scholarly journals Understanding wetland sub-surface hydrology using geologic and isotopic signatures

2009 ◽  
Vol 13 (7) ◽  
pp. 1313-1323 ◽  
Author(s):  
P. K. Sikdar ◽  
P. Sahu
Keyword(s):  
Surface Water ◽  
Urban Areas ◽  
Isotope Composition ◽  
Operation Time ◽  
Freshwater Wetland ◽  
Bengal Basin ◽  
Silty Clay ◽  
Deep Groundwater ◽  
Deep Aquifer ◽  
Deep Aquifers

Abstract. This paper attempts to utilize hydrogeology and isotope composition of groundwater to understand the present hydrological processes prevalent in a freshwater wetland, source of wetland groundwater, surface water/groundwater interaction and mixing of groundwater of various depth zones in the aquifer. This study considers East Calcutta Wetlands (ECW) – a freshwater peri-urban inland wetland ecosystem located at the lower part of the deltaic alluvial plain of South Bengal Basin and east of Kolkata city. This wetland is well known over the world for its resource recovery systems, developed by local people through ages, using wastewater of the city. Geological investigations reveal that the sub-surface geology is completely blanketed by the Quaternary sediments comprising a succession of silty clay, sand of various grades and sand mixed with occasional gravels and thin intercalations of silty clay. At few places the top silty clay layer is absent due to scouring action of past channels. In these areas sand is present throughout the geological column and the areas are vulnerable to groundwater pollution. Groundwater mainly flows from east to west and is being over-extracted to the tune of 65×103 m3/day. δ18O and δD values of shallow and deep groundwater are similar indicating resemblance in hydrostratigraphy and climate of the recharge areas. Groundwater originates mainly from monsoonal rain with some evaporation prior to or during infiltration and partly from bottom of ponds, canals and infiltration of groundwater withdrawn for irrigation. Relatively high tritium content of the shallow groundwater indicates local recharge, while the deep groundwater with very low tritium is recharged mainly from distant areas. At places the deep aquifer has relatively high tritium, indicating mixing of groundwater of shallow and deep aquifers. Metals such as copper, lead, arsenic, cadmium, aluminium, nickel and chromium are also present in groundwater of various depths. Therefore, aquifers of wetland and surrounding urban areas which are heavily dependent on groundwater are vulnerable to pollution. In the area south of ECW isotope data indicates no interaction between shallow and deep aquifer and hence this area may be a better location to treat sewage water than within ECW. To reduce the threat of pollution in ECW's aquifer, surface water-groundwater interaction should be minimized by regulating tubewell operation time, introducing treated surface water supply system and artificial recharging of the aquifer.

scholarly journals Understanding wetland sub-surface hydrology using geologic and isotopic signatures

2009 ◽  
Vol 6 (2) ◽  
pp. 3143-3173 ◽  
Author(s):  
P. K. Sikdar ◽  
P. Sahu
Keyword(s):  
Surface Water ◽  
Urban Areas ◽  
Isotope Composition ◽  
Shallow Groundwater ◽  
Operation Time ◽  
Freshwater Wetland ◽  
Bengal Basin ◽  
Silty Clay ◽  
Tritium Content ◽  
Deep Aquifers

Abstract. This paper attempts to utilize hydrogeoloy and isotope composition of groundwater to understand the present hydrological processes prevalent in a freshwater wetland, source of wetland groundwater, surface water/groundwater interaction and mixing of groundwater of various depth zones in the aquifer. This study considers East Calcutta Wetlands (ECW) – a freshwater peri-urban inland wetland ecosystem located at the lower part of the deltaic alluvial plain of South Bengal Basin and east of Kolkata city. This wetland is well known over the world for its resource recovery systems, developed by local people through ages, using wastewater from the city. Geological investigations reveal that the sub-surface geology is completely blanketed by the Quaternary sediments comprising a succession of silty clay, sand of various grades and sand mixed with occasional gravels and thin intercalations of silty clay. Aquifer within the depths of 80 m to 120 m has the maximum potential to supply water. Groundwater mainly flows from east to west and is being over-extracted to the tune of 65×103 m3/day. δ18O and δD values of shallow and deep groundwater are similar indicating resemblance in hydrostratigraphy and climate of the recharge areas. Groundwater originates mainly from monsoonal rain with some evaporation prior to or during infiltration and partly from bottom of ponds, canals and infiltration of groundwater withdrawn for irrigation. Relatively high tritium content of the shallow groundwater indicates local recharge, while the deeper groundwater with very low tritium is recharged mainly from distant areas. At places the deeper aquifer has relatively high tritium, indicating mixing of groundwater of shallow and deep aquifers. Metals such as copper, lead, arsenic, cadmium, aluminum, nickel and chromium are also present in groundwater of various depths. Therefore, aquifers of wetland and surrounding urban areas which are heavily dependent on groundwater are vulnerable to pollution and hence surface water-groundwater interaction should be minimized by regulating tubewell operation time, introducing treated surface water supply system and artificially recharging the aquifer.

