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Engineering Natures Way
SUDS in Scotland Experience & Opportunity
November 2013
in association with
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Contents
1. Introducing SUDS in Scotland Experience & Opportunity 3
2. About Engineering Natures Way 3
3. Key Findings 4
4. Survey Methodology 7
5. Detailed Survey Results 8
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1. Introducing SUDS in Scotland Experience & Opportunity 2013
The SUDS in Scotland Experience & Opportunitysurvey was carried
out during September and October 2013 with practitioners involved
in the specification, design, delivery and approval of SUDS in Scotland.It set out to investigate how successful professionals believe Scotland
has been in delivering SUDS and to what extent legislation has helped
to drive success.
The survey was designed to identify lessons learned and to examine
whether respondents believed there were any barriers to future progress.It aimed to provide a snapshot of views based on professionals sharing
their experiences. Given that Scotland is further ahead in having a
legislative framework for SUDS in place, it was hoped the findings wouldprovide insights for the delivery of SUDS in England and Wales, as well as
identifying issues to address for future SUDS delivery in Scotland.
Thank YouWe would like to thank all of the 151 practitioners who participated
in the survey, many of whom took the time to provide detailedcomments. We are also grateful to our supporting organisations.
The survey was conducted in association with CIWEM (The Chartered
Institution of Water and Environmental Management) and British Water.
2. About Engineering Natures Way
Engineering Natures Way is the knowledge-sharing initiative for
Sustainable Drainage Systems. Engineering Natures Way aims to share
news, opinion and best practice about SUDS and floods issues in theUK, to raise awareness and stimulate debate.
The award-winning initiative began in May 2009 and has attracted a wide
community of followers to its website www.engineeringnaturesway.co.uk,twitter feed @engnaturesway and regular e-newsletter.
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3. SUDS in Scotland Experience and Opportunity. Key Findings:
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How successful has SUDS delivery been in Scotland?
The overwhelming majority (96.8%) believe Scotland has successfully implemented SUDS since the
implementation of the Water Environment and Water Services (Scotland) Act (WEWS). However, very few
believe it has been completely successful.
Legislation:
84.7% agree legislative drivers have helped Scotland to make more effective progress with SUDSthan England and Wales.
Adoption and Maintenance:
Many commented, however, that authorities had been slow to adopt and maintain SUDS.
Affordability:
The majority (61.1%) believe affordability presents a barrier to SUDS design and implementation
on new developments.
Retrofit:81.3% agree more could be done to retrofit SUDS in Scotland.
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3. SUDS in Scotland Experience and Opportunity. Key Findings (continued):
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Facilitating effective design and specification
Only about half of respondents were satisfied that current regulation and guidance gives practitioners
freedom to specify from a full toolbox of both natural and manufactured/proprietary SUDS features.
Water quality:
The majority agreed that the requirements for design and implementation of surface water treatment
are clearly defined by regulation and guidance in terms of an effective treatment train (77.2%) and whatconstitutes a level of treatment (67.8%).
Proprietary Systems:
However the majority (65%) of those who had experience believe that SEPAs policy to classify
proprietary systems as a level of treatment only in exceptional circumstances was a barrier to design
of effective SUDS solutions.
Many comments highlighted that designers and developers felt frustrated by the limitations in
specifying proprietary systems.
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3. SUDS in Scotland Experience and Opportunity. Key Findings (continued):
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Optimising through-life performance, maintenance and costs
A significant majority believed regulation and guidance for SUDS maintenance and adoption was insufficiently
clear and required further clarification.
Funding:
The vast majority (77.8%) felt there was inadequate funding for the adoption and maintenance of SUDS
in Scotland.
Maintenance:
69.2% believe that proprietary SUDS features either require the same maintenance or are easier to
maintain than natural SUDS features with less than a third (30.8%) believing they are more difficult
to maintain.
Tools:
The vast majority (84.4%) would welcome further developments of The SUDS for Roads Whole Life Cost
and Whole Life Carbon Toolkit from SCOTS and the development of other industry tools to assist withthe design and costing of both proprietary and natural SUDS.
