Posted on December, 14 2017

Dams provide significant benefits to people but they are also a primary cause of the loss and degradation of river ecosystems and the services these ecosystems provide to society. Recognising this, several tools and approaches have emerged over the last two decades to promote better dams – i.e. dams that have fewer impacts and deliver greater benefits to society. This primer reviews these new tools and approaches, as well as some of the factors responsible for bad dams, and it offers a pragmatic way forwards. It is intended to prompt dialogue and guide engagement with decision-makers.

While the context and environmental conditions for dams vary considerably around the world, there are a number of concepts that underpin an effective approach to planning, developing, renovating and operating dams.

 1. Construction of new dams is not always the optimal solution to meet development needs. Dam planning should be part of strategic planning for economic and social needs (such as energy, food, and flood and drought protection). Alternatives such as demand management, green infrastructure, and importing and trading energy or food can reduce the need to build new dams. Depending on context, these alternatives can be less controversial and disruptive and can provide a blend of strategic, economic, social and environmental benefits at lower costs. Governments should consider all possible options to meet societal needs.

2. System-scale planning of dams helps produce a greater and broader range of benefits to society. System-scale planning considers the cumulative impacts and benefits of multiple potential infrastructure portfolios 1 against a range of social, environmental and economic objectives. Identifying the best dam locations for the optimised delivery of multiple benefits and minimisation of adverse impacts is at the core of system-scale planning. System-scale planning of dams and other water infrastructure must take place within the context of river basin/landscape planning, which takes into account water and land use, and which is informed by strategic economic planning.

3. In a rapidly changing world, dams must be adaptable to be effective over the long-term. Dams must be planned, designed, operated and monitored to allow for adaptive management in response to climate change and resulting hydrological extremes, and shifting societal preferences. Planning must take account of a number of different climate and societal scenarios, and upfront capital investment is needed to build in design features that allow for flexible operation.

4. Provision of environmental flows and maintenance of fluvial connectivity should be prioritised to safeguard aquatic biodiversity and ecosystem services to downstream communities. Dam developers should undertake an environmental flow needs assessment as part of the Environmental Impact Assessment (EIA), and dam features and operation rules should be designed to enable these needs to be met. Dams should be sited and designed to maximise fluvial connectivity within river systems.

5. Planning processes are most effective when they involve meaningful participation of representatives of different economic sectors, interest groups and affected communities in order to balance the benefits and costs of dams. Participation is required throughout the whole planning, construction and operational lifespan of dam projects. A key component is sharing of knowledge and perspectives about how dams affect local communities, indigenous peoples, ecosystem services and biodiversity. Local perspectives and needs must be balanced with basin, national and transboundary perspectives and needs.

6. Governance reform will often be required if dams are to effectively balance a range of societal interests. Strong institutional frameworks are needed that enable independent regulation of all actors, that guard against capture by interests of powerful players, and that ensure transparent decision-making, which takes account public interests, including those of marginalised and underprivileged groups.

7. In addition to system-scale planning, reducing adverse environmental and social impacts requires meaningful impact assessments at the project scale. EIAs should be the result of genuine interaction between different interest groups and should be carried out well ahead of key decisions being made. The EIA process must be genuinely independent and peer reviewed. In some countries, policy/regulatory reform is likely to be required to achieve this.

8. A number of tools exist for assessing and reducing the environmental, social and financial risks of dam projects. Developers and investors need to consider impacts from dams, but also risks that may affect the dam’s performance. WWF’s Water Risk Filter helps assess risks linked to the river’s catchment – such as low flows – that could affect dam projects; the Hydropower Sustainability Assessment Protocol benchmarks hydropower dams against broadly agreed sustainability criteria. The application of internationally recognised environmental-social-governance (ESG) safeguards (such as the Equator Principles and the World Commission on Dams principles) in conjunction with stakeholder engagement, can reduce several sources of risk, leading to reduced delays and cost overruns and improved financial performance. The application of ESG safeguards can be facilitated by finance sources with ESG commitments, such as green bonds and loans from development banks. New finance models are also emerging which are helping to de-risk projects for financial investment.

9. System-scale analysis of existing stocks of dams can optimise benefits, reduce impacts and facilitate responses to climate change, societal needs and economic development imperatives. Such analysis involves basin-scale assessments to determine whether infrastructure should be repaired, reoperated, renovated or removed.

10. Removal should be considered where obsolete or inefficient dams are preventing the restoration of ecosystems and/or having negative impacts on communities. Comparing the likely costs and benefits of dam removal against those of renovation and ongoing maintenance can inform decisions. Dam removal costs should incorporate a budget for multiyear monitoring and evaluation of environmental, social and economic impacts before and after the event.