Dam disasters of the 1920s made reservoirs safer – now the climate crisis is increasing risk again – The Conversation

Report on Reservoir Safety and Sustainable Development in the United Kingdom

Introduction: Historical Context and Relevance to Sustainable Development

The 1925 Dolgarrog dam disaster in North Wales serves as a critical case study in infrastructure failure and its human cost. The catastrophic collapse of the Eigiau and Coedty reservoirs, resulting from inadequate construction and maintenance, led to the deaths of 16 people and significant destruction. This event underscores the foundational importance of resilient infrastructure, a core component of SDG 9 (Industry, Innovation and Infrastructure), and the imperative to create safe and sustainable communities as outlined in SDG 11 (Sustainable Cities and Communities).

Legislative and Institutional Responses to Infrastructure Failure

The Reservoirs (Safety Provisions) Act of 1930

In response to the Dolgarrog disaster and a similar failure at Skelmorlie, Scotland, the UK government enacted the Reservoirs (Safety Provisions) Act of 1930. This legislation established a formal regulatory framework for reservoir safety, marking a significant step towards building strong and accountable institutions, in line with SDG 16 (Peace, Justice and Strong Institutions). The key provisions of the act included:

1. Mandatory design and construction oversight by qualified engineers.
2. A legal requirement for regular inspection and certification of large reservoirs.
3. The establishment of statutory safety measures to ensure structural integrity.

Modern Incidents and Renewed Focus on Safety

Despite a strong safety record, the near-failure of the Toddbrook reservoir in 2019 highlighted modern vulnerabilities. Extreme rainfall, an impact of climate change, caused damage to the dam’s spillway, necessitating the evacuation of over 1,500 residents. This event demonstrated the ongoing risk to community safety (SDG 11). The incident prompted a renewed institutional response, including:

• An independent government review into reservoir safety commissioned in 2021.
• A ministerial direction making emergency on-site flood plans a legal requirement for all large reservoir owners.

These actions reflect an adaptive approach to governance (SDG 16) in the face of evolving environmental threats.

Climate Change and its Impact on Water Infrastructure and Community Safety

Amplified Risks from Extreme Weather Events

Climate change presents a significant threat to the UK’s aging water infrastructure, much of which was constructed in the 19th century under different hydrological conditions. This challenge directly relates to the need for urgent climate adaptation as specified in SDG 13 (Climate Action). The primary risks include:

• Overtopping: Intense rainstorms, predicted to become more frequent, can overwhelm spillway capacity, leading to erosion and failure.
• Structural Instability: Prolonged droughts can alter pore pressures and cause soil cracking in embankments, compromising their stability.

These vulnerabilities threaten not only the provision of clean water (SDG 6: Clean Water and Sanitation) but also the fundamental resilience of national infrastructure (SDG 9).

The Imperative for Climate Adaptation and Resilience

The location of much of the UK’s water storage infrastructure in steep, upland catchments exacerbates the risk of flash flooding from extreme weather. The Dolgarrog disaster illustrated how such topography can amplify the destructive power of a dam breach. Ensuring future safety requires a proactive approach to climate adaptation, focusing on upgrading infrastructure to withstand the “new normal” of intense storms and droughts. This is essential for mitigating disaster risk and fulfilling the objectives of SDG 11 to make communities safe and resilient.

Conclusion: Integrating SDGs for Future Reservoir Safety

The historical lesson of the Dolgarrog disaster and the modern warning from the Toddbrook incident demonstrate that ensuring reservoir safety is a complex challenge that intersects with multiple Sustainable Development Goals. A forward-looking strategy must integrate climate adaptation, infrastructure resilience, and robust institutional oversight. Achieving long-term security for communities living downstream of reservoirs requires a holistic approach grounded in the principles of the SDGs.

• SDG 6 (Clean Water and Sanitation): Safeguarding the structural integrity of reservoirs is essential for sustainable water management.
• SDG 9 (Industry, Innovation and Infrastructure): Investment is required to upgrade and maintain resilient water infrastructure capable of withstanding climate impacts.
• SDG 11 (Sustainable Cities and Communities): Protecting communities from dam-related flood risks is critical to ensuring they are safe, resilient, and sustainable.
• SDG 13 (Climate Action): Urgent action must be taken to adapt critical water infrastructure to the unavoidable impacts of climate change.
• SDG 16 (Peace, Justice and Strong Institutions): Continuous development and enforcement of effective safety regulations and emergency preparedness plans are necessary.

