Land Journal July-Aug 2016

R I C S L AN DSTR A P L I N E JO U R N A L

Land Journal Head

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Maps to apps Benefits of 3D mapping in a mobile app PG. 10

The right values Valuation of land for affordable housing – new guidance PG.

8 1   M A R C H /A P R I L 2 0 1 4

A helping hand

Down to earth

Managing farmland to help pollinators and crops

The surprising impact of soil on our lives

PG.

12

PG.

24

July/August 2016

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C O NTENTS RI CS L AN D J OU RN AL

RI C S LAND JOUR NAL

RICS L A NDSTR A P L IN E JO U RNA L

Land Journal Author Author Standfirst

Head

T

contents

Maps to apps Benefits of 3D mapping in a mobile app PG. 10

The right values Valuation of land for affordable housing – new guidance PG.

8 24

A helping hand Managing farmland to help pollinators and crops PG.

M A R C H /A P R I L 2 0 1 4

12

Down to earth The surprising impact of soil on our lives PG.

July/August 2016

rics.org/journals

24

Images ©

Front cover: © eeGeo

CO N TAC TS

4 From the chairmen

LAND JOURNAL

5 Update

Editor: Mike Swain T +44 (0)20 7695 1595

E mswain@rics.org

Editorial team: James Kavanagh, Fiona Mannix, Tony Mulhall (Land Group) Land Journal is the journal of the Environment, Geomatics, Minerals and Waste, Planning and Development and Rural Professional Groups Advisory group: Tim Andrews (Stephenson Harwood LLP), Philip Leverton (College of Estate Management), Rob Yorke (rural chartered surveyor), Michael Rocks (Michael Rocks Surveying), Tim Woodward (rural chartered surveyor), Michael Birnie (Buccleuch Estates), Marion Payne-Bird (consultant), Frances Plimmer (FIG – The International Federation of Surveyors), Duncan Moss (Ordnance Survey), Kevin Biggs (Royal Bank of Scotland) The Land Journal is available on annual subscription. All enquiries from non-RICS members for institutional or company subscriptions should be directed to: Proquest – Online Institutional Access E sales@proquest.co.uk T +44 (0)1223 215512 for online subscriptions or SWETS Print Institutional Access E info@uk.swets.com T +44 (0)1235 857500 for print subscriptions To take out a personal subscription, members and non-members should contact licensing manager Louise Weale E lweale@rics.org

6 Smart cities, intelligent buildings

Tony Mulhall looks at the differences between smart cities and buildings, and how to bring them closer together

8 The right values

Charles Solomon explains why and how RICS guidance on the valuation of land for affordable housing has been updated

10 The future in your hands

Ian Hetherington explores the benefits for the property industry offered by 3D mapping in a mobile app

12 A helping hand

Managing farmland to encourage pollinating insects can boost crop quality and yield, report Claire Carvell, Adam Vanbergen and Lynn Dicks

14 Protection matters Published by: Royal Institution of Chartered Surveyors, Parliament Square, London SW1P 3AD T +44 (0)24 7686 8555 www.rics.org ISSN: ISSN 1754-9094 (Print) ISSN 1754-9108 (Online) Editorial and production manager: Toni Gill Sub-editor: Matthew Griffiths Designer: Nicola Skowronek Advertising: Emma Kennedy T +44(0)20 7871 5734 E emmak@wearesunday.com Design by: Redactive Media Group

Richard Nicholson discusses how to go about working on trees that are subject to preservation orders

18 Upstream thinking

Organisations in the South West of England are working together to improve water management by changing land-use practices, Lorna Devenish reports

20 London on track?

Laura Nation examines the National Infrastructure Commission’s proposals to change planning rules for London and assesses whether they would work

22 Property valuation in Ghana

Kwasi Gyau Baffour Awuah summarises recent RICS research that found major variations in Ghanaian property valuations and discusses the implications for Africa

24 Getting down to earth

Tim Farewell reflects on the many different ways soil has an impact on our daily lives

26 Not so unpredictable

Checking records is essential to identify areas that are prone to sinkholes before development starts, as Clive Edmonds explains

16 Threats to our trees

John Lockhart and James Broom provide an update on the pests and diseases attacking our trees and look at how to deal with them

Printed by: Page Bros

While every reasonable effort has been made to ensure the accuracy of all content in the journal, RICS will have no responsibility for any errors or omissions in the content. The views expressed in the journal are not necessarily those of RICS. RICS cannot accept any liability for any loss or damage suffered by any person as a result of the content and the opinions expressed in the journal, or by any person acting or refraining to act as a result of the material included in the journal. All rights in the journal, including full copyright or publishing right, content and design, are owned by RICS, except where otherwise described. Any dispute arising out of the journal is subject to the law and jurisdiction of England and Wales. Crown copyright material is reproduced under the Open Government Licence v1.0 for public sector information: www.nationalarchives.gov.uk/doc/open-government-licence

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RICS L A N D JO U RN A L

CH A I R M E N

FROM THE

CHAIRMEN RUR A L

Gerard

Smith FRICS

Accompanying this edition of Land Journal is our rural brochure, which I encourage all rural members to read. It aims to increase awareness of relevant activity throughout RICS and of the work being done to promote the rural practitioner’s skill base, and outlines where members can find further information. Copies will be available at our UK rural conferences and regional offices, but if you are not a rural member and would like a copy, email fmannix@rics.org Agriculture continues to face difficulties with market volatility and low commodity prices. While there are concerns about productivity across many sectors, we need to be mindful not just of the financial aspects of agriculture but also the key role that it plays in the social fabric of many rural communities. With the continued uncertainty, I believe that our roles as rural surveyors will become more important.

Meanwhile, I look forward to meeting many of you at our RICS Wales Breakfast at the Royal Welsh Show on 18 July.

Resources Group. We have recommended detailed changes to pathways for waste and mineral surveying and environmental surveying, and work is also completed on the Mineral-Bearing Land and Waste Management Sites guidance note; we will also be working on insight papers. Board members maintain links with other bodies such as the Institute of Environmental Management and Assessment and the Society for the Environment, and assess prospective RICS members for chartered environmentalist (CEnv) status.

We have also responded to the Land Forum on the proposed National Quality Mark scheme on contaminated land, which suggests changes in accreditation. If you would like to comment on this developing agenda, please visit www.claire.co.uk Meanwhile, the next Minerals, Waste and Environment conference is in October in Bristol – ideas for topics are welcomed – and a review of RICS professional groups, PG 20/20, is under way to give all of them a clearer role and mandate. We are also keen to encourage new board members, notably in environmental surveying.

LAND & RESOURCES GLOBAL BOARD

Barney

Pilgrim FRICS

ENVI RON ME N T & RES O UR C E S

Stephen

McKenna Acting chair, MRICS

Andrew Fitzherbert’s tenure as chair ended in May after another successful conference – a big thank you to Andrew, who will remain involved in future events.

While our role has focused on professional standards and development, we have been involved in the APC update for our pathways and creating a complementary one for the Land and 4 J U LY/A U G U S T 2 0 1 6

This is another diverse, cross-disciplinary edition of the Land Journal.

The Land and Resources Group has recently given presentations and held side events at the World Bank, the International Federation of Surveyors Working Week in New Zealand, GeoBusiness, the RICS Africa and Americas summits, the Council of European Geodetic Surveyors, the GIM International Summit in Amsterdam and LandAc Utrecht. The group has informed international colleagues of International Land Measurement Standards work and gauged the current state of play.

Feedback on the Land Journal has been overwhelmingly positive. Copies are

snapped up by delegates, students and lecturers as far afield as the University of Otago in Dunedin, New Zealand, and the University of Cape Town, South Africa. The content appeals to the global surveyor, a much more generalist land professional than their UK counterpart.

The journal is something of which we can be proud. Recent issues have had timely articles on fracking, rural energy policy and mapping powerlines. Chartered surveyors have a key role in providing a sustainable, secure UK energy supply and combating climate change. We can discuss technology and urbanisation all we like, but without a strong energy policy and localised supply this will remain all talk.

GEOMAT I CS

Gordon

Johnston FRICS

May’s GeoBusiness event highlighted the ever-evolving technology that generates spatial data and information and the overall strength of our industry.

Elsewhere, World Hydrography Day on 21 June had the theme of well-managed seas and waterways. These two events illustrate both how diverse and how specific our work can be, and yet reminds us of the importance of promoting and pushing our expertise, knowledge and value to the widest community.

One example of such technology and skills making a major impact is in the discovery of the wreck of Australia’s HMAS Sydney and the processing of half a million images and 300 hours of video to generate an amazing 3D visualisation of this naval tragedy (http://ab.co/1TcCtu9 and http://bit.ly/1Vvizu2).

