Real-Time Fine-Scale Measurement of Water Quality Parameters Along the Bagmati River in the Kathmandu Valley

Real-time fine-scale data was collected along the Bagmati River, in Kathmandu Valley, using mobile and fixed sensor system during the winter season. The water quality parameters; pH, conductivity, total dissolved salt (TDS), salinity, oxygen reduction potential (ORP), dissolved oxygen (DO), and turbidity were measured in the space domain using a fixed sensor and mobile sensor (small rafting boat loaded with sensor) systems. The water quality parameters from the fixed sensor system revealed that the Bagmati River was comparatively less polluted upstream from Gokarna to Tilganga sites and molecular oxygen present in the water was enough to decompose organic pollutants. However, the water quality downstream from Tinkune to Balkhu sites was degraded drastically making it unfit for living organisms. Temporal variation of water quality attributes that human activity significantly enhanced pollutants which severely degraded the water quality in the daytime. The fine-scale space domain heat map data of the mobile sensor system also suggested that the water quality continuously deteriorated from Shankhamul to Sundarighat sites. The ORP value was always negative and decreased with downflow and becomes -263 mV near the Sundarighat Bridge. The mixing of tributaries and increment of solid waste and untreated sewer along the river enhanced pollutants excessively and decreased oxygen level to zero. The results attributed that decomposition of the sewer by microorganism consumed almost all oxygen which produced volatile compounds and generated malodorous odor downstream of Bagmati River.

Development of rainfall – runoff model for extreme storm events in the Bagmati River Basin, Nepal

This study is based on the Bagmati river basin that flows along with the capital city, Kathmandu which is a small and topographically steep basin. Major flood occurring in 1993 and 2002 as stated in the report of DWIDP shows that the basin is subjected to water-induced disaster in monsoon season affecting people and property. This study focuses on the development of a rainfall-runoff model for Bagmati basin in HEC-HMS using the Synthetic Unit Hydrograph (SUH) with Khokana as the outlet. The coefficients for SUH like Lag time coefficient (Ct), peak discharge coefficient (Cp), unit hydrograph widths at 50% and 75% of peak and base time were determined calibrating the Synder’s equation where Ct varies from 0.244 to 1.016 and Cp varies from 0.439 to 0.410. The rainfall-runoff model in HEC-HMS has been calibrated from daily data of 1992-2013 and validated from hourly data for July 2011, August 2012, and July 2013. Furthermore, the model has been tested to compare the discharge for various return periods with the observed ones which are in close agreement. The determination of Peak Maximum Flood (PMF) using the calculated Peak Maximum Precipitation (PMP) is also another application of the model which can be used to design various hydraulic structures. Thus the values of coefficients, Ct and Cp can be used to construct unit hydrograph for the basin. Moreover, the satisfactory performance of the model during calibration and validation proves the applicability of the model in flood forecasting and early warning.

Right to Freedom of Religion and Right to Clean Environment: A case of Bagmati River, Pashupatinath Temple

This research deals with two fundamental rights listed in the Constitution of Nepal, 2015; the Right to freedom of religion and the Right to clean environment with a special reference to the Bagmati River and riverbank in Pashupatinath Temple. The aim of the research is to visualize a clean river while keeping in mind the continuation of centuriesold traditions. The research explores the question of whether the religious practices performed in the river are destructible to the river ecosystem or not. It further tries to see the stance of state regarding its approach to finding the middle ground between the two different fundamental rights. The researchers have assessed this dimension through the study of ritual performance in the banks of Bagmati River, state policy and citizen’s attitude regarding this issue. Bagmati River is considered as a holiest of holy by followers of Hinduism. It provides a sample to understand the significant role played by other Hindu temples and their river banks located in the territory of Nepal in determining the river’ s purposes along with the sustainability of the river and its tributaries.

Faecal pollution source tracking in the holy Bagmati River by portable 16S rRNA gene sequencing

A suitcase laboratory was used for 16S rRNA amplicon sequencing to assess microbial water quality in the holy Bagmati River, Kathmandu, Nepal. SourceTracker analysis and Volcano plots revealed that microbial communities in the downstream part of the river were mainly contributed by untreated sewage. Seasonal variability in the sewage microbiome was reflected in the downstream river water quality. The bacterial genera Acidovorax, Geobacillus and Caulobacter predominated in the upstream sites, while genera containing putative human pathogens and gut bacteria, such as Clostridium, Prevotella, Arcobacter, Lactobacillus, Enterococcus and Streptococcus become prominent in the downstream sites. Marker gene qPCR assays for total bacteria, total coliforms, Human E. coli, Arcobacter butzleri and Vibrio cholerae confirmed the sequencing data trends. Even though basic sanitation provision is nowadays near universal in Nepal, our findings show how inadequate wastewater management may turn an urban river into an open sewer, which poses a public health risk.