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4. Survey Methodology
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The survey set out to use a mixture of quantitative and qualitativeelements to:
understand the key issues for delivery of SUDS in Scotland andidentify the opportunities for, and barriers to, further adoption.
examine the critical factors that have delivered successful SUDS
projects to date in Scotland and consider what more needs to
be achieved.
test experience of, and attitudes to, SUDS delivery in relation to
water quality and the design of treatment tra ins.
identify progress made and lessons learnt in Scotland to deliverinsights for SUDS delivery in England and Wales.
Practitioners working with SUDS in Scotland were contacted and
invited to take part in the survey. An online questionnaire comprising 17
questions was devised. The questions provided multiple choice answerswith the option for further comment if respondents wished.
To encourage maximum participation and an open sharing of views,
respondents were assured that their identity would remain confidential.Whilst requested to record their details to help build a picture of
responses, they were not obliged to do so.
The survey opened on 23 September 2013 and closed on 23 October 2013.
Sample who took part?A total of 151 people took part in the survey. The respondents who
made contributions covered a wide range of professional disciplinesin Scotland involved in the design, delivery and approval of SUDS
systems. The respondents represent a snapshot of SUDS activity in
Scotland based on those who were willing to respond. Those whoresponded represented consulting engineers, housebuilders and
developers, local authorities, environment agency (SEPA) and
Scottish Water.
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5. Detailed Survey Results
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Question 1
Before we begin, please indicate which of the following
best describes your role.
In Question 1 of the survey respondents wereinvited to indicate their role.
0%
20%
40%
60%
Consultingengineer,
architect,specifier
Housebuilder
anddeveloper
Loca
l
authority
Contractor
Envir
onment
Agen
cy
Othe
r
47.6%
6.6%
19.9%
4.0% 6.0%
15.9%
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Question 2
To what extent do you believe Scotland has been
successful in implementing SUDS since the implementation
of the Water Environment and Water Services (Scotland)
Act (WEWS)?
The overwhelming majority (96.8%) believeScotland has enjoyed success in implementingSUDS since the implementation of the WaterEnvironment and Water Services (Scotland) Act(WEWS). However very few believe it has beencompletely successful.
49.2% believed it had been mostlysuccessful
while 45.2% believed it had been onlysomewhat successful.
More people in the local authority andenvironment agency groups felt that SUDS wassomewhat rather than mostly successful.
Only 2.4% agreed it had been completely successful.Completely successful
Mostly successful
Somewhat successful
Unsuccessful
2.4%
49.2%
45.2%
3.2%
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Question 2: Comments
Adoption and Maintenance
issues were often cited as a
barrier to further success.
Comments also pointed to
difficulties in interaction
between local authorities
and Scottish Water.
There is still too much confusion for
developers, the failure of Section 7 hasnt helped
anyone and maintenance is still an unknown.
The tiny number (if any) of adopted SUDS
remains a cause for concern. There is far to go
before we can say that the implementation of
SUDS has been successful.
Local Authority
Adoption of SUDS is still very poor.
Sewers for Scotland has failed to work
and so far only 1-2 SUDS adopted by
Scottish Water. Most SUDS currently in
place are not being properly maintained
so will fail in the long term.
Local Authority
Local AuthorityIn my experience there are always
problems associated with the
interaction of Local Authorities and
Scottish Water re maintenance of
treatment systems.
Consulting Engineer
The constraints put in
place by Scottish Water and
the Local Council as to what
they are willing to adoptmakes it difficult to use the
full range of SUDS features.
Consulting Engineer
There remain significant issues for
construction phase SUDS ... Despite
our best efforts in SEPA we are
constantly taking enforcement action
for construction phase run off issues.
There is also a need for post completion
phase monitoring and this should
include assessment of effectiveness of
maintenance. There seems to be a lack
of info for this.
Environment Agency
Public SUDS should be adopted by Scottish Water but this
rarely occurs for some reason or another. The types of publicSUDS which are acceptable in the Sewers for Scotland2 are
too restrictive for small to mid-size developments. The whole
approval and adoption process is very complicated given the roles
and responsibilities of the various authorities in relation to flood
risk, roads, surface water drainage and pollution prevention.
