2021 River Basin Management Plan - Water levels and flows challenge - Environment Agency
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2021 River Basin Management Plan
Water levels and flows challenge Published: October 2019
Contents
1. Summary ............................................................................................................ 1
2. Water levels and flows pressures ....................................................................... 3
3. Addressing the challenge ................................................................................. 10
4. Future challenges and actions .......................................................................... 13
5. Case studies ..................................................................................................... 15
6. Choices ............................................................................................................. 17
7. Contacts ........................................................................................................... 18
8. References ....................................................................................................... 18
1. Summary
Water from rivers and groundwater provides essential water for people, agriculture
and industry. But in England nearly 20 per cent of surface water bodies, and 26 per
cent of groundwater bodies are being damaged by over abstraction.
The natural flow regime of our rivers and estuaries can be changed by activities such
as navigation, recreation, power generation or irrigation. Dams, weirs and other
structures, or water released from reservoirs can give rise to pressures on the
environment that may mean flows do not always support the ecology.
Having the right flows in our rivers is essential to support a healthy environment and
for the achievement of good ecological status. Not over abstracting from
groundwater resources will help safeguard groundwater dependent features such as
springs and wetlands and helps achieve good groundwater quantitative status.
It is vital that we address the problems of over abstraction to:
• protect river and groundwater supplies
• provide the freshwater we use
• support the ecology and resilience of our rivers, wetlands and groundwater
The damage caused by over abstraction can be severe:
• reduced water slows the flow of rivers and increases the percentage of
sediments and pollutants. As a result the quality of water will fall
1
• the shape of the river can alter and fish will face increased difficulties in
navigating over obstructions
• water temperature can increase
• there is less space for habitats which affects fish and other wildlife
• the quality of recreation provided by rivers and wetlands diminishes
Rainfall provides and replenishes our water resources but there is a large variation in
the amount of rainfall across England. The more densely populated south-east area
of England is also one of the driest part of the country so has the least available
water for abstraction (see Figure 2). As well as the amount of rainfall received, a
catchment’s topography and the different land management practices also influence
the:
• speed of water run-off
• rate that water filters into the ground
• water storage capacity across different catchments
The effect of climate change with prolonged periods of hot and dry weather can only
exacerbate these conditions, leading to greater environmental, economic and social
stress. In the future, demand for water is also expected to increase due to population
growth and development.
Tackling these flow issues now will help us to manage water resources more
sustainably in the future.
2
2. Water levels and flows pressures
2.1 Groundwater pressures
Groundwater is essential both for drinking water supplies and for supporting
dependent surface waters and wetlands. About 30 per cent of groundwater bodies
in England are not achieving good groundwater quantitative status. Groundwater
quantitative status provides an assessment of the condition of groundwater bodies
across the country.
To understand the impact of abstraction on groundwater we use four tests:
• an assessment of abstractions against the available groundwater resources
• the contribution an abstraction might make to a wider area of reduced river
flow
• the ‘Wetlands Test’, which looks at wetlands dependent on groundwater and
assesses the effects abstraction might have on them
• the ‘Saline and Other Intrusions Test’, which reviews areas of poor water
quality to determine if abstraction will lead to further deterioration
In all four tests the assessment result is either ‘good’ or ‘poor’ based on current
pressure; or ‘not at risk’ or ‘at risk’ under future pressure. Figure 1 shows the
groundwater quantitative status for England. A groundwater body is classed as either
‘good’ or ‘poor’ groundwater quantitative status based on groundwater abstraction
pressures. The assessment of quantitative status uses a ‘one out all out’ approach
where if one of the tests fails, the groundwater body status is ‘poor’. This approach
reflects that groundwater supports a wide range of natural capital assets.
Groundwater in some areas has been over exploited due to growth in public water
supply and historic industrialisation. Where this has occurred, there are difficult
choices to make for two significant reasons. Firstly, there could be little opportunity
to transfer the abstraction to other sources of water. Secondly, housing
development and associated infrastructure may have developed on natural spring
areas that, if the water recovers to a natural state, could result in groundwater
flooding.
3Figure 1. Groundwater quantitative status for England
42.2 Water resources reliability and abstraction pressures
Most abstractions are sustainable and well managed. However, some may be
causing an environmental impact. This might be due to how or when the water is
abstracted, as well as how much of the water is returned to the environment.
Whether they are from groundwater or surface water sources, these abstractions can
impact or put at risk protected or sensitive environments.
