1
Comments on two consultation documents from the Environment Agency: (1) Draft
Update to the River Basin Management Plans; (2) Draft Flood Risk Management Plan
(Thames River Basin District)
River basin plans: https://consult.environment-agency.gov.uk/portal/ho/wfd/draft_plans/consult/
Flood risk plan: https://consult.environment-agency.gov.uk/portal/ho/flood/draft_frmp/consult
From: Greening Godalming. Contact: Heather Hullah (heather.hullah@zen.co.uk), cc.
Alan Hamilton (alanchamilton@btinternet.com).
Date: 11 January 2015
1. Our comments relate to our concern to reduce the risk of future flooding in
Godalming, especially in the face of predictions that flood risk will increase with
climate change1,2,3. This is a single response to the two documents, given the
close links that should exist between steps taken to reduce flood risk and river
basin management plans according to the EU Floods Directive4, as has also been
confirmed for the Thames River Basin District by the Environment Agency 5.
2. We welcome the fact that the reality of climate change is recognised in the
documents, especially given that the earlier River Wey Catchment Vision
Consultation Draft (June 2014)6 and River Wey Flood Risk Management Strategy
(for 2012-2112) – as originally published in 20127, made little reference to climate
change in relation to flood risk.
3. We appreciate the participation of the Environment Agency in the public event
which we organised in Godalming on 21st November 2014 Climate change and
future flooding risk for Godalming. We hope that this event was useful for the
Agency in developing its plans. An account of the talk on predicted climate
change and future flood risk given by Greening Godalming at the event is
available on-line8.
1
http://www.metoffice.gov.uk/media/pdf/t/r/UK.pdf
Kendon, E.L. et al. (2014). Heavier summer downpours with climate change revealed by weather forecast resolution
model. Nature Climate Change 1 June 2014. DOI:10.1038/NCLIMATE2258.
3 Climate change report card for water.
http://www.lwec.org.uk/sites/default/files/attachments_biblio/10%20Future%20flood.pdf
4 EU Floods Directive (Directive 2007/60/EC). http://ec.europa.eu/environment/water/flood_risk/
2
5
Water for life and livelihoods. A consultation on the draft update to the river basin management plan for the
Thames River Basin District. https://consult.environmentagency.gov.uk/portal/ho/wfd/draft_plans/consult?pointId=s1405418030714#section-s1405418030714
6
http://www.surreywildlifetrust.org/sites/default/files/wey_landscape_partnership_catchment_vision_draft.pdf
https://www.gov.uk/government/publications/river-wey-flood-risk-management-strategy/river-wey-flood-riskmanagement-strategy
8 https://greengodalming.files.wordpress.com/2014/12/climate-change-and-future-flooding-risk-for-godalming.pdf
7
2
4. We welcome the following two measures included in the Draft Flood Risk
Management Plan (Thames River Basin District) (pages 303-304), with the proviso
that we do not know whether ‘partnership funding’ will be the best way to fund
any schemes put forward.
(1) On-going measure: “Catchment flood modelling River Wey - undertake
detailed hydraulic modelling to more accurately model the flood risk in the
Wey catchment”. Objective: “To better understand flood risk in key locations
across the Wey catchment, and to ensure there is a suitable model to assess
flood risk reduction schemes which may be taken forward along the River
Wey.”
(2) Proposed measure: “Look for future opportunities - Godalming - progress the
initial assessment to investigate what can be done to reduce flood risk in
Godalming. Explore partnership funding to fund schemes put forward”.
We have approached the Environment Agency to enquire whether the word
‘hydraulic’ in Measure (1) had been a typo for ‘hydrological’, but were informed
that ‘hydraulic modelling’ is correct (‘how the water moves downstream, in the
channel and in the floodplain’) and that, as part of hydraulic modelling, there will
also be a hydrological assessment (‘to assess the amount of water which is likely
to be received in an area and go down the channel’). We are grateful for this
clarification. We urge that procedures for manipulation of flood gates, weirs and
locks in the event of potential flooding events also be considered.
We understand that there is a set timetable for implementation of the EU
Flooding Directive, including that flood risk management plans should be
completed and published by the end of December 2015 – ready to link into the
next cycle of River Basin Management Plans in 2016-20219. We therefore look
forward to the incorporation of flood risk reduction schemes emerging from
Measure (1) into the next River Basin Management Plan covering the River Wey.
We take the following quote from a summary document on the consultation for
the Thames River Basin Management Plan to give an indication of thinking within
the Environment Agency of the sorts of measures that might be taken to reduce
flood risk (page 57)10: “Measures can provide significant resilience to a changing
climate. Sustainable Drainage Systems (SuDS), such as green roofs, permeable
pavements and storm water detention ponds, are designed to mimic natural
9
Water Framework Directive factsheet (European Union).
http://ec.europa.eu/environment/pubs/pdf/factsheets/water-framework-directive.pdf
10
Water for Life and Livelihoods. Summary and Consultation Questions for updating the Thames River Basin
Management Plan. Environment Agency. https://consult.environmentagency.gov.uk/portal/ho/wfd/draft_plans/consult?pointId=s1405418030714#section-s1405418030714
3
drainage and to allow excess rainwater to percolate into the ground or flow into
local rivers and stream. They can also trap and remove nutrients, sediments, oils
and other accumulated pollutants released during heavy rainfall following dry
periods (first flush events).”
The reference here to ‘green roofs’ suggests that the types of measures being
contemplated are on a modest scale. However, the SuDS approach can be applied
to the whole catchment. We believe that the opportunity should be taken to
develop a long-term vision for the River Basin Management Plan (covering, for
instance, the next 100 years) that aims to introduce flood risk reduction measures
throughout the whole catchment according to the best scientific advice. This
could be done step by step as conditions allow, working towards an ideal
catchment. We believe that this should take account of the hydrological features
of all the main types of land use within the catchment (agricultural, forestry and
urban; also geological substratum) and different ways in which these can be
managed from a flood risk perspective. Such a long-term vision should prove a
useful tool when management of flood risk is balanced against other demands
made on the catchment (such as for more housing; production of food and
forestry produce, etc.).
