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Sponge Cities: What are those?

The 34 hectares urban storm water park in the city of Harbin in northern China is an example of successful Sponge City intervention. The storm water park provides multiple ecosystems services: it collects, cleanses and stores storm water and lets it infiltrate it into the aquifers. At the same time it protects and recovers the native natural habitats and provides an aesthetically appealing public space for recreational use. Photograph:

The 34 hectares urban storm water park in the city of Harbin in northern China is an example of successful Sponge City intervention. The storm water park provides multiple ecosystems services: it collects, cleanses and stores storm water and lets it infiltrate it into the aquifers. At the same time it protects and recovers the native natural habitats and provides an aesthetically appealing public space for recreational use. Photograph:

Sponge City: Is it another term on the growing list next to:

  • regenerative,
  • sustainable,
  • green,
  • eco,
  • resilient,
  • low-impact,
  • future proofing,
  • zero-carbon,
  • smart and so on?

What is a Sponge City?: A re-imagining of the urban environment, where almost every raindrop is captured, controlled and reused. The Sponge City indicates a particular type of city that does not act like an impermeable system, not allowing any water to filter through the ground, however more like a sponge, to actually absorb the rainwater. This water is then naturally filtered by the soil and allowed to reach into the urban aquifers. This allows for the extraction of water from the ground through urban or peri-urban wells. This water can be easily treated and used for the city water supply. This also contributes towards making the Green Spaces as Adaptive Measures to Flooding in the Face of Climate Change.

Sponge cities has actually gained a huge amount of support recently, especially in China. The Chinese government has already chosen 16 pilot cities and allocated to each of them between 400 and 600 million yuan for the implementation of innovative water management strategies that would gradually transform these cities into “Sponge Cities”.

Key issues the Sponge City wants to solve?

There are mainly five drivers of urban water crisis (population, rising middle class, climate change, tainted water, leaks) according to a recent book by Seth M. Siegel titled, Let There Be Water: Israel’s Solution for a Water-Starved World. The sponge cities work towards solving these crises by doing the following:

  • Less water available in urban and peri-urban areas. Since less rain water is allowed to filter through the urban soil, less water is available to be extracted from aquifers in urban and peri-urban areas.
  • Polluted water discharged into rivers or the sea. Much of rainwater mixed with wastewater is discharged untreated into rivers. The more impermeable the city is, the more water will be mixed with wastewater and will not be able to be treated but discharged directly into rivers.  This increases the level of pollution of local water bodies.
  • Degradation of urban ecosystems and green areas due to sprawling. This leads to a considerable loss of urban biodiversity, a drop in available green areas for natural ground filtration of storm water, a decrease in CO2 capture by plants, fewer spaces for natural cooling through urban green microclimates and generally less liveable, healthy, comfortable and attractive public spaces.
  • Increase in the intensity and frequency of urban flooding  As the absorbing capacity of the urban surface is decreased, storm flooding risk is increased. Flooding leads to increased groundwater pollution and has considerable impact in terms of damage to properties and health related issues. The most recent examples are the flooding incidences in the US and Chennai, the southern Indian capital city of the state of Tamilnadu in 2015.

Sponge City needs in practice:

A sponge cities needs to be abundant with spaces that allow water to seep through them.

  • Contiguous open green spaces, interconnected waterways, aquifers, channels and ponds across neighborhoods that can naturally detain and filter water as well as foster urban ecosystems, boost biodiversity and create cultural and recreational opportunities.
  • Green roofs that can retain rainwater and naturally filters it before it is recycled or released into the ground.
  • Porous design interventions across the city, including construction of bioswales and bioretention systems to detain run-off and allow for groundwater infiltration; porous roads and pavements that can safely accommodate car and pedestrian traffic while allowing water to be absorbed, permeate and recharge groundwater; drainage systems that allow trickling of water into the ground or that direct storm water run-off into green spaces for natural absorption
  • Water savings and recycling, including extending water recycling, particularly of grey water at the building block level, incentivize consumers to save water through increased tariffs for increase in consumption, raising awareness campaigns, and improved smart monitoring systems to identify leakages and inefficient use of water.