Changes in river flows and groundwater levels can have the following effects on the
in river ecology and habitat:
• reduced flows will change the shape of river channels and the geomorphology
of the river system which will alter natural river habitats, disadvantaging
species that need fast flowing and/or deeper water
• rivers could dry up more frequently than they would naturally, disrupting the
life cycles of species requiring flowing water
• reduced flows can exaggerate the impacts of barriers such as weirs which
affects migratory and non-migratory species
• reduced flows can increase deposition of fine sediments carried in flowing
water, affecting sensitive species
• too much abstraction can lead to unsustainable water bodies with reduced
resilience during prolonged dry weather
• groundwater abstraction can induce poorer quality groundwater to move, for
example inducing saline intrusion from deep groundwater or from the sea
• reductions in water levels may prevent bank overtopping and inundation of the
floodplain, disrupting life cycles of species requiring floodplain habitats
• reduced flows can increase the risk of toxic algal blooms, especially during
drought conditions and warm temperatures
• altered flows may change water temperature which can have an impact on
river ecology and habitat
The Environment Agency (EA) is responsible for granting water abstraction licences.
The EA ensure some water is reserved to meet the needs of the environment
throughout the year and to protect the rights of existing abstractors. The need to
safeguard the lower reaches of river catchments with abstraction or flow problems
means that water is sometimes not available upstream even though there is no
shortage locally. Environmental effects of abstraction are likely to be magnified in
future by changes in population and climate.
Figure 2 gives an indication of the reliability of water for new abstractions showing
the variation in availability, and taking into account any low flow related restrictions
on current abstractions. For example, in the palest blue areas, water is only available
30 per cent of the time which will tend to be in the winter when river flows are higher.
5Figure 2. Water resource reliability. Percentage of time water would be available for
abstraction under a new licence
Having the right flow in our rivers is essential to supporting a healthy ecology. For
rivers and lakes, the UK has developed specific flow thresholds which set a limit of
6allowable reduction from natural flows (essentially abstraction limits) according to
river type. These are implemented by the Environment Agency as the environmental
flow indicator (EFI). The EFI is set at a level that is believed to support good
ecological status (GES) under the Water Framework Directive (WFD). GES is the
primary WFD objective for each water body.
The EFI is used in the hydrological classification to identify the water bodies where
reduced river flows may be causing or contributing to a failure of good ecological
status. This is called the flow compliance assessment and it is carried out for each
classified water body.
Flow compliance is assessed at low flows taking into account current levels of
abstraction. The compliance assessment shows where flows are below the EFI, and
indicates by how much. This is used to identify areas where flows may not be
supporting GES, target investigation of actual impact on ecology and identify what
measures are needed to achieve GES. Flow compliance results are reported in four
bands to indicate our level of confidence in that assessment.
Table 1. The flow condition for each compliance band (how much the flow falls
below the EFI, expressed as a percentage of natural flow)
Flow supports Flow does not support GES (lower Flow does not
GES confidence) support GES (higher
Confidence)
Compliant with Noncompliant Band Noncompliant Noncompliant Band 3
EFI 1 Band 2 (greater than 50 per
(up to 25 per cent (25 to 50 per cent cent below the EFI at
below the EFI at low below the EFI at low flows)
flows) low flows)
Investigations of flow impacts overall indicate that abstraction and flow pressures are
preventing achievement of good ecological status or good ecological potential (GEP)
in about 6 per cent of surface water bodies in England. A further 6 per cent of
surface water bodies are still under investigation.
There may be some water bodies where GES can be achieved with a flow regime
below the EFI. However sufficient evidence is needed to have confidence in this and
the future risk of deterioration to the ecology as a result of abstraction pressure will
still need to be managed.
Some areas of the country are recognised for their internationally and nationally
important wildlife. These areas receive special legal protection (designated sites).
Abstraction and flow pressure is one of the reasons for designated riverine sites to
fail their conservation objectives and the amount of allowable abstraction to improve
and protect these sites may differ from that required to meet GES. Figure 3 shows
the risk to ecology from current abstraction. More information on this can be found in
the biodiversity document in the Challenges and Choices consultation.
7Figure 3 Risk to ecology from current abstraction
2.2 Heavily modified water body pressures
The natural flow regime can change where rivers have been managed or modified to
support various uses and activities. Some waters bodies have been designated
‘heavily modified’ because these uses prevent them being restored to GES without
compromising the specified use. In this case the WFD objective is good ecological
potential (GEP). Surface water bodies designated as heavily modified for water
supply uses are shown in Figure 3 (approximately 13 per cent of surface water
8bodies). Investigations into these water bodies have identified abstraction as a
reason for not achieving GEP in approximately 3 per cent of surface water bodies. A
further 4 per cent are still under investigation. Measures to mitigate the modification
and achieve GEP should be implemented providing the mitigation measures don’t
cause a significant adverse impact on the designated use.