The use of technology can be equally compelling in the flying of remote-piloted aircraft systems – drones – for the inspection of mine workings, utilities and farmland. Regulations and standards have

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UPDATE yet to catch up, but with people’s privacy being a factor some further regulations are likely. The real value for most survey companies and RICS surveyors will be in the data collected and its use. The 6th Digital Earth Summit in Beijing in July will emphasise this, and we must continue to develop our profession and young surveyors to ensure spatial data is managed for everybody’s benefit.

PLA N N I N G & DEV E LOPME N T

Paul

Collins

Scotland energy rules

Smart cities survey

From September, owners of buildings larger than 1,000 sq. m in Scotland will have to provide an Action Plan when they sell or rent the property and ensure that energy improvement data, including the Action Plan and Energy Performance Certificate (EPC), are sent to the Scottish EPC Register.

Mat Lown, Partner and Head of Sustainability at Tuffin Ferraby Taylor, said: “40% of UK carbon emissions come from buildings. These regulations should reduce energy use, emissions and – importantly – running costs for larger commercial buildings.”

While 37% of people aged 18–34 have heard of smart cities, only 6% of those over 65 recognise the term, a survey of 531 people by the Institute of Engineering and Technology (IET) has found.

Intelligent street lighting was rated the most useful technology, while 25% of respondents thought buildings adopting measures such as generating power and recycling water and waste would also help.

Alan Howard, IET Head of Thought Leadership, said: “In spite of substantial investment, most people don’t understand how smart-city digital communications technology could improve quality of life.”

MRICS

Under the Neighbourhood Planning and Infrastructure Bill, included in the Queen’s speech, the government intends to: bb give communities more neighbourhood planning powers bb limit use of some planning conditions bb make compulsory purchase orders (CPOs) easier to understand and quicker to implement bb base compensation claims on market value regardless of the reason for a CPO bb establish a National Infrastructure Commission to provide expert advice bb privatise the Land Registry.

These changes serve as reminders of the need to keep up to date through CPD. Also look out for our roadshows on Placemaking and Commercial Value.

You might want to look at a lecture by Alejandro Aravena on low-cost homes in Chile, which proposes building half a good house rather than a full-sized cheaper one, letting occupants add to it as they can afford (http://bit.ly/1z1s5Hh).

Another question for the future might be whether the government should think about ‘codifying’ the contribution to affordable housing expected on certain sites, so the residual valuation and acquisition of such sites would lead to fewer unviable projects. Just a thought.

Enterprise Act 2016 receives Royal Assent The Enterprise Act 2016 has received Royal Assent, making damages for late payment a reality.

The act’s provisions introduce into every contract of insurance an implied term requiring the insurer to pay sums due within a reasonable time. Failure to do so entitles the insured party to remedies, including damages.

The key provisions will slot in as sections 13A and 16A of the Insurance Act 2015, but will not come into effect until 4 May 2017.

Conference dates RICS CONFERENCES CPD Day, Bournemouth – 22 September Environment and Resources Conference, Bristol – 6 October Rural Conference, Hexham – 6 October CPD Day, Leeds – 11 October CPD Day, Southampton – 12 October RICS CPD FOUNDATION Keep up to date with your CPD by signing up for a new, more convenient annual subscription. n For more information, visit www.rics.org/cpdfoundation

Making woodlands pay conference A conference jointly hosted by the Royal Forestry Society and Confor will advise woodland owners how to tap into new and emerging opportunities.

Expert speakers will examine the economics of woodland management, compare and contrast silviculture systems and suggest how owners can add value using timber and non-timber products.

Forestry Commission Chairman Sir Harry Studholme will detail key considerations for profitable woodland

management. Other speakers at the event include Oliver Coombe of Timber Auctions, Justin Mumford from consultancy Lockhart Garratt, Jason Sinden of Tilhill Forestry, Dr Steve Lee and Dr Gary Kerr from Forest Research, and Dr Jenny Wong from the University of Bangor.

Making Woodlands Pay will be held at the National Memorial Arboretum in Staffordshire on 1 November. n Tickets are available from www.rfs.org.uk.

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RICS L A N D JO U RN A L

S M A RT C I TI E S

Smart cities, intelligent buildings Tony Mulhall explores the differences between smart cities and buildings, and argues for a business model that would bring them closer together n 1 Space Syntax model of London l 2 Building information model

A

lthough it is difficult to imagine a city without buildings, when we talk about smart cities we may unconsciously be talking about abstract amalgams of disparate buildings without recognising that the individual structures originated as discrete projects.

We may therefore be making plans for smart cities without being fully conscious that there is a distinct difference between how and for what purpose the building is procured, and how the city is run and whom it serves.

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may not be talking to each other with these scales or origins in mind. As a result, we may be missing out on a whole range of opportunities for their inter-operation. This article supports the argument for a new business model to integrate these two scales.

Different kinds of ‘smart’ In commercial and governance terms, the building and the city originate as completely different enterprises.

The building results mainly from a private procurement process with all the characteristics of private-sector motivation, proprietary commercial interests and confidentiality requirements.

In contrast, the city has emerged from agglomeration to serve the needs of citizens, governed by concepts of communality, democracy and openness.

Unsurprisingly, digital manifestations of the city and the building are being generated separately with distinct objectives, wrapped in quite different concepts of good governance. The concern is that the city and the building

Images 1 and 2 provide typical representations of these two different scales. Image 1 is a digital version of London, based on the space syntax method of analysis developed at University College London, delivered on a two-dimensional geographic information system (GIS) platform; image 2 is a building information model (BIM) developed on a three-dimensional one.

How these two systems interact has taken on a new urgency in the UK. The government has stipulated that all centrally procured projects should be planned to BIM Level 2, that is, a managed three-dimensional environment with data attached but created in separate discipline-based models that may include construction sequencing and

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“ The UK government regards the ‘smart’ agenda as essential to competitive advantage in the global economy

cost information – essentially, a building design-based platform geared to the requirements of building procurement.

In contrast, two-dimensional GIS has been the typical platform on which municipalities have constructed the digital city, although this is increasingly being realised with a three-dimensional GIS model.

Cultural difference Despite the obvious interdependencies between buildings and cities, the following clear-cut distinctions emerge: bb city scale v site scale bb city planning v building design bb public interest governance v private interest governance bb public-sector objectives v private-sector objectives bb public data v private data.

At the higher level, the city tends to be urban policy-driven for plan-making, whereas the building is developer- or investor-led, focusing on the creation of a secure property asset. Alignment of these interests will require the development of new business models combining the open, sharing culture of city governance with the private, proprietorial demands of commerce, ensuring necessary safeguards for both.

The business end of smart The UK government regards the ‘smart’ agenda as essential to competitive advantage in the global economy. It sees the development of expertise as highly transformative in generating new services and expertise for citizens, as well as keeping the UK at the forefront of developments. But it is not just about economic development. As well as creating a new economy, the smart city agenda is about “effective integration of physical, digital and human systems in the built environment”, according to PAS 180 Smart cities. Vocabulary (BSI UK 2014).

Images © Space Syntax; Shutterstock

Economic drivers At a basic level, the economic drivers for smart cities are about managing ‘dumb’ 19th-century networked infrastructure more efficiently through the application of sensors, actuators and a host of other digital aids to service maintenance and delivery. The benefits include reducing outages and more efficient distribution.

In smart buildings, there are clear economic benefits to be achieved, with savings on costs of up to 20% predicted through the application of Level 2 BIM. But there are the following challenges to effective exploitation of data. bb Additional costs: ensuring that data being collected for internal use by an agency is done in a standards-based, open format; making it widely available will have additional costs. bb Data security and privacy: maintaining data security and privacy in a way that will give confidence to those providing data and the individuals to which data relates. bb Workable commercial arrangements: income from data needs to be distributed fairly to a number of different agencies, reflecting the costs of making it available and the value it has for others. bb Data capture: a consistent approach to capturing data at every scale in a city, specifically data-modelling processes used by city planners and those used by architects, is currently lacking.

Professional challenges, therefore, include the following: bb different professionals are using different data modelling systems bb there is a scale gap between the micro, building-focused scale of the architect and the macro, city-focused scale of the planner bb the meso scale (the street), where important social and economic life takes place, falls through the gap, though it is also where most of the city’s networked infrastructure is located bb identification of useful data; how could it be most easily collected and made available, and what exactly could it be used for? bb limited appreciation of digital design; while architects and planners use computers, many have yet to explore the technology’s full potential to enable them to design in different ways.

From BIM to CIM It is not difficult to see the connection between digital modelling at the building

level and at the city level. It has been observed that when BIM is more widely adopted, the possibility of city information modelling (CIM) will emerge.