scholarly journals Multi-Technique groundwater flow system analysis and dating of deep aquifers in Alessandria Basin (Piedmont - IT)

2020 ◽  
Author(s):  
Nicola Quaranta ◽  
Elena Cogo ◽  
Adriano Simoni ◽  
Elisa Sacchi ◽  
Mariachiara Caschetto ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Groundwater Flow ◽  
System Analysis ◽  
Dissolved Inorganic Carbon ◽  
Flow System ◽  
Isotope Composition ◽  
Radioactive Isotopes ◽  
Deep Groundwater ◽  
Groundwater Flow System ◽  
Deep Aquifers

The aim of the study was to set up a protection system from pollution of the deep aquifer of the Alessandria basin, by redefining the recharge areas, focused on this portion of Piedmont territory, and therefore by creating some reserve areas of deep groundwater, to be preserved for future human drinking purposes. In addition to the classical hydrodynamic and geochemical monitoring techniques, the groundwaters were analyzed with reference to a monitoring network of 25 selected wells with deep screens (80-300 m below ground surface) combining radiochemical dating (14C and δ13C of dissolved inorganic carbon - DIC) with anthropogenic tracers (CFCs, SF6) as indicators of recent recharge/ mixing. Stable isotope composition (δ2H and δ18O – H2O) was assessed during a 1-year sampling of snow-rain precipitations gauges distributed in altitude in order to define Local Meteoric Water Lines; the isotopic composition was also seasonally measured for the main rivers and in selected deep-wells. The 3D numerical model was implemented in FEflow platform and calibrated on the basis of the available monitoring data; it was used as a support tool in the delimitation of the recharge areas, starting from the analysis of the distribution of flows. This model was crucial for delimiting the “reserve areas”, since it was able to simulate groundwater flows using both purely advective transport conditions (particle tracking technique), and more realistic conditions of advective and dispersive transport, by introducing dispersive parameters and using the Life Time Expectancy (LTE) reservoir distribution. The integrated use of “traditional” techniques of regional groundwater flow system monitoring (hydrochemistry, stable isotopic composition) and of dating techniques based on radioactive isotopes and anthropogenic tracers, provided a reliable support to the validation of flow and transport simulation model, oriented to identify recharge areas and “reserve areas” of future extraction of deep groundwater for drinking purpose.

scholarly journals Analysis of Aquifer Pumping Test Data to Determine Deep Groundwater Security in Southeastern Bangladesh

2018 ◽  
Vol 8 ◽  
pp. 125-143
Author(s):  
Anwar Zahid ◽  
Farhana Islam ◽  
M. Rashidul Hassan ◽  
Kamrul Islam ◽  
Nur Ahmed
Keyword(s):  
Groundwater Resources ◽  
Coastal Region ◽  
Pumping Test ◽  
Groundwater Potential ◽  
Deep Groundwater ◽  
Deep Aquifer ◽  
Fresh Groundwater ◽  
Deep Aquifers ◽  
Quality Of Water ◽  
Upper Aquifer

In southeastern Bangladesh, where water quality in the upper aquifers is a serious constraint, future development will likely be confined to deep fresh groundwater. Owing to the importance and pervasive use of deep groundwater, the sustainability of water use has received extensive attention. However, excessive extraction from deep aquifers may pose a threat to the storage as well as the quality of water due to the high susceptibility to salinization and arsenic contamination from upper aquifers. Hence, determining the extension of aquifer units and the characterizing aquifer sediments are very important to ensure sustainable development and management of limited fresh groundwater resources. The study area extends over six districts of the southeastern coastal region of Bangladesh. In order to assess and monitor deep fresh groundwater potential in the study area, aquifer pumping tests were performed at six locations with up to 72 h of constant-discharge prior to recovery. Different methods were used to analyze the drawdown and recovery data considering aquifers as confined or leaky-confined. Based on transmissivity values it was found that the studied deep aquifers have moderate to high potential for potable water supply. However, this deep fresh groundwater may not be safe for a longer period where upper aquifer units contain saline groundwater and where there is no significant aquitard encountered above or below the deep aquifer. Irrigation extraction of the deep groundwater is not recommended.

scholarly journals Hydrogeological Classification and the Correlation of Groundwater Chemistry with Basin Flow in the South-Western Part of Bangladesh

2018 ◽  
Vol 42 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Shahpara Sheikh Dola ◽  
Khairul Bahsar ◽  
Mazeda Islam ◽  
Md Mizanur Rahman Sarker
Keyword(s):  
Groundwater Flow ◽  
Water Chemistry ◽  
Sea Water ◽  
Shallow Groundwater ◽  
Shallow Aquifer ◽  
Deep Basin ◽  
Deep Groundwater ◽  
Deep Aquifer ◽  
Delta Plain ◽  
Type Water

