Distribution and Community Composition of Anammox Bacteria in Shallow Groundwater of the Kathmandu Valley, Nepal

Groundwater is the water which is present in pore spaces and in the fractures of the geological materials beneath earth surface. Water is incompressible substance and presence of small amount of water in geological material modifies the behavior of geological material under stresses. Determination of engineering behavior of the geological material is almost impossible skipping the role of water. The objective of this study was to map and evaluate shallow groundwater level of the northern Kathmandu Valley covering main rivers such as the Bagmati River, Bishnumati River, Dhobi Khola and the Manahara Khola. These rivers flow from the North to the South across the sand rich sediment zone. Static groundwater levels of 239 wells were measured from different locations of the study area in April/March 2017 (Dry Season) and in August 2017 (Wet Season). Shallow groundwater level was measured from soil surface to water level using well water depth logger (Qin and Li, 1998). The result showed that groundwater level ranged from 0.6 m to 12.5 m in dry season and 0.1 m to 13 m in wet season. The groundwater level increased by average of 34.68% (n = 235) as compared to that in dry season. Increase in the groundwater level suggests recharge of groundwater in wet season of the study area. The flow pattern of groundwater levels from the study shows flow of shallow groundwater towards the major rivers of that particular river watershed. As a consequence, seepage flow and piping erosion is likely along the riverbank slopes. Increase in recharge of groundwater during wet season exhibits that the northern region of the Kathmandu Valley is potential for groundwater recharge and can be used to manage water for the dry period.

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Arsenic Contamination in the Deep and Shallow Groundwater of Kathmandu Valley, Nepal

Scientific World ◽

10.3126/sw.v11i11.8548 ◽

2013 ◽

Vol 11 (11) ◽

pp. 25-31 ◽

Cited By ~ 4

Author(s):

SM Shrestha ◽

K Rijal ◽

MR Pokhrel

Keyword(s):

Shallow Groundwater ◽

Arsenic Contamination ◽

Kathmandu Valley ◽

Scientific World

Scientific World, Vol. 11, No. 11, July 2013, page 25-31 DOI: http://dx.doi.org/10.3126/sw.v11i11.8548

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Seasonal variation in the microbial quality of shallow groundwater in the Kathmandu Valley, Nepal

Water Science & Technology Water Supply ◽

10.2166/ws.2013.213 ◽

2013 ◽

Vol 14 (3) ◽

pp. 390-397 ◽

Cited By ~ 12

Author(s):

Sadhana Shrestha ◽

Takashi Nakamura ◽

Rabin Malla ◽

Kei Nishida

Keyword(s):

Groundwater Level ◽

Seasonal Variations ◽

Shallow Groundwater ◽

Dry Season ◽

Kathmandu Valley ◽

Microbial Quality ◽

Wet Season ◽

Groundwater Levels ◽

E Coli

To develop effective groundwater pollution control strategies for the Kathmandu Valley, Nepal, seasonal variations in microbial quality and their underlying mechanisms must be understood. However, to date, there are no studies that address these topics. In this study, groundwater samples from dug wells were collected during the dry and wet seasons from 2009 to 2012, and Escherichia coli (E. coli) and total coliforms were analysed. Three wells were monitored each month for a year. Microbial concentrations in shallow groundwater were significantly higher during the wet season than during the dry season. Analyses of rainfall and E. coli concentrations in different seasons indicated that a high level of faecal material infiltration during the rainy season may have caused the seasonal variations in microbial quality. A moderate to strong relationship between E. coli concentrations and groundwater level suggested that the rise in groundwater levels during the wet season may be another reason for this variation. This long time-scale survey detected a significant decline in the microbial quality of shallow groundwater during the wet season as compared with the dry season. We propose that the infiltration of contaminants and change in groundwater level are the two probable mechanisms for the observed seasonal differences.