The capacity to move beyond policy-making and to begin managing the resources of the city to achieve more with less is a goal worth pursuing through smart technologies. It would mean less waste in locations and better services for longer periods in places with extreme scarcity. So when we talk about the city and its infrastructure, the need for inter-operability at all scales becomes fundamental to effective mediation between building and city.

CIM could address one of the key deficiencies in the construction and development process caused by the lack of precise, open-source data about the most basic daily challenges – for instance, how to identify the location of underground services when trying to connect to or avoid them. The repeated failure to capture such information to enable its shared use has proved to be one of the most contentious, disruptive and time-consuming characteristics of urban development.

Whoever might take on the role of CIM custodian would need to promote the benefits of sharing information with developers and contractors, and then ensure that the resulting model is shared on a commercial basis to inform and enhance future projects.

The long-term relationship between the building and the evolving city, where BIM-enabled buildings become lasting, multi-dimensional sensors, must be the goal. Clearly, there will be a requirement for planners and architects to use a common approach to enable this to happen. But there are also cultural differences between those operating at the scale of the city and those operating at building level, which will also need to be overcome. C

Tony Mulhall is an associate director at RICS tmulhall@rics.org

Competencies Planning, Economic development, BIM

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RICS L A N D JO U RN A L

HOUSING

Charles Solomon explains why and how RICS guidance on the valuation of land for affordable housing has been updated

The right values

I

In 2010, RICS published the first edition of the Valuation of land for affordable housing guidance note. Since then, there have been significant changes to the way in which affordable housing is developed, and in particular how grants and other subsidies are applied.

We recently completed our review of the first edition, and the revised note was published in April. The aim is to help practitioners in valuing such land, because housing and planning policy is in a constant state of flux and they will need to take account of both recent changes and emerging policies.

The guidance applies to England and Wales, where affordable housing provision is governed through the planning system; in Scotland and Northern Ireland, it falls under housing policy.

Although the means of provision may differ in terms of their detail, the valuation approach is essentially the same and the guidance note may be adapted as necessary. The guidance is recommended best practice 8 J U LY/A U G U S T 2 0 1 6

and describes the standard of work that is expected of a reasonable, competent valuer experienced in this area.

What is affordable housing?

In England, the National Planning Policy Framework (NPPF) defines such housing as: “Social rented, affordable rented and intermediate housing, provided to eligible households whose needs are not met by the market.

Eligibility is determined with regard to local incomes and local house prices.

“Affordable housing should include provisions to remain at an affordable price for future eligible households or for the subsidy to be recycled for alternative affordable housing provision.”

Wales In Wales the definition is contained in Technical Advice Note 2: Planning and Affordable Housing: “housing provided to those whose needs are not met by the open market”.

The note goes on to say that affordable housing in Wales should:

bb meet the needs of eligible households, including availability at low enough cost for them to afford, determined with regard to local incomes and house prices bb include provision for the home to remain affordable for future eligible households, or, if a home ceases to be affordable or staircasing to full ownership takes place, any subsidy should generally be recycled to provide affordable housing to replace it.

Affordable Housing in Wales can be considered to fall into two categories: bb social rented housing – provided by local authorities and registered social landlords, the latter also

“ The guidance is recommended best practice and describes the standard of work that is expected of a reasonable, competent valuer

referred to more commonly as housing associations bb intermediate housing – where prices or rents are above those of social rented housing but below market housing prices or rents. This can include equity sharing schemes; for example, HomeBuy. Intermediate housing differs from low-cost market housing, which the Welsh government does not consider to be affordable for the purpose of the land-use planning system.

Tenure types To identify eligible households, studies are undertaken at a local level to assess housing needs, as well as the relationship between incomes and house prices.

There are several different tenure types that qualify as affordable housing. Figure 1 shows the three main tenures and types.

Approach The approach to the valuation of land for affordable housing and the methodology adopted Image © Alamy

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Figure 1 Affordable housing tenure types

Affordable housing

Affordable rent

Intermediate housing

Social rent

£250,000 elsewhere in the country, inclusive of a minimum 20% discount.

PPG recommends that local planning authorities should require no Community Infrastructure Levy (CIL) or affordable housing provision in relation to these dwellings.

Any market housing included in these schemes to make them financially viable would, however, incur CIL.

Methods Shared ownership Rent to buy Rent to save (London only) Intermediate rent

have much in common with a conventional valuation of development land; therefore the guidance needs to be understood in the context of Valuation Information Paper (VIP) 12: Valuation of Development Land, which is currently being revised.

Valuation of affordable housing land is a special basis for a special purpose.

Assumptions such as the inclusion of grants, subsidies and so on should be clearly stated where they have been taken into account as part of the valuation.

Any planning application for new development will need to comply with the relevant national and local planning policies, which may affect development viability. The NPPF explains the government’s advice on delivering sustainable housing development, with general principles on assessing viability provided in Planning Practice Guidance (PPG). The RICS guidance note Financial viability in planning responds to these documents and gives detailed advice on area-wide and scheme-specific viability assessments.

The valuation of affordable housing land can be very complex and relates to

Shared equity Discounted market sale Other immediate products

specialised markets. It requires a high level of expertise, and practitioners should be aware that assistance may be needed from other professionals.

A development scheme may range from one that is 100% affordable to one where affordable housing is an element of a larger mixed-tenure residential or mixed-use development, that is market-housing-led developments with provision for affordable housing through section 106 agreements.

The guidance note only gives advice on how to value land for the affordable housing element of a development scheme on a cleared or greenfield site, or where the site is to be redeveloped by removing all or most of the existing buildings and constructing new ones. The other elements are valued as discussed in VIP 12. The guidance also does not apply to redevelopment based on refurbishment of existing buildings with limited demolition, although many of the principles will apply.

throughout a scheme for social or other reasons, a practice known as “pepperpotting”.

Such a distribution of accommodation in blocks of flats or throughout a housing or mixed-use development precludes the identification of a separate land value that can be attributed specifically to the affordable housing element, however.

While an apportionment of the value for the whole site can be made between that used for affordable and open-market accommodation, pepperpotting is not generally favoured by registered providers because of management issues and is becoming less widely used.

The opportunity to develop starter homes on exception sites should be taken into account as a potential alternative to both market housing-led development and affordable housing schemes.

Exception sites include: bb commercial and industrial sites not currently identified as residential development sites bb rural exception sites.

Pepperpotting

Starter homes have prescribed maximum sale values: in 2016, these were £450,000 in London and

Some planning authorities favour distribution of the affordable housing elements

There are two approaches to the valuation of development land for affordable housing: bb comparison method: comparison with the sale price of land for similar kinds of development bb residual method: assessment of the value of the completed scheme and deduction of the costs of development, including the developer’s profit, to arrive at the underlying land value.

In practice, a valuation would typically rely on both techniques, with the comparable method normally being used more as a reality check. The degree to which either, or both, are used depends on the nature of the development being considered, the certainty about the costs and factors that relate to affordable housing and the complexity of the issues involved. b

Charles Solomon, MRICS, is the author of the RICS Valuation of Land for Affordable Housing guidance note, 2nd edition censolomon@gmail.com

The guidance note is available at http://bit.ly/1XursUR

Related competencies include Valuation, Planning, Housing strategy and provision

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RICS L A N D JO U RN A L

P R O P E RTY

Ian Hetherington explores the wide-ranging benefits and return on investment to the property industry offered by 3D mapping in a mobile app

O

The future in your hands ur world is becoming increasingly mobile, and with it, industry is also mobilising. But many businesses struggle to use this transition to increase their return on investment.

For the property industry, mapping complex data sets in 3D in a mobile application enables businesses across every sector – construction, facilities management and real estate – to create an engaging and intuitive tool for navigating and visualising resources and managing assets.

The benefits for all property sectors are significant, and include building and occupancy optimisation, employee satisfaction, building information modelling (BIM) compliance and mobilising blueprints, as well as allowing estate agents using 3D models to display a property being bought off plan.

Construction Any decision can instantly change the plan and shape of a building and render traditional blueprints ineffective, so it is extremely important to have a representation of the building that can be modified in real time.

All government contractors have had to comply with Level 2 BIM since 4 April. This marked a milestone in the adoption of BIM, and most of the construction industry now realises its importance and benefits. But a Royal Institute of British Architects’ National BIM report surveyed 1,000 firms between December and February and found that, although 96% were aware of BIM — up from 43% in 2011 — only 54% had adopted it.

Of those respondents aware of BIM, 86% said they expect to be using it by the same time next year, and 97% within five years.

BIM enables digital technologies to support the more efficient design, construction and maintenance of buildings.

By embedding product and asset data in multi-dimensional computer models, information can be managed more efficiently throughout the project lifecycle.

