Droughts occur at multiple spatial scales and evolve over timescales that make them distinctive compared to other ‘natural’ hazards. The impacts of drought and water scarcity on the environment, society and the economy are complex, reflecting meteorological and hydrological conditions as well as human choices and trade-offs between competing claims for water.
Drought management is a problem of minimising negative impacts, given uncertain information about past, present and future conditions. This will be dependent on how specific impacts and risks of droughts and water scarcity are understood, managed by key stakeholders, and shaped by institutions, regulation and markets.
The current legal regime in the UK involves a range of statutory provisions, regulations as well as non-binding soft law, which provide significant discretion for key actors to decide which demand and supply options are chosen to manage the impact of water scarcity. How key decision-makers exercise this discretion depends also on what evidence is available about drought impacts and options.
The below figure maps the drought planning framework in England. The key actors in the governance space for drought planning in England are Defra, Ofwat, the EA, water companies, customer-citizens, and consultants. Other actors include Natural England (NE), the Consumer Council for Water (CCW) the Drinking Water Inspectorate (DWI), and the European Union (EU).
A wide range of drought management options have been explored and reviewed as part of MaRIUS. A non-exhaustive list of options is shown in the chart below. The review has also highlighted which options for drought management practice in England & Wales are currently used or mentioned within water companies’ Water Resources Management Plans (WRMPs).
A risk-based approach enables the development of management measures whose costs and impacts are in proportion to the probability and consequences of water scarcity, informed by a mature understanding of droughts from the perspectives of a range of communities and stakeholders. Improved understanding of uncertainties provides the basis for identification of management responses that are robust to uncertainty, reflect society’s attitude to risk, and help to make the case for adaptive management approaches informed by targeted data acquisition.
A wide range of management options have been modelled as part of MaRIUS. For example, different water resource management strategies related to the abstraction and allocation of water; water resource management strategies related to water demand and abstraction and effects on river flow, water quality, ecology, and the economy; and effects of irrigation management strategies on farming.
Water Supply Options
Water supply drought is where a shortage of rainfall causes water companies concern about supplies for their customers. Central to drought management will be decisions made about quantities of water to abstract (from a range of different sources), for storage or for allocation to different water users. Water resources simulation models (WRSM) can simulate abstractions, stores (including groundwater), transfers, the consumption of water and return flows. They can also be used to represent current or potential rules and arrangements for managing water resources.
In MaRIUS we have improved on existing WRSMs to provide capability to model the potential for, and robustness of, more sophisticated water allocation and management arrangements during droughts. This provides information on the probability of water shortages for different users under given management strategies, and allowed us to test a wide range of water abstraction, allocation and transfer strategies before and during droughts and during drought recovery.
It is anticipated that population growth and increased demand for water from households and industry will place more strain on the water supply system in the future, particularly when coupled with the projected effects of climate change on drought characteristics. As such, options to manage demand can be as crucial as options to manage or increase supply.
The Environment Agency have highlighted a number of measures water companies can implement to help manage demand, with such options explored and reviewed as part of our MaRIUS governance work. For example:
- water efficiency information and initiatives
- active leakage control
- water metering
- and regulatory options such as non-essential use restrictions and temporary use bans