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Questions 3 & 4
How successful do you believe Scotland has been in
implementing SUDS as a solution for (3) flood risk (4)
water quality?
47.3% believe Scotland has been mostlysuccessful and 45.5% somewhatsuccessful inimplementing SUDS as a solution for flood risk
More people (55%) believe Scotland has beenmostlysuccessful in implement SUDS forwater quality, with 41.3% believing it has beensomewhat successful.
Some commenters pointed to the challenges intackling flood risk in the existing urban infrastructure.
Scotlands focus on water quality was welcomed,however some felt that there were issues toaddress concerning the limited options to specifyproprietary systems as well as problems withinadequately constructed SUDS.
3.6%
47.3%
45.5%
3.6%
Completely successful Mostly successful
Somewhat successful Unsuccessful
2.8% 0.9%
55.0%
41.3%
3. Flood Risk 4. Water Quality
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Questions 3 & 4: Comments
Flood Risk
Flood Risk Management was not at the fore of SEPAs
mind when SUDS were introduced. This was a matter
for local authorities but the guidance on SUDS was not
designed with flood risk management in mind.
Still a reluctance to incorporate
ponds and basins in residential areas
due to perceived Health & Safety
risks, therefore SUDS are being used
more for treatment with flood risk
being managed by upsizing pipework
and use of underground tanks etc.
Flooding from poorly
maintained systems of undercapacity drains still and will
occur. Also, the retrofitting of
SUDS could be better funded.
Water Quality
We still have limited options for treating water...
through lack of acceptance from Council /
Scottish Water. Most of SUDS are seen as storing
and restricting flows by a lot of people and few
acceptable options for treating water. Reluctance to
accept hydrodynamic separators etc.
Most SUDS being developed are for
greenfield sites, so tend to be preserving
status quo and not addressing existing
pressures. Housebuilders and others
are developing some very poor systems
which are often marginalised within
developments, poorly constructed andunlikely to be valued by people...
As [water quality] was the original driver for SUDS
this has been a little more successful in application.
However the lack of adherence to the technical standards
during construction has resulted in very limited vesting.
Environment Agency
Local Authority
Consulting Engineer
Consulting Engineer
Water Company
Local Authority
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Question 5
Do you believe affordability has presented a barrier
to SUDS design and implementation on new
developments in Scotland?
The majority of respondents (61.1%) agree thataffordability is a barrier to SUDS design andimplementation in Scotland.
Consulting Engineers were the highest groupto agree at 64.7%.
However, most environment agency respondents(57.1%) disagreed, and believed that affordability
was not a barrier.
The issue of affordability prompted some strongviews and comments from respondents.
Yes
No
61.1%
38.9%
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[Affordability] is a major issue in getting quality SUDS in
Scotland. The perceived land take puts people off, and if
they are to be created in urban situations, as they should,
they must be designed appropriate to place and as part of
an integrated landscape plan ... Engineers should insist that
they work in an integrated team, if successful and attractive
SUDS are really to happen and be maintained with a clearlandscape maintenance plan.
Cost to build a well integrated surface water/drainagearrangement pays for itself in terms of avoided insurance
claims, flooding and enhances the built environment.
I believe this relates to the perception
of developers and consultants on cost.
They need to consider whole life cost
and include maintenance. There is a
lack of understanding of what SUDSare designed to do and why they are
needed; why SUDS are beneficial.
Question 5: Comments
Water Company
I dont think affordability
has been a major problem
as many SUDS options are
not that expensive.
However, as developers
want to maximise their profit,
they often dont want to let
the SUDS have the land
area that is required tomaximise treatment.