One key benefit of using digital technologies – in particular 3D mapping – to improve the efficiency of a build is the lower costs they enable. Visualising a property on a mobile 3D map rather than traditional blueprints offers a clear return-on-investment model for construction firms of all sizes, for several reasons. bb Having one integrated building information model in a single 3D mapping app enables multiple data sets to be visualised in one resource, and allows conflicts and solutions to be identified in real time – reducing rework, conflicts, waste and delays. bb Visualising a building in a 3D, geospatially accurate simulation helps clients explore spatial requirements. This could reduce 1 0 J U LY/A U G U S T 2 0 1 6

client variations and scope creep from the outset all the way through to completion. bb Providing one app that can be accessed by all contractors encourages closer collaboration. In the long term, this can lead to reductions in tender risk premiums, fewer overall variations and fewer opportunities for claims. bb Recording execution plans in one app ensures that documentation is coordinated, timely and accessible for everyone involved in the build. Making project objectives visible can help ensure it progresses as planned. bb Details of component manufacturing and building tolerances can be integrated into the collaborative design process, enabling everyone on site to see them as well as better planning throughout the construction process. bb The use of 3D mapping can allow project programming simulations, which allow identification of the most efficient construction sequences and locations for key elements such as cranes, access and waste management.

Aside from saving costs, a 3D model of a building in a mobile app adds value to the build, and can often work as a competitive advantage. This is especially the case now that Level 2 BIM has come into play. Balfour Beatty is being seen as an industry leader, for instance, after announcing that it is one of only five UK construction companies to have been awarded the BSI certification for Tier 1 Lead Contractor and Lead Designer, following compliance with Level 2 BIM. The most important focus for Level 2 BIM requirements is monitoring maintainable assets following a construction handover. Embedding metadata on maintainable assets such as electricity and plumbing in a 3D map makes the tracking process more efficient and accurate.

This adds value when selling a property because, historically, homeowners have faced problems further down the line owing to a lack of communication throughout the building process from the architect to the seller. Providing a homeowner with all the information on their new home, packaged in an easy-to-navigate, engaging app, is not only a unique selling point but helps them make decisions on future home improvements and renovations.

Real estate The ability to walk potential homebuyers through an interior and exterior 3D representation of a property bought off plan is not only a sales tool but also adds value to the customer experience, opening up new revenue streams for estate agents as a premium service. Similarly, it can be difficult and costly for potential buyers to view properties abroad, so an interactive 3D map can help them visualise these remotely, yet in context. Aesthetics aside, buyers can also get an idea of the property’s dimensions as the 3D map will be geospatially accurate and to scale.

Images © eeGeo

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k Examples of indoor (top) and outdoor (above) 3D maps

Property management For property managers, a 3D mapping app for the interior and exterior of buildings – whether shopping centres, office suites or stadia – is more than just an intuitive navigation tool. If provided as a mobile app, it can help facilities managers to control assets and monitor resource usage, as well as encouraging compliance and greater efficiency by building users, saving on costs and improving business efficiency. Presenting complex data sets graphically in their geographic context also allows property managers to make practical insights from big data with ease.

As the workforce continues to go mobile, we are seeing an increase in the number of remote and freelance workers; co-working locations are popping up in all major cities, providing flexible office space to meet their requirements. Facilities managers have the opportunity to use mobile applications to visualise complex data and use devices to collect information.

Engaging with building users and employees through an intuitive

guide and utility application encourages compliance in resource booking and usage, reduces time spent finding those resources, and empowers users to report any facilities issues they might encounter quickly and directly.

Through a single portal, a facilities manager can identify usage trends to cut wastage and monitor office assets, while reception can operate a real-time booking system and users can better navigate the building.

Managers of property that contains retail space can realise fresh revenue streams thanks to the additional route this provides to communicate with customers. With the ability to layer social media feeds and proximity marketing services, the app becomes a hub for visitors to communicate with each other as well as retailers themselves. Geolocation advertising enhances the user experience by giving access to information tailored to their needs through personalised notifications.

We hear lots of hype around the term mobile, but 3D mapping in a mobile app is one way the property industry can cut through that hype and generate a clear return on investment. From the initial planning stage, through construction and sale to the management of property, such apps will not only reduce error and costs but also open potential revenue streams. b Ian Hetherington is CEO of software company eeGeo enquiries@eegeo.com www.eegeo.com

Related competencies include GIS, Mapping, Legal and regulatory compliance

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P O L L I N ATO RS

A helping hand Managing farmland to encourage pollinating insects can boost crop quality and yield, report Claire Carvell, Adam Vanbergen and Lynn Dicks

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here are a number of pollinating insects in the UK, including the managed honeybee as well as hundreds of species of wild bumblebee, solitary bee, fly, butterfly and moth, all of which support food production and biodiversity by pollinating crops and wildflowers. Over the last five years, the Insect Pollinators Initiative has been researching how to encourage thriving pollinator populations in farmed landscapes.

Insect pollinators face multiple threats in these areas, including the loss of wild habitats, agrochemicals, climate change and disease. Scientists have shown that land management practices to increase floral resources and improve semi-natural habitats, such as agri-environment schemes, can benefit these important insects, wildflowers and food production.

What pollinators need Insect pollinators improve or stabilise the yield and quality of three-quarters of crop species worldwide, and are important for biodiversity and helping to maintain the populations of wild plants that provide shelter and food for animals. But they need a range of different resources throughout their lifecycle.

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bb Pollinators feed on nectar as adults, providing energy, and many also feed on pollen, providing protein. bb Most pollinator species collect food from a broad range of flower species to meet their particular nutritional needs, whereas some specialise, collecting food from a few or a single plant species. bb Bees feed their larvae on pollen and nectar; and, while some species are active from March to October, others only forage for a few weeks. A diverse bee community therefore requires a continuous succession of flowers to maintain food supplies. bb The offspring of some pollinators depend on leaves and insect prey, rather than flowers e.g. certain hoverfly larvae hunt aphids, while butterfly larvae (caterpillars) eat the leaves of various host plants. bb Flowering crops, such as apples or oilseed rape, provide abundant nectar and pollen for short periods, but wild plant sources, e.g. from field margins and hedgerows, are required to sustain the food supply for pollinators. The mining bee Andrena dorsata is a key pollinator of apples blooming in spring, for instance, but its second summer generation needs later-flowering plants to survive. bb Pollinators need suitable places to nest, mate and hibernate over winter, whether underground, as solitary mining

Queen of Bombus ruderatus, a nationally rare bumblebee species, which has responded well to clover-based flower mixtures sown under agri-environment schemes

bees and bumblebees prefer, in dense tussock vegetation, which carder bumblebees need, or in cavities, where mason and leafcutter bees can dwell.

Some pollinating flies require damp and wet areas or animal dung during their larval stages.

How much habitat is enough?

The amount and arrangement of flower-rich habitats can affect the population size and foraging behaviour of pollinators. Measuring the size of pollinator populations is very difficult, but recent research has shown that: bb nests of most common bumblebee species occur at a minimum density of 10–35 nests per 100ha; there is evidence for some bumblebee species of higher nest densities on farms with agri-environment schemes that provide suitable flower resources bb an estimated 2% flower-rich habitat – equal to 2ha and up to 1km of flowering hedgerow in every 100ha of farmland – can supply enough pollen for populations of six common wild bee species bb food resources need to be available within foraging distance of the nest, usually around 100m–1,000m, but this may range from tens of metres for small solitary species to several kilometres for bumblebees and honeybees; to achieve Images © Claire Carvell

RI CS LAND JO UR NAL this across an agricultural landscape, flower patches should be at least 0.25ha in size and no further than 250m apart bb increasing the amount of flower habitat in farmed landscapes reduces the distance that bumblebees have to fly from their colony to find food, meaning that they can devote more energy to raising healthy queens who will survive the winter.

Working together Pollinators operate at scales larger than individual farms, so management needs to be coordinated by farmers and other land managers, who should work together to target the needs of conservation-priority species. There are several simple steps that can help. bb Enhancing food resources for pollinators can increase their numbers and diversity at the landscape scale and locally. This could involve sowing or maintaining floral resources both in fields and along boundaries, including early-flowering trees and flowers such as willows and dead nettles. Most of these are commercially unavailable as seed, but can provide vital pollen and nectar for queen bumblebees and other early-flying pollinators. bb Flower mixtures are most effective if sown in landscapes where existing floral resources are scarce, although they are likely to benefit all landscapes. bb Sown flower patches or strips along lower-yielding field edges can increase both pollinator numbers and crop yields, as has been demonstrated with important crops such as field beans and field-grown blueberry. However, such yield improvements can take a few years to develop as the enhanced pollinator community becomes established. bb A mixture of habitats such as grassland, hedgerow, woodland and scrub in the landscape surrounding farms to provide both food and nesting resources often increases wild pollinator diversity and crop pollination services. bb Providing a diversity of nesting resources – short turf, bare ground, plant stems, logs or ditches – may increase pollinator numbers. bb High-quality habitats for pollinators can also help other beneficial species such as ground beetles and hoverfly predators of crop pests. bb Priority or rare pollinator species, such as section 41 species in England, are targeted where these species occur through the new agri-environment schemes, with detailed guidance on the best management approaches to meet their specific habitat requirements.

k Legume-based nectar flower mixture in its second year. Such mixtures may be short-lived so can be rotated round the farm, in contrast to native wildflower mixtures that can last 10–20 years if suitably managed

Positive steps Agri-environment schemes are a key means of supporting pollinators, and scientists have urged the government to promote greater uptake of these.

