enw suds in scotland

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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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SUDS best practice, policy, SUDS Techniques, News and Resources.


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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


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



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.


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.


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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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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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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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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33



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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34



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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35



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

Engineering Natures Way is the

initiative of Hydro International

Visit: www.engineeringnaturesway.co.uk

Published by:

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Victoria RoadClevedon BS21 7RD

Tel: 01275 337977Fax: 01275 874979

@engnaturesway

enw suds in scotland

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