ADB_book_18 April.qxp - Himalayan Document Centre - icimod

Bagmati River PollutionThe Bagmati River with its tributaries—the Bishnumati, Manohara, Dhobikhola, Icchumati (Tukucha), Nakkhu,Hanumante, Karmanasa, and Godavari—is the main river in Kathmandu Valley. The Bagmati River system is extremelyimportant for both the Valley and downstream areas. The river system has been the Valley’s main source of water fordrinking and irrigation, and an important component of its ecosystem. It also has tremendous religious, cultural, and socialsignificance—the river is worshipped by millions of Hindus in Nepal and India. Several temples (including Pashupatinath),ghats, and maths are located along the banks of the Bagmati River and its tributaries. People perform various religious andcultural activities and rituals, and take holy ablution there. It is often referred to as the Ganges of Nepal.Over the last few decades, the Bagmati’s condition has gradually deteriorated and it has become the most pollutedriver in Nepal. Direct disposal of untreated sewage and throwing garbage into the river system, withdrawal of sand, tappingriver water to meet the water demand of the increasing population as well as of the increasing number of factories, andencroachment of the river banks are the main causes of the degradation and extreme pollution. During the dry season, thevolume of water is so reduced and the river is so polluted that it looks like an open sewer. One study conducted by theEnvironment and Public Health Organization (Dhakal 2003) showed that the chemical oxygen demand (COD) is in excessof 400 mg/l within the city and immediate downstream areas. This is alarming, as the normal COD of river water is around40 mg/l. However, as the river flows out from the Valley, the pressure on it reduces considerably and due to natural selfpurificationprocesses, the COD is reduced to 25 mg/l by the time it reaches Gaur in Rautahat.The effects of this extreme pollution are many. The most visible is aesthetic: a highly polluted, sewage-filled, blackstream flowing through the heart of the city obviously destroys the city’s beauty. Pollution has also affected cultural andreligious activities and rituals—ritual bathing is almost a thing of the past, and people do not use river water even whenperforming puja. The health of the people living along the banks is also at risk. Villagers immediately downstream ofKathmandu have now stopped using the river water for irrigation, and fishermen have stopped their traditional occupation,as there are no fish left in the river. The river is almost dead, and aquatic life is almost nonexistent when the river reachesChobhar area (Dhakal 2003; Phuyal 2003).including toxic waste, to roadside drains and openspaces. The only industrial wastewater treatmentplant, at Hetauda, often encounters operationaldifficulties (ADB 2000; IUCN 1992). Thus, the rivershave become major places for disposal of untreatedsewage and industrial effluents, as well as urbansolid waste dumping. This is the principal cause ofsurface water pollution. As a result, many rivers inurban areas have practically become open sewers,especially during the dry season. The adverse effectsof this are many, such as eutrophication affectingriver ecology and aquatic life, and making the waterunfit for most human uses including bathing andirrigation. The effects are not confined to urbanareas, but can be felt for long distances downstream.Groundwater in most urban areas iscontaminated due to seepage from pits and septictanks, and open defecation. Studies of water qualityfrom shallow aquifers throughout Nepal have foundthat the fecal coliform contamination consistentlyexceeds World Health Organization (WHO)guidelines for water for human consumption (ADB2000).Drinking water supplies are often pollutedthrough runoff into storage sites or cross-leakagesbetween overloaded sewer lines and water pipes(IUCN 1991). Sewage is the primary cause of drinkingwater pollution. Nearly one-third of the urbanpopulation of Nepal do not have direct access to apiped water supply. The availability of improvedWaste Dumping along the Bagmati River in Kathmanduwater supply, including non-piped, within 15 minutesof walking distance is nearly 80% (WaterAid Nepal2004; CBS 2004). Even those with access do notnecessarily have adequate water. The quantity ofwater delivered by the water supply system is mostlybelow 50 liters per capita per day and the qualityoften falls below WHO recommendations (ADB2000), mainly due to bacteriological contaminationcaused by poor sanitation facilities. Unservedhouseholds obtain water from traditional watersources such as wells, rivers, springs, or ponds.These sources are typically unprotected, and waterquality is usually poor. Water pollution is the mostserious public health issue in Nepal. Contaminateddrinking water and lack of sanitation facilities resultB. PradhanChapter 8: Urban Environment111