In England, the new Countryside Stewardship scheme targets wild pollinators through the Wild Pollinator and Farm Wildlife Package. Applications containing management options from the package score highly and are more likely to proceed to an agreement.

More systematic monitoring of uptake, quality and provision of agri-environment schemes and voluntary initiatives on farms across the country would also be helpful and enable policy-makers to adjust their options on the basis of new evidence.

Simple metrics for habitat quality could offer a rapid assessment tool for land managers, while systematic UK-wide monitoring using standardised methods would help to track changes in the status of pollinators and pollination services.

Land managers can take many positive steps to promote healthy pollinator populations. Joint applications from farms for agri-environment or other financial support to manage entire landscapes for pollinators – such as that provided by the new Countryside Stewardship Facilitation Fund – are particularly important and can offer major benefits. Land managers should also be aware of options in the mandatory greening measures of the Common Agricultural Policy, such as Ecological Focus Areas, which can provide flower-rich habitats including grassland or scrub.

Providing resources throughout the course of the season is essential.

For instance, by sowing a mixture of summer-flowering legumes, diverse

mixes of perennial wildflowers, managed hedgerows cut on a three-year rotation and trees including willow, you can provide important spring forage. Leaving verges or ivy uncut also provides late summer flowers.

A range of habitats is important, and land managers can help by ensuring wherever possible that management of priority and semi-natural habitats accounts for the lifecycle needs of wild pollinators, for example by varying grassland sward height or managing scrub habitat sympathetically. Areas of semi-natural habitat such as woodlands, heathlands and meadows provide important resources and should also be protected, if possible.

Options and opportunities Training opportunities are available for farmers on establishing and managing pollinator habitats, for example via the Campaign for the Farmed Environment.

A new practical guide for conserving insect pollinators was also published in April, entitled Habitat Creation and Management for Pollinators.

This represents a 20-year research partnership between Marek Nowakowski, a practitioner with a passion for wildlife conservation on farmland, and applied ecologists working for the Natural Environment Research Council’s Centre for Ecology & Hydrology, led by Prof.

Richard Pywell. It provides farmers and other land managers with advice on creating and managing habitats for bees on farmland (http://bit.ly/1rTIakQ). C

Dr Claire Carvell is a senior ecologist at the Centre for Ecology & Hydrology (CEH) in Wallingford, Dr Adam Vanbergen is an invertebrate ecologist at CEH Edinburgh and Dr Lynn Dicks is a Natural Environment Research Council Research Fellow at the University of Cambridge ccar@ceh.ac.uk ajv@ceh.ac.uk lvd22@cam.ac.uk

More information about the Insect Pollinators Initiative and all the Living with Environmental Change policy and practice notes from the research programme are available at www.insectpollinatorsinitiative.net.

Related competencies include Management of the natural environment and landscape

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TR E E S

Protection matters Richard Nicholson discusses how to go about working on trees that are subject to preservation orders

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tree preservation order (TPO) can be issued by a local planning authority to protect individual trees, groups of trees or woodlands in the interests of public amenity. It takes the form of a legal document that includes a plan showing the location of the trees and a schedule that describes those protected.

TPOs date from the first Town and Country Planning Act 1947 and some authorities still have orders in place from the early 1950s, so the documentation comes in all shapes and sizes. In April 2012, however, the government published new regulations cancelling the provisions in TPOs issued before 6 April 2012 and replaced them with the provisions of the same year’s Town and Country Planning (Tree Preservation)(England) Regulations (http://bit.ly/1PRZscf).

The only parts of a TPO from before this date that remain in effect are its name, its endorsement and the details, by way of the plan and the schedule, of the trees protected. The Welsh Assembly decided not to adopt the 2012 regulations, though, retaining TPO documentation that dates from different periods.

A TPO can protect anything that can ordinarily be described as a tree and 1 4 J U LY/A U G U S T 2 0 1 6

is listed in the schedule. This is why surveyors must take the trouble to look at the plan and the schedule.

Consider a property that has an oak in the front garden and a willow and a maple in the rear garden. The property has a TPO on it and the schedule lists a T1 oak as growing in the front garden and a T2 elm in the rear. There are two circles on the plan labelled T1 and T2 showing the position of the trees.

Clearly the elm has long since died, probably from Dutch elm disease, but the oak is still growing. While there may be more than one TPO on the property, if the council record shows only one then the maple and the willow are not protected.

Be aware that a tree preservation order frequently contains more than one tree, can cover more than one property and can contain more than one classification

Some TPOs protect individual trees, shown as a circle and labelled T1, T2 and so on; some protect groups of trees, shown as a polygon edged with a dashed line and labelled G1, G2, etc. An “area” classification is shown as a polygon edged with a dotted line and labelled A1, A2 and the like, while a “woodland” classification is shown as a polygon edged with a solid line and labelled W1, W2 and so on.

In every case, however, the protected trees will be detailed in the schedule. Be aware that a TPO frequently contains more than one tree, can cover more than one property and can contain more than one classification.

If the local planning authority issues a TPO on a property, the owner has the right to object before the TPO is confirmed. They will receive guidance on this from the authority in the bundle of documents served on them, and their objections are heard by that authority.

Should the TPO be confirmed against the owner’s wishes, their best course of action is to make an application for works under the new TPO and appeal to the Secretary of State. The good news is that there is no fee or any other charge for TPO applications, notifications or appeals.

Application Should you wish to carry out work on a tree that is the subject of a TPO, you

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Conservation areas

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2 1 Roadside oak trees implicated in subsidence event 2 One oak established as cause of subsidence is subsequently felled will need to apply to the relevant local planning authority. To do this, you should download and complete a tree work application form from either the online Planning Portal or the local authority’s own website.

Guidance notes attached to the form state that, where the reason for the work concerns alleged damage to a structure, a higher level of evidence must be submitted to demonstrate that the tree is a material cause of the problem, and that other potential causes have been eliminated so far as is possible.

Subsidence cases often involve information outside the expertise of the authority’s arboriculturists.

Authorities use engineers and building control officers for advice and employ consultants where the tree in question is of significant amenity value. The list of information required for the 1App tree work application form in these cases is mandatory, and an authority can refuse to determine an application without it.

Proving a tree to be the cause of subsidence can be difficult, but as a minimum authorities will need root identification from live samples below the seat of damage, evidence of a shrinkable clay subsoil and level monitoring that demonstrates seasonal movement.

In determining any application for tree work, the authority must balance the public amenity that the tree offers against

the reasons provided for requiring the work. The authority has to consider, in the light of its assessment and the submitted evidence, whether the proposal is justified. It follows that the more drastic the nature of the proposed work – felling, for example – the better the reasons provided for it should be.

If the local authority grants consent for the work, usually with conditions about the standard required, an applicant can carry this out within two years of the date of the decision. Should the authority refuse, however, it will include with its paperwork details of how to appeal the decision to the Secretary of State through the Planning Inspectorate.

Not all works require consent. There are exemptions in the regulations that permit works on dead trees and branches, and on trees and branches that present an immediate risk of serious harm. Other exemptions are listed in the regulations; if in doubt, the authority should be approached.

Where a tree is protected, it is an offence to cut down, remove the top from, cut branches off, uproot or wilfully damage or destroy the tree. The local authority can pursue enforcement action in the case of unauthorised tree work, and fines can be imposed on the tree owner or the person instructing or carrying out the work where an offence has been established.

Images © Shutterstock; Richard Nicholson

Trees growing in conservation areas are automatically protected where they have a stem that exceeds 75mm in diameter, measured at 1.5m above ground level.

The offences and exemptions contained in conservation area legislation are not dissimilar to those in TPOs; the significant difference is that when an applicant wants to work on a tree growing in a conservation area that is not also subject to a TPO, they need to notify the authority of their intentions rather than apply for consent, though they do not have to provide so much information as they would under a preservation order.

While there is no requirement to use a 1App form, it is probably easier to do so. The local authority has six weeks to respond, and may take one of two courses of action: either allow the works to proceed, or issue a TPO that prohibits the work from taking place. If it allows the works, then it will usually respond to the application, although should the applicant hear nothing they can go ahead six weeks after notifying the authority.

