Disaster Risk Reduction

Description

Disaster risk reduction (DRR) aims at preventing and reducing the risks arising from a potential disaster. Disaster risk reduction strategies focus on one or several of the three components of risk, namely (1) the hazard (e.g. of a glacier lake outburst), (2) the exposure of people and assets, and (3) the vulnerability of people and assets (figure 1). For the risk reduction of glacier lake outburst floods (GLOFs), hazard reduction strategies try to lower the probability of a  GLOF to happen, and/or to lessen the magnitude of a potential GLOF. This can be achieved for example by lowering the water level and volume of glacial lakes or by reinforcing and stabilizing the dams of such lakes. Disaster risk reduction can also act on exposure, for example, through hazard mapping that informs communities of hazard-prone areas, and through adjusted land use planning. Disaster risk reduction can finally be achieved by a reduction of vulnerability of people and systems. For instance, capacity building and education about the processes, their causes, impacts and dangers of GLOFs as well as mock drills to foster proper preparedness in case of a GLOF, can reduce people’s vulnerability to disasters.

 

Figure 1: Concept of risk reduction based on the International Panel on Climate Change (IPCC) Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), Adjusted from Abram et al., 2019. The arrows indicate a reduction of one of the three components of risk (i.e., hazard, exposure and vulnerability) and the subsequent reduction of risk (lighter shaded areas). 

Definitions

Hazard:

A process, phenomenon or human activity that may cause loss of life, injury or other health impacts, property damage, social and economic disruption or environmental degradation Hazards may be natural, anthropogenic or socionatural in origin (UNDRR: https://www.undrr.org/terminology/hazard). Within the GLOFCA project, we are confronted with natural hazards originating from the outburst of glacier lakes (see theme What is a GLOF).

Disaster:

A disaster is a serious disruption of the functioning of a community or a society at any scale due to hazardous events interacting with conditions of exposure, vulnerability and capacity, leading to human, material, economic and or environmental losses and impact (UNDRR: https://www.undrr.org/terminology/disaster)

Exposure:

The situation of people, infrastructure, housing, production capacities and other tangible human assets located in hazard-prone areas. Measures of exposure can include the number of people or types of assets in an area. These can be combined with the specific vulnerability and capacity of the exposed elements to any particular hazard to estimate the quantitative risks associated with that hazard in the area of interest. (https://www.undrr.org/terminology/exposure)

Resilience:

The ability of a system, community or society exposed to hazards to resist, absorb, accommodate, adapt to, transform and recover from the effects of a hazard in a timely and efficient manner, including through the preservation and restoration of its essential basic structures and functions through risk management. (https://www.undrr.org/terminology/resilience).

Risk:

In the context of climate impacts, the IPCC defines risk as the potential for adverse consequences of a climate-related hazard, on lives, livelihoods, health and well-being, ecosystems and species, economic, social and cultural assets, services, and infrastructure. Risk results from the interaction of the three components (1) hazard and the likelihood of its occurrence, (2) the exposure of any kind of assets, and (3) the vulnerability of the affected asset or system. 

Vulnerability:

Vulnerability is defined as the conditions determined by physical, social, economic and environmental factors or processes which increase the susceptibility of an individual, a community, assets or systems to the impacts of hazards (UNDRR: https://www.undrr.org/terminology/vulnerability). 

Disaster Risk Management (DRM):

Disaster risk management is the application of disaster risk reduction policies and strategies to prevent new disaster risk, reduce existing disaster risk and manage residual risk, contributing to the strengthening of resilience and reduction of disaster losses (UNDRR: https://www.undrr.org/terminology/disaster-risk-management)

Disaster Risk Reduction (DRR):

Disaster risk reduction (DRR) is the policy objective of disaster risk management, and its goals and objectives are defined in disaster risk reduction strategies and plans (UNDRR: https://www.undrr.org/terminology/disaster-risk-reduction).

GLOF DRR examples in the high mountain context

Glacier lake outburst flood (GLOF) disaster risk reduction (DRR) includes a variety of different approaches and strategies. 

