Geology for Global Development

Landslides

Climate change: to mitigate or to adapt? Managing disaster: Cyclone Fani in India, a stronger Atlantic hurricane season. That and more in Jesse Zondervan’s May 2019 #GfGDpicks #SciComm

Climate change: to mitigate or to adapt? Managing disaster: Cyclone Fani in India, a stronger Atlantic hurricane season. That and more in Jesse Zondervan’s May 2019 #GfGDpicks #SciComm

Each month, Jesse Zondervan picks his favourite posts from geoscience and development blogs/news which cover the geology for global development interest. Here’s a round-up of Jesse’s selections for the last month:

This month Cyclone Fani hit India with full force. An effective mass evacuation resulting in the loss of no human lives is an impressive disaster management feat.

As disaster was averted in India, the Guardian published a briefing on the risk of hurricanes, and whether climate change is to blame for stronger ones. Are people adapting to these changes?

Adapting, argues Marketplace show host Molly Wood in her Wired article, isn’t surrender, it is survival. Can we afford to keep attempting to mitigate climate change if we need to adapt to the effects that are already there?

Susannah Fisher and Andrew Norton agree with Wood that adaptation is often overlooked in climate campaigns. They seek to open our eyes to the adaptation experience that the global South has to offer. Let’s put these good practices to work in Europe! they say.

More this month, better ways to stem arsenic poisoning in Bangladesh, the struggle with landslides in Rio and much more.

Go ahead and look through this month’s picks!

Cyclone Fani

Cyclone Fani hits Indian coast, a million people evacuated at Thomson Reuters Foundation

INTERVIEW – Mass texting and 50,000 volunteers – how India moved a million people to safety by Annie Banerji at Thomson Reuters Foundation

Climate Adaptation

Climate Adaptation isn’t Surrender. It’s Survival by Molly Wood at Wired

Adapting to climate change in Europe: Building a systemic and urgent vision by Susannah Fisher and Andrew Norton at EIT Climate-KIC

Cambodians try out smartphones to track – and ease – climate woes by Jeffrey Barbee at Thomson Reuters Foundation

Climate now biggest driver of migration, study finds by Inga Vesper at SciDevNet

Climate Change

Are hurricanes getting stronger – and is the climate crisis to blame? By Oliver Milman at the Guardian

Lake sediment records reveal recent floods in NW England (UK) unprecedented at ScienceDaily

Climatologist Testifies to Senate Subcommittee Regarding Costs of Extreme Weather by Marie Denoia Aronsohn at State of the Planet

Disaster Risk Reduction

As climate shifts bring ‘horror movie’ floods, Rio struggles to adjust by Karla Mendes & Gregory Scruggs at Thomson Reuters Foundation

China eyes earthquake warning and prediction technology by Chen Xi at Global Times

Sharing Data Helps Puerto Ricans Rebound After Hurricane Maria at Eos Earth & Space News

Ritter Island gives new insights into the dynamics of volcanic landslides at ScienceDaily

Integrated urban flood risk management: Learning from the Japanese experience by Jolanta Kryspin-Watson & Jia Wen Hoe

Geology for Development

Study Identifies Better, Cheaper Ways to Stem Arsenic Poisoning in Bangladesh by Sarah Fecht at State of the Planet

 

Check back next month for more picks!

Follow Jesse Zondervan @JesseZondervan. Follow us @Geo_Dev & Facebook.

Rainfall related geohazards: floods, landslides and mudslides in Rio – A dangerous combination of nature and human-related factors

Rainfall related geohazards: floods, landslides and mudslides in Rio – A dangerous combination of nature and human-related factors

Rainfall-related geohazards in Brazil’s poorer, mountainous city margins could be mitigated using better urban planning and communication. Our own Brazilian blogger Bárbara Zambelli Azevedo explores the problem and possible solutions.

I come from Brazil, a country well-known for its beautiful landscapes, football and carnival. Ok, some stereotypes are true, indeed.

Situated in the middle of the South American tectonic plate and away from geohazards such as earthquakes, volcanoes and tsunamis, this tropical country may seem like paradise to some. However, we are not completely safe from geohazards.

Every year during the summer, which is a heavy rain season, many lives are lost, and people are displaced by floods, landslides and mudslides all over the country. I want to give a particular focus on the state of Rio de Janeiro, where a summer storm killed at least 6 people on the 6th of February this year. I should mention that it was not an isolated event at all.