Benefits of a Sponge City:

The obvious short and long term benefits include:

  • More clean water for the city. Replenished groundwater and thus greater accessibility to water resources for the cities.
  • Cleaner groundwater due to the increased volume of naturally filtered storm water.
  • Reduction in flood risk as the city offers more permeable spaces for the natural retention and percolation of water.
  • Lower burdens on drainage systems, water treatment plant, artificial channels and natural streams.
  • Greener, healthier, more enjoyable urban spaces. Greener urban spaces improve quality of life, create more pleasant landscape aesthetics and recreational areas that are enjoyable and attract people.
  • Enriched biodiversity around green open spaces, wetlands, urban gardens and green rooftops
  • Solves the Twin Crises of Energy and Water Scarcity for most major and upcoming cities across the world.

Countries like India and the US should take a cue from China and learn from their experience for implementing the Sponge Cities.

Disclaimer: This article has been adopted from the original article that appeared in the Power to the People blog of World Future Council. All views and hyperlinks provided have been taken from my past posts and information available online. Please acknowledge the appropriate sources while citing.

Another decade, another take on water cooperation




It is widely agreed that initiating dialogue and cooperation on water and related issues at all levels, along with the identified stakeholders, is one approach (out of many) that needs to be emphasized, scaled and strengthened even further. That said it means that underrepresented groups such as women, the grassroots communities and civil society organizations cannot be left out from the dialogue and decision making process. At the same time it cannot be ignored that both technical and political solutions are needed to reap the benefits and alleviate the danger from proposed solutions, especially the ones around trans-boundary infrastructure projects.

International Cooperation in water management:

In 2003, the United Nations General Assembly declared 2005 to 2015 to be the decade of “water for life”. In summing up the last 10 years, it is noted that “water cooperation” had been promoted widely. Water cooperation is described to have the potential to enable peace and sustainable development. We cannot ignore the following  too for making the cooperation more effective:

Way forward until 2025:

Water cooperation and issues and challenges surrounding it being global, it is true that no one country or approach can solve the rapidly increasing problems around water. Water related issues and challenges have a wide range such as the availability of water in the natural and man made channels, clean and safe drinking water for all, water for irrigation, wastewater management in the wake of rapid urbanization and so on to name a few.
Looking at 2025, we will need to consider the opportunities such as market based approaches, economical, geo-political, non-tangible and non-materials as well as service based value attached to the water and water resources. Esoteric approaches may not work in these situations and settings.

Freshwater vulnerable cities due to rapid urbanization

Manhattan skyline in the view ©RohithRoy

Manhattan skyline in the view ©RohithRoy


According to a new research, more than 40% of the world’s great cities supplied by surface water could become freshwater vulnerable to shortages and drought by 2040. More than 3 out of 10 were already vulnerable in 2010, the study states.

Factors responsible:

For the first time in history, more than half the world’s population is now concentrated in cities, and this proportion is predicted to increase to two-thirds by 2050. Cities expand near abundant water supplies. As population explodes, so does the demand. The environmental flows (E-Flows) remain much the same.
Some major cities are already under drought stress. Chennai and Hyderabad in South India had to be supplied with tankers in 2004 and 2005 and so was Delhi in North India. These cities in India depend on River Krishna and River Yamuna’s freshwater resources. Delhi also gets part of it’s supply from neighboring states of Rajasthan and Haryana.  São Paulo in Brazil in LatAm is now at a crisis point and cities in CA are struggling with unprecedented droughts.

Demand and supply:

Environmental scientist Julie Padowski and Steven Gorelick, director of the Global Freshwater Initiative at Stanford University in California, analyzed supplies to 70 cities in 39 countries, all of them with more than 750,000 inhabitants, and reliant on surface water.

