How Singapore’s water management has become a global model for how to tackle climate crisis
Singapore is at the forefront of nearly all countries that have formulated a long-term plan for managing climate change and is steadfastly implementing that plan.
The small island state of 6 million people was among the 40 nations invited by the US President Joe Biden to attend his leaders’ summit on tackling climate change last April.
Singapore is one of most densely populated countries in the world. It faces the twin challenges of ensuring sustainable water supply during droughts as well as effective drainage during intense rain seasons amid climate change.
Much of Singapore is also as flat as a pancake and stands no more than 5 metres above the mean sea level. This puts the country at risk from rising sea level due to climate change.
But thanks to its water system management, Singapore has been a success story as a resilient and adaptable city.
The country has to be prepared for when rights to draw water from Malaysia end in 2061. Singapore draws up to 50% of its water supply from the neighbouring country.
For over two decades, Singapore’s National Water Agency, PUB, has successfully added large-scale nationwide rainwater harvesting, used water collection, treatment and reuse, and seawater desalination to its portfolio of conventional water sources, so the nation-state can achieve long-term water sustainability.
The agency has been collecting and treating all its sewage to transform it into clean and high-quality reclaimed water. As a result, the PUB has become a leading exponent of using recycled water, dubbed locally as NEWater, as a source of water.
In 2017, NEWater succesfully supplied up to 40% of the total water demand of 430 million gallons per day in Singapore. As the projected demand will double by 2060, the PUB plans to increase NEWater supply capacity up to 55% of demand.
Under the plan, desalinated water will supply 30% of total demand in 2060 – a 5% increase from its share in 2017.
The remaining share of the country’s water demand (15%) in 2060 will come from local catchments, which include 17 reservoirs, and imported water. The country does not have the land area to collect and store enough run-off despite abundant tropical rains.
To increase the economic viability of these plans, much of the PUB’s current research and development effort is aimed at halving energy requirements for desalination and used water treatment.
Other than that, reducing carbon emissions from water treatment and generating energy from the byproducts of used water treatment have become essential for Singapore.
Embracing ‘life and death’ matters
Based on this success story, the Singapore government applies the same approach of long-term planning and implementation to tackle threats of climate change, including rising sea level.
In 2019, Singapore’s Prime Minister, Lee Hsien Loong, described the country’s seriousness in treating climate change as “life and death matters”. The government estimates it will need to spend US$75 billion, around 20% of the country’s GDP, on coastal protection over the coming decades.
The government has tasked PUB to lead and co-ordinate whole-of-government efforts to protect these coastal areas. The agency is working hard to ensure Singapore does not become a modern-day Atlantis, Plato’s famous sunken city.
PUB’s first order of business is to develop an integrated coastal-inland flood model. This will allow it to simulate the worst-case effects of intense inland rainfall combined with extreme coastal events. PUB expects its flood model to become a critical risk-assessment tool for flood risk management, adaptation planning, engineering design and flood response.
The agency has also undertaken coastline protection studies of different segments. The first study began in May 2021 along City-East Coast, covering 57.8km of the coastline. This section had been identified as prone to flooding and has various critical assets such as airports and economic and industrial districts.
Other segments to be analysed are in Jurong Island, in southwestern Singapore, with the study to begin later this year, and the north-west coast, comprising Sungei Kadut and Lim Chu Kang, starting in 2022.
Rather than mere adaption to coming crisis, protection measures will be designed for multi-functional land use. Nature-based solutions will be incorporated whenever possible, to create welcoming spaces for living, work and play.
For sure, whatever Singapore does in climate mitigation will never move the global needle. But it is a very good example of what a country can do to successfully adapt to the dangers of climate change through good planning.
If its policies are duplicated in other countries, these combined efforts will most certainly cause the needle to move significantly.
After the United Nations High Level meeting on climate change, COP26, just completed this month in Glasgow, UK, Singapore can be considered to be a very good model of how countries can successfully adapt to the dangers of climate change in the coming decades.
Peter Joo Hee Ng is a co-author of this article.
Beavers offer lessons about managing water in a changing climate, whether the challenge is drought or floods
It’s no accident that both the Massachusetts Institute of Technology and the California Institute of Technology claim the beaver (Castor canadensis) as their mascots. Renowned engineers, beavers seem able to dam any stream, building structures with logs and mud that can flood large areas.
As climate change causes extreme storms in some areas and intense drought in others, scientists are finding that beavers’ small-scale natural interventions are valuable. In dry areas, beaver ponds restore moisture to the soil; in wet zones, their dams and ponds can help to slow floodwaters. These ecological services are so useful that land managers are translocating beavers in the U.S. and the United Kingdom to help restore ecosystems and make them more resilient to climate change.