SDGs Addressed in the Article

SDG 11: Sustainable Cities and Communities

• The article directly addresses the safety of human settlements by detailing the catastrophic 1925 Dolgarrog dam failure, which “destroying several homes, a bridge and the local chapel” and caused the death of 16 people. It also discusses the 2019 Toddbrook reservoir incident, which necessitated the “evacuation of more than 1,500 residents,” highlighting the ongoing risk to communities living downstream of dams.

SDG 9: Industry, Innovation and Infrastructure

• The core of the article revolves around the resilience and safety of critical infrastructure, specifically reservoirs and dams. It points out historical failures due to “poor dam construction and inadequate maintenance practices” and warns that “ageing upland water storage infrastructure” is at risk, emphasizing the need for resilient infrastructure.

SDG 13: Climate Action

• The article explicitly links the increased risk to dam safety with climate change. It states that “Climate change is increasing both storm and drought intensity” and that “intense rainstorms that cause flash flooding will be five times more likely by 2080.” This highlights the need to adapt infrastructure and safety plans to climate-related hazards.

Specific SDG Targets Identified

Target 11.5: Reduce the number of deaths and people affected by disasters

• This target is central to the article’s narrative. The Dolgarrog disaster is a clear example of a water-related disaster causing deaths (“Ten adults and six children lost their lives”) and affecting a community. The evacuation of 1,500 residents in the Whaley Bridge incident is a direct measure of “people affected” by a potential disaster.

Target 11.b: Implement policies and plans for disaster risk reduction

• The article details the policy response to dam failures. The 1925 disasters “led directly to the Reservoirs (Safety Provisions) Act of 1930.” Similarly, the 2019 incident prompted an “independent review into reservoir safety” and a “ministerial direction” making “emergency flood plans a legal requirement.” These actions are direct examples of implementing disaster risk reduction plans and policies.

Target 9.1: Develop quality, reliable, sustainable and resilient infrastructure

• The discussion focuses on the structural integrity of dams. The failure of the Eigiau and Coedty reservoirs and the near-failure of the Toddbrook reservoir demonstrate a lack of resilience in this infrastructure. The subsequent safety acts, inspections, and repairs mentioned are all efforts aimed at developing more reliable and resilient infrastructure to ensure human well-being.

Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards

• The article argues that historical infrastructure was built for hydrological conditions that “no longer hold” due to climate change. The increased risk from “intense storms and prolonged droughts” necessitates strengthening the resilience of dams. The implementation of emergency flood plans and the review of safety standards are adaptive measures to cope with these new climate-related hazards.

Indicators for Measuring Progress

Disaster Impact Indicators

• Number of deaths and missing persons attributed to disasters: The article explicitly provides this data for the Dolgarrog disaster (“Ten adults and six children lost their lives”) and notes it was the “last time anyone was killed in the UK by a dam failure,” implying this is a tracked metric.
• Number of people affected by disasters: The article quantifies the number of people evacuated during the Whaley Bridge incident (“more than 1,500 residents”), which serves as a direct indicator of the population affected by a potential disaster.
• Direct economic loss and infrastructure damage: The destruction of “several homes, a bridge and the local chapel” in Dolgarrog is a qualitative indicator of infrastructure damage and economic loss from a dam failure.

Policy and Preparedness Indicators

• Adoption and implementation of national disaster risk reduction strategies: The article mentions the creation of the “Reservoirs (Safety Provisions) Act of 1930” and the 2021 “ministerial direction” for “emergency flood plans.” The existence and enforcement of such legislation serve as a key indicator of progress.
• Regularity of infrastructure safety inspections: The 1930 Act introduced “legal requirements for regular inspection and certification by qualified engineers.” The frequency and outcomes of these inspections are an implied indicator of proactive risk management.

Infrastructure Resilience Indicators

• Number of infrastructure failures or near-failures: The article chronicles specific events of dam failure (Dolgarrog) and near-failure (Toddbrook). Tracking the incidence of such events over time measures the overall resilience of the infrastructure network.
• Status of infrastructure maintenance and repair: The article notes that “Repairs were nearing completion in late 2025” for the Toddbrook reservoir. The progress and completion of maintenance and repair on critical, ageing infrastructure is an indicator of investment in resilience.

Table of SDGs, Targets, and Indicators

Source: theconversation.com