Working collaboratively across the South East

The water companies of the southeast of England recognise that as an industry we need to work collaboratively to share knowledge and best practice, co-ordinate and align communication to customers and stakeholders, and promote the efficient use of water resources. Therefore, we work closely with other water companies in our region as part of the WRSE and WRE groups. This is set out in the regional groups Statement of Intents (SOI) which were updated for the draft Drought Plan 2027 submissions (sections of the WRSE SOI are included below for reference).

We participate in the WRSE Dry Weather Working Group (DWMG). The purpose of the group is to support close collaboration, understanding and pre-planning for drought, dry weather and high demand events, or other issues, which threaten the resilience of the supply demand position of member companies. It provides a forum for members to discuss, provide updates and share information; undertake scenario testing, to progress and improve planning for co-ordinated regional management of a developing drought. Through exception reporting, it monitors and alerts water company members when the region is operating at heightened levels of risk and advises when increasing levels of regional coordination of joint actions and preparedness is desirable, including communication with customers and the introduction of restrictions. It draws information from national, regional and local assessments and provides updates to help inform regional and national awareness and early preparedness. Under normal conditions, the DWMG meets on a bi-monthly basis and the frequency of meetings increases during dry weather and drought events.

The basis for the variability of responses to water use restrictions from water companies in Southeast England.

In the South East region water companies source their supplies of raw water in the following ways:

1. River abstraction;
2. Reservoirs filled by river abstraction or impoundment of river water;
3. Groundwater abstraction from boreholes and springs.

The percentage balance of these varies from company to company, and even within company areas and this causes variability in drought resilience and response.

The impact of drought is felt in different areas and over different timescales. An agricultural drought affecting crop production and other farming practices can occur over the growing season reducing water supply and moisture in soils. In contrast, a water resources drought affecting the availability of water for potable supplies, takes much longer to develop after several months of below average rainfall. The low groundwater levels, reservoir levels and river flows that result from this type of dry period cause challenges in a water company’s ability to maintain a secure supply of water to customers.

To manage this risk, water use restrictions are an important measure that water companies can use to reduce demand during drought. They not only enable companies to maintain essential supplies but also help to reduce the environmental impacts of abstraction during this critical period.

Water companies will only impose water use restrictions upon their customers if they are absolutely necessary and in accordance with their Levels of Service for water supply. Water companies fully appreciate the confusion that can be caused when one company introduces restrictions, but a neighbouring company does not. One of the reasons for this is the geographical extent of the drought: it may be very localised and not extend beyond the area served by an individual water company.

The reasons why companies may have to react differently in terms of restrictions and their timing are explained below:

Differing levels of drought severity across the region: Whilst droughts across the South East will generally be caused by a regional trend of several months of below average rainfall, sub-regional differences in rainfall amount may cause differing levels of water shortages across the region. In other words, the need to impose restrictions for one company may not equally apply to another.

Differing vulnerabilities at Water Resource Zone level: Due to the way the water supply system has developed over time, many water company supply areas are sub-divided into Water Resources Zones (WRZs). These are defined as the largest possible zone in which all resources, including external transfers, can be shared and hence the zone in which customers experience the same risk of supply failure from a resource shortfall. WRZs can be divided into those dependent upon:

• River abstraction only;
• Groundwater abstraction only;
• Reservoirs filled by abstracting local river water or by impounding river water;
• Various combinations of the above.

This mix of WRZ types means that even if there were not a significant difference in drought severity across the region, WRZs will tend to react differently to the same drought, with certain zones experiencing higher levels of risk to potable supplies than others. That means in similar drought conditions, rivers, groundwater sources and reservoirs across the region can respond differently in terms of risk to supply. For example, a WRZ dependent on combined river abstraction and reservoir storage for supply may have a different level of risk to one based on groundwater abstraction. This difference in WRZ vulnerability has an impact both at the company level and regional level. A water company may need to introduce water use restrictions in its more vulnerable WRZs but not need to extend the ban to the remaining zones in its area of supply.

The introduction of the new powers in the form of the Temporary Use Ban (TUB) in 2011 provided an opportunity for the water companies in the South East to review their Drought Plans with a view to finding a clearer, more consistent and more unified approach to introducing water use restrictions across the region than in the past.

The water companies in the South East have held meetings to discuss the development of their plans and ensure that they are implementing the powers as consistently as possible. The companies are committed to working collaboratively during periods of water shortages. In this context they have worked together to align the drought levels in their plans and to align as closely as possible the restrictions and exemptions that would be imposed when a TUB and a non essential use ban (NEUB) are implemented. However, due to the local differences highlighted above, the timing of drought plans and actions will vary across the region.