City supply system vulnerability

City supply system vulnerability

Freshwater vulnerability:

Vulnerability is the failure of an urban supply basin to meet demands from human, environmental and agricultural users, and they set the supply target as 4,600 litres per person per day. This factors in “virtual water”, defined as the total volume of water needed to produce and process a commodity or service.
They proposed three different kinds of measure of supply.

  • If a city failed to meet one or two of these metrics, it was considered threatened.
  • If it failed to meet all three, it was rated as vulnerable.

The six cities that will begin to face water shortages are Dublin in Ireland, Charlotte in the US, Ouagadougou in Burkina Faso, and Guangzhou, Wuhan and Nanjing in China. Curiously, none of the cities in India have been listed to be freshwater vulnerable in the assessment.  Most of the cities that are already vulnerable rely on reservoirs, and the study implies that urban planners will need to think about

Precipitation data:
The article states that the scientists cannot rely on rainfall data because, the network of dedicated satellites “fails to meet operational data needs for flood management”.
4 of the 10 satellites have exceeded their design life. There are already weak spots in the network, especially in developing countries, which means that floods could take people by surprise. When 4 fail to deliver, the potential for catastrophe will be even worse. The scientists call for better international co-ordination of satellite replacement.

Vulnerable versus threatened status:

For both categories reservoir and river supplied cities were considered vulnerable, if all demand thresholds were violated. If a city had one or two but not all three metrics exceeding a threshold, then it was considered threatened, as these supplies may no longer be able to support urban demand without causing damage to agriculture, the environment, or both. The scientists referred to a city as susceptible if it has either threatened or vulnerable status; the number of susceptible cities is the sum of those that are threatened or vulnerable. Finally, cities were considered non-threatened if no demand thresholds were violated.

Future predictions:

Importantly, the scientists did not factor in climate change, which might make conditions worse. Instead, they simply considered current demand and supply, and then projected demand in 2040.
Of the 70 cities, they found that 25 (36%) could already be considered to have become vulnerable by 2010. By 2040, this number will grow to 31 (44%).

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World Water Day 2015 #Waterisliberating



‘Water and Sustainable Development’ is this year’s World Water Day theme. It is much broader compared to the past year’s themes. UN’s official email says “This year, we need you, more than ever, to celebrate water. And we need you to help others think about what water means to them. For World Water Day and in the months that follow, we invite you – and the rest of the world – to take a piece of paper and write what water is to you.”

This year’s theme also gives us a chance to reflect on how interconnected water issues are. Water is a critical component of urbanization, energy, industry, agriculture, food, equality, economy, environment, health, and security. This includes the 748 million, who cannot access an improved source of drinking water, despite the progress and development being made worldwide.

Earlier this year, World Economic Forum also announced water to be the top global risk. This highlights water’s role in critical and myriad fields, from India’s agricultural, urbanization and transboundry resources struggles, China’s growing middle class’s ordeal to “water wars” in the Middle East, and population dynamics affecting water scarcity in Nepal.

For me #wateris what I have seen to be one the costliest resources in various rural and urban parts of India. My #waterisliberating is for all the women and girls, who spend countless hours of their lives fetching water for their households for potable and other purposes.

This article has been adopted from the original articles that appeared on theflipsideofdevelopment over the years. To read the original articles, please click on the hyperlinks above.

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Smart Cities need to be futureproof too

Ducks snorkeling in Ganga (The Ganges) ©NitinKaushal/WWF-India

Ducks snorkeling in Ganga (The Ganges) ©NitinKaushal/WWF-India

Cities around the world are continually growing as they attract people, resources and ideas, and are drivers of global and national development. This is most evident in countries like India, where by 2030, 70% of the GDP and 70% of new jobs will come from cities.

