreed well, with average relative root mean squared error values of 24.0%, 9.3%, 26.1%, 20.9%, 21.3%, 7.9%, and 4.6%, respectively. Crop yield showed no significant difference under different water and N management practices. Compared with conventional flooding system, controlled irrigation saved 34.1% of irrigation water and greatly reduced nonproductive water consumption (evaporation + runoff + deep percolation) by 16.9%–20.0%, thus increasing the water use efficiency (WUE). Site-specific N management substantially reduced N losses from ammonia volatilization, leaching, denitrification, and runoff by 50.1%, 33.8%, 13.3%, and 42.7%, respectively, compared with those of the farmers’ N fertilization practice. These results indicated that the combination of controlled irrigation regime and site-specific N management regime reduced the water consumption, N losses, and N2O emission and increased WUE and N use efficiency.

Using nutrient transport data to characterize and identify the presence of surface inlets in regions with subsurface drainage.

Surface inlets route ponded surface water into subsurface drainage networks and are prevalent throughout North America. Despite serving as a nutrient loss pathway, contributing to downstream water quality degradation, surface inlets are thought to be underreported in drainage studies within the literature. Previous studies have demonstrated the footprint that surface inlets have on nutrient transport and drainage effluent but are site specific and focused on individual events. Moreover, although their ubiquitous presence is assumed, no regional surface inlet database exists. To this end, a structured review was undertaken with two goals. First, the MANAGE Drain Load database, consisting of nearly 1,500 site-years of drainage and nutrient data, was analyzed to determine distinctions between areas with and without surface inlets. The median annual total phosphorus (TP) load was greater at site-years with surface inlets (0.40kg ha-1 ) than site-years without (0.21kg ha-1 ). The opposite emerged for dissolved nitrogen (DN) loads as site-years with surface inlet had a smaller median annual load (3.3kg ha-1 ) than site-years without (23.0kg ha-1 ). This relationship is attributed to immobile TP being transported primarily through overland flow and routed to subsurface drains via surface inlets and to relatively more mobile DN being subsurface driven, bypassed in settings with surface inlets. No statistical differences were found in annual drainage or ratios of particulate P to TP between site-years with and without surface inlets. Second, a logistic regression model was developed that predicts the presence of surface inlets within MANAGE. Eighteen percent of site-years and 21% of sites were predicted to have surface inlets.

Analysis of Microbe&amp;apos;s from Municipal Waste Water (Pond) and Uses the Microbes for the Application of Waste Water Treatment

Water contamination was a serious problem throughout the world. Various technologically advanced treatment methodologies for example activated sludge process, membrane bioreactor, trickling filter, rotating biological contractor and oxidation ditch are widely studied well documented and adopted in practice. However, attention to promising low-investment-cost technologies such as slow biological waste water treatments after preliminary/primary treatment techniques was quite effective water treatment technology. It is also efficient in removing coli form microorganisms such as Cryptosporidium, E. coli and bacteriophage from wastewater. Apart from reduction of pathogenic load which is ascribed to the biological processes. This way of technology adopted the methodology taking the sample in the field of water surface two parts in sampling pond water in the surface pond water and inner parts also handling two different glass bottles. Then in analysis their analysis the sample subjected to physiochemical analysis then again the sample subjected to serial dilution to identify the microbe’s spp in the water sample (surface and deepest) part of pond water surface part of sample more microbes familiar conducted in this experiment. Then by using those identified microbes dosing this is done using 10-6 and 10-5 by prepared nutrient agar (3.25 gram with 250 ml of distilled water). Then take 1% (0.5), 3% (1.5) and 5% (2.5) by volume of broth added into waste water of 49.5 ml, 48.5 ml and 47.5 ml respectively. This means that for 50 ml of conical flask as the colonies of culture increase the probability of waste water to be clear was too been high so 47.5 with 5% (2.5) combined form of broth high potent of cleaned.