Comparative Assessment 0f Water Quality in the Bagmati River Basin, Nepal

Kathmandu, the capital city of Nepal is one of the most populated destinations of the country. The water pollution remains a challenging issue for the sustainable development in the valley despite several pollution control devices, awareness-raising and policy measures. During monsoon period 2018, surface water samples were collected from 10 sites of the Bagmati River and its tributaries within the valley to evaluate the water quality. The different physico-chemical parameters were determined to assess pollution along a 26.5 km stretch between Sundarijal Dam to Balkhu Bridge of the Bagmati River and its selected tributaries. The Electrical Conductivity (EC) ranged from 33-816μS/cm while turbidity ranged from 0.3- 981 NTU and Total Dissolved Solids (TDS) ranged from 16 to 612 mg/l. The ionic concentrations were higher in the lower sections where the population density is high compared to the head waters. The high value of TDS and low value of Dissolved Oxygen (DO) in the lower belts of rivers were due to large inputs of waste water, uncoordinated rapid urban expansion, inadequate waste water treatment facilities and organic loads caused by anthropogenic activities. A comparative study for the water quality variables in the urban areas showed that the main river and its tributaries were equally polluted. From water analysis, downstream sites showed contamination and comparatively polluted among the tributaries and Bagmati River. There is a need to take action plan against polluted site for sustainability of aquatic health of the riverine environment and to address the river for its longer life both by public and government sectors.

Water quality status of groundwater and municipal water supply (tap water) from Bagmati river basin in Kathmandu valley, Nepal

Poor waste management in the Kathmandu valley has deteriorated the water quality of surface and groundwater sources. The objective of this study was to assess the status of water quality (WQ) in drinking water sources of groundwater and municipal supply (tap water) from the Bagmati river basin in Kathmandu valley. A total of 52 water samples from deep tube-well, tube-well, dug-well, and tap water were collected and analyzed for physical, chemical, and microbiological parameters using standard methods. The results revealed that chloride, total hardness (TH), copper, nitrate, sulfate, and turbidity were within the recommendations of the National Drinking Water Quality Standard (NDWQS). Total coliform (TC) bacteria in 84.6% of the samples exceeded drinking water guidelines. Similarly, the isolates of different enteric bacteria, namely Escherichia coli (21.5%), Citrobacter spp. (20.9%), Klebsiella spp. (19.8%), Proteus spp. (13.9%), Enterobacter spp. (8.72%), Salmonella spp. (5.8%), Shigella spp. (5.2%), and Pseudomonas (4.1%) were identified in the samples collected from the respective sources. Out of the 52 water samples, 7.7% of samples had fecal contamination of somatic coliphage. The groundwater and municipal water supply in the study area are not safe for drinking purposes. Treatment of water is required before its use for household applications.

Water quality assessment along the segments of Bagmati River in Kathmandu valley, Nepal

Identification of pollution in the river helps to know the state of the river ecosystem. The study aimed to assess the water quality of the Bagmati River by analyzing the physical and chemical condition and comparing it with national and international standards. The water samples were taken from 10 different sampling sites along the length of the Bagmati River inside Kathmandu Valley, i.e., from Sundarijal to Saibubhanjyang. A total of 30 physical and chemical parameters were examined. The results showed that the pH ranges from 6.0 to 7.5 in different sampling locations. The highest dissolved oxygen (DO) (8.5 mg/L) was found at the upstream while the lowest, i.e., 3.4 mg/L and 3.5 mg/L, was found at the urban core of the valley, i.e., Teku and Thapathali, respectively. The BOD, COD, oil, and grease considerably exceeded the WHO and national generic effluent standard. Most of the heavy metals in the river water were below the range of standard. The concentrations of all pesticides were found below 10 µg/L except heptachlor exoepoxide. The highest concentration of heptachlor exoepoxide (75 µg/L) was found at Balkhu, followed by Thapathali (69 µg/L) and Teku (62 µg/L). The result showed that the middle-urbanized segment, i.e., from Gokarna to Teku, is heavily polluted than the upstream and downstream segments of the river. The results are of great significance for policy formulation and implementation of the ecosystem restoration project of Bagmati River in the Kathmandu valley, Nepal.

Physico-chemical Parameterization and Determination of Effect of Tributaries on Enhancement of Pollutants in Bagmati River

Water quality parameterization is a great concern because chemical contaminants and microbiological impurities including pathogenic bacteria may pose a health risk and unfit for its domestic use. Alkalinity, pH, conductivity, chlorine demand, turbidity, and ammonia were measured to characterize the water quality of the Bagmati River. The effect of tributaries on Bagmati River was determined by sampling water from five different sites such as Pashupati (B-1), Shankhamul (B-2), Kupondol (B-1), Balkhu (B-4), and Jalbinayek (B-5) sites. The water samples B-2, B-3, B-4 and B-5 were less turbid but black in color while water sample B-1 was more turbid but grey in color. The pH of water samples ranged from 6.7 to 7.3. The alkalinity, conductivity and chlorine demand were 60 ppm, 95.7 µs and, 5.44 ppm, respectively for B-1 sample and increased almost continuously from B-2 to B-5 sample. The alkalinity was 360 ppm, conductivity was 862 µs and chlorine demand was 23.7 ppm for the last sample (B-5). The concentration of ammonia in the B-1 sample was only 0.0625 ppm whereas it was 3.32 ppm in the B-5 sample. The enhancement of chlorine demand and concentration of ammonia attributed that tributary and local effluent loaded extremely high levels of pollutants into the Bagmati River which might include pathogenic microorganisms. The random chance of some parameters like pH, conductivity, ammonia, turbidity along the Bagmati River indicates the impacts of different tributaries on Bagmati River. The chorine demand showed a positive correlation with conductivity, alkalinity and ammonia while the negative correlation with turbidity. This revealed that the conductive alkaline pollutants consumed more chlorine than colloidal particles. From the study it is considered that the Bagmati River water contains natural as well as anthropogenic pollutants which is extremely hazardous not only to the people using river water but also for the living organism rely on the river.