The Latest:

Prime Minister, Mr. Modi government’s ambitious “100 Smart Cities” plan is making urban planning lucrative. India has been plagued by rapid and haphazard urbanization. People are migrating to the cities at an unprecedented rate. This creates problem, which is two folds. It makes the rural population dwindle and impacts the agriculture, eventually threatening food security. On the other hand, the migrating population increases pressure on the limited urban resources such as housing, water, wastewater management systems, electricity, transport, communication and so on.

India is estimated to have over 400 million urban inhabitants by 2050.  This is more than any other country in the world. Managing such growth will require unprecedented levels of planning and investing in housing, infrastructure and utilities especially water supply and wastewater management.

Payment for Services:

A leaking wastewater pipeline

A leaking wastewater pipeline

People believe that amongst other utilities, water should be free in a city and expect that government and utility providers should take care of maintaining them.  Water systems cost $3-$6 per month per household, in countries like India. At first glance it does not seem a lot, however when people make only $1-$3 a day, it can be a lot. When water supply  and wastewater management systems fail, poor people suffer the most in the cities. Urban poor, especially women and girls, do not get any return on their money or time invested.

Futureproofing Smart Cities’ water systems:

Cities will be smart if  water and wastewater services are planned based on the below criteria:

Smart cities do all the above mentioned and more by:

  • Integrating data from a wide range of sources–surveys, closed circuit cameras, utilities, public works and services, citizen reports and service providers to aid informed decision-making by policy makers, businesses and citizens.
  • Adapting continuously in the face of rapidly changing urban landscape, both in chronic (traffic, infrastructure, public utilities) and acute or long term events (upcoming neighborhoods, natural disasters) etc.
  • Building utilities and systems around the needs of population.
  • Providing essential infrastructure and services that make cities liveable.
  • Putting people at the center of all planning processes and projects.
Solar Powered water ATMs in Ahmedabad, India ©

Solar Powered water ATMs in Ahmedabad, India ©

Way ahead:

“Creative cities”, “sustainable cities”, “eco-cities”, “resilient cities” and “liveable cities” and now “Smart Cities”.  Doesn’t matter what name you call it, India, in order to sustain the growth of its robust economy and provide for growing needs of its urban populations, needs to recognize the value of its natural capital/resources and biocapacity in the planning process. It needs to develop strategies and policies to promote innovative solutions to foster efficiency in the use of limited urban resources, disposal of wastes and wastewater management and create opportunities for urban growth among others by

  • Maintaining water resources and wastewater systems over long term
  • Enabling reasonable support to issues that impact large urban population especially marginal and poor
  • Identifying costs and financing mechanisms for addressing these issues for present and future

This article has been adopted from the original sources. To read the original content, please click on the hyperlinks in the article.

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Cost Benefit Analysis of Water Investments

Promotion by Aqaufina

Investment in Water and Sanitation in Poor/Developing Countries:

A recent World Bank (WB) estimate showed that investing to provide drinking water to 750 million people in poor nations make clear sense with larger than expected health benefits. Senior Economist at WB’s Water and Sanitation Program (WASH) said “Provision of basic water and sanitation facilities would be a good investment in economic terms,” in the report.

Indian Context:

Prime Minister, Narendra Modi, addressed the nation by making basic toilets as a national priority on India’s 68th Independence Day (August 15, 2014). Mr. Modi highlighted that this would also yield strong returns, without even considering improved human dignity during his address.

Economics of water investments:

WB report states that the universal access to basic drinking water at home would cost $14 billion a year until 2030, and yield benefits of $52 billion, or about $4 for every dollar spent, according to the preliminary findings that will form part of a wider review.

New Findings:
The benefits were twice those estimated in a previous global study done in 2012. This is partly because of larger than expected falls in diarrheal disease (water born diseases), and lower costs of digging wells/boreholes. Overall, building toilets to eliminate defecation outside in rural areas would cost $13 billion a year to 2030 and give benefits of $84 billion, a return of $6 for every dollar spent. The benefits were slightly less than in a previous study.

