Urban Water Management
This article was supposed to be written long before when a little school child drowned in uncovered storm water sewer in the monsoon of 2017 or even before the dying “Punyamata River” flooding the Banepa municipality in 2016. Obviously, the incident drawn a lot of attention in national and international media. Urban flooding is a common these days during the strong storm events. Urbanization is a worldwide phenomenon. If there is no proper planning and management of urban settlements and its infrastructures it can create an environmental turmoil. The urban centers in Nepal are growing rapidly as a result of growing population and economy. The urban population in Nepal has increased from 13.9% in 2001 to 17% of the total population in 2011 with the average urban population growth rate of 3.38%[1]. Moreover, the number of towns has been increased from 10 in 1952 to 217 in 2016. According to the population 2011 census, the projected urban population in the year 2016 would be 5.0 million from 4.5 million in 2011 and the population in 2030 would be double i.e. 10 million1.In addition, the floating population (migration) and tourists in the city areas are expected to cause pressure on the available resources. Moreover, these growing urban centers are facing severe challenges of haphazard planning and inadequate infrastructures. The fact that the access of households to piped water supply in urban areas in Nepal has declined from 68% in 2003 to 58% in 2010 is an example of developmental activities that could not pace-up with increasing population. Urbanization has stressed available water resources due to increasing population, poor planning, poverty, pollution as well as competing demands on limited resources. Therefore, the current situation demands smart management of water to properly address the associated issues especially in urban water management sector.
In Nepal, the coverage for basic water supply and basic sanitation facilities were 86.45 % and 81.95 %, respectively (SEIU-MWSS, 2016). Though, the basic sanitation coverage is increasing, the wastewater infrastructures in Nepal is still inadequate, outdated or non-existent in many cities. Untreated sewage from human settlements along with industrial wastewater is polluting the surface as well as ground water. Continual growth of urban areas as well as the increasing demand for water resources likely to increase the wastewater production in large metropolitan cities like Kathmandu. The estimated WW generation in the capital city is around 75 million liters per day (MLD) while the installed capacity is only around 35 MLD and only a few treatment facilities are functional. Nepal government is upgrading and constructing five centralized wastewater treatment plants (90.5 MLD capacity) at the major urban centers in the capital city, Kathmandu. However, an estimated wastewater production will be 200 MLD after the operation of Melamchi Water Supply Project in 2017-18 as it is going to bring 170 MLD of drinking water. This additional wastewater is definitely going to stress our existing urban sewers which are mostly combined sewers carrying both stromwater from the rainfall events and wastewater produced from households, industries and other commercial institutions. The development of sewer system in the country has started only towards the 1920s that include 55 km long brick channel to collect and dispose combined sewer and rainwater runoff in Kathmandu and Patan (Nyachhyon,2006, Nepal Country Paper)[2]. With 232 km long sewer system developed in Kathmandu Valley, only 40% of the population has access to sewer facility[3]. The major water related impacts such as hydrological disruption, ground water depletion, downstream flooding, receiving stream water quality degradation, stream ecosystem damage and among other are becoming major challenge. Due to unplanned urbanization, flooding from overwhelmed urban storm drains and sewers during extreme rainfall events may become more common in the future in the light of the impact of climate change. The urban flood events are getting frequent due to increase in the intensity of the rainfall[4]. Several parts of Banepa and Thimi municipality were flooded during the monsoon rain of early June, 2016. Every monsoon several parts of Kathmandu city gets flooded. The surface as well as groundwater sources are deteriorating as a results of the impact of urbanization[5]. The surface water bodies are contaminated heavily with domestic and industrial effluents due to lack of effective wastewater treatment as most of the wastewater treatment plant fails to operate. As a result, the ground water sources are also contaminated with nitrate and E. coli. Furthermore, the groundwater level is gradually decreasing over the time as a result of over-extraction, for example, in Kathmandu Valley the average groundwater depletion was 13 – 33 m during the years 1980 – 2000 and 0.37 – 7.5 m during 2000 – 2008[6]. This situation can worsen if the rising water supply demands are not met.
Conventional urban water management plan has failed to deliver the services as it is based upon isolated planning of each component of water resources. It neglects to acknowledge cross-scale interdependencies among fresh water, wastewater and storm water. Therefore, it remains disconnected from broader urban planning processes and basin level management. So, there is the urge of paradigm shift at the broader perspective.
An integrated water management strategy, known as a “Whole-of-water-cycle (WoWC)” could provide a framework for interventions over the entire water cycle and a reconsideration of the way water is used and reused. This approach takes into account evidence-based approach to utilize all water resources available to us, i.e. water source (rainfall, surface water & ground water), drinking water, storm water, wastewater, offers more diverse and versatile options for dealing with larger and more complex urban water challenges. It not only encompasses the different water resources within an urban catchment but also addresses tradeoffs among water users: agriculture, industry, household, and ecosystems. This approach even plans for protection, conservation and exploitation of water resources at their sources.
Let’s wait to see the urban drainage turmoil in coming monsoon!
[1]Central Bureau of Statistics (CBS). 2011. National Population and Housing Census 2011. Nepal
[2]Nyachhyon BL. 2006. Service Enhancement and Development of Sanitary Sewerage System in Urban and Semi-Urban Settings of Nepal. Economic Policy Network, Policy Paper No. 23. Ministry of Finance, Government of Nepal and Asian Development Bank
[3]ICIMOD, MOEST/GON and UNEP. 2007. Kathmandu Valley Environmental Outlook. International Center for Integrated Mountain Development (ICIMOD), Ministry of Environment Science and Technology of Government of Nepal (MOEST/GON) and United Nations Environmental Program (UNEP).
[4]Department of Hydrology and Metrology. Government of Nepal. URL: http://www.mfd.gov.np/city?id=31[accessed: 23.08.2016]
[5]Niranjan Shrestha, Alaka Rijal, Ram Kumar Regmi and Binaj Kumar Mishra, Current Status of Water Environment in Kathmandu Valley, Nepal. Water and Urban Initiative (WUI), a research project of the United Nations University Institute for the Advanced Study of Sustainability (UNU-IAS).
[6]V.P. Pandey, S. Shrestha and F. Kazama. 2012. Groundwater in the Kathmandu Valley: Development dynamics, consequences and prospects for sustainable management. European water 37: 3-14
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