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The Bagmati River has been widely recognised as polluted in the Kathmandu Valley where municipal waste and sewage flow into its waters. There has been a concentration of studies within the Kathmandu valley but few along the rest of the river to see the effects downstream and document other impacts on and of the river. TheNational River Summit 2014 in Nepal highlighted the need for gathering and essentially sharing more data about river systems in the country to enable better planning and management of water resources and ecosystems in Nepal.
A team comprising young and passionate Nepali scientists went on a 12-day expedition from 12th April 2015 along the Bagmati River starting from the south of Kathmandu to the Indian border to study these issues. The team used the methods for indicating water quality and environmental health and social survey methods among the communities living along the river to document different aspects of human river interaction. During the expedition the team hiked approximately 15km each day, stopping for measurements, interacting with the communities and spent their nights at local accommodation along the Bagmati River.
The data collected during the Bagmati River Expedition will be made openly available for both experts and general population shortly. The experiences and lessons learned from this expedition will be valuable for conducting similar expedition in other rivers within Nepal.
Bagmati River has extensively been used as a medium of sewerage and waste disposal, for agriculture, aquaculture, energy, water supply, mining, and recreation. The needs of society is growing more than ever for water, however, recognition and addressing the impacts resulted due to large scale alteration of rivers to serve human needs goes missing.
Prior to expedition, secondary information about the overall river system is gathered from remote sense mapping, satellite imagery, hydrometeorological stations and previous studies on different aspects of the river system. During the expedition different methods were applied to study several aspects of the river and communities. In addition, the team was open to learn and experiment the local, traditional practices to explore the river system.
GPS mapping and ground-truthing
While travelling mapping of the route, recording of location data and observations was done. This has facilitated thorough understanding of the terrain and ground-truthing of remote sensing information.
Hydrology and hydraulics
Hydrological information about the flow and width of the river was gathered. Though the water level in the river in April (dry season) was low, identification of average and extreme water level was done by observation. Along the way, dams, irrigation canals, diversion canals, embankments, river training structures, bridges, spurs, sand mining areas, barrage, cross draining structures and other hydraulic structures were located. The observation of existing meteorological and hydrological stations was done as far as possible. This will provide information on execution and monitoring of the stations that strongly impact many development projects within the river basin.
The downstream of Bagmati River is prone to flooding and the hydrological data collected assist preparedness and resilience from flooding. The team members will prepare flood hazard map for the Bagmati River basin and identify the most vulnerable communities. The public perception of existing flood preparedness and management has been studied which will be valuable in designing programs that contribute in creating flood resilient society. Invertebrates The invertebrates in a river reflect the water quality as different species prefer different conditions. By studying the invertebrates present at each site and comparing with the water quality data it may be possible to identify certain indicator species. The invertebrates reflect the ecosystem over time not only at the instant of testing.
Biodiversity is one of the major aspects useful in determining the status of river system. The status of birds and fish in the Bagmati River system were identified by observation and communicating with local communities. Several studies have been conducted to assess the status of bird along the Bagmati River within the valley. BRE 2015 aims to study the status of birds along the river downstream of Kathmandu valley since no studies are available for this section of the river.
Through this expedition it is aimed to appreciate the existing human river interaction through observation and conducting structured and semi-structured questionnaire survey. Questionnaires and interviews recorded the interactions and experiences between local communities and the river. The uses of the water, the inputs to the river, historical and observed changes, impacts on communities, and concerns will be documented and compared. Interacting with the communities has allowed looking at the river system from different perspective and identify the core issues on the lives of communities influenced by the river and impacts caused by human intervention on the river system.
The social aspects that this expedition will look at are:
• Water as resource
• Waste management
• River as a whole
Testing the hardness and EC shows overall salt loadings from both natural minerals and other sources. Further laboratory tests will allow identification of the chemicals in the water and their concentrations.
Turbidity and total dissolved solids (TDS) shows the amount of particles in the water. These come from the land and urban runoff, mining in the river for sand and rock and weathering of the substrate. All the particles in the water can carry bacteria and other pollutants so increase the transportation downstream of pollutants and decrease the light available to plants for photosynthesis. PH affects the chemical reactions taking place in the water and at extremes can affect the potential biota.
The sewage and general waste entering the river will be decomposing and using oxygen, therefore the dissolved oxygen test (DO) will show us how much oxygen is left to allow plants and other aquatic organisms to live. The Phosphate measurement can also be used as an indication of eutrophication.
The Nitrate, ammonia and phosphate measurements will also show the nutrients available for plant life. Plants need these chemicals to grow but if in excess they limit the aquatic life by causing algal blooms which reduce oxygen available for other plants and block light through the water. Agricultural runoff, sewage, municipal waste, and industrial waste may increase the amount of these chemicals in the river.
Plastic pollution can be split into two categories, micro and macro. The micro plastic carries hydrophobic pollutants in water and enters the food chain mistaken for tiny organisms and then can transfer the hydrophobic chemicals to the fatty tissues of the animals and pass up the food chain. Macro plastic can choke or block the digestive system of larger creatures and also carry other pollutants. The larger plastic pieces also change the substrate and soil drainage capabilities and block irrigation and drainage systems.
Coliform enters the water from both sewage and land run off especially in areas with farm animals. This can cause gastrointestinal problems for humans (or animals) when the water is drunk untreated. This can also be an issue for irrigation water used for food crops.
A selection of other tests on the water samples include: Chloride, Sulphate, Silicate, Calcium, Sodium, Potassium, and Magnesium – which are useful for plant growth; but in high concentrations can be toxic and reduce growth.
Mercury, Arsenic, Cadmium, Chromium, Copper, Zinc, Lead, and Nickel – which can all have a detrimental effect on living organisms at certain concentration or loading.
The Bagmati River Expedition 2015 took 11 days covering the distance of approximately 170 km from Chobhar to the Indian border. The team hiked approximately 15 Km everyday stopping for measurements every 5km and meeting local communities for the questionnaire survey. Along the route the team passed through the hilly areas into the Terai, and past the Bagmati Barrage. Theywitnessed beautiful landscapes and changes in flow and composition of the river.
The hikes will start from early morning and the itinerary of the expedition will be as follows:
Day 1: Hike from Chobhar to Sisneri/ Kerabari – 15 km
Day 2: Hike to Khairenibesi – 17 km
Day 3: Hike to Okhale – 13 km
Day 4: Hike to Ramechhap -13 km
Day 5: Hike to village -13km
Day 6: Hike to Tinkuna – 13 km
Day 7: Hike to Raigaun – 13 km
Day 8: Hike to Karmaiya – 15 km
Day 9: Hike to Dharmapur/ Rajghat – 15 km
Day 10: Hike to Malahatol – 17 km
Day 11: Hike to Bramhapuri and– 17 km
Day 12: drive back to Kathmandu
The data collected during the Bagmati River Expedition 2015 will be presented and made openly available online for both experts and general population. The results will also be taken back and discussed with communities along the river who have contributed by sharing their valuable experiences and knowledge with the team.
After the analysis of data collected during the expedition, recommendations of further detailed studies wherever necessary will be made. The experience gained and lessons learnt about the methodologies used in this expedition will be analysed and improved for further studies.
We thank you all from the bottom of our heart.
This expedition is being organized by Nepal River Conservation Trust with the support of Bagmati River Waterkeeper, Biosphere Association and Waterkeeper Alliance.
It is sponsored by Lush CharityPot, SonTek/Xylem and 3M.
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