We suggest that the Environment Agency consider taking the Wey catchment
above Godalming as a trial catchment to implement flood reduction measures at
a whole catchment (landscape) level.
We thought we were a lone voice crying in the wilderness, but have recently
discovered that the Environment Agency itself recognises the importance of
taking measures to reduce flood risk at the level of the whole catchment.11
Gloucestershire Wildlife Trust is also considering the techniques 12: “Measures are
now being sought to help prevent or reduce these peak events, and one area
being looked at is land management for flood risk reduction. … In basic terms,
Rural SuDS is about attenuating the water flow in the upper catchment areas so
that at peak flow times it reduces the flooding impact lower down the catchment.
One method is the replacement of large woody debris in rivers and streams. … In
recent years the trend has been to take (large woody detritus out of channels) to
create more efficient drainage channels. This may stop localised placement
flooding but it means that flood events further down the catchment can be even
more intense … Agricultural land use also plays a part – as farming has intensified
with more mechanical involvement, there is pressure for more land to be used for
increased food production. This means that at times, there is bare soil, and this is
11
Rural sustainable drainage systems. Environment Agency 2012.
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/291508/scho0612buwh-ee.pdf
12
New techniques: water retention! Wildlife Winter 2014 issue, page 24, Gloucestershire Wildlife Trust.
4
more vulnerable to heavy rainfall events, and can lead to an increase of water
gushing down into the watercourse.” The article make it clear that RuDS can be of
considerable benefit to wildlife, as well as helping to alleviate flooding.
Recommendations: (1) The whole catchment be taken into account in modelling
hydrology to assess possible flood reduction measures for the River Wey. (2) Full
integration of flood reduction measures with the River Basin Management Plan.
(3) An early meeting of knowledgeable people concerned about whole catchment
management to reduce flood risk be held to consider the case of the catchment
of the River Wey above Godalming (some names available on request).
5. Your Partnership Group Host for the Wey Catchment is the Surrey Wildlife
Trust.13 We welcome the interest of the Trust in taking this role, including
because of its interest in pursuing a landscape-level conservation of biodiversity
(appropriate with climate change) and because there can potentially be strong
linkages between flood reduction measures taken at landscape level and
improvement of habitats for wildlife14,15.
A considerable part of the catchment of the River Wey above Godalming has a
geological substratum of chalk. We suspect that agricultural changes here over
recent years have been subject to short-term whims of the market and the
availability of subsidies. A long term vision for how this catchment is best
managed for hydrological purposes (including future water supplies, as well as
flooding reduction) might show that encouragement of permanent pasture might
be a valuable form of agricultural management, also favourable to wildlife.
We have a concern that a considerable part of the Wey catchment above
Godalming is not in Surrey and that some of steps needed to ensure good
management from a flood risk viewpoint may not be appropriate to be the
responsibility for a voluntary organisation (e.g. stronger legislative action may be
needed).
6. In preparing this response, we have become aware that flood risk maps produced
by the Environment Agency labelled ‘Risk of Flooding from Rivers and Seas’16 do
not take account of the effects of climate change (which predict a rising risk of
increased flooding). An explanation attached to the maps makes this clear:
13
Water for Life and Livelihoods. Environment Agency. 2014. https://consult.environmentagency.gov.uk/portal/ho/wfd/draft_plans/consult/?pointId=s1405418030714#section-s1405418030714
14
Rural sustainable drainage systems. Environment Agency 2012.
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/291508/scho0612buwh-ee.pdf
15
New techniques: water retention! Wildlife Winter 2014 issue, page 24, Gloucestershire Wildlife Trust.
16
http://watermaps.environmentagency.gov.uk/wiyby/wiyby.aspx?layerGroups=default&lang=_e&topic=floodmap&scale=9&ep=map&y=14450
5&x=498392#x=498392&y=144505&scale=9
5
“NaFRA is an assessment of flood risk based on information last updated in
2008. It shows the likelihood and consequences of flooding that could happen
now. It does consider climate changes that have already happened but it does not
show how the risks will increase in the future due to climate change.”17 We
believe that the title of these maps is misleading and that they would be better
labelled ‘Historic risk of flooding from Rivers and Seas’. This is because we
consider that most users of these maps, such as planners, developers and
potential house buyers, will be interested in the future and will naturally view the
term ‘risk’ in this context, without necessarily looking carefully at the small print.
A recent document on surface flooding produced by the Environment Agency
contains the statement: “The nationally produced surface water flood mapping
presents the surface water flood risk for a 'current day' scenario. The mapping
does not take into account possible 'future' scenarios such as climate change,
urban creep, or various post-scheme implementation scenarios.” 18 We question
the use of ‘current day’ here (and ‘now’ in the preceding paragraph), since we
understand that one of the principle sources of information contributing to these
maps is the probability of flooding, as shown by the frequency of past flooding
events (of various magnitudes).
This is graphic representation of our point:
PAST
FUTURE
PRESENT
Most users of flood
risk maps will be
interested in future
risk
EA flood risk maps are
based largely on the
frequency of past flooding
events
A ‘current day’ or ‘now’
scenario applied to flooding
should take account of the
rising risk (not implicitly assume
a steady state).
17
http://apps.environment-agency.gov.uk/wiyby/31662.aspx
18
What is the updated flood map for surface water. Environment Agency. 2013.
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/297432/LIT_8988_0bf634.p
df