Figure 4. Water bodies designated as ‘heavily modified’ for water supply use
93. Addressing the challenge
3.1 What needs to be achieved?
Where abstraction does not support GES or GEP, flows and resources in these
water bodies need to be improved between now and 2021 and beyond to 2027 to
move towards GES or GEP.
Whilst changing abstraction licences is the primary method to resolving
unsustainable abstraction, it is unlikely that flows can be recovered to the EFI in all
cases, particularly where costs outweigh the benefits of flow recovery. Implementing
measures such as habitat restoration within the river channel or catchment,
alongside licence changes, can enhance the ecological benefits of increasing the
amount of water in our rivers.
Where ecological problems are caused by a combination of issues, other solutions
will also be required to improve ecological status. Wider benefits on the catchment
scale will take time to realise and assess but, if effective combinations of measures
can be introduced (subject to economic appraisal), then the number of water bodies
supporting a healthy ecology by 2021 can be expected to increase.
Where abstraction is unsustainable and does not support good quantitative status in
groundwater bodies, then action needs to be taken to move towards good status. To
achieve a sustainable environment we have taken a pragmatic approach in
addressing dependent features first, with an underlying objective to avoid
deteriorating groundwater. This means that it may take longer for groundwater
bodies to achieve compliance by 2021 or 2027.
We are also aware that due to historic levels of over exploitation of groundwater we
will not be able to achieve good status in some groundwater bodies in the future.
Where over exploitation is assessed we will introduce measures to reduce
abstractions to an acceptable level that considers socioeconomic needs.
As well as working towards a good ecological status in water bodies, the
Environment Agency and water companies need to prevent deterioration, ensuring
that river flows continue to support environmental objectives and that all elements of
groundwater quantitative status are maintained or improved where necessary.
3.2 Who needs to be involved?
The scale of action needed means that collaboration and partnership working will be
essential to be able to deliver these improvements to ecological status and resilience
using the approaches and funding currently available. Everyone with an interest in
the health of England's rivers and wetlands, such as local and national government,
water companies, abstractors or local river trusts, need to take action to secure the
required improvements.
The Water Abstraction Plan 2017 i sets out how the government will reform
abstraction management over the coming years and how this will help to protect the
environment and improve access to water. The ‘catchment focus’ section of the plan
describes how the Environment Agency will continue to promote a catchment based
approach working with abstractors and existing catchment partnerships and other
10local groups to identify and implement local solutions in catchments, starting with 10
priority catchments. The Report to Parliament (2019)ii on progress with abstraction
reform May 2019 outlines some of the progress already made and action taken on
reform.
We are also encouraging the water companies and other large water users to
organise themselves into regional groups and have asked them to explore the best
solutions to deliver a secure water resources. This regional approach will be guided
by the water resources national framework which will assemble the evidence on
where we expect water to be in surplus or in short supply. The framework will then
set out strategic water needs, nationally and regionally, up to 2050.
3.3 Regulated flows and mitigating pressures
The Environment Agency and water companies have undertaken investigations on
mitigating the impacts on heavily modified and artificial water bodies (HMWBs)
designated for water supply and water resource purposes.
The measures include actions to ensure downstream river flows are appropriate to
maintain river habitats, and to ensure the impacts on the morphological character of
the river are reduced including the mimicking of natural sediment movement.
3.4 Demand management
Reducing the amount of water we consume and waste could make a significant
difference to water availability for people and the environment.
Reducing the amount of water we use, for instance through metering, can also allow
development, housing and sustainable business growth in areas where it would
otherwise be restricted because of water supply and environmental pressures.
Industry, agriculture and other sectors can use methods such as sustainable
irrigation, water efficiency targets, awareness raising, water audits and use of good
practice guidance.
In addition, Defra has set out its plans to improve water efficiency in its water
conservation report to parliament in December 2018 iii.
3.5 Water resources management plans
Under the Water Resources Management Plan Direction 2017, water companies
have to prepare Water resources management plans to say how they propose to
manage water supply and demand over the following 25 years and comply with their
environmental obligations. Water resource management plans should ensure an
efficient, sustainable use of water resources.
They should focus on delivering efficiently the outcomes that customers want, while
reflecting the value that society places on the environment. The plans show how the
companies plan to provide enough water to their customers over the next 25 years.