The situation of the state of Rio de Janeiro is complicated, and its analysis should take into consideration the geomorphology of the area, its climate and – importantly – urban planning.

According to the Brazilian Geological Survey, the bedrock in the area is composed mainly of igneous and metamorphic rocks, and the relief is characterised by steep mountain slopes over 2,000 m, alternated with sedimentary basins.

In 2011 floods, landslides and mudlslides resulted in 903 deaths and over 2,900 people had their homes destroyed

These mountains are a part of a major structure named Serra do Mar (Sea Ridge), a 1,500 km long system of mountain ranges and escarpments parallel to the Atlantic Ocean, running from Rio de Janeiro State until Santa Catarina, in the south of Brazil. Geomorphological features seen today started to form during the opening of the Atlantic Ocean during the Cretaceous, were consolidated throughout the Tertiary and still are modified by erosional and sedimentary events.

The climate is described as tropical in coastal areas such as Rio de Janeiro City and Angra dos Reis. It is warm and humid all year round, with a mean temperature around 23°C and an average annual precipitation of 1,300 mm. The rain season occurs in the summer (Dec-Mar) when 45% of precipitation falls.

In mountainous areas such as Nova Friburgo and Teresópolis, the climate is characterised as temperate. Temperatures are milder at an annual mean of 18°C and the average annual rainfall is 1700 mm, with 59% falling in the summer months of December to March. Therefore, extreme rainfall events are not rare, and they are usually associated with floods and landslides.

The worst weather-related natural hazard-induced disaster in Brazil happened in January 2011, when it rained 166 mm in a 24 hour period in the Serra dos Órgãos region, which is a local denomination of Serra do Mar. Six cities were affected by floods, landslides and mudslides: Teresópolis, Petrópolis, Nova Friburgo, Bom Jardim, Sumidouro and São José do Vale do Rio Preto. These flows resulted in 903 deaths and over 2,900 people had their homes destroyed.

A year earlier the state of Rio had been the scene of another tragedy. It was New Year’s Eve and the city of Angra dos Reis was full of tourists. After intense rainfall, many mudslides were triggered and left at least 44 people dead. Such events repeat themselves every year.

Satellite imagery of the 2011 mudslides in Nova Friburgo - before and after. Via Google Earth, collected in 2019.

Satellite imagery of the 2011 mudslides in Nova Friburgo – before and after. Via Google Earth, collected in 2019.

Just like Rio, most Brazilian cities lack urban planning and settlements are segregated socio-economically. Usually an impoverished population is pushed to marginalised areas of cities, which are usually steep and mountainous areas where the risk of landslides is higher.

In this article geologist and former president of the Institute of Technological Research of São Paulo Álvaro Santos states that only few Brazilian geohazards are triggered exclusively by nature.

In fact, most of our geological and hydrological issues are, somehow, led by poor land-use management, both in cities and in the countryside. Santos also explains that tragedies related to rainfall are usually caused by a lack of land-use planning and housing, and inefficient government communication.

We must learn from our own history and examples from other places like Indian Chennai and Tamil Nadu to tackle the challenge elevated hazard risk in city margins. A good starting point is raising the awareness of the population living in high-risk areas by using geoscience education and science communication.

Geoprevention aims to raise the awareness of the local community about geotechnical and environmental risks such as floods, landslides, infiltration, river erosion and sedimentation and waste disposal

We have a good example from the city of Curitiba, where students from the Federal University of Paraná developed a project titled GeoPrevention. This project aims to raise the awareness of the local community about geotechnical and environmental risks such as floods, landslides, infiltration, river erosion and sedimentation and waste disposal. The students use didactic material like folders, manuals, booklets and provide mini-courses and lectures about these topics with a playful character that is easily understood.

This initiative is important because it provides an interdisciplinary dialogue between a university and civil society, in particular, the population affected by those geohazards, to recognise and avoid them at the individual level.

At a higher level, we need governments and policy-makers to take action on effective urban planning and risk management, and invest more in the prevention of rainfall-related geohazards than on their remediation.

In addition, the active participation of civil society and the private sector is crucial to building resilient societies. Technological innovations such as the internet of things and dashboards should also be used to improve disaster prediction and population warning.

The city of Rio de Janeiro has two big data operation centres, the Operation Centre and Integrated Centre of Command and Control, both launched before World Cup which granted Rio the title of “World Smart City” in 2013.

The centres improved disaster management by mapping areas with high risk of flood-related landslides and implementing a critical early warning and evacuation system for Rio’s favelas. However, according to this article, they have failed at “go[ing] beyond high-tech marketing rhetoric and help[ing] real people living in the city”.