X‐ray computed tomography imaging of solute movement through ridged and flat plant systems

AbstractThe aim of this investigation was to experimentally compare the movement of a solute through soils with two field‐representative surface geometries: ridge and furrow surfaces versus flat surfaces. X‐ray computed tomography (XCT) imaging was undertaken to trace the movement of a soluble iodinated contrast medium, here used as an XCT‐visible analogue for field‐applied solutes, through soil columns with either a ridge and furrow or flat soil surface geometry. In addition to the soil surface geometry, the experimental treatments included the presence or absence of plants and surface water ponding. Experimental results were compared to existing numerical simulations adapted to represent the present experimental column systems. Similar infiltration patterns were observed in imaging results and the numerical simulations for most treatments. The experimental results suggest that plant roots present a significant localized effect to reduce the infiltration depth of solutes, particularly in planted ridges where the infiltration depth of the contrast medium was minimal. There is variability within the results because the number of replicates was limited to three due to the exploratory nature of the study (testing eight different treatments) and the cost and availability of XCT facilities capable of imaging such physically large samples. Discrepancies between the imaged infiltration depth of the solute and the numerical simulations are attributed to variation in plant root distribution and also spatial soil moisture, as measured using resistive soil moisture sensing. The results of this investigation elucidate the nature of solute movement through soil surface geometries, indicating that plant root water uptake can reduce solute infiltration depth, but surface ponding can negate this. These results suggest that soil surface shape, plant age and the timing of solute application with anticipated rainfall could be important considerations for reducing solute leaching and improving solute application efficiency.Highlights Investigating factors affecting solute infiltration in flat or ridge and furrow soil geometries. X‐ray CT imaging traces soluble contrast media movement in soil columns and is compared to modelling. Plant root water uptake can reduce solute infiltration depth, but surface ponding can negate this. Considering soil surface shape, rain and plant age in solute application could reduce leaching.

Exploring the multiscale hydrologic regulation of multipond systems in a humid agricultural catchment

Assessing the hydrologic processes over scales ranging from single wetland to regional is critical to understand the hydrologically-driven ecosystem services especially nutrient buffering of wetlands. Here, we present a novel approach to quantify the multiscale hydrologic regulation of multipond systems (MPSs), a common type of small, scattered wetland in humid agricultural regions, because previous studies have stopped in commending the catchment scale flood and drought resilience of these waters, and contemporary models do not adequately represent the corresponding intra-catchment fill-spill relationships. A new version of Soil and Water Assessment Tool (SWAT) was developed to incorporate improved representation of: (1) perennial or intermittent spillage connections of pond-to-pond and pond-to-stream, and (2) bidirectional exchange between pond surface water and shallow groundwater. We present SWAT-MPS, which adopts rule-based artificial intelligence to model the possibilities of different spillage directions and GA-based parameter optimization over the two simulation years (June 2017 to May 2019), with successfully replicated streamflow and pond water-level variations in a 4.8 km2 test catchment, southern China. Water balance analysis and scenario simulations were then executed to assess the hydrologic regulation at single pond, single MPS, and entire catchment scales. Results revealed (1) the presence of 9 series- or series-parallel connected MPSs, in which pond overflow accounted for as much as 59% of the catchment water yield; (2) seasonally- and MPS-independent baseflow support and quickflow attenuation, with ranked level of pond water storage for baseflow support across different landuse types: forest > farm > village, and inversed correlation of pond spillage to baseflow and quickflow variations in the farmland; and (3) MPS-aggregated catchment flood peak reduction (>20%) and baseflow increment (26%) in the following dry days. Meteorological data analysis and simulated average daily values indicated these hydrologic patterns are credible even if extending to a 5-year period. As a first modelling attempt to explore the intra-catchment details of MPSs, our study underscores the water storage and connectivity in their hydrologic regulation, and suggests inventories, long-term field monitoring, and several research directions of the new model for integrated pond management in watersheds and river basins. These findings can inform refined assessment of similar small, scattered wetlands elsewhere, where restoration efforts are required.