Environment Agency
Environment AgencyLocal Authority
The restrictions on SUDS measures
acceptable to Scottish Water and others
have frequently impinged on design. No
consideration is given to Capital Cost and
although Whole Life Cost is frequently
quoted, in the majority of instances, the
provider and maintainer are differententities, each looking after their own
budgets. Scottish Water & local authorities
look to the maintenance costs and pay
scant heed to the cost of provision,
Housebuilder
Although a requirement, SUDS still present a
significant part of the construction costs of new
development; this can be in the form of cost
to construct the SUDS but also the land take
required reduces the developable areas.
Housebuilder
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Question 6
Do you believe that more could be done to retrofit
SUDS in Scotland?
There is broad agreement amongst practitionersfrom all professional disciplines that more couldbe done to retrofit SUDS in Scotland.
81.3% agreed that more could be done toretrofit SUDS.
Many who commented believed cost could bea barrier or that retrofit needed to be enabled
through greater funding.
Commenters highlighted the particular need totarget water quality in urban environments.
Some suggested that more retrofit SUDS couldbe enabled via the planning system and otherscalled for clear roles and responsibilities to beestablished for implementing retrofit SUDS.
Yes
No81.3%
18.7%
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100% Yes. Surface water separation needs more
funding, which would allow further local plan type
development as combined systems would have less
surface water contribution... Ownership and long term
responsibility needs to be looked at.
Question 6: Comments
There is no incentive for anyone to
retrofit SUDS at present.
Local Authority
Where development is in an area where there
are already sewer capacity and water course
quality issues, planning conditions could be
explored to do more retrofitting within the public
networks ... Scottish Water should be funded to
do more using their powers to access third party
land, and explore more retrofit options as part of
a capital investment programme.
Consulting Engineer
Very little has been done in terms of retrofitting
in Scotland. Tanks and oversized pipes are too
often seen as the simplest solution and the
multifunctional benefits of SUDS are overlooked.
Consulting Engineer
Consulting Engineer
The majority of diffuse pollution emanates from historical developments mainly
in towns and cities. Whilst there is attention being paid to flood prevention in
these areas, very little is being done regarding SUDS.
Housebuilder
Cost will be a barrier in this instance and
therefore only flood alleviation where the
risk is high will be implemented.
Contractor
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Question 7
Do you believe that the legislative drivers have helped
Scotland to make more effective progress with SUDS
than England and Wales?
There was strong agreement that legislation hasenabled Scotland to implement SUDS and toprogress further than its neighbours in Englandand Wales.
84.7% of respondents agreed that legislationhad supported successful SUDS implementationin Scotland.
Commenters agreed that success throughvarious elements of regulation had beenachieved, but were clear that Scotland couldnot rest on its laurels.
Many comments pointed out that more canstill be done, and highlighted some barriers tofurther progress.
Yes
No84.7%
15.3%
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Question 8
Do you believe current regulation and guidance
for Scotland gives practitioners freedom to specify
appropriately from a full toolbox of both natural and
manufactured/proprietary SUDS features?
Only about half of respondents were satisfiedthat current regulation and guidance givespractitioners freedom to specify appropriatelyfrom a full toolbox of both natural andmanufactured/proprietary SUDS features.
A significant number (48.0%) felt they lacked thefreedom to specify from a full SUDS toolbox asthey would like. Amongst housebuilders anddevelopers the number was 80%.
Some strong views reflected a frustration withthe authorities, especially SEPA, who werereluctant to approve proprietary SUDS systems.Maintenance provision and adoption were alsohighlighted as issues.
Some felt that a lack of consensus betweendifferent authorities also presented a barrier andcalled for greater partnership working from theearliest stages of design.
Yes
No
52.0%
48.0%
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Question 8: Comments
What are the barriers?
Very prescriptive conditions set by SEPA on
what are SUDS. The flexibility to assess the
benefits / performance of innovative products
versus traditional SUDS is not embraced.
Drainage Authority
Manufactured/proprietary
SUDS features are not
currently favoured.
Developer
The key is that the tool box is chosen that is appropriate to
place ... the separation between the design professions should
not exist and it should be emphasised in these documents
otherwise there is no possibility that the engineer can
persuade the client for a greater design input.