I have written in several of my blog posts that the world’s costliest water is when women and girls in a household spend countless hours a year fetching water and doing no other activity. Open defecation also poses a threat to girls and women, in terms of abuse and getting attacked by animals in the wild.

What does this mean ultimately?
Investments in better water could mean 170,000 fewer deaths a year, while basic sanitation would cut 80,000 deaths, mostly from infectious diarrhea.

Urbanization and water:

In the past 25 years, more than two billion people of a world population now totaling about 7.3 billion have gained access to better water and almost two billion to sanitation. The study estimated only health benefits and time saved, such as from walking to a river to fetch water. They hide intangible impacts such as dignity, social status and security.

Water as Fundamental Human Right:

The United Nations in 2010 defined improved sanitation and water as fundamental human right.

Way forward:

In addition to the economics of water investments behavioral change, translated which means feeling pride in building a basis toilet at home and abandoning open defecation for good, would drive the movement in India. The country can also take lessons from neighboring Bangladesh.


This article is an adoption of the original articles that appeared on various websites. To read the original content, please visit the source websites by clicking the hyperlinks. Thoughts expressed are my own.

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Culprit behind polluted aquifers

Urban pollutants and agriculture run off effect an aquifers' quality ©

Urban pollutants and agriculture run off affect aquifers’ quality ©Neer Foundation, Meerut India

Its no news that agriculture (farming practices, irrigation and others) and rapid urbanization are two major factors to change the land usage and availability. Recent US Geological Survey  report reveals that concentrations of natural and man-made pollutants that could persist for decades otherwise known as Persistent Organic Pollutants (POPs) in essential underground water sources can change the chemistry and physical properties of the nation’s aquifers leading to greater concentrations.

The report:

About 130 million people in the United States rely on groundwater for drinking water, and the need for high-quality drinking-water supplies becomes more urgent as our population grows. Although groundwater is a safe, reliable source of drinking water for millions of people nationwide, high concentrations of some chemical constituents can pose potential human-health concerns. Some of these contaminants come from the rocks and sediments of the aquifers themselves, and others are chemicals that we use in agriculture, industry, and day-to-day life. When groundwater supplies are contaminated, millions of dollars can be required for treatment so that the supplies can be usable. Contaminants in groundwater can also affect the health of our streams and valuable coastal waters. By knowing where contaminants occur in groundwater, what factors control contaminant concentrations, and what kinds of changes in groundwater quality might be expected in the future, we can ensure the availability and quality of this vital natural resource in the future.

Major Findings:

  • Contaminants from geologic or man-made sources were a potential human-health concern in one of every five wells sampled in the parts of aquifers used for drinking water
  • Differences in geology, hydrology, geochemistry, and chemical use explain how and why aquifer vulnerability and concentrations of contaminants vary across the Nation
  • Changes to groundwater flow have also altered groundwater quality
    Our actions today are determining groundwater quality for decades to come

These finding are not something unique to just the US aquifers. The type of soil (porous limestone in to volcanic basalts and from frozen surfaces in the high altitudes to parched deserts) have a unique chemical property and alter the composition of groundwater aquifers in countries like India and others.

Detection of pollutants in water or aquifers is not always a bad news. Its the affect that these pollutants might have on human health and organisms that raises a red flag. Moreover, you cannot define the aquifer boundaries as easily as land can be divided. In lay terms, if one farmer or city is causing pollution, then the chemicals and pollutants can easily bleach into the neighboring city’ (or farmer’s) aquifer.

We need to take the historic account of how much groundwater has been drawn by us over the years. Each day more than 288 million (76 billion gallons) are pumped from aquifers for farms and cities. 

This article has been adopted from the original article that appeared on Circle of Blue and USGS’s report. To read the original articles, please click on the hyperlinks above.

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