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Physico-Chemical and Oxygen-Hydrogen Isotopic Assessment of Bagmati and Bishnumati Rivers and the Shallow Groundwater along the River Corridors in Kathmandu Valley, Nepal

Journal of Water Resource and Protection ◽

10.4236/jwarp.2015.717117 ◽

2015 ◽

Vol 07 (17) ◽

pp. 1435-1448 ◽

Cited By ~ 4

Author(s):

Rabin Malla ◽

Sarita Shrestha ◽

Saroj K. Chapagain ◽

Maneesha Shakya ◽

Takashi Nakamura

Keyword(s):

Shallow Groundwater ◽

Kathmandu Valley ◽

Physico Chemical ◽

River Corridors

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Risk of diarrhoea from shallow groundwater contaminated with enteropathogens in the Kathmandu Valley, Nepal

Journal of Water and Health ◽

10.2166/wh.2014.036 ◽

2014 ◽

Vol 13 (1) ◽

pp. 259-269 ◽

Cited By ~ 14

Author(s):

Sadhana Shrestha ◽

Eiji Haramoto ◽

Rabin Malla ◽

Kei Nishida

Keyword(s):

Water Treatment ◽

Cryptosporidium Oocyst ◽

Shallow Groundwater ◽

Kathmandu Valley ◽

Giardia Cyst ◽

Quantitative Microbial Risk Assessment ◽

Total Risk ◽

E Coli ◽

Tube Wells ◽

Increased Risk

Shallow groundwater is the main water source among many alternatives in the Kathmandu Valley, Nepal, which has a rapidly growing population and intermittent piped water supply. Although human pathogens are detected in groundwater, its health effects are unclear. We estimated risk of diarrhoea from shallow groundwater use using quantitative microbial risk assessment. Escherichia coli, Giardia cyst and Cryptosporidium oocyst levels were analysed in dug and tube wells samples. E. coli concentrations were converted to those of enteropathogenic E. coli (EPEC). Risks from EPEC in dug wells and from Cryptosporidium and Giardia in both dug and tube wells were higher than the acceptable limit (<10−4 infections/person-year) for both drinking and bathing exposures. Risk from protozoan enteropathogens increased the total risk 10,000 times, indicating that ignoring protozoans could lead to serious risk underestimation. Bathing exposure considerably increased risk, indicating that it is an important pathway. Point-of-use (POU) water treatment decreased the risk six-fold and decreased risk overestimation. Because removal efficiency of POU water treatment has the largest impact on total risk, increasing the coverage and efficiency of POU water treatment could be a practical risk management strategy in the Kathmandu Valley and similar settings.

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Identifying Groundwater and River Water Interconnections Using Hydrochemistry, Stable Isotopes, and Statistical Methods in Hanumante River, Kathmandu Valley, Central Nepal

Water ◽

10.3390/w12061524 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1524

Author(s):

Ramita Bajracharya ◽

Takashi Nakamura ◽

Subesh Ghimire ◽

Bijay Man Shakya ◽

Naresh Kazi Tamrakar

Keyword(s):

River Water ◽

Statistical Methods ◽

Shallow Groundwater ◽

Dry Season ◽

Kathmandu Valley ◽

Water Type ◽

Wet Season ◽

Groundwater Samples ◽

Dry Seasons ◽

Wet And Dry Seasons

Interconnection between river water and groundwater plays an important role in maintaining water quantity and quality in hydrological systems. Furthermore, the exact interconnection is often difficult to observe and measure. This study attempts to explain river and shallow groundwater interconnection in urbanized areas of the Kathmandu Valley, Nepal. Isotopic (δD and δ18O) and chemical analyses were performed on river and groundwater samples, and the results were analyzed using statistical methods to identify areas of interconnection between river water and groundwater. Higher concentrations and positive strong correlations of Na+ with K+, NH4+-N, Cl−, HCO3−, and PO4−-P, and a change of water type from Ca-HCO3 during the wet season to Na-K-HCO3 during the dry season indicate higher contamination in river water during the dry season. Hierarchical cluster analysis was used in grouping water samples into clusters on the basis of isotopic and chemical (Na+ and Cl−) composition. Grouping of river and groundwater samples in one–one clusters from wet and dry seasons shows the presence of interconnection, indicating the contribution of river water in recharging shallow groundwater. These results imply that shallow groundwater found near rivers is chemically contaminated by polluted river water through bank infiltration, in both wet and dry seasons.

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Water Taxation and Subsidy Analysis Based on Consumer Water Use Behavior and Water Sources Inside the Kathmandu Valley

Water ◽

10.3390/w10121802 ◽

2018 ◽

Vol 10 (12) ◽

pp. 1802 ◽

Cited By ~ 1

Author(s):

Rajit Ojha ◽

Bhesh Thapa ◽

Sadhana Shrestha ◽

Junko Shindo ◽

Hiroshi Ishidaira ◽

...

