Over Abstraction

Water quantity and quality is essential to healthy rivers and good fisheries. Over-abstraction can be very destructive to fish and invertebrates.

Abstraction is the permanent or temporary removal of water from rivers, canals, lakes, reservoirs or aquifers for human water management. The restoration and preservation of native stream biota requires the rehabilitation of natural flow regimes, yet it is predicted that by 2025, 40% of the world’s population will be facing water poverty. The challenge is how we balance these needs.

Hydrological variability within rivers and streams is one of the primary factors influencing the distribution of aquatic wildlife. Unnaturally low flows and altered flow regimes caused by water abstraction can have damaging impacts on river systems, and their associated fish, invertebrates and plants.

Over-abstraction of river systems can cause:

• Hydrological and hydraulic changes; modifying in-stream habitat and altering the width, depths, velocity patterns and shear stresses within the system.
• Increase the invasion of non-native species
• Shifts and reductions in invertebrate assemblages
• Water quality changes; reducing the rivers ability to dilute pollutants, such as phosphorus.
• Increase sediment deposition, thus reducing available fish spawning habitat
• Increase water temperature, and thus decrease dissolved oxygen in the water, which can seriously impact salmonids
• Disruption to migratory fish and invertebrate passages
• Reduce the growth of aquatic flora such as Ranunculus
• Reduced connectivity with floodplains and riparian margins.

Current Management

The Environment Agency is responsible for managing water systems and abstraction licenses in England and Wales. Its duties stem from the 1963 Water Resources Act, which requires a balance between the licensing of water abstraction for the needs of water users and the needs of the environment. Historically, this was undertaken on a piecemeal basis, with many local precedents and “rules of thumb”. A general principle was the protection of the lowest flows, commonly those experienced naturally only 5% of the time, through the use of “hands off flows”; specific flow criteria at which abstraction had to cease or be significantly reduced.

The legislative changes were realised in the 2003 Water Act.

• Time limits for all new abstraction licences; a start and expiry date.
• Greater flexibility to raise or lower licensing thresholds
• Deregulation of small and environmentally insignificant abstractions
• Water company drought plans and water resource management plans to become a statutory requirement.

Non legislative initiatives also include the development of;

• Catchment Abstraction Management Strategies (CAMS); developed to provide a consistent mechanism for managing water use through catchment planning and licensing, and to provide the information necessary for the review of existing time-limited licences and for the assessment of new time-limited licenses. The first formal cycle of CAMS commenced in 2001, and concluded in March 2008.
• Restoring Sustainable Abstraction (RSA) Programme; set up in 1999 to identify sites which may be at risk from abstraction, and to prioritise how to resolve the conflicts in these areas. An ongoing review is taking place to identify environmental damage still occurring as a result of abstraction, focusing on sites designated under the Habitats and Birds Directives.

The Environment Agency has the power, under existing legalisation, to vary or revoke abstraction licenses causing environmental damage. However, in many circumstances, this requires compensation to be paid to the licence holder. For example, eight years of consultation on how to alleviate over-abstraction of the Rivers Brennand and Whitendale in the upper Ribble catchment, which results in important salmonid spawning and nursery areas being reduced to pools in the drier months, has ended in no changes being made to the current abstraction licences, because no funds are available to compensate water companies for abstracting less water.

There is also concern over the effectiveness of the CAMS process in aquifer-fed catchments such as the Bourne Rivulet, where the Environment Agency are still allowing high levels of winter abstraction in the Test & Itchen CAMS. This is deemed acceptable because of high seasonal rainfall, but continuing abstraction during these winter months is jeopardising replenishment of the aquifer, with potential to impact the ecology of the Bourne Rivulet.

Despite the conservation of aquatic biodiversity and ecosystem health being embedded in current policies, there seems to be little political will to prioritise it. Environmental protection tends to favour small scale site protection or rehabilitation. However, structural river restoration will provide very little environmental benefit if other key stressors on the system are not removed. The conservation of running water systems requires the restoration of the underlying processes that support the biota. Restoring natural flow regimes is fundamental to improving aquatic habitats, and increasing biodiversity. Restoring flow regimes should not be considered in isolation, but linked with water quality and morphology targets.

Action Required

The S&TA believes that WFD compliance will be compromised if further action is not taken to address damaging abstractions through altering their licenses. This could lead to the EU initiating legal infraction proceedings against the UK Government.

S&TA seeks:

• Action to make all existing licences time limited, and to remove the requirement to provide compensation to the licence holder if the abstraction is causing environmental damage.
• The Government to quantify the effectiveness of the Restoring Sustainable Abstraction Programme.
• An urgent review of the CAMS process to 1) make allowances for inadequacies in historical flow data in assessing future flows, 2) take full account of the necessary dilution requirements needed to reduce the impact of consented discharges and diffuse pollution and 3) to make allowances for climate change.
• Sufficient funding for monitoring, so the impacts of abstraction can be separated from other stressors to provide clear evidence of the environmental damage caused by abstractions.

For further information see;

S&TA Scientific Briefing Paper: River and Groundwater Abstraction
SNIFFER. (2006). Development of Environmental Standards (Water Resources). Stage 2.
SNIFFER. (2005). Development of Environmental Standards (Water Resources). Stage 1.