An important part of the Planning Practice Guidance Tree Preservation Orders and trees in conservation areas document is that it contains endorsements showing that the TPO has been confirmed. If the TPO is more than six months old and has not been confirmed then it will have no effect (http://bit.ly/1LqnJx6).

Finally, a TPO will generally only protect trees that were growing at the time it was issued. There are a couple of exceptions: a TPO with a “woodland” classification covers trees of any age, including saplings, and there might also be occasions where a tree has been planted as a replacement for one that died or was removed in contravention of the TPO. The arboriculturist in the local authority’s planning department should be able to help with this information. b

Richard Nicholson is Planning Team Leader responsible for trees, landscape and conservation and listed buildings at Christchurch and East Dorset Partnership nicholsonrm@live.co.uk

Related competencies include Legal/regulatory compliance, Conservation and restoration

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TR E E S

John Lockhart and James Broom provide an update on the pests and diseases attacking our trees and look at how to deal with them

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Threats to our trees

Threats

under-planted, should also be developed to help diversify the stand. In mature stands, it is advisable to remove ash trees with more than 50% of the crown affected by dieback as these are likely to be severely stressed, have limited genetic resistance and will be actively spreading spores.

The threat level for ash dieback is high, as the tree is a hugely significant component of many of our ancient broadleaved woodlands, in particular in the lowlands, as well as being a prevalent hedgerow tree in many landscapes. Current predictions still indicate natural resistance of less than 5%.

Chalara fraxinea: ash dieback The fungus Chalara is present across much of England, and key stands at risk from it include pole-stage, unthinned ash (Fraxinus excelsior) plantations, coppice and natural regeneration.

In such places it is important to thin by 20–30% to increase airflow, which will help prevent a build-up of spores. A vibrant understorey of a range of species, whether naturally regenerated or

Emerald ash borer Originating from Eastern Asia, the Emerald Ash Borer (Agrilus planipennis) is a species of beetle that has already killed extensive amounts of ash in northern America following its arrival in packaging material. It should be expected to appear in the UK, and estates and landowners need to diversify their ash stands.

The beetle presents a high threat level; the implications

There has been a significant increase in tree pests and diseases in the last few years, with, for instance, the threat of ash extinction in Europe and the recently discovered tree in Norfolk, named “Betty”, that is potentially resistant to the disease.

k Blackened dead ash leaves still hanging on the tree: tell-tale symptom of ash dieback in woodland in Norfolk 1 6 J U LY/A U G U S T 2 0 1 6

could be very significant, and combined with Chalara this paints an extremely grim picture for the future of ash in the UK. Phytophthora ramorum Although many Phytophthora species are present in the environment, ramorum is of greatest concern. Trees of the genus larch (Larix), particularly Larix kaempferi (Japanese Larch) – a common timber species in the west of Britain and the uplands – are particularly susceptible to the pathogen. Infected stands are given a statutory plant health notice by the Forestry Commission (FC) and landowners are required to fell all trees within 100m of the infection at once to control and prevent further spread.

Infected larch timber is also subject to a movement licence issued by the FC. Phytophthora ramorum has also been found to affect Sitka spruce (Picea sitchensis) and Douglas fir (Pseudotsuga menziesii) in laboratory trials, although no infections have yet been observed in the wild.

More recently, Phytophthora ramorum has been observed in Devon and Cornwall on sweet chestnut (Castanea sativa).

Phytophthora is a particular concern that carries a high threat level, since scientists have demonstrated its capacity for rapid evolution through the hybridisation and mixing of genes, giving it the potential to move across different tree species.

Dothistroma needle blight This fungus causes premature needle defoliation on pine species – reducing growth

rate and therefore timber yield, which can lead to high mortality – and is of particular concern in the lowlands where Corsican pine (Pinus nigra subspecies maritima) is often a major component of commercial woodlands, in particular on lighter soils in the east of Britain. Scots pine (Pinus sylvestris) is also susceptible. The preferred management method is regular thinning to increase airflow and prevent the conditions under which the fungus can thrive.

The threat level is medium, since the fungus is restricted to pine and the timber quality does not suffer significant effects quickly, thus enabling time to harvest.

Acute oak decline Suspected to have first arrived in the UK 30–35 years ago, acute oak decline is a condition that commonly affects mature trees.

Those in decline will have vertical, weeping fissures that seep black fluid down the trunk, known as stem bleeds, and some die four to six years after the onset of symptoms. The larval galleries of the native buprestid beetle (Agrilus biguttatus) are usually found in relation to the lesions, with their characteristic D-shaped exit holes identifiable in the bark.

The potential implications of acute oak decline are serious, and the excellent work currently being undertaken by Forest Research, supported

by Woodland Heritage, is essential if we are to better understand the causes and develop potential management strategies.

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RICS Rural Policy paper recommendations RICS Rural Policy paper, which was launched at this year’s Oxford Farming conference, contains recommendations across a number of key themes: bb property in the rural economy bb land industries: farming, forestry and tourism bb energy: production and use bb natural capital markets.

These themes emerged during our policy consultation with rural property professionals, employed in the public, private and third sectors. Members placed particular emphasis on the multi-functionality of land and the need to resolve competing land uses.

k Oak processionary moth The threat level of acute oak decline is medium, but it is one to watch closely because of its potential impact on such an important tree in the UK. Oak processionary moth The principal risk from this moth is to human health, as the fine hairs of the caterpillars are an irritant.

This pest is currently restricted to London, Surrey and Berkshire, but is spreading relentlessly. It is extremely important to notify the FC on discovery of the caterpillar. Current management is expensive, and based on manual removal of nests and caterpillars as well as careful application of insecticide in spring.

The threat level is medium, in terms of its implications for timber, but is of critical concern in urban or more populous areas.

Massaria disease This is found on plane trees (Platanus x hispanica) and causes lesions on major branches that can lead to branch drop. This is an obvious concern in urban settings, where London plane is such a critical component of the urban tree resource.

Regular assessments should be undertaken and appropriate remedial work carried out.

In terms of its implications for our vital urban trees, the threat level is high.

Images © Alamy

Other threats include chestnut blight, Asian longhorn beetle and spruce bark beetle, among others.

Mitigation and management Tree vigour As with any plant or animal, healthy and vigorous trees have a greater likelihood of resisting threats from both pests and diseases. Good silviculture and positive management are key, and provide critical protection against many threats.

Tree diversity (resilience) A good financial advisor would always advise having a diverse investment portfolio to reduce risk.

This also applies to a good forestry or tree portfolio. A diverse mix of tree species, although more complicated to manage, will help increase resilience to pest and disease threats.

Securing timber value Tree pests and diseases will detrimentally affect timber quality and value. It is vital to manage and survey your woodlands actively to identify any of these at the earliest opportunity.

Timely management can help limit or prevent loss of potential revenue from timber, enable development of more diverse tree stock and build resilience in an estates forest.

Recommendations bb Increase the amount of woodland in active management through improved markets and better infrastructure. bb Promote the development of other opportunities to manage woodlands and forests as valuable property assets. bb Promote sustainable silviculture such as continuous cover practices to ensure resilience to climate change and pests and diseases. bb Continue the approach established by the Forestry Regulation Task Force to simplify further regulation and take a risk-based approach. bb Support the conversion of forest products and planning in the countryside for small-scale seasoning, storage and manufacture of wood products.

Biosecurity The FC’s “Keep it Clean” campaign demonstrates the importance of everyday good practice in minimising risks from pests and pathogens.

The importance of using good, healthy nursery stock that has traceable sources is also fundamental.

Tree risk and safety Frequent tree assessments should be undertaken on estates. High-risk trees, such as those over busy roads, should be a primary concern.

The role of secondary pathogens – those that attack weakened trees following an earlier pest or disease outbreak – should not be underestimated either.

Some key examples are honey fungus (Armillaria) or Ganoderma root decay.

Final thought The tree pests and diseases in this article are not an exhaustive list.

All practitioners working with trees should explore the information on the FC website, while the commission’s Tree Alert app enables you to identify and report any pest and diseases.

You should also follow the vital work of Forest Research, which should be supported by all. b John Lockhart is Chairman and James Broom is Forestry Placement student at Lockhart Garratt Ltd john.lockhart@lgluk.com

www.forestry.gov.uk/ forestresearch

Related competencies include Forestry and woodland management, Management of the natural environment and landscape

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F LO O D I N G

Organisations in the South West of England are working together to improve water management by changing land-use practices, Lorna Devenish reports

Upstream thinking uestions around land use and water have spread across the country in the wake of yet more devastating floods last winter.

Since the deluge receded, water treatment professionals up and down the country have worked overtime to turn the heavily silted spate into tap water that we can drink.

Floods have a wide-ranging impact on society, and not only in terms of devastating homes and communities. But could different land management practices help? In the South West of England, a group of organisations who believe that land use is critical for water management is working together for change.