Even though it is very complicated and takes time to solve the problem of rainfall-related hazard risk in city margins, it must start sometime: why not now?!

Guest Blog: Could agroforestry do more to protect Rwandans from hazardous landslides?

Megan Jamer is a geoscientist from Canada, and an avid cyclist and explorer. Megan is currently travelling around East Africa on bicycle, taking in some remarkable sites and observing first hand the relationship between geoscience and sustainable development. Today Megan makes her debut on the GfGD blog site, writing on the relationship between agroforestry, landslides, and disaster risk reduction.

Some landslide interventions are hard to miss along Rwanda’s highways. There are gabions, and concrete drainage pathways, kept unclogged by women and men in fluorescent vests. Other strategies are more subtle. Where cassava or bean plots are mixed with banana trees or ringed within a hedge, this may also reduce the damage caused by landslides in this central African nation. Rwandan agroforestry is getting attention. The strategy, which combines trees and crops in the same area, is being used to work towards the 2020 goal of trees covering thirty percent of Rwanda’s total surface area. In 2014, more than half of new seedlings distributed by the government were agroforestry or fruit varieties. Food and land scarcity pressure Rwanda’s slopes, and agroforestry is one way to address the root causes of these shortages, protecting against landslides in the process.

A rural dwelling in the hills of northern Rwanda, excavated into the slope (author’s own).

The Problem of Landslides

At least sixty-seven people were killed last year by landslides and mudslides in the north and west, and in the capital, Kigali. Deadly or not, they cause wide-ranging infrastructure damage, harming public infrastructure and trading patterns, as well as hillside settlements and agriculture. Landslides here disproportionately affect the poor, who pursue subsistence agriculture on steep slopes or live in vulnerable urban areas because they have few alternatives.

In the ‘land of a thousand hills’, slopes are made more vulnerable by rainfall patterns that some say are difficult to manage. In The New Times last year, coffee grower Pierre Munyura said that in western Rwanda“we receive about the same amount of rainfall as ever, but the rain comes in heavier and more destructive bursts.” Rainstorms are considered to be the main trigger of landslides in Rwanda, but human activities prepare the slopes for failure. They are cleared and levelled for walking pathways, homes, latrines, small plots and gardens. Other areas are hollowed out for small-scale mining. The result of these activities is a complex pattern of slope disturbance and deforestation.

Hillside communities cultivate in a manner that reflects traditional knowledge, regulations, and the resources available to them (author’s own)

Similar environmental and human conditions come together on the slopes of Mount Elgon in Uganda, where the causal factors of landslides were investigated. The researchers’ prognosis was bleak: “The growing population density not only increases the risk of damage, but hampers the search for solutions for the landslide problem as well.”  Understanding occurrence is the first step in managing rainfall-induced landslides, says Dave Petley of The Landslide Blog, and here Rwanda has made big strides. Its Ministry of Disaster Management and Refugee Affairs (MIDMAR) published a National Risk Atlas in 2015, an analysis of the earthquakes, landslides, windstorms, droughts and floods that challenge Rwanda’s resiliency. The Atlas inventories hazardous landslides, estimates slope susceptibility, and shows maps of properties that affect landslide incidence, including rainfall, slope angle, ground cover and soil characteristics.

MIDMAR’s analyses estimated that nearly half of Rwanda’s population lives in areas with moderate or high slope susceptibility to landslides. These hazards are commonly small and localized, requiring community action, but “knowledge at the citizen level [about landslides] is still low,” says Dr. Aime Tsinda, a Senior Research Fellow at the Institute of Policy Analysis and Research-Rwanda. Translating information in studies like the National Risk Atlas into local knowledge is a slow process. While it’s underway, communities are motivated to adopt agroforestry because of a hazard they are already familiar with: poor quality soil.

More Trees!

Agroforestry is the ‘intentional integration of trees and shrubs into crop and animal farming systems to create environmental, economic and social benefits’. On cultivated slopes where agroforestry isn’t practiced, small plots drape over them, resembling smooth patchwork blankets. Like blankets, their soils can more easily wash away, creep or slide catastrophically. This is what happened last year, says J.M.V. Senyanzobe, a Forestry Lecturer at the University of Rwanda. “If you observe the concerned areas,” he says, “they were empty of trees, just grasses which are not strong enough to stop the soil from being eroded.”