Attempt has been made to find the relationship between the basin groundwater flow and the current water chemistry of south-western part of Bangladesh considering their lithological distribution and aquifer condition. The correlation of water chemistry and basin groundwater flow is depicted in the conceptual model. The water-types of shallow groundwater are predominantly Mg-Na-HCO3 and Ca- Mg-Na-HCO3 type. In the deep aquifer of upper delta plain is predominately Na-Cl, Ca-HCO3 and Mg- HCO3 type. In the lower delta plain Na-Cl type of water mainly occurs in the shallow aquifer and occasionally Ca-HCO3, Ca-Mg-Na-HCO3 and Mg-HCO3 type may also occur in shallow aquifer of the eastern part of lower delta plain which could have originated from the recent recharge of rain water. Na- Cl type water is also found in the deep aquifer of lower delta plain. The origin of Na-Cl type water in the deep aquifer of lower delta part might be connate water or present day sea water intrusion. Fresh water occurring in the deep aquifer in the lower delta area is mostly of Mg-Ca-HCO3 and Na-HClO3 types. This type of water originate from intermediate or deep basin flow from the northern part of Bangladesh. The probable source of deep groundwater is Holocene marine transgression (Khan et al. 2000) occurred in 3000–7000 cal years BP and the deep groundwater of Upper Delta plain and Lower Delta plain is clearly influenced by deep basin flow coming from north part of BangladeshJournal of Bangladesh Academy of Sciences, Vol. 42, No. 1, 41-54, 2018

scholarly journals Environmental Impact Statement on Kolleru Lake Water

2020 ◽  
Vol 8 (6) ◽  
pp. 2509-2512
Keyword(s):  
Surface Water ◽  
Lake Water ◽  
Urban Areas ◽  
Water Source ◽  
Agricultural Runoff ◽  
Climatic Conditions ◽  
Water Bodies ◽  
Surface Water Bodies ◽  
Alternative Water ◽  
The Impact

Catchments are most important for the purpose of practicing irrigation and recharging groundwater by collecting water during the rainy season so that the nearby land will be in surplus quantity of groundwater due to the continues percolation of water from the catchments, even the stored water in the form of catchments will be used as an alternative water source for other requirements apart from the irrigation practices such as for industries and other developmental activities taking place nearby the catchments. Year by year it was noticed that in the world scenario the pollutant concentration is keep on increasing especially water and air pollution due to the excessive load of population that is increasing from the rural to urban areas [10]. Coming to water pollution the major portion of pollution is increasing in the surface water bodies [4] due to various activities like surface runoff, intentionally releasing of untreated effluents from the nearby industries into the catchments [8] and the agricultural runoff etc, whatever the reason there is an immediate need and an emergency to monitor these catchments as the average rainfall is gradually decreasing due to the changing climatic conditions like global warming which leads to the reduced availability of water in the surface water bodies at the other side the existing water is being contaminated [5] by the activities of nearby people. The impact will be severe when the same situation continues in the days to come where the living standards of the people will be decreased at a notable level and the impact will be much more severe on the irrigated land which depends on the catchments. The study has done at Kolleru Lake in west godavari district, Andhra Pradesh. Collected Six Water samples from six locations around the lake for analysis [7] and then the results of the analysis compared with Central Pollution Control Board 1979and Indian standards 1982 guidelines for water in the surface water bodies to find out the present scenario of lake water.

scholarly journals Impact of extreme drought and incentive programs on flooded agriculture and wetlands in California’s Central Valley

2018 ◽  
Author(s):  
Matthew E Reiter ◽  
Nathan Elliott ◽  
Dennis Jongsomjit ◽  
Gregory H Golet ◽  
Mark D Reynolds
Keyword(s):  
Surface Water ◽  
Large Fraction ◽  
Central Valley ◽  
Open Water ◽  
Extreme Drought ◽  
Freshwater Wetland ◽  
Post Harvest ◽  
Incentive Programs ◽  
Managed Wetlands ◽  
The Impact