South West Water, Devon Wildlife Trust, Cornwall Wildlife Trust, the Westcountry Rivers Trust and Exmoor National Park Authority came together in 2008 under the banner Upstream Thinking to develop a programme of landscape-scale changes to land use. They now work with a wider group of partners, including the Environment Agency and the University of Exeter.

The academics are a key part of the project. They have collected data that is beginning to show that significant amounts of water can be stored on the land, river flows can be slowed in winter and boosted in summer, and carbon can be locked into peat bogs instead of being lost into the atmosphere or into rivers. If soil compacting is tackled and degraded peatlands are restored, the landscape can provide a significant buffer to downstream flooding.

Advisors across 11 catchments offer support and guidance on alternative techniques to manage and farm the land, techniques which bring both economic and environmental benefits. They discuss in detail what can be done on farms to protect water

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quality and develop a farm water management plan. Grant funding is also available for capital works.

Putting the peat back One part of the project is peatland restoration. On Exmoor, more than 2,000ha of peatland have been surveyed, assessed and restored where possible, using ditch blocks to stimulate the bogs’ hydrological function. Up to 500ha more are to come.

Lead researcher Prof. Richard Brazier has coordinated an award-winning research programme to quantify the benefits of

Case study: slurry storage Cornish farmer Andrew Jones from Higher Trevallett Farm near Launceston was awarded a £75,000 Upstream Thinking grant in 2013 after an assessment by the Westcountry Rivers Trust (WRT).

The money, which Andrew matched, went towards building a new covered slurry store for his dairy heifers.

The tank is immediately below the barn where the cows are housed and provides five months’ storage where previously he had space for just a month’s slurry.

“It’s a big weight off my mind,” Andrew says. “I can sleep easy at night knowing that the slurry store is not going to overflow, and I can spread the nutrients on the land at the optimum time so that it stays on the land and doesn’t run into the rivers. It means we can wait for exactly the right conditions before we spread.”

Senior Farm Advisor Ross Cherrington from the WRT says it has recorded an increase in the number of varieties of invertebrates, suggesting an improvement in water quality in the nearby River Kensey, which flows into the Tamar above South West Water’s raw water intakes at Gatherleigh and Gunnislake.

Images © Alamy

RICS Rural Policy paper recommendations bb The Environment Agency needs to adopt an Integrated Catchment Management approach in order to help mitigate flooding and, where possible, protect and enhance good agricultural land. bb Practical work in the uplands such as tree planting and measures to slow water can complement sustainable hill farming, and has been shown to be successful in preventing downstream flooding. Such work should be given incentives through agri-environment schemes and taxation. bb The aim should be to hold water in the landscape. The nexus of flooding, drought, aquatic fauna extinction and water quality decline is a harbinger of enhanced loss of water from the landscape, where run-off rates are left unchecked. Run-off attenuation can recharge groundwaters for abstraction, intercept overland flow flood pathways, and retain valuable suspended sediment and nutrients for enhanced farm productivity.

the work that has been carried out. He explains: “During wet winters, as we have recently experienced, you only need to look around the landscape to see that there is evidence of local flooding and soil erosion everywhere.”

The research team has shown how enhancing water storage on Exmoor’s peatland can improve water quality, as well as releasing less into the River Exe during flooding.

With a third less water leaving experimental sites on the moorland during peak storm flows, the initial results indicate that the work could provide benefits in terms of both water quality and quantity. Wildlife is also benefitting, with the return of rare wading birds to the restored sites.

South West Water has brokered an agreement with Exmoor National Park Authority and the National Farmers Union for a groundbreaking system that will guarantee a per-hectare payment for participating upland landowners for 10 years, in recognition of their contribution to maintaining the land in a way that enhances water quality and storage.

It has drawn heavily on the evidence of increased water storage and quality benefits from mire restoration.

Looking further afield The work on Exmoor demonstrates the complex economic and legal challenges that can arise if we are to manage rural land for more than simply food production and compliance with stewardship requirements.

How do the new opportunities for land-water management play out with existing commitments under the Basic Payment Scheme, a range of statutory designations and existing arrangements such as the Higher Level Stewardship of the new Countryside Stewardship schemes? And what are the economic and practical implications for existing farming practices?

The work on Exmoor has led the way: many of the lessons can apply in a much wider range of situations, and provide a basis for further work in different locations. The £12m programme for 2015–20 includes two distinct strands of work: ongoing restoration of peat bogs on Exmoor, working with owners of upland areas; and advice and grants for lowland farmers, whose land adjoins key rivers used for public drinking water supply.

Charles Cowap is a rural chartered surveyor and registered valuer who has been involved with the partnership, and he has used this experience as the basis for a number of briefings for the profession, working in conjunction with RICS Rural Professional Group. RICS sees this as an increasingly important area of professional practice, given the growing complexity and challenge of rural land management.

He was commissioned by RICS to write a thought leadership paper entitled Challenges for International Professional Practice: from market value to natural value, and a second paper looking at the valuation of ecosystem services commissioned from him is due shortly. The National Trust’s experience with storm run-off management at Holnicote, Somerset, is another valuable example of what can be achieved.

Cowap says: “Taking projects like these together it soon becomes clear that the water challenge is about far more than just pumping, dyke-clearing or tree-planting. We need to think about the full water cycle from the uplands to the sea.”

On the lowlands, grants of up to 50% are available to enable farmers to make practical changes – for instance measures such as slurry storage, riverbank fencing, buffer strip planting and pesticide management. These grants are subject to a 20-year covenant agreement.

In the headwaters of the Exe, grants and advice are available for a range of interventions including woodland creation. In addition, by participating in Upstream Thinking, farmers can often access further subsidies in recognition of their environmentally sensitive farming practices.

Prof. Brazier concludes: “It has a benefit for the water company – cleaner water and more water storage; it has a benefit for society, because it alleviates flooding downstream and reduces the need for dredging; and it has a financial benefit for the farmer, as soil is retained on the fields and the farmer is rewarded financially for looking after their soil and water.

“A landscape that stores water in the wet season and releases it more slowly in dry periods is more resilient to climatic variability and can help society to adapt to the kind of extreme weather that we have seen in recent months.” b

Lorna Devenish is Communications Officer for South West Water ldevenish@southwestwater.co.uk

Related competencies include Water management, Management of the natural environment and landscape, Sustainability

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RICS L A N D JO U RN A L

PLANNING

London on track?

Laura Nation examines the National Infrastructure Commission’s proposals to change planning rules for London and asks whether they would work

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he National Infrastructure Commission (NIC) was set up last year, and part of its remit is to consider the strategic case for additional largescale transport infrastructure in London.

In a report published in March, Transport for a World City, the NIC recommended that Crossrail 2 be taken forward to alleviate pressures on underground lines, on commuter rail services and on strained orbital links.

The NIC advises significant changes to planning policy to realise these proposals – but how will those changes work in practice, and what do they mean for developers seeking to capitalise on the drive for growth?

Crossrail 2 The proposed Crossrail 2 would run from north to south across the capital, connecting commuter networks in Surrey and Hertfordshire. It is envisaged that it would open in 2033, in time for the arrival of phase 2 of High Speed 2 at Euston station.

The NIC’s report recommends that Crossrail 2 should be a priority for the new London Plan, integrated with Transport for London’s wider programme of smaller works on national rail, the underground and cycling networks.

The report indicates that the following planning policy changes are necessary, as part of “a clear, transformative plan to turn the proposed 200,000 homes into a reality”: bb an increased rate of strategic industrial location (SIL) release for housing development bb an increase in the housing density levels applied by the London Plan, 2 0 J U LY/A U G U S T 2 0 1 6

including the intensification of existing housing estates bb densification around Crossrail 2 stations including, where appropriate, the limited release of metropolitan open land and the green belt.

Industrial land release Currently, SIL is protected by the London Plan for functions such as general and light industry, logistics, waste management and transport. Where the release of SIL is allowed, the plan makes clear this only applies to surplus sites “around public transport nodes and town centres to enable higher-density redevelopment, especially for housing”.

The London Plan cautions against hasty SIL release, however, suggesting instead that this ought to be managed carefully through opportunity area planning and development frameworks, while it maintains that the power to declassify such land should lie with local planning authorities. The NIC’s proposals for release of industrial land would require coordination between central government, London’s mayor, transport agencies and local authorities.

The government may be wary of a top-down approach to declassification and choose to remain faithful, at least, ostensibly, to the more restrained London Plan. However, more bullish developers may familiarise themselves with SIL along the proposed route, including the sites most suited for reclassification. It would appear, though, that the winners and losers have all but been decided, with price hikes being witnessed at sites along the proposed route already.