Local Authority
SEPA dont fully recognise proprietary SUDS, insisting upon natural SUDS. They need tobe more flexible if research is available to back up proprietary claims, especially in industrial
development as 3-stage cleaning naturally is very onerous for most sites.
Consulting Engineer
SEPA is not keen on proprietary products and roads
departments do not have appropriate maintenance in place for
anything other than gullies, so there is a conflict there already.
Many steering groups etc have come up with a wide range of
SUDS (as per CIRIA guidance) - but Scottish Water, SEPA, and
roads departments all have differing views on this, and it can be
impossible to gain a consensus.
Consulting Engineer
SEPA are very reluctant
to approve any non
natural suds, their motto
seems to be if it doesnt
have grass forget about it.
Housebuilder
There is a prejudice in SEPA
against proprietary systems.
Housebuilder
Barriers are put in place from councils, Scottish Water and
SEPA on what represents green sustainable drainage systems
(generally manufactured), there are a number of systems
available that are not deemed green although they can clean
water more efficiently than approved green systems.
Housebuilder
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Questions 9 & 10
Do you believe the requirements for design and
implementation of surface water treatment are clearly
defined by regulation and guidance in Scotland in
terms of (9) what constitutes an effective treatment
train and (10) what constitutes a level of treatment?
Most people agreed that regulation andguidance clearly defines requirements for designand implementation of surface water treatment.With 77.2% of all respondents in agreementconcerning the treatment train and 67.8% forlevels of treatment.
Nevertheless, the question attracted a largenumber of comments. Some referred to a lack ofclarity in the definition of what a level of treatmentactually is. Some suggested that interpretationsmay vary, or that there may be a lack of awareness.
Some felt that there was too much guidance andsome of it was ill defined.
77.2%
22.8%
Yes No
67.8%
32.2%
9. Treatment Train 10. Level of Treatment
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Questions 9 & 10: Comments The regulations are clear. There is too muchguidance and no one appears to refer to it. It needs
to be clear and simple and broadly the same across
the country. There is little or no maintenance
and no incentive to do so. There is no clear way
of determining when maintenance is required.
SEPA should have a lead role to determine the
effectiveness or otherwise of SUDS systems. SEPAs
role is currently ill-defined.
Local AuthorityThere is still a lot of
interpretation made on the
guidance and regulations
available. Sewers for Scotland
contradicts the SUDS manual.
Consulting Engineer
Generally accepted levels of treatment are as
per CIRIA guidance - but there needs to be more
research done on what this level of treatment
actually achieves and how flexible the definition
could be depending on site conditions.
Consulting Engineer
For some reason SEPA exclude proprietary systems as
constituting a level of treatment, even though documented
evidence can be provided to prove their effectiveness.
Housebuilder
The SUDS guidance refers to levels of treatment without
defining what a level of treatment actually is. One SUDS
element can be twice as effective as another, but both are
regarded as one level of treatment. A treatment train comprises
various SUDS elements linked to deliver the required number of
levels of treatment without regard to the effectiveness of each
element. Research at Heriot-Watt University has determined a
significant reduction in the cost effectiveness of subsequent
elements in the treatment train af ter the first one.
HousebuilderThere is sufficient information provided
out there (CIRIA, SUDS for Roads, Sewers for
Scotland etc) for someone to determine what
constitutes an appropriate level of treatment
in a SUDS treatment train, provided that
they know what they are doing and spend
a bit of time investigating the site specific
conditions and going through the guidance...
Unfortunately there is no one design for
say a filter trench that constitutes a level
of treatment for every situation, but the
guidance to do this is there.
Environment Agency
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Question 11Currently SEPAs Regulatory Method on SUDS
(WAT-RM-08 v5) states that proprietary systems may
only be classified as a level of treatment in exceptional
circumstances. In your experience has this been a
barrier to the design of effective SUDS solutions?
The majority (65%) of those with experiencebelieve that SEPAs regulatory method to classifyproprietary systems as a level of treatment onlyin exceptional circumstances was a barrier todesign of effective SUDS solutions.
However 71.4% of environment agencyrespondents disagreed.