Keyword(s):

Water Use ◽

Rainwater Harvesting ◽

Groundwater Resources ◽

Shallow Groundwater ◽

Water Source ◽

Water Sources ◽

Water Price ◽

Kathmandu Valley ◽

Total Expenditure ◽

Groundwater Exploitation

Groundwater is a major alternative water source used to cover the deficit of water supplied by Kathmandu Upatyaka Khanepani Limited (KUKL), the authority responsible for water supply inside Kathmandu Valley. The groundwater price relative to that of KUKL affects priority of usage, and hence, groundwater resources sustainability. Therefore, taxation or subsidies on water sources become necessary based on their implication on environment. In this study, we evaluate volumetric water price, including initial investment, operation and maintenance (O&M) cost for different water sources, and compare it with the water price of KUKL, Kathmandu. The results show that shallow groundwater is cheaper than KUKL’s water. For groundwater sustainability, taxation on shallow groundwater seems necessary. For the recent water use of 97 LPCD (liters per capita per day) the taxation requirement is Nepalese Rupee (NRs.) 320/month (0.35% of total expenditure) if the initial investment for well construction and O&M cost are considered, and NRs. 626 (0.7% of total expenditure) if only O&M cost is considered. On the other hand, rainwater harvesting and recharging, the measures to cope with groundwater exploitation, might need 40% to 50% subsidy for their initial investment.

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Bacterial community involved in the nitrogen cycle in a down-flow sponge-based trickling filter treating UASB effluent

Water Science & Technology ◽

10.2166/wst.2015.154 ◽

2015 ◽

Vol 72 (1) ◽

pp. 116-122 ◽

Cited By ~ 10

Author(s):

E. F. A. Mac Conell ◽

P. G. S. Almeida ◽

K. E. L. Martins ◽

J. C. Araújo ◽

C. A. L. Chernicharo

Keyword(s):

Bacterial Community ◽

Community Composition ◽

Bacterial Community Composition ◽

Nitrogen Loading ◽

Upflow Anaerobic Sludge Blanket ◽

Uasb Reactor ◽

Anaerobic Sludge ◽

Anammox Bacteria ◽

Ammonium Oxidation ◽

Trickling Filter

Abstract The bacterial community composition of a down-flow sponge-based trickling filter treating upflow anaerobic sludge blanket (UASB) effluent was investigated by pyrosequencing. Bacterial community composition considerably changed along the reactor and over the operational period. The dominant phyla detected were Proteobacteria, Verrucomicrobia, and Planctomycetes. The abundance of denitrifiers decreased from the top to the bottom and it was consistent with the organic matter concentration gradients. At lower loadings (organic and nitrogen loading rates), the abundance of anammox bacteria was higher than that of the ammonium-oxidizing bacteria in the upper portion of the reactor, suggesting that aerobic and anaerobic ammonium oxidation occurred. Nitrification occurred in all the compartments, while anammox bacteria prominently appeared even in the presence of high organic carbon to ammonia ratios (around 1.0–2.0 gCOD gN−1). The results suggest that denitrifiers, nitrifiers, and anammox bacteria coexisted in the reactor; thus, different metabolic pathways were involved in ammonium removal in the post-UASB reactor sponge-based.

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Water Quality Index of southern part of the Kathmandu Valley, Central Nepal; evaluation of physical water quality parameters of shallow wells

Bulletin of the Department of Geology ◽

10.3126/bdg.v19i0.19989 ◽

2016 ◽

Vol 19 ◽

pp. 45-56

Author(s):

Bimal Bohara

Keyword(s):

Water Quality ◽

Water Quality Index ◽

Quality Index ◽

Shallow Groundwater ◽

Quality Parameters ◽

Capital City ◽

Kathmandu Valley ◽

Wet Season ◽

Central Nepal ◽

Shallow Wells

Physical water quality of shallow groundwater of the southern part of the Kathmandu Valley was studied and analysed. Being the capital city of the country, the population is increasing day by dayand consequently the demand of water supply has also increased. Analyses reveal ranges of temperature to be 15.3–24.2 °C, pH to be 5.67–8.07, electrical conductivity to be (EC) 230–2860 μS/cm, and dissolved oxygen (DO) to be 0.09–9.1 mg/L in dry season whereas in wet season temperature, pH, EC and DO ranges are respectively 19.6–27.3 °C, 5.92–8.3, 183–3030 μS/cm and 0.19–7.9 mg/L. Water Quality Index (WQI) map shows that the upstream river areas contain good water quality than the downstream areas. The areas like Kalanki and Satdobato have poor water quality according to the guidelines of Nepal Drinking Water Quality Standard.Bulletin of the Department of Geology, Vol. 19, 2016, pp. 45–56

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