GLOF hazard reduction is based on measures that can be implemented at the glacial lake or at sites on potential impact areas downstream. Such measures can aim at the drainage, lowering or regulation of lakes and the artificial fortification and stabilization of the lake dam, as well as at flow channel adaptation or erosion control, for example. One of the most important structural measures for reducing GLOF hazard is the reduction of the water volume in glacial lakes and increase of the freeboard at the dam, which can be done through pumping or siphoning out the water from the lake, controlled breaching, construction of an outlet control structure, and/or making a tunnel through the moraine barrier or under an ice dam, as well as sediment infilling into the lake (figure 2). Artificial dams are built to increase dam freeboard and to prevent a lake outburst due to the direct impact of a displacement wave and protection from erosion at the dam, as well as unexpected increase in water levels. They are often implemented in combination with open cuts or tunnels in order to regulate the water level. 

  

Figure 2: Top left: Channel deepening works at lake No. 6 in the Kishi Almaty River basin, Ile Alatau, Kazakhstan in 1997. Top right: Clearing and deepening of the drainage channel of a moraine lake in Kazakhstan. Bottom left: Construction works on water pump installation for the drainage of moraine lake No. 13 in the Ulken Almaty river basin, Kazakhstan. Bottom right: Running siphons draining a moraine lake in Kazakhstan. Photos provided by Kazselezashita, Kazakhstan.

GLOF exposure reduction concentrates on the people and assets at stake rather than on the hazard itself, and therefore does not affect the physical processes of GLOFs. Exposure can be reduced on the very short term through evacuations or on the long term through relocation or spatial planning (Figure 3). Early warning systems (EWS) are non-structural measures, lowering the GLOF risk by reducing the damage potential through monitoring of the hazard and warning and evacuation of the population in case of a lake outburst. An EWS’ main objective is to avoid harm to human lives. EWS, as most other risk reduction measures, cannot reduce risks to zero, they should ideally be accompanied by other risk reduction measures, in particular appropriate land-use planning. 

GLOF vulnerability reduction acts on the conditions determined by physical, social, economic and environmental factors or processes which increase the susceptibility of an individual, a community, assets or systems to the impacts of hazards (UNDRR: https://www.undrr.org/terminology/vulnerability). GLOF vulnerability reduction, thus, aims at the reduction and mitigation of the effects of GLOFs. This can be achieved through, for instance, knowledge generation, information and communication, capacity building, good governance (e.g. the strengthening of institutions, clarifications of roles and responsibilities), fostering of economic diversity, different preparedness and disaster relief plans, and insurances and compensations for losses. Comprehensive EWS, including risk understanding, communications and response capacity, are also effective on vulnerability reduction (figure 3). 

Figure 3: Top: Calculation of water height and potentially affected zones for different debris flow scenarios (Zaginaev et al., 2019). Bottom left: Monitoring system for early warning at lake Faverge, Switzerland (Gletschersee-lenk.ch). Bottom right: Ground observation works at lake No. 1 in the Turgen river basin, Ile Alatau in Kazakhstan in 2020. Photo provided by Kazselezashita, Kazakhstan.

Sendai framework

The Sendai Framework for Disaster Risk Reduction 2015-2030 is an agreement that was adopted by the United Nations member states in 2015 in the city of Sendai, Japan. It is a high level international policy instrument that sets goals and guides disaster risk reduction. The Sendai Framework aims to achieve a substantial reduction of disaster risk and losses in lives, livelihoods and health and in the economic, physical, social, cultural and environmental assets of persons, businesses, communities and countries. It outlines seven clear targets and four priorities for action to prevent new and reduce existing disaster risks. The four priorities are: (i) Understanding disaster risk; (ii) Strengthening disaster risk governance to manage disaster risk; (iii) Investing in disaster reduction for resilience and; (iv) Enhancing disaster preparedness for effective response, and to “Build Back Better” in recovery, rehabilitation and reconstruction (UNDRR: https://www.undrr.org/publication/sendai-framework-disaster-risk-reduction-2015-2030)

Sources

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Further reading

Amendola, A., Linnerooth-Bayer, J., Okada, N., & Shi, P. (2008). Towards integrated disaster risk management: Case studies and trends from Asia. Natural Hazards, 44(2), 163–168. https://doi.org/10.1007/s11069-007-9152-z

Carey, M., Huggel, C., Bury, J., Portocarrero, C., & Haeberli, W. (2012). An integrated socio-environmental framework for glacier hazard management and climate change adaptation: Lessons from Lake 513, Cordillera Blanca, Peru. Climatic Change, 112(3–4), 733–767. https://doi.org/10.1007/s10584-011-0249-8