3.6 Water Industry National Environment Programme (WINEP)
Where water company abstraction is shown to damage or pose a risk to the
environment, companies will work with the Environment Agency to develop
11alternative solutions. Some of these solutions are included in the Water Industry
National Environment Programme (WINEP). The WINEP is a programme of
environmental improvement schemes that ensure that water companies meet
European and national targets related to water. More information on this can be
found in the water industry waste water document in the Challenges and Choices
consultation.
3.7 Physical impacts of low flows and mitigating pressures
The physical effects of low flows can be reduced by improving river habitats and
restoring the natural processes that take place in our rivers. For example, using
fencing to stop cattle encroaching into rivers and removing redundant weirs can
support the recovery to a more naturally functioning ecosystem. Where measures to
improve flows are completed in combination with those to improve physical habitat
there is a multiple benefit.
3.8 Catchment hydrology and land management
Different land management practices can change the way that water moves through
or is retained within a catchment. Improved practices include, cultivating land early to
minimise erosion and establish ground cover in winter and restoring large areas of
upland wetlands which may help to slow runoff. Trees can slow water movement
over and through soils, reducing peak flow rates and possibly increasing base flow in
streams.
Sustainable drainage systems (SuDS) provide an opportunity to treat polluted runoff
from both urban and rural diffuse sources before it enters watercourses. Many SuDS
schemes put the water to ground which can replenish groundwater supplies and help
mitigate against excessively high and low flows.
3.9 Water level and site management at wetlands
Some wetland plant communities (for example, the calcareous fen sites in East
Anglia) are critically dependent on groundwater. As a result, one of the WFD
groundwater quantitative tests is that groundwater abstraction should not cause
significant damage at wetland sites. Some ecological impacts can be mitigated
through water level or site management. An example is through water level
management plans (WLMPs) agreed between the Environment Agency and Defra.
124. Future challenges and actions
Preventing deterioration in ecological status and groundwater status are essential to
retain the value of the environment and the ecosystem services we rely on now and
in the future.
In the future, population growth and economic development are likely to increase
demand for water. Climate change is likely to significantly change the pattern and
volume of rainfall that England receives and the average temperatures we
experience. This may result in less water being available for surface water flows and
groundwater recharge in the future. Sustainable management of future water
supplies to take account of economic growth and more intensive future food
production will be a significant challenge.
Demand management will play an increasingly important role in ensuring water
availability up to the 2050s. However, demand management alone will not fix the
problem. New approaches to water resource management, such as the national
framework described in section 3.2, will be necessary in order to maintain public
water supply resilience and resilience for other water uses, including the
environment.
The Environment Agency carried out assessments in 2016 of the risk of deterioration
due to forecast changes in abstraction up to 2030. Results derived using a national
model identified around 50 surface water bodies probably at risk of deterioration in a
‘business as usual’ demand forecast scenario. If abstraction was to increase further
in future, many more surface water bodies in England could be at risk.
For groundwater bodies, assessment of the risk of deterioration in status and risk of
not achieving GES indicates 106 groundwater bodies are at risk and a further 122
probably at risk due to abstraction pressures.
Water companies are expected to complete investigations where growth in
abstraction is likely to cause deterioration in ecology or groundwater resources and
take action to prevent the deterioration from occurring.
Chalk rivers
Chalk rivers and streams are highly valued culturally and provide valuable
recreational fisheries. They are rare and an important haven for wildlife. Chalk rivers
emerge from chalk aquifers, so the very pure water is rich in minerals and remains at
a fairly constant temperature year round. They are typically very diverse and the
good water quality supports many invertebrate and fish species. Only 200 chalk
rivers are known globally, 85 per cent of which are found in the UK in southern and
eastern England. Classic examples include the rivers Test and Itchen in Hampshire.
Current legislation requires that chalk rivers are protected from deterioration due to
human activity. They are well represented in both the national and European
designated site network, which aims to protect sites of high conservation value.
We are working with water companies to ensure their future plans reflect the need to
protect the environment and ensuring new rules for farmers tackle agricultural diffuse
pollution in chalk river catchments.
134.1 Climate Change
We have made a preliminary assessment of possible effects of climate change on
river water body flows in 2050. Future pressure on low flows maps (higher, central
and lower) illustrate a range of results using future flow scenarios based on the
UKCP09 climate models (medium emissions). These illustrative maps for 2050 are
shown below; the method assumes that future abstraction demand for the main
sectors will be constrained and not increase beyond 2030 forecast rates.