Antibiotic resistance gene profiling in response to antibiotic usage and environmental factors in the surface water and groundwater of Honghu Lake, China.

There is an increasing concern that aquaculture has been implicated in the formation of antibiotic resistance gene (ARG) reservoirs; however, little is known about the consequences of their presence in groundwater. In this study, 22 antibiotics, including four acetylated metabolites, and 27 ARGs were analyzed in fish pond water, surface water, and groundwater of the Honghu Lake in China. Correlations between conventional parameters, ionic composition, antibiotic concentration, and relative abundance of ARGs in water samples were analyzed. Among the three different sources of water, total antibiotic levels were the highest in fish pond water and the lowest in groundwater, with moderate levels in lake water. In surface water, sulfonamides and their metabolites accounted for the highest antibiotic content, whereas tetracyclines were the most frequently found in groundwater samples. Despite the near-undetectable levels of antibiotics in groundwater, the relative abundance of ARGs in groundwater samples was even higher than that in surface waters. The magnitude and extent of ARG migration are likely to be dependent on local antibiotic contamination levels as well as on the local environmental and hydrogeological conditions, with the class 1 integrons (intI1) being essential for the dissemination of such ARGs. The effects of environmental parameters such as antibiotics, dissolved oxygen, HCO3-, and pH on ARGs were highly significant, reflecting the potential impact of these factors on the abundance of ARGs. Our findings thus highlight the need for improved control of the spread of ARGs in and from aquaculture environments.

Purification efficacy of different parts of Mangifera indica on water samples from contaminated drinking water sources in chanchaga local government area of Niger State, Nigeria

The use of natural coagulant in water purification has gain popularities owing to the public health consequences of consuming untreated water and the carcinogenic properties of synthetic coagulant. In the present study, the leaf, stem, seed and bark powdered samples Mangifera indica were used to treat contaminated river, stream and pond water at concentrations of 0.1, 0.2, 0.3, 0.4 and 0.5 g/L. Microbial quality and physicochemical properties of the water samples were investigated after 0, 12 and 24 h of treatment. The results showed that the addition of M. indica considerably decreases or even eliminated (in most cases) the aerobic heterotrophic bacteria, coliforms, salmonella and shigella in the water samples. All parts of M. indica tested decreased the pH, dissolve oxygen, total dissolved solid, calcium, nitrate, turbidity and chemical oxygen demand contents of the water samples when compared with untreated water. The activities of the plant materials increase with increase treatment time and concentrations. In conclusion, the raw surface water (stream, river and pond) used for the study fall short of standard. Mangifera indica leaf, stem, seed and bark materials improved the quality of the raw surface water based on the maximum permissible limit of microbial load and physicochemical parameters. This could serve as a cheaper and safer alternative to the synthetic coagulant.

Numerical modelling of leachate transport into water bodies at a landfill site

This study was carried out to assess the possibility of reclamation of a closed landfill site located at Mavallipura near Bangalore, India. The existing liner system at this site had not completely prevented leachate migration to the underlying aquifers, which required management and control to avoid adverse impact on the surrounding environment. Batch leaching tests and column tests were conducted to estimate the migration rates of different contaminants through soil. The transport rates thus obtained were used as input to the fluidyn-Pollusol model to assess the leachate migration from the landfill. This model may be useful in analysing leachate migration from the landfill and its associated environmental impacts, particularly on groundwater wells and surface water ponds downstream of the site. The results indicated that landfill leachate leakage had a significant effect on the quality of surrounding water bodies.

