Kathmandu, October 23
Kathmandu Valley’s major rivers are becoming severely polluted as they flow through urban areas, with untreated sewage and other waste leaving sections of the Bagmati, Bishnumati, Dhobikhola, Nakhu Khola, Tukucha and Hanumante rivers virtually indistinguishable from open sewers, according to a water quality report.
The River Water Quality Analysis Report for August 2026, prepared by the High-Powered Committee for Integrated Development of the Bagmati Civilization, found that water quality deteriorates sharply downstream from the rivers’ sources as sewage, organic waste and chemical pollutants enter the waterways.
The Bagmati’s water is relatively clean at its source in Sundarijal and may be suitable for drinking after basic treatment. However, by the time it reaches Gokarna, the river has already been heavily contaminated by direct sewage discharge. Pollution increases further around Jorpati and Guhyeshwari.
The committee collected Bagmati water samples on August 2 and 3 at multiple locations, including Sundarijal, Gokarna, Jorpati, Guhyeshwari, Aryaghat, Minbhawan, the Manohara-Bagmati confluence, Thapathali, the Bagmati-Bishnumati confluence, Sundarighat and Chobhar.
The findings show that the river’s condition fluctuates along its course, with some improvement near Aryaghat following treatment at a water treatment plant. However, pollution rises again downstream, particularly in densely populated urban areas.
Bagmati becomes critically polluted downstream
At Sundarijal, the Bagmati has relatively high dissolved oxygen, low turbidity and low levels of faecal coliform bacteria, indicators of contamination from human and animal waste. The relatively low levels of organic and chemical pollution also suggest that the water is in better condition near its source.
By Gokarna, direct sewage discharge has sharply increased faecal contamination. Pollution intensifies further at Jorpati and Guhyeshwari, where turbidity also reaches high levels.
The river’s condition deteriorates further in the central urban areas. At Thapathali, turbidity is extremely high and dissolved oxygen is very low, leaving the water unsuitable for aquatic life. The report also records substantial organic and chemical pollution, alongside increased faecal coliform levels.
By the time the Bagmati reaches Chobhar, the combined effects of pollution entering from tributaries and urban settlements have left the river in an extremely degraded state. The report describes the water as effectively resembling sewage and says it is extremely unsafe for uses such as irrigation.
Dhobikhola deteriorates sharply after its source
The Dhobikhola follows a similar pattern, with relatively clean water at its source in Chapali but severe pollution further downstream.
The committee collected samples from six locations along the river on August 6. At Chapali, dissolved oxygen levels are high, turbidity is low and contamination from organic and chemical waste is limited.
However, by Ekta Basti, the river’s water quality has deteriorated significantly. Dissolved oxygen falls, turbidity rises and faecal coliform levels increase sharply, indicating the entry of sewage and other pollutants.
Pollution is particularly severe around Gopikrishna and Ratopul. At Ratopul, the report identifies extensive waste contamination, high turbidity, very low dissolved oxygen and elevated faecal coliform levels associated with direct sewage discharge.
The river remains heavily polluted around Buddhanagar. At its confluence with the Bagmati, the two rivers’ polluted waters mix.
Bishnumati turns into sewage by Khusibu
The Bishnumati is relatively clean near its source in Budhanilkantha, where water quality is considered suitable for aquatic life and contamination levels are comparatively low.
But the river becomes heavily polluted before reaching Tokha. Dissolved oxygen decreases, turbidity rises and faecal waste and other pollutants enter the water.
At the confluence with the Mahadev Khola, pollution reaches a particularly concerning level, with conditions unsuitable for aquatic life.
By Khusibu, the river has effectively taken on the characteristics of sewage, a condition that continues towards Teku. The report describes the river at this stage as severely degraded, with oxygen levels falling to zero and strong odours accompanying the polluted water.
Nakhu Khola polluted from its upper reaches
Unlike rivers that begin relatively clean before deteriorating downstream, the Nakhu Khola shows signs of pollution from its upper reaches.
Samples collected on August 11 revealed high turbidity and substantial soil and sand content near an asphalt plant. However, pollution associated with organic sewage was relatively low at that point.
Water quality remained similarly turbid near Kantipur Colony, without a comparable increase in other pollution indicators.
By Rani Bu Bridge, however, sewage contamination had severely degraded the water. Pollution reached a critical level at the confluence of the Nakhu Khola and the Bagmati, making the water harmful.
Tukucha loses its river characteristics
The Tukucha is in an even worse condition, according to samples collected on August 4.
At Putalisadak, a densely urbanised area, the river has extremely low dissolved oxygen, high turbidity and elevated faecal coliform levels. These indicators point to direct discharge of sewage into the waterway.
By the time it reaches the Kalmochan Ghat area, the Tukucha has effectively lost the characteristics of a healthy river and has become heavily polluted by sewage.
Hanumante also suffers from sewage and chemical pollution
The Hanumante Khola, which flows through Bhaktapur, has relatively good water quality near Gonsa and Brahmayani Ghat. The water in these upper stretches has low turbidity and relatively low faecal coliform levels, making conditions more suitable for aquatic life.
Further downstream, pollution begins to increase around Bhadra Khola, where sewage and chemical fertiliser enter the waterway. Dissolved oxygen decreases while coliform levels rise.
By the time the river reaches the Bira Khola area, it is heavily polluted. At the confluence with the Kasan Khola, oxygen levels fall further. The report also records high turbidity and a significant increase in suspended solids at the confluence of the Ghatte Khola and Hanumante.
The committee collected Hanumante samples on August 14.
A wider urban pollution problem
The findings across the six river systems point to a common problem: water quality deteriorates as rivers pass through settlements where sewage and other waste enter the waterways.
While some upper stretches retain conditions that can support aquatic life, pollution downstream reduces dissolved oxygen, increases turbidity and raises the concentration of faecal bacteria. These changes undermine the rivers’ ecological health and make their water increasingly unsafe for human use.
The report highlights the scale of the challenge facing efforts to restore Kathmandu Valley’s rivers. Without controlling sewage discharge and other sources of pollution along their courses, improvements near the sources are unlikely to translate into healthier rivers downstream.
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