Scientists estimate that hundreds of millions of beavers once dammed waterways across the Northern Hemisphere. They were hunted nearly to extinction for their fur in the 18th and 19th centuries in Europe and North America but are making comebacks today in many areas. As a geoscientist specializing in water resources, I think it’s important to understand how helpful beavers can be in the right places and to find ways for humans to coexist with them in developed areas.
How beavers alter landscapes
Beavers dam streams to create ponds, where they can construct their dome-shaped lodges in the water, keeping predators at a distance. When they create a pond, many other effects follow.
Newly flooded trees die but remain standing as bare “snags” where birds nest. The diverted streams create complicated interwoven channels of slow-moving water, tangled with logs and plants that provide hiding places for fish. The messy complexity behind a beaver dam creates many different kinds of habitats for creatures such as fish, birds, frogs and insects.
Human dams often block fish passage upstream and downstream, even when the dams include fish ladders. But studies have shown that fish have no trouble migrating upstream past beaver dams. One reason may be that the fish can rest in slow pools and cool pond complexes after navigating the tallest parts of the dams.
The slow-moving water behind beaver dams is very effective at trapping sediment, which drops to the bottom of the pond. Studies measuring total organic carbon in active and abandoned beaver meadows suggest that before the 1800s, active and abandoned beaver ponds across North America stored large amounts of carbon in sediment trapped behind them. This finding is relevant today as scientists look for ways to increase carbon storage in forests and other natural ecosystems.
Beavers may persist in one location for decades if they aren’t threatened by bears, cougars or humans, but they will move on if food runs out near their pond. When abandoned beaver dams fail, the ponds drain and gradually become grassy meadows as plants from the surrounding land seed them.
Dried meadows can serve as floodplains for nearby rivers, allowing waters to spill out and provide forage and spawning areas for fish during high flows. Floodplain meadows are valuable habitat for ground-nesting birds and other species that depend on the river.
The value of slowing the flow
As human settlements expand, people often wish to make use of every acre. That typically means that they want either land that is solid and dry enough to farm or waterways they can navigate by boat. To create those conditions, humans remove floating logs from streams and install drains to draw water off of fields and roads as quickly and efficiently as possible.
But covering more and more land surface with barriers that don’t absorb water, such as pavement and rooftops, means that water flows into rivers and streams more quickly. Rainfall from an average storm can produce an intense river flow that erodes the banks and beds of waterways. And as climate change fuels more intense storms in many places, it will amplify this destructive impact.
Some developers limit this kind of damaging flow by using nature-based engineering principles, such as “ponding” water to intercept it and slow it down; spreading flows out more widely to reduce the water’s speed; and designing swales, or sunken spots, that allow water to sink into the ground. Beaver wetlands do all of these things, only better. Research in the United Kingdom has documented that beaver activity can reduce the flow of floodwaters from farmlands by up to 30per cent.
Beaver meadows and wetlands also help cool the ground around and beneath them. Wet soil in these zones contains a lot of organic matter from buried and decayed plants, which holds onto moisture longer than soil formed only from rocks and minerals. In my wetland research, I have found that after a storm, water entering the ground passes through pure mineral sand in hours to days but can remain in soils that are 80 per cent-90 per cent organic matter for as long as a month.
Cool, wet soil also serves as a buffer against wildfires. Recent studies in the western U.S. have found that vegetation in beaver-dammed river corridors is more fire-resistant than in areas without beavers because it is well watered and lush, so it doesn’t burn as easily. As a result, areas near beaver dams provide temporary refuge for wildlife when surrounding areas burn.
Making room for beavers
The ecological services that beavers provide are most valuable in zones where nobody minds if the landscape changes. But in the densely developed eastern U.S., where I work, it’s hard to find open areas where beaver ponds can spread out without flooding ditches or roads. Beavers also topple expensive landscaped trees and will feed on some cultivated crops, such as corn and soybeans.
Beavers are frequently blamed for flooding in developed areas, even though the real problem often is road design, not beaver dams. In such cases, removing the beavers doesn’t solve the problem.
Culvert guards, fences and other exclusion devices can keep beavers a safe distance from infrastructure and maintain pond heights at a level that won’t flood adjoining areas. Road crossings over streams that are designed to let fish and other aquatic animals through instead of blocking them are beaver-friendly and will be resilient to climate change and extreme precipitation events. If these structures are large enough to let debris pass through, then beavers will build dams upstream instead, which can help catch floodwaters.
A growing body of research shows that setting aside pockets of land for beavers is good for wetland ecosystems, biodiversity and rivers. I believe we can learn from beavers’ water management skills, coexist with them in our landscapes and incorporate their natural engineering in response to weather and precipitation patterns disrupted by climate change.
