Environmental assessment in water company drought plans

23rd April 2012

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  • Water ,
  • Natural resources



Clare Black from Cascade Consulting explores the role of environmental assessment in how water companies plan for water shortages

Hosepipe bans hit the headlines recently as drought was declared across most of England after a prolonged period of below-average rainfall. Officially known as “temporary use bans”, these restrictions are the most visible element of the implementation of drought management plans drawn up by water companies to safeguard water resources across the country.

Drought planning

Drought plans set out how water companies will identify and respond to droughts, to maintain security of supply and deliver targets on how often restrictions are placed on water use (known as levels of service).

In their drought plans, water companies identify key decision points (drought triggers) at which various drought management actions should be considered. Modelling is used to test these triggers under different drought scenarios to demonstrate how a range of actions would be implemented to meet planned levels of service.

A drought plan needs to include the full range of actions that could be required by the water company during a drought, both to reduce demand and to increase supply (see table 1, below).

Table 1 Examples of drought management actions

To reduce demand: To increase supply:
  • temporary use bans (hosepipe bans);
  • increased abstraction from existing sources;
  • increased communication on how to use water more efficiently;
  • re-commissioning unused sources of water;
  • collaboration with industry and businesses to reduce water use; and
  • transfer water between water companies; and
  • increased water company activity to repair leaks.
  • investment in alternative techniques, for example, desalination.

The role of environmental assessment

Drought management actions that increase supply take additional water from the environment, potentially placing extra pressure on ecosystems already under stress.

Each supply-side action in the drought plan therefore requires an assessment of environmental impacts, including identification of appropriate monitoring and mitigation techniques (figure 1, below).

This ensures that water companies are able to include environmental impacts of each supply-side action in the decision-making process and prioritise actions accordingly.

Figure 1: The role of environmental assessments in a drought plan

(Source: Environment Agency Water company drought plan guidelines)

During a drought, each supply-side action requires a drought permit or drought order application to be implemented, and each application needs to be accompanied by a full environmental report. Assessing environmental impacts at the drought-planning stage means that water companies are prepared and able to provide necessary information to support these applications, reducing the amount of work and lead-in time required.

Overview of environmental assessments

The requirements for environmental assessments in water company drought plans are set out in the Environment Agency’s drought plan guideline and Defra's guidance on drought permits and drought orders. The environmental assessment consists of several stages:

  1. Hydrological impact: an assessment of likely changes in the extent, nature, duration and timing of the flow/level due to implementing the proposed drought option.
  2. Environmental sensitivity: a review of potentially sensitive receptors (for example, protected areas, sensitive fisheries and heritage sites) located in the impact area to identify those which could be affected by hydrological changes.
  3. Assessment of likely impacts: a review of the baseline physical environment and likely impacts of implementing the drought option on sensitive environmental features under a worst-case scenario compared to the baseline. This includes assessment of potential cumulative effects with other drought options from the same or neighbouring water companies.
  4. Mitigation: identification of measures that may be required to prevent or reduce impacts on sensitive features likely to be subject to a major or moderate impact (or a minor impact for designated features).
  5. Environmental monitoring plan: recommendations for monitoring prior to, during and after implementation of the drought option for features requiring consideration. This should include location, timing and frequency of the monitoring required, and a specification of any monitoring linked to particular mitigation measures.

A Habitats Regulations assessment is required if the drought plan, either alone or in combination with other plans, is likely to significantly affect the integrity of a European conservation site, leading to an appropriate assessment. Under these circumstances, or if the drought plan includes other options likely to have significant effects on the environment, a strategic environmental assessment is also likely to be required.

The impacts of drought cannot be entirely avoided, but it is possible to ensure the effect on people and the environment is minimised. To do so, it is essential that impacts are clearly and robustly assessed, monitored and mitigated, and that this takes place in the context of reconnecting people with the water they use and increasing awareness in both the short- and long-term of the value of water.

This article was written as a contribution to the EIA Quality Mark’s commitment to improving EIA practice.

Clare Black is an environmental scientist at Cascade Consulting. [email protected]


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