Figure 5. Future pressure on low flows, showing higher, central and lower scenarios
from left to right
The higher scenario map indicates that pressure on low flows is likely to be:
• higher than present in areas where there are already high rates of abstraction
such as the Chilterns, the West Midlands, parts of East Anglia, Yorkshire,
Lincolnshire and Kent
• much higher than present in parts of Cornwall, Devon, Dorset and Somerset,
where abstraction pressure is currently relatively low
Implementation of the Water Abstraction Plan will mean that we are better prepared
to cope with the pressures of climate change and future demand for water, through a
more flexible abstraction licensing system and more resilient water environment.
We are also looking into using more nature-based solutions (NBS) to address water
management challenges. NBS such as re-connecting rivers to floodplains, use of
woody debris dams, and restoring river systems, can help to hold more water in the
natural system during periods of high flows that can help sustain the riverine
ecosystem during periods of low flows. Not only will these solutions help to sustain
water in the natural system, but they can provide wider benefits in terms of improving
water quality, reducing flood risk, increasing biodiversity and making the riverine
system more resilient to a changing climate.
145. Case studies
Case study: River Lark, Bury St Edmunds, Suffolk
The River Lark runs through the town of Bury St Edmunds in Suffolk. Water in
the river comes mainly from rainfall, runoff, and discharge from the chalk
aquifer over which it flows. The river adds value to the local amenity but does
not have any conservation status such as a Site of Special Scientific Interest
(SSSI) or Wildlife Site.
There have been concerns about the flow in the River Lark through Bury St
Edmunds since the early 1990s when there was a drought period (1989 to
1992) and the river dried up and fish died.
Photograph 1 River Lark
Anglian Water Services Ltd (AWS) operate boreholes to abstract from the
chalk aquifer to supply water to Bury St Edmunds. Between 2000 and 2005,
AWS carried out investigations to reassess whether its abstractions were
affecting the flows in the River Lark. The investigations indicated that they
were, so AWS considered options to resolve this.
The Environment Agency (EA) conducted groundwater modelling and
appointed consultants to carry out research into specific requirements of the
fisheries and ecology. This identified a bespoke flow requirement for the River
Lark in Bury St Edmond and allowed the EA to assess the options considered
by AWS.
A set of conditions was agreed with AWS to protect flows in the river, with
some interim conditions being applied whilst engineering work takes place to
allow the more stringent conditions to become effective in 2025.
15Case study: Banister Farm, Eastern England
` The river flowing through the farm relied on sewage effluent for flow. The river
suffered from low flows during dry periods and was not achieving its objective
for dissolved oxygen. The Environment Agency advised the farmer to change
abstraction times, from the summer period to a high flow abstraction regime.
The farmer paid for relevant works to reduce the width of the river channel to
ensure sustainable flows during dry periods whilst also leaving sufficient flood
plain to allow for flooding during wetter periods. The Environment Agency is
currently monitoring the river to confirm whether reducing the width of the river
channel has resulted in an increase in dissolved oxygen.
Photograph 2 Showing the result of reducing the width of the river
166. Choices
Question 1: What can be done to address the challenge of changing water levels
and flows?
Question 2: The abstraction plan, referenced in the changes to water levels and
flows narrative, explains our current and future approach for managing
water abstraction. What else do we need to do to meet the challenges
of climate change and growth while balancing the needs of abstractors
and the environment?
Question 3: What kind of a water flow environment do we want? Should we
maintain statutory minimum water flow and level standards universally
across England as we do now, or go further in some places based on
environmental risk?
177. Contacts
If you have any feedback or comments on the evidence contained in the summary
then please contact:
enquiries@environment-agency.gov.uk
8. References
Figure 1: Groundwater Quantitative Status map, Environment Agency (2015).
Figure 2: Water Resources Reliability map, based on September 2014 data,
Environment Agency (2014).
Figure 3: Recent actual compliance with environmental flow indicators (at low flows),
Environment Agency (2015).
Figure 4: Surface water bodies designated as ‘heavily modified’ for water supply
uses as of September 2014, Environment Agency (2014).
iWater abstraction plan https://www.gov.uk/government/publications/water-
abstraction-plan-2017
ii
Abstraction reform report https://www.gov.uk/government/publications/abstraction-
reform-report-2019
iii
Water conservation report https://www.gov.uk/government/publications/water-
conservation-report-2018
Further reading links
Water-abstraction-plan:
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attach
ment_data/file/601943/WFD_state_aid_exemption_2017.pdf
Managing Water Abstraction
River basin management plans
Abstraction Statistics (Defra website)
Abstraction Reform consultation (Defra website)
Abstraction Reform Statement of Response (Defra website)
Defra / EA Water Abstraction Plan, December 2017
Defra Abstraction Reform Report to Parliament, May 2019
Large scale water transfers
Waterwise, ideas for saving water
Water white paper – water for life
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