Floods are going to get worse: we need to start preparing for them now
For many, 2021 was the year of the flood. From Canada to India, and across western Europe and Australia, this year’s deluges have led to hundreds of deaths, enormous financial costs and immeasurable suffering.
Research by myself and others on flood risk around the world shows how changing our perspective on floods can help us avoid disasters. No matter how much rain falls, flood disasters happen because of decisions that put people and places in harm’s way – and they can be averted.
For example, the southern part of the province of British Columbia in Canada has a lengthy history of floods and landslides. Deluges in November killed at least four people, washed away highways and forced towns to evacuate.
The excessive rain that caused this was most likely exacerbated by human-driven climate change, but its effects were made far worse by widespread deforestation, as well as the building of infrastructure on floodplains and even in a drained lake.
And in western Europe, many places hit by rising water in July 2021 – such as the town of Altena in Germany – were known to be at high flood risk thanks to floods over past decades and centuries. Despite a flood alert system forecasting heavy rain days in advance, this information was never translated into action.
Each of these tragic situations, however, could have been prevented from becoming a disaster by taking simple measures to reduce risk before storms strike: measures like planning buildings on safer, higher land, improving forest and river management, reducing poverty and providing relevant safety education.
How to reduce risk
In 1970, a cyclone tore through Bangladesh, causing hundreds of thousands of deaths. Another cyclone in 1991 killed over 100,000 people. But in subsequent decades concerted efforts by governments and local leaders focused on risk awareness, livelihood resilience and evacuation procedures – these measures reduced the death toll across the country to just dozens when cyclones struck in 2020 and 2021.
Similar work saved thousands during hurricanes in Texas. In 1900, a hurricane passing through the city of Galveston left at least 6,000 bodies in its wake. But more recently, Tropical Storm Allison in 2001, Hurricane Rita in 2005, Hurricane Ike in 2008 and Hurricane Harvey in 2017 each led to a much smaller loss of life.
For Rita, over 80 per cent of Texas’ 119 fatalities were attributed to poorly managed evacuation procedures. Similarly, despite record rainfall during Harvey, the hurricane’s destruction was largely the result of Texans covering floodable areas with buildings, without preparing citizens for what to do when floods hit.
Dealing with water
As climate change worsens, it’s projected that tropical cyclones – and the floods they cause – will become less frequent but more intense. The consequences of future storms depend on our actions now. If fewer storms mean that our preparation for them becomes slapdash, then disasters will be worse.
We can see this phenomenon at work when people build flood-related structures like dikes, levees and dams. Since they create a barrier between water and floodable areas, people often assume that those areas are safe to build on and that they don’t need to worry about flood risk. Indeed, the structures get rid of many smaller floods. But when large floods inevitably occur and a river or ocean reclaims its territories, devastation is equally inevitable.
The history of New Orleans offers a classic example. Around half of the city currently lies below sea level, and records of city flooding from the Mississippi River date back over a quarter of a millennium. Plus, New Orleans has always been prone to storms, facing Hurricane Betsy in 1965 and Hurricane Camille in 1969.
In July 2004, the Hurricane Pam training exercise for emergency officials demonstrated how ill-prepared the city was for a direct hurricane hit: especially when it came to hospital evacuation, search-and-rescue efforts, debris removal and temporary shelters. Tragically, this scenario was recreated in real life when Hurricane Katrina tore through the city in 2005. Levees breached, evacuation and sheltering systems were chaotic, and people drowned while on the phone awaiting rescue.
Flood-prone cities are often “protected” by flood “defences”, which have served mainly to encourage housing and business development on floodable land such as in London and Singapore. Both cities sit upstream from vast defences which reduce the numbers of small floods, allowing construction of huge financial centres on floodplains.
But when, not if, a flood exceeds a defence’s capabilities, the lack of preparation will be apparent in the ensuing disaster. Warning systems, which are highly capable of issuing accurate flood alerts, exist – but as in this year’s floods in Germany, these won’t be effective without preparing populations for evacuation.
Instead of rebuilding flood-ravaged residential streets, Toronto turned them into nature reserves to keep buildings out and water in. City planners then integrated the reserves into the expanding city by creating walking and cycling pathways alongside them. Now, these have become recreational and commuting routes, environmental education sites and a haven for wildlife.
When Hurricanes Isabel in 2003 and Sandy in 2012 again transformed Toronto’s watercourses into raging torrents, its floodplains were bare of buildings. Fallen trees littered mud-slicked paths, transportation and power was disrupted. But there was only one fatality. Let’s use this knowledge and wisdom to prepare other towns and cities for handling future floods.