A resident of Kathmandu has adopted ecological solutions to cope with the city’s persistent water shortage and power cuts.
Report of a visit to Dr. Shrestha’s Eco-home on 14 March 2010.
Dr. Roshan Raj Shrestha in his Eco-home. Photo: C. Dietvorst
Dr. Roshan Raj Shrestha built his Eco-home in November 2002. The two and a half story building is neither connected to the city water supply nor to the sewerage network. It uses several kinds of water conservation methods including rainwater harvesting, greywater recycling, ecological sanitation, Solar Water Disinfection (SODIS) and organic waste composting. Dr. Shrestha says he was able to recover the extra investment of US$ 1,000 for his water conservations systems within three years.
The Eco-home has helped Dr. Shrestha cope with Kathmandu’s severe water crisis. The public water supply can only meet half of the actual demand and the city’s Bagmati river is turning into an open sewer. The ground water level is decreasing by 2.5 metres a year due to over extraction. The mega Melamchi Water Supply Project, started in 1998 to tackle Kathmandu’s water crisis, has been plagued by delays.
Rainwater catchment terrace and tanks. Photo: C. Dietvorst
With an average annual precipitation of 1,600 mm in the Kathmandu Valley, Dr. Shrestha found that rainwater would provide with enough water for his family of five. Rainwater is collected on two roof terraces and stored in a 9,000 litre underground tank. Excess rainwater is diverted into a dug well, which acts as an intermittent tank that can store nearly 10,000 litres and also supports shallow groundwater recharge. SODIS is used to treat rainwater for drinking water, while water from the dug well is pretreated first in a biosand filter.
Residents constructing new houses in Kathmandu now get a 10% tax rebate on their building permit fee if they include a rainwater harvesting system in their design. The rebate can reach 30% in other municipalities in Nepal, says Prakash Amatya, the Executive Director of NGO Forum.
No water goes wasted in the Eco-home. Dr. Shrestha has installed a urine diversion dry toilet in his master bedroom. Urine and composted feces are used as garden fertilizer. A small reed bed treatment system is used to recycle grey water for garden watering, washing the car and for an extra flush toilet.
Solar panel. Photo: C. Dietvorst
The latest addition to the Eco-home is a 100-Watt Solar House System (SHS), installed in 2009. The solar panels provide enough energy to light the lamps in the house. Costing US$ 1,000, the system is only affordable for middle-class families, Shrestha admits, but it has proved its worth now that power cuts of up to 12 hours a day have become standard in Kathmandu.
Dr. Shrestha is proud of his model Eco-home. He is happy to give visitors and groups of students a tour. He finds that people readily accept the concept of rainwater harvesting and greywater recycling. They are not so keen about ecological sanitation though, because of the socio-cultural barriers associated with feces.
Dr. Roshan Raj Shrestha is Chief Technical Advisor, South-Asia Region for the UN-HABITAT Water for Asian Cities Programme
- Eco-home for sustainable living, Himalayan Times / UrbWatSan Nepal, 19 June 2009
- Eco-home for sustainable water management : a case study in Kathmandu, Nepal. Ministry of Physical Planning and Works / UN-HABITAT. October 2008 (brochure)
- Shrestha, R.R. (2007). Sustainable water management : a case study in Kathmandu. Presentation at Ecosan – Fortaleza 2007
SODIS water bottle. Photo: C. Dietvorst
Reed Bed Treatment System for greywater recycling. Photo: C. Dietvorst
Urine diversion dry toilet. Photo: C. Dietvorst
Biosand filter. Photo: C. Dietvorst