EFFECT OF WATER QUALITY AND DIFFERENT MEALS ON GROWTH OF CATLA CATLA AND LABEO ROHITA

The human body cannot make significant required quantities of vital nutrients but fish is minimum-fat, big-protein nutrition that delivers a variety of health advantages. Several external factors including temperature, oxygen level, alkalinity and photoperiod have impact on growth rate while water is also an important parameter in fish rising. Therefore, there is need to work and evaluate impact of fish food and water quality to improve the fish growth. For this purpose, twelve glass aquaria (six with ground water and six with surface water) were considered to assess growth and food conversion ratio (FCR) of Catla Catla and Labeo Rohita and two feeds (i.e. sunflower and bone meal) were provided. The feed has been given twice a day and changed 4% on the rate of body weight of fingerlings in the ground water pond and surface water pond as well. The fingerlings get the most elevated body weight in ground water and on sunflower meal (1.43 ± 0.01 g) as compared to surface water and bone meal (1.39 ± 0.03 g). The general lengths obtained using the fish feed have gotten to be (5.78 ± 0.03cm) on sunflower meal and (5.47±0.03 cm) on the bone meal. The values of FCR had been lower (better) on sunflower meal (2.13±0.01) as compared to bone feast (2.32±0.03). In conclusion, it was observed from the results that fishes fed on sunflower meals had shown better growth with improved morphometric parameters and lower FCR values.

Performance Evaluation of Subsurface Drainage System under Waterlogged Saline Vertisols for Sugarcane Crop in Ukai Kakrapar Canal Command, Gujarat

Crop productivity in canal command areas of India is declining due to waterlogging and soil salinization problems, and it is posing a big threat to livelihood security of small and marginal farmers. Subsurface drainage (SSD) technology, which restores favourable condition in the crop root zone by reclaiming waterlogged saline soils, can be one of the options to restore the crop productivity in such areas. The SSD system was installed at Mulad village in the Ukai Kakrapar canal command area, Gujarat, in the year 2012 to address the problem of drastic yield reduction of sugarcane due to twin problems of waterlogging and soil salinity in Vertisols. It was found that the SSD helped in desalination of soil profile as soil electrical conductivity was reduced to a range of 0.42 to 3.90 dS.m-1 from its initial range of 1.2 to 7.3 dS.m-1. Electrical conductivity of drained water was in the range of 1.3 to 4.4 dS.m-1. Further, there was reduction in waterlogging condition, both surface and sub-surface, as water table lowered below crop root zone depth (depth of 0.6 m) and surface water ponding duration reduced to 6-8 days from earlier 25-30 days during peak monsoon days. Overall performance of SSD system was satisfactory as average sugarcane yield in the study area increased significantly from 39.29 to 97.29 t.ha-1 as result of reduction in soil salinity and waterlogging in drainage area. Economic analysis also indicated 114% increase in benefit-cost ratio after SSD installation. Thus, large scale installation of SSD system for reclamation of waterlogged saline Vertisols is economically viable in the state of Gujarat.

Performance Evaluation of Subsurface Drainage System under Waterlogged Saline Vertisols for Sugarcane Crop in Ukai Kakrapar Canal Command, Gujarat

Crop productivity in canal command areas of India is declining due to waterlogging and soil salinization problems, and it is posing a big threat to livelihood security of small and marginal farmers. Subsurface drainage (SSD) technology, which restores favourable condition in the crop root zone by reclaiming waterlogged saline soils, can be one of the options to restore the crop productivity in such areas. The SSD system was installed at Mulad village in the Ukai Kakrapar canal command area, Gujarat, in the year 2012 to address the problem of drastic yield reduction of sugarcane due to twin problems of waterlogging and soil salinity in Vertisols. It was found that the SSD helped in desalination of soil profile as soil electrical conductivity was reduced to a range of 0.42 to 3.90 dS.m-1 from its initial range of 1.2 to 7.3 dS.m-1. Electrical conductivity of drained water was in the range of 1.3 to 4.4 dS.m-1. Further, there was reduction in waterlogging condition, both surface and sub-surface, as water table lowered below crop root zone depth (depth of 0.6 m) and surface water ponding duration reduced to 6-8 days from earlier 25-30 days during peak monsoon days. Overall performance of SSD system was satisfactory as average sugarcane yield in the study area increased significantly from 39.29 to 97.29 t.ha-1 as result of reduction in soil salinity and waterlogging in drainage area. Economic analysis also indicated 114% increase in benefit-cost ratio after SSD installation. Thus, large scale installation of SSD system for reclamation of waterlogged saline Vertisols is economically viable in the state of Gujarat.