Carey, M., McDowell, G., Huggel, C., Jackson, J., Portocarrero, C., Reynolds, J. M., & Vicuña, L. (2015). Integrated Approaches to Adaptation and Disaster Risk Reduction in Dynamic Socio-cryospheric Systems. In Snow and Ice-Related Hazards, Risks, and Disasters (pp. 219–261). https://doi.org/10.1016/B978-0-12-394849-6.00008-1

Cuellar, A. D., & McKinney, D. C. (2017). Decision-making methodology for risk management applied to Imja Lake in Nepal. Water (Switzerland), 9(8), 14–16. https://doi.org/10.3390/w9080591

Emmer, A., Vilímek, V., & Zapata, M. L. (2018). Hazard mitigation of glacial lake outburst floods in the Cordillera Blanca (Peru): the effectiveness of remedial works. Journal of Flood Risk Management, 11, S489–S501. https://doi.org/10.1111/jfr3.12241

Fakhruddin, B., & Basnet, G. (2018). Community Based Flood and Glacial Lake Outburst Risk Reduction Project (CFGORRP) in Nepal. Final Report. https://www.env.go.jp/en/earth/cc/casestudy/2016/casestudy_2_3.pdf

Frey, H., Huggel, C., Bühler, Y., Buis, D., Burga, M. D., Choquevilca, W., Fernandez, F., García Hernández, J., Giráldez, C., Loarte, E., Masias, P., Portocarrero, C., Vicuña, L., & Walser, M. (2016). A robust debris-flow and GLOF risk management strategy for a data-scarce catchment in Santa Teresa, Peru. Landslides, 13(6), 1493–1507. https://doi.org/10.1007/s10346-015-0669-z

Gurung, S., Joshi, S. D., & Parajuli, B. (2021). Overview of an early warning system for Glacial Lake outburst flood risk mitigation in Dudh-Koshi Basin, Nepal. Sciences in Cold and Arid Regions, 13(3), 206–219. https://doi.org/10.3724/SP.J.1226.2021.20076

Haeberli, W., Kääb, A., Mühll, D. V., & Teysseire, P. (2001). Prevention of outburst floods from periglacial lakes at Grubengletscher, Valais, Swiss Alps. Journal of Glaciology, 47(156), 111–122. https://doi.org/10.3189/172756501781832575

Huggel, C., Cochachin, A., Drenkhan, F., Fluixá-Sanmartín, J., Frey, H., García Hernández, J., Jurt, C., Muñoz, R., Price, K., & Vicuña, L. (2020). Glacier Lake 513, Peru: Lessons for early warning service development. WMO Bulletin, 69(1), 45–52. https://library.wmo.int/doc_num.php?explnum_id=10223

Ikeda, N., Narama, C., & Gyalson, S. (2016). Knowledge sharing for disaster risk reduction: Insights from a glacier Lake workshop in the Ladakh Region, Indian Himalayas. Mountain Research and Development, 36(1), 31–40. https://doi.org/10.1659/MRD-JOURNAL-D-15-00035.1

NDMA. (2020). National Disaster Management Authority Guidelines. Management of Glacial Lake Outburst Floods (GLOFs). http://ndma.gov.in/sites/default/files/PDF/Guidelines/Guidelines-on-Management-of-GLOFs.pdf

Portocarrero Rodríguez, C. A. (2014). The Glacial Lake Handbook. Reducing risk from dangerous glacial lakes in the Cordillera Blanca, Peru.

Rana, B., Shrestha, A. B., Reynolds, J. M., Aryal, R., Pokhrel, A. P., & Budhathoki, K. P. (2000). Hazard assessment of the Tsho Roipa Glacier Lake and ongoing remediation measures. In Journal of Nepal Geological Society (Vol. 22). https://doi.org/10.3126/jngs.v22i0.32432

Shrestha, B. B., & Nakagawa, H. (2014). Assessment of potential outburst floods from the Tsho Rolpa glacial lake in Nepal. Natural Hazards, 71(1), 913–936. https://doi.org/10.1007/s11069-013-0940-3

Somos-Valenzuela, M. A., McKinney, D. C., Byers, A. C., Rounce, D. R., & Portocarrero, C. (2013). Modeling Mitigation Strategies for Risk Reduction at Imja Lake, Nepal (Issue CRWR Online Report 13-06).

UNISDR. (2015). Sendai Framework for Disaster Risk Reduction 2015-2030.

Wang, S., & Zhou, L. (2017). Glacial Lake Outburst Flood Disasters and Integrated Risk Management in China. International Journal of Disaster Risk Science, 8(4), 493–497. https://doi.org/10.1007/s13753-017-0152-7