Some comments expressed their frustration withthe situation and pointed to projects where theyhad specified proprietary features even thoughthey were not accepted as a level of treatment.
Some speculated that SEPAs reluctance may bedue to a lack of confidence in the commitmentby the owner/operator to the maintenance ofproprietary systems or called for more case studyevidence of their performance.Yes
No
No experience
38.9%
40.0%
21.1%
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Question 11: Comments
Problems occur when the consultant is
unwilling to fully accept the principles of
SUDS at the outset, such as when too many
properties have been squeezed into a site
without first taking into account the SUDS
footprint. I would not classify this as a barrier,
but it does refocus minds on the basic SUDS
principles. Ultimately if standard SUDS are
not appropriate for justifiable reasons, SEPA
will not prevent development unless we have
strong reasons to do so.
Environment Agency
There are very few proprietary products
Ive seen submitted as SUDS. A lot of the
technology lacks effective case studies.
Environment Agency
All treatment benefits the environment. SEPA has been
reluctant to value road gullies, grit busters, downstream
defenders etc on the grounds that they may not be
maintained. That, however, also applies equally to
natural systems. In my experience, systems that can be
maintained routinely alongside gully cleaning operations
for example are more sustainable.
Local Authority
SEPAs view is that they are only a method of pre-treatment anddo not constitute a level of treatment in the treatment train.
Consulting Engineer
In some situations, a proprietary system is
the only feasible option. Surely this is better
than no treatment at all. I have worked on
projects where a Downstream Defender
has been specified, though SEPA did not
accept it provided any treatment.
Consulting Engineer
When I design or use these systems
its normally ... for an additional level of
treatment. If the owner/operator does not
clean them to the manufacturers spec,
they do not perform this single level ... so I
can see SEPAs point. Again, Scottish Water
or the local authority need to improve
here but they need the funding to do so.
Consulting Engineer
Sites with limited space,conventional road and
footpath arrangements
and small numbers would
easily benefit from Vortex
Separators etc. Instead they
are forced to install ponds,
filter strips and so on which
can be totally inappropriate
to the specific location.
Housebuilder
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Question 12Do you believe there is adequate funding available for
the adoption and maintenance of SUDS in Scotland?
The overwhelming majority (77.8%) believed fundingfor adoption and maintenance was inadequate.
Agreement was high amongst all respondentgroups and 100% in the housebuilder anddeveloper group.
Comments suggested that both Scottish Water andlocal authorities could do considerably more to
adopt SUDS and that responsibility for maintenanceof SUDS could be falling between the two bodies.
Some felt that more funding for local authoritieswould help to resolve the difficulties currentlybeing experienced.
However, not all were in agreement, with someenvironment agency respondents suggesting thatSUDS can be adopted if properly designed and that
a lack of understanding amongst local authoritiesmade them overly concerned about maintenance.
Yes
No
22.2%
77.8%
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Question 12: Comments
If designed properly, they will be
adopted and maintained by either the
local authority or Scottish Water.
Government funding is available to all public
bodies as part of their settlement agreement.
Ensuring that priority is placed on SUDS againstcompeting activities and ring fencing these
monies is more the issue.
Drainage Authority
Councils are reluctant/cautious to enter
into Section 7 agreements; reluctant to
resolve legacy SUDS issues.
Water Company
The adoption and maintenance costs are not
considered to be any greater than those associated
with conventional below ground pipe systems.
It is known that local authorities are concerned by
maintenance costs, but I believe this is to be an
overreaction based on limited knowledge.
Water Company
Ownership of maintenance is falling between local council
& Scottish Water. Provision of funding would assist in one of
the public bodies taking on the responsibility.
Developer
Environment Agency
There are no ponds in
Scotland formally adoptedby Scottish Water.
Consulting Engineer
Scottish Water should be adopting
more and a wider variety of features.
Consulting Engineer
In my experience Scottish Water are not pro-
active in any way in adopting fully functioning
SUDS which have been constructed in accordance
with the approved design.
Consulting Engineer
Scottish Water is making inroads into this area,
but council roads depts. are almost universally
ignoring the issue, and are certainly not changing
their approach to allow the adoption of SUDS.