Long-term thermal and settlement characteristics of air convection embankments with and without adjacent surface water ponding in permafrost regions

Surface water is an important local factor in engineering geological conditions in permafrost regions. In this paper, the impacts of surface water ponding on the long-term thermal and settlement characteristics of an air convection embankment (ACE) were investigated based on 13 years of data records from field observations along the Qinghai-Tibet Railway (QTR). The time series of the ground temperatures and the settlement of two ACEs with and without adjacent surface water ponding were investigated and compared. The results indicated that surface water ponding could significantly affect the thermal performance of the ACE. Without surface water ponding, the ACE showed a satisfactory cooling effect; the underlying permafrost table rose, and the shallow permafrost layer cooled significantly after construction of the embankment. However, with surface water ponding, the great heat capacity and latent heat of the ponded water and related capillary action impeded the thermal interaction between the ACE and the underlying permafrost. Before the drainage of the ponded water, no permafrost cooling occurred beneath the embankment. The settlement of the two ACEs also differed significantly. The creep of the ice-rich permafrost layer immediately beneath the permafrost table was inferred as the main contribution of the settlement. The temperature of the layer was the main factor determining the rate of settlement. The results can help the hydro-thermal analysis of engineering foundations built over permafrost and provide a reference for embankment construction and maintenance in permafrost regions with rich surface water.

Microbial Communities of Culture Water and African Catfish Reared in Different Aquaculture Systems in Nigeria Analyzed Using Culture Dependent Techniques

The microbial communities of culture water and catfish C. gariepinus from three replicates of earthen, concrete and tarpaulin ponds in Nigeria were analyzed. Waters was collected from 25 cm below pond water surface per culture system. Three catfish per replicate system were also collected and analyzed in the lab. Catfish gut, skin and gills were analyzed. Earthen ponds had significantly more diverse microbial community and coliform forming units (CFU/ml) 2.43 x10-4 CFU/ml than the rest systems. Earthen ponds had consortium of Klebsiella pneumonia, S. aureus and Salmonella enteritidis and E. coli, which was more diverse than all other aquaculture systems. Microbiota of tarpaulin ponds was 2.10x10-4 /ml CFU and this was significantly (P&lt;0.05) higher than concrete ponds (1.50x10-4 CFU/ml). Tarpaulin ponds had K. pneumoniae and E. coli, while concrete pond had S. aureus and S. enteritidis. Biofilm formation could have lead to colonization of the fish body part. The skin and gills had similar microbiota as the culture water compared to the gut. The gut microbial communities were not synonymous with the culture water.

Determining conventional and unconventional oil and gas well brines in natural sample II: Cation analyses with ICP-MS and ICP-OES

Flowback and produced water generated by the hydraulic fracturing of unconventional oil and gas plays contain a suite of cations (e.g., metals) typically in a high salt (e.g., NaCl) matrix. Here, we analyzed the chemical (cation) composition of production fluids associated with natural gas and oil development (e.g., flowback, produced water, impoundment fluids), along with mine drainage, and surface and ground water samples using ICP-OES and ICP-MS. ICP-MS and ICP-OES analytical performance and interference effects were evaluated. Both platforms exhibited excellent analytical spike recoveries, detection limits for blank and spiked solutions, and accuracy for standard certified reference materials. Mass ratio analyses using Ca/Sr, Ca/Mg, Ba/Sr, Mg/Sr, and B and Li, were assessed for their efficacy in differentiation among brines from conventional oil wells, produced water from unconventional oil and gas wells and impoundments, mine drainage treatment pond water, groundwater, and surface water. Examination of Mg/Sr ratios when compared with Li concentrations provide clear separation among the different types of samples, while Ca/Mg versus Ca/Sr correlations were useful for distinguishing between conventional and unconventional oil and gas fluids.