Between 2013 and 2015 a large part of the western United States, including the Central Valley of California, sustained an extreme drought. The Central Valley is recognized as a region of hemispheric importance for waterbirds which use flooded agriculture and wetlands as habitat. Thus, the impact of drought on the distribution of surface water needed to be assessed to understand the effects on waterbird habitat availability. We used satellites to quantify the impact the recent extreme drought on the timing and extent of available waterbird habitat during the non-breeding season (July – May) by examining flooding in agriculture (rice, corn, and other crops) and managed wetlands across the Central Valley. We assessed the influence of habitat incentive programs, particularly The Nature Conservancy’s BirdReturns and the Natural Resources Conservation Service’s Waterbird Habitat Enhancement Program (WHEP), at offsetting waterbird habitat loss related to drought. Overall, we found significant declines in open water in post-harvest agriculture (20 – 80% declines) and in managed wetlands (47 – 59% declines) during the 2013 – 2015 drought compared to non-drought years 2000 – 2011. Crops associated with the San Joaquin Valley, specifically corn, as well as wetlands in that part of the Central Valley exhibited larger reductions in open water than rice and wetlands in the Sacramento Valley. However, seasonal wetlands on protected lands had a marginally significant (P<0.10) higher amount of open water in the drought years than those on non-protected lands. A large fraction of the daily open water in rice during certain times of the year, particularly in the fall for BirdReturns (64%) and the winter for WHEP (100%), may have been provided through incentive programs underscoring the contribution of these programs. However, further assessment is needed to know how much the incentive programs directly offset the impact of drought in post-harvest rice or simply supplemented funding for activities that might have been done regardless. Our, first of its kind, landscape analysis documents the significant impacts of the drought on freshwater wetland habitats in the Central Valley and highlights the value of using satellite data to track surface water and waterbird habitats. More research is needed to understand subsequent impacts on the freshwater dependent species that rely on these systems and how incentive programs can most strategically support vulnerable species during future drought.

scholarly journals Analysis of the potential contamination risk of groundwater resources circulating in areas with anthropogenic activities

2005 ◽  
Vol 5 (1) ◽  
pp. 109-116 ◽  
Author(s):  
M. Spizzico ◽  
N. Lopez ◽  
D. Sciannamblo
Keyword(s):  
Anthropogenic Activities ◽  
Groundwater Resources ◽  
Shallow Groundwater ◽  
Deep Groundwater ◽  
Deep Aquifer ◽  
Eastern Area ◽  
Contamination Risk ◽  
Basement Rocks ◽  
Geological Features ◽  
Nitrate And Nitrite

Abstract. The area investigated is located in the province of Brindisi (Italy). It is a generally flat area separated from the nearby carbonatic plateau of the Murgia by quite indistinct and high fault scarps. As regards the geological features, carbonatic basement rocks and post-cretaceous terrains made up of calabrian calcarenites and middle-upper Pleistocenic marine terraced deposits can be distinguished. In the examined area there are two different hydrogeological environments. The first is represented by deep groundwater, the main groundwater resource in Apulia. The second hydrogeological environment, now of lesser importance than the deep aquifer in terms of size and use, is made up of some small shallow groundwater systems situated in post-calabrian sands and located in the eastern area. During some sampling cycles carried out in the studied area, water was withdrawn from both the deep aquifer and from the shallow groundwater. For every sample, the necessary parameters were determined for the physical and chemical characterisation of two different hydrogeological environments. Moreover, some chemical parameters indicating anthropogenic activities were determined. Analysis of the aerial distribution of the measured parameters has shown some main areas subject to different conditions of contamination risk, in accordance with the hydrogeological and geological features of the investigated area. In the south-eastern part of the investigated area, the important action performed by the surface aquifer for protecting the deep groundwater from contamination of anthropogenic origin is clear. On the other hand, in the shallow groundwater, areas of nitrate and nitrite contamination have been identified, which result from the extensive use of fertilizers.

scholarly journals Microplastic Pollution in Surface Water of Urban Lakes in Changsha, China

2019 ◽  
Vol 16 (9) ◽  
pp. 1650 ◽  
Author(s):  
Lingshi Yin ◽  
Changbo Jiang ◽  
Xiaofeng Wen ◽  
Chunyan Du ◽  
Wei Zhong ◽  
...  
Keyword(s):  
Surface Water ◽  
Urban Areas ◽  
Maximum Concentration ◽  
Emerging Pollutants ◽  
Anthropogenic Factors ◽  
Dominant Type ◽  
Urban Lakes ◽  
Research Areas ◽  
The World ◽  
The City

As emerging pollutants, microplastics have attracted the attention of scholars from all over the world. However, there is a lack of research on freshwater areas, even in densely populated urban areas. This study investigated eight urban lakes in Changsha, China. It was found that microplastic concentrations ranged from 2425 ± 247.5 items/m3 to 7050 ± 1060.66 items/m3 in the surface water of research areas and the maximum concentration was found in Yuejin Lake, a tourist spot in the center of the city. Anthropogenic factors are an important reason for microplastic abundance in urban lakes. The major shape of microplastics was linear and most of the microplastics were transparent. More than 89.5% of the microplastics had a size of less than 2 mm. Polypropylene was the dominant type in the studied waters. This study can provide a valuable reference for a better understanding of microplastic pollution in urban areas of China.

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