Consulting Engineer
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Questions 13 & 14How clear do you believe regulation and guidance
for SUDS in Scotland is for (13) maintenance and
(14) adoption?
The majority of respondents believe thatregulation and guidance for SUDS in Scotlandneeds to be clarified for both maintenance andadoption.
Many respondents believe that more needs to bedone to maintain and adopt SUDS in Scotland.
Some very strong opinions were expressed that
responsibility for adopting SUDS features wasbeing resisted or was falling between the rolesof Scottish Water and local authorities.
Designers and developers referred to theirexperiences and the frustrations they felt.
Very clear Suciently clear
Not clear enough Needs further clarification
36.3%
39.1%
2.2%
30.7%
5.4%
34.8%
20.7%30.8%
13. Maintenance 14. Adoption
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Question 13 (Maintenance): Comments
The need for comprehensive
solutions adopted in perpetuity by
a reliable authority has not been
established in practice.
Drainage Authority
Generally sufficiently clear but only for simple one
system locations e.g. SUDS pond. Where there are more
integrated SUDS systems installed then complications
can arise. Through partnership and commitment to
succeed these can be addressed.
Water Company
There seems to be a lack of clear guidance about vegetation
maintenance - a manual created for contractors explaining thevarious aspects, including the vegetation, would be helpful as
would regulation that insisted that the landscape drawing done for
a scheme clearly indicates which parts of the landscape are part of
the functional SUDS scheme and which is amenity landscape.
Local Authority
The guidance is sufficiently
clear but, in my experience,
it is rarely carried out.
Consulting Engineer
There is a set of maintenance regimes published
for many of the SUDS solutions, but there is little
evidence that this maintenance is actually carried
out. Even in private areas (supermarket car parks for
example) a maintenance regime is not evident.
Consulting Engineer
The available guidance is not all in one place and what
there is, is too unwieldy for all but the most interested
to get their heads around ... Many systems are not the
responsibility of any organisation to maintain.
Consulting Engineer
There is no detailed guidance available
on the maintenance regimes for the
various SUDS measures. There is no
mandatory schedule available either.
Housebuilder
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Question 14 (Adoption): Comments
Many organisations have either contrived to avoid
adopting SUDS or have failed to adopt and maintain such
systems through negligence and/or insufficient funding /
prioritisation. There is no apparent penalty for the latter.
Local Authority
Scottish Water is
attempting to pass at least
some of the responsibility
onto local authority
roads. There is no clear
guidance on this.
Housebuilder
Each stakeholder (SEPA, Councils and Scottish Water)
has their own views on adoption/responsibility and thesedo not align with each other. For this reason developers
are left in limbo trying to satisfy all stakeholders, which
is impossible, and finding that ultimately getting anyone
to accept adoption responsibility for the constructed
features is an uphill struggle.
Consulting Engineer
I only had one site where I was tasked with taking the
SUDS through the actual adoption process. Scottish Waters
SUDS inspector seemed determined not to adopt, despite
the common perception that it was one of the most well
constructed SUDS features. Goalposts were continually
moved, despite all parties determination to finalise.
Consulting Engineer
Section 7 of the Sewerage Scotland Act
requires agreement between authorities and
experience shows that the Local Authorities
are unwilling to take on extra spending.
Consulting Engineer
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Question 15In terms of maintenance of SUDS features do you
believe that proprietary systems such as vortex
separators are:
The majority (69.2%) believe that proprietary SUDSfeatures either require the same maintenance orare easier to maintain than natural SUDS featureswith less than a third (30.8%) believing they aremore difficult to maintain.
Some comments revealed that respondentsneeded more information about maintenanceregimes for proprietary features. Some had aconcern that underground systems might beforgotten about by the owners. However, somealso pointed to disadvantages of maintainingnatural SUDS features.
