Nepal WASH Blog Water, Sanitation and Hygiene (WASH) & Development in Nepal

April 27, 2011

Apartments to grounds

Filed under: Ground water,Rain Water Harvesting,Urban — Anita Pradhan @ 9:00 am

Groundwater, a reliable resource for drinking and production, is under severe stress in Kathmandu Valley because of the excessive groundwater. The process of urbanisation in Nepal has altered the natural setting of the environment; land surface is completely disturbed reducing groundwater recharging area and direct infiltration of excess rainfall. Ultimately this increases the surface runoff that quickly removes the rainwater, influencing the total amount of infiltration, reducing the subsurface flow and recharge.

A suitable and applicable method of recharging groundwater is through rainwater harvesting. Simple calculations have suggested that substantial amounts of water could be made available if shallow groundwater can be recharged with the help of rainwater. With a catchment area of 656 Km2, Kathmandu Valley receives an annual rainfall of 1,500 mm on an average. Data collected (as of 2065 BS – 2008/09) from the Department of Urban Development and Building Construction (DUDBC) shows that there are altogether 103 numbers of housing and high rise apartments, including both constructed and under-construction. 

The study found that the total theoretical volume of water available for natural recharge (due to rain fall) in the areas covered by 12 apartments and housings (before construction) is 1,251,563 m3. Considering practicality in rainfall recharging, it has been stated that only 15 – 20 percent of the total rainfall in a particular area gets recharged. According to this, the possible recharge that could take place naturally in these areas is 250,313 m3 (20 percent of 1,251,563 m3, i.e. theoretical natural recharge within these areas). Based on Nepal’s experience, the cost of rainwater harvesting installation is 68.8 USD per sq m of the roof catchment but this does not include the cost of preliminary treatment units. 

The total potential volume of water that can be harvested from these 12 apartments and housings is 3.33 times the total volume of water consumption (155,104 m3) in a year. When we generalise from this study conducted in 12 apartments and housings with 681 units, it can be said that 77 percent of the total volume of water can be harvested from built up areas and 41 percent of theoretically available volume of rainwater in any apartment and housings for natural recharge can be tapped for recharging groundwater.

The post is written by Mr Kabir Das Rajbhandari, Programme Manager – Urban, WaterAid in Nepal.

April 21, 2011

Link of the week – 21 to 27 April 2011

Filed under: Ground water,Link of the week,Media,Rain Water Harvesting,Urban — Anita Pradhan @ 9:00 am

Apartments to the grounds

Water management is a very critical aspect of growth and development of any economy, more so in a developing country like Nepal which is endowed with many water resources that need to be conserved, better managed, recharged and channelized for meeting the ever increasing requirements of present trend of urban growth of Nepal which is one of the highest in the South Asian region. Groundwater is a reliable resource for drinking and production, both in terms of quantity and quality. More – Click here for our link of the week – 21 to 27 April 2011

The article is written by Mr Kabir Das Rajbhandari, Programme Manager – Urban at WaterAid in Nepal and published on Republica on Sunday 17 April 2011.

December 22, 2010

Drinking water forever?

Filed under: Climate change,Ground water,MDG — Tags: , , — Barun Kanta @ 3:15 pm

WaterAid has always been big on sustainability; whether it be promoting affordable technology or up-skilling people for the on-going management of services. We’re an organisation committed to innovation; making sure we’re constantly adapting to meet the needs of the changing times. In the spirit of innovation then, I’d like to put forward some suggestions about how WaterAid and our peer organisations may want to adapt our work in the face of the world’s current emerging global crisis: climate change, particularly in the area of drinking water source sustainability. 

- Environmental awareness components could be incorporated into our Water, Sanitation and Hygiene project plans, for example, components that focus on land use patterns, deforestation, extraction of ground water and overgrazing of pasture land.

- The issues of how infrastructure development, housing, upstream diversion, carbon emissions etc impact on drinking water source sustainability should be added to the agenda for discussion

- Research could be conducted into the annual rainfall versus source yield change patterns within the micro watershed areas (or WaterAid project areas). This would help us to understand any emerging trends during the period of a project, (2-3 years) and to explore adaptation strategies. Learning gained from such research can be applied to the engineering and design of future projects.

- Proven science from forestry and botanical fields can be utilized as potential ways of improving source yields. For example we could explore whether bio-engineering techniques close to the source are effective in terms of improving the water infiltration and holding capacity of sub soil. We could increase awareness about the types of species that consume more underground water and therefore reduce source yields and the types of species that can retain more water in the soil for longer periods, contributing to improved source yields during dry seasons.

- We could pilot alternative techniques of improving ground water recharging in WaterAid supported projects in Nepal, for example by tapping rain water, storm water and waste water

- Local knowledge and appropriate technologies that could potentially improve source yields should also be explored, proven and promoted

These are some ideas of how WaterAid is looking to adapt its working practices in the face of the current changing climate but I would be interested in hearing your thoughts and suggestions. Is this the right approach do you think? Is there anything else we need to consider? Please don’t hesitate to share your views below.

Written by Barun Kanta Adhikari, Planning and Monitoring Manager, WaterAid in Nepal

This blog was created by WaterAid under the creative commons licence