When trees are cut down their roots decay, eventually rendering them ineffective soil binders. The slopes of Mount Elgon demonstrate the difference. Forested areas lacked evidence of landslides, even when they grew on slope angles and in soil types that contributed to slope instability elsewhere in the study area. Deforestation began as early as 3000 BC in what was Rwanda-Urundi! Reforestation and tree cultivation have been encouraged since the 1930s and it’s working: In 1996, an FAO agroforestry study exclaimed that “photographs taken in Rwanda in the early years of this [twentieth] century show landscapes almost devoid of trees, a stark contrast to the present.

Some Rwandans are motivated to plant because of what the trees themselves offer. Bananas are brewed into beer, coffee trees have been called ‘Rwanda’s Second Sunrise’, and eucalyptus and pine provide construction materials. Other trees are valued for their structure, for example marking plot boundaries. And it’s taken some convincing, but more people are trying out types of agroforestry that plant trees and crops together, in an effort to improve soil quality. There are techniques that do more to increase soil stability. This guide recommends mimicking the plant diversity of a natural forest as much as possible, or to plant tree rows within crops along topographic contours. Within Rwanda, living hedges were found to greatly reduce soil erosion, but landslide prevention wasn’t specifically investigated. Senyanzobe recommends a combination of reforestation between cultivated areas, and agroforestry species within crop areas.  Ultimately, “the sustainable solution is to plant trees as much as possible,” he says.

Outside of agroforestry, is there a way to reduce hazardous landslides in Rwanda? Enforcing rules about how people should excavate slopes or use terracing appropriately is difficult, especially in remote areas. Similarly, mass relocation of vulnerable hillside communities is unrealistic in mainland Africa’s most densely populated country. Large-scale agroforestry interventions, by contrast, are already underway. But because they aren’t undertaken to address landslides specifically, their effectiveness is currently limited.

Pieces of the Puzzle

Speaking to the effectiveness of agroforestry for any goal, “it needs to be implemented with sensitivity to people’s needs, priorities and sociocultural and economic conditions,” says the FAO. It’s not yet clear whether many Rwandans choose tree planting specifically for reducing landslide risk—today, selling the tree’s products or increasing soil fertility are more powerful motivators. If this is how communities prioritise, then agroforestry will be pursued to the extent that those benefits are gained. The damage by landslides may be mitigated, but as a by-product.

Obstacles to agroforestry being used for disaster risk reduction overlap with the challenges of agroforestry in general. One major hurdle in Rwanda is the belief that trees can damage crops by shading them, drying them out, or otherwise competing. Unfortunately this is sometimes true. Avocado trees can harm the crops closest to them. Pine and eucalyptus trees are resilient, but also invasive.

Making the most of agroforestry involves more conversations about the risk—and prevention—of landslides. On the heels of its efforts to understand occurrence of its natural hazards, Rwanda is trying to increase public awareness of landslides in a number of ways. In the official guide to primary school construction, choosing a stable slope location is a ‘must,’ and instructions are given to this end. Public radio broadcasts, disaster committees at the district level, and discussions during monthly community service day (umuganda) on topics including disasters are other examples. Currently, about a quarter of disaster-related spending in Rwanda is directed to prevention and mitigation.

Seedling distribution on National Tree Planting Day looks pretty good, but so does a new home. Recently, several high-risk families were relocated to ‘disaster resilient’ homes in collaboration with UN-HABITAT. Both of these events received media coverage, but were largely treated as separate topics.

The collapsed downslope shoulder of a road in southern Rwanda (author’s own)

These conversations in the media and during umuganda need to continue, but hopefully soon when there’s talk of landslides in Rwanda, trees and agroforestry will be a bigger part of the discussion.

Do trees keep you safer from hazards in your environment? Do you think that any tree planting is a good thing when it comes to landslides, or can it bring mixed results?

Nepal Earthquake – Further Reading

At the weekend we published a selection of reading on the geological and humanitarian aspects of the Nepal earthquake. Over recent days much has been written reflecting on aspects of disaster relief and learning lessons as soon as possible from this awful event, to reduce the impact of future geohazards. These articles are accessible and give geoscientists much to consider:

Ilan Kelman (UCL IRDR)
How earthquake safety measures could have saved thousands of lives in Nepal.

Sam Jones (Guardian, with comment by Katie Peters, ODI)
Nepal Earthquake – Learn lessons or more will die in future disasters

ReliefWeb Situation Page
Maps, reports and details of the current situation

BBC News
The challenge of disaster relief