Amongst those most familiar with themaintenance regimes of proprietary features,comments appeared to support them for theirease of maintenance and predictable regimes.28%
29%
30%
31%
33%
32%
34%
35%
More dicultto maintain than
natural SUDS
features
Require the samemaintenance as
natural SUDS
features
Are easierto maintain than
natural SUDS
features
30.8%
34.6% 34.6%
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Question 15: CommentsA vortex separator is only another type of system; it isnt
overly complex and is easily accessed/maintained. In my
opinion it is far more easy to maintain a vortex separator
with its direct access than some private stone systems. The
principles for each are similar, but the more complex one is
easier to maintain as consideration has gone into it through
manufacturing and design.
Contractor
Project experience. Natural SUDS features
sometimes dont work as anticipated.
Contractor
The question is not relevant
unless we are speaking
about a constrained,
exceptional site.
Environment Agency
They can be integrated into existing maintenance regimes. The fact that
they are few in number has not helped ensure that they are successfully
integrated into maintenance regimes however.
Local Authority
They are contained and easily accessed (although vortex
separators are not classed as a level of treatment by SEPA).
Consulting Engineer
Natural SUDS are more preferable. Buried systemshave more onerous maintenance issues and indeed in
some cases are likely to require significant upheaval to
allow adequate maintenance to be provided.
Local Authority
Special teams are required to maintain these items.
Consulting Engineer
Although levels of silt build-up etc cant be easily
seen in a separator, nobody is really looking for it in
a natural SUDS feature. I think that once the initial
months of monitoring are completed, the silt amounts
can be quantified and a programme of regular
maintenance set up to suit. No grass to cut, no debris
to clear etc. One squad/gully sucker, job done.
Consulting Engineer
These can be maintained by emptying using a gulley sucker
which, under normal circumstances, would be doing the
rounds anyway. Soft SUDS can require access by plant,drained down; filter material excavated which is a much more
intensive operation.
Housebuilder
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Question 16The SUDS for Roads Whole Life Cost and Whole Life
Carbon Toolkit from SCOTS is available to support
costing of SUDS in Scotland. Would you welcome
further developments to the tool to help with costing?
Many people commented that an expansionof the tool to include more measures or SUDSfeatures would be welcome.
Responses indicated that the tool is currentlybeing reviewed and improved.
Yes
No84.0%
16.0%
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Question 16: Comments
We have undertaken an appraisal of the tool and
identified improvements / better assumptions and have
been developing this tool for our use.
Drainage Authority
Scottish Water are
currently altering the tool.
Water Company
Anything which helps develop the understanding
of the benefits of SUDS for those building,
installing and maintaining SUDS. Should have
reference to construction phase aspects.
Environment Agency
Update would be useful and it shouldinclude more measures/options.
Consulting EngineerFull range of SUDS, including
proprietary features. More realistic
costs and more councils to use it.
Consulting Engineer
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Question 17Would you welcome the introduction of further industry
tools to assist with costing and/or design of both
proprietary and natural SUDS?
An overwhelming majority (86%) would welcomefurther industry tools to aid costing and/or designof SUDS features.
Comments suggested that costing models basedon actual, real-life examples would be useful.
Some suggested that any tool should also ratethe effectiveness of SUDS features.
Yes
No86.0%
14.0%
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Question 17: Comments
More detailed costing
models using actual
incurred costs.
Drainage Authority
Realistic costing assessments - that can
be supported by real life examples.
Water Company
More robust costings of all measures
including the ability to assess the benefits
not just in flooding and water quality benefit
terms e.g. social and economic benefits.
Water Company
Investigation of effectiveness of proprietary
systems and some are better than others.
Environment Agency
More tools (free) for the design
of both natural and proprietary.
Consulting Engineer
More education for
Councils / SW so that a
wider range of SUDS will be
available to designers.
Consulting Engineer
I would like to see details of the effectiveness of SUDS elements rated and developments
required to meet a target level using SUDS measures which reach that target, rather thansimply talking about levels of treatment which are unspecified. In general, most developers
will have a fairly good idea of the cost of provision which I believe is likely to be more accurate
than any guidance, particularly as costs can vary from time to time and area to area.
Housebuilder
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Hydro International November 2013
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