Density The London Plan links the declassification of surplus SIL with an increase in housing density. Unsurprisingly, the NIC promotes both as means of unlocking Crossrail 2’s potential for housing.

The London Plan is clear that density should not be applied mechanistically. Rather, other factors relevant to optimising the potential of a development site must be taken into account, having regard to transport capacity and social infrastructure with an emphasis on high-quality residential environment and public realm.

The plan also recognises: bb the principle of higher-density residential and mixed-use development in SIL bb ● that it may be acceptable for a scheme to exceed the ranges in density, with regard to local context, existing and planned public transport connectivity, local amenities and appropriate design and management, among other factors bb ● the potential for large sites to define their own setting and accommodate higher densities, progressed through a plan-led process.

There would appear to be sufficient flexibility in the London Plan to permit the densification envisaged by the NIC. The plan also provides unitary authorities with a framework to implement a local approach, including increasing density where proposals such as Crossrail 2 will improve accessibility to public transport.

Increased densification along the route of Crossrail 2 will require the coordination of planning between London's boroughs and affected authorities around the capital. Until now, density outside London has been a local matter. This will be a source of tension, however, and another challenge will be to gain public support for increased densification.

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Metropolitan open land and green belt release The NIC’s most controversial proposal is the release of land in the green belt, which has gained an almost sacrosanct status, protected by the National Planning Policy Framework as well as the London Plan and all local plans.

The unaffordability of housing has been cited as the biggest risk to the UK economy, so it is perhaps disingenuous to suggest that brownfield sites are sufficient to meet the capital’s housing needs, or that short-term improvement measures such as extensions to the Croydon Tramlink and the Northern Line of the underground, can serve as a panacea for housing supply in the South East of England.

The NIC’s proposals come at a time when a number of local authorities are reviewing green belt designations and the Department for Communities and Local Government has granted consent for one of the biggest residential developments in the green belt in a decade, comprising 1,500 homes north of Brockworth in Gloucestershire. For years, authorities have carried out ad hoc, inefficient green belt reviews that allow for limited encroachment, arguably at the expense of the openness that the policy restrictions seek to protect.

While people living close to areas identified for green belt release are likely to oppose its loss of protection, the NIC suggests a more strategic approach of controlled green belt release, protecting areas of true environmental value while releasing that which seeks only to prevent sprawl.

Image @ Shutterstock

The potential of Crossrail 2 to remove viability constraints and support increased densities will not be lost on developers, who may take a second look at green belt sites that they previously discounted. Furthermore, given that 200,000 homes only represent four years’ supply for London, the green belt release envisaged by the NIC will be considered against a wholesale review of such boundaries.

Collaborative working The NIC’s recommendations are a common-sense response to the deepening housing crisis.

However, they will not be easily achieved. It will be necessary to gain the support of City Hall, the various London boroughs and other local authorities, which have been promised the power to decide those sites that can be developed through their own local and neighbourhood plans.

The NIC signposts the more extensive use of the Greater London Authority’s land acquisition powers, Crossrail 2’s potential compulsory purchase powers and the possibility of a joint plan, by compulsion if necessary, as part of its coordinated framework.

The prospect of the government creating its own policy framework, with the confidence that local plans must follow suit, and the establishment of one or more development corporations to coordinate housing delivery are also mooted. It appears, therefore, that the NIC recognises the potential for challenge and the inevitability of a top-down approach to the

implementation of its recommendations – a move that is likely to meet further opposition from politicians and local residents, and, if the passage of the High Speed 2 Bill through Parliament is anything to go by, will mean that the housing crisis deepens before any benefits materialise. Local and national politics aside, and given the potential for Crossrail 2 to unlock new housing, it would seem that developers could only gain from the NIC’s suggestions.

However, prices along the proposed route are already rising, and for those who have made speculative acquisitions the report sounds a note of caution with regard to the “high costs associated with Crossrail 2 and the inherently uncertain nature of the benefits”.

At £28bn, Crossrail 2 would be almost double the current cost of Crossrail 1. In part, paying this will rely on an enhanced mayoral Community Infrastructure Levy at twice the existing rates; this will be borne by the developer, along with already-rising land acquisition costs.

While the Treasury is likely to recoup the benefits of Crossrail 2, the advantages for developers may not be so clear cut. C

Laura Nation is an associate at global law firm Clyde & Co. laura.nation@clydeco.com

Related competencies include Planning, Economic development

J U LY/A U G U S T 2 0 1 6 2 1

RICS L A N D JO U RN A L

VA L UATI O N

Property valuation in Ghana Kwasi Gyau Baffour Awuah summarises recent RICS research that found high variations in Ghanaian property valuations and discusses the implications for Africa

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lobal real estate investment interests in Africa have increased over the last decade or so, and investible real estate value on the continent is expected to increase from 8% of GDP to between 20% and 28% by 2020.

The total volume of commercial real estate investment over 2011 and 2012 in South Africa alone was US$4.5bn. More recently, Momentum Global Investment Management and Eris Property Group raised the first $50m of the targeted $250m for the Africa Real Estate Fund from institutions, financial services businesses run by and for comparatively wealthy families, and high-net-worth individuals. Market analysts suggest that 20 cities – including Cairo, Lagos, Nairobi, Johannesburg and Accra – offer key opportunities for commercial real estate growth.

Africa’s real estate markets therefore require highly professional property services in areas such as land administration and management, property valuation, property management and investment analysis.

In addition to constituent countries, local property service institutions and international organisations such as BROLL and Jones Lang Lasalle continue to operate in parts of the continent. Similarly, local and international professional bodies and organisations such as RICS, the Commonwealth Association of Surveying and Land Economy (CASLE) and the Federation of International Surveyors have intensified their activities in Africa to improve the quality of property services, among other things.

Nevertheless, the standard of property valuation practice has often come under criticism, relating to errors usually attributed to the non-availability of reliable property market data. Ghana is one country where such criticism is rife, but it is largely based on anecdotal evidence. This article summarises the findings of a recent investigation into valuation practice in Ghana using Accra, the country’s capital city, as a case study.

Methodology The study drew on a systematic identification and review of literature, a stakeholder workshop, the examination of the archival database of the Land Valuation Division (LVD) of 2 2 J U LY/A U G U S T 2 0 1 6

Accra, Ghana

Ghana’s Lands Commission, and a questionnaire for real estate valuers in Accra. The literature review and workshop allowed the study to be contextualised and informed the type of data to be collected, as well as the choice of data collection approaches, including sampling strategies and the design of instruments.

Examination of the LVD’s archival database and the questionnaire were carried out between July and October 2015. The database yielded data sets of compensation valuations conducted by the LVD and private practitioners on the same properties at or around the same time, and this was complemented by the questionnaire, which asked a sample of real estate valuers to conduct a market valuation of a hypothetical three-bedroom residential property at a particular date based on the same set of instructions.

The survey also elicited respondents’ views on property market data issues such as the frequency of use and reliability of sources, proposals for a property market data collection template and the information that the template should contain, based on a Likert scale. These issues had been identified from the literature review and the workshop. The data obtained from both the LVD and the questionnaire were used to analyse the extent of variations in valuations, using appropriate statistical tools such as the coefficient of variation.

Findings The study established that there were considerable levels of variation in valuations, higher even than the international evidence in the literature.

The variation in both the archival and survey data analyses were about 34% and 64% respectively – far in excess of the margin error of ±5% suggested at the stakeholder consultation workshop for valuation practice in Ghana.

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“ These findings provide new

insights into property valuation practice in Ghana and highlight a need for future improvement

There were significant differences in the levels of the variation among all property types. However, variations in the valuations for fuel service stations and residential properties were particularly pronounced.

A number of possible causes for the high variability were identified, including paucity of property market data, lack of standardisation in applying valuation methods and the complexity of the properties themselves.

Although several property market data sources exist, access to reliable data for valuation practice was identified by the majority of valuers as a challenge. This can often be the case, as a consequence of the incomplete and scattered nature of property market data resulting from administrative lapses and from the confidentiality arrangements under which property transactions are undertaken.

The study found that, although there are concerns over valuation practices in Ghana, there is a dearth of empirical research and evidence into their impacts and causes.

These findings provide new insights into property valuation practice in Ghana and highlight a need for future improvement.

Regulators such as the Ghana Institution of Surveyors (GhIS), RICS and other stakeholders, such as CASLE, government and financial institutions, should therefore continue to initiate and progress efforts to improve practice.

Recommendations The findings also imply a need to develop a systematic approach to property market data collection, which will require practitioners to demonstrate care and consciousness in their data collection skills. Standardisation in valuation in Ghana is essential in order to reduce variation and other errors and improve practice.

Image © iStock

A property market database should also be established to support valuation practice in Ghana. With the backing of its members, the GhIS is in a better position to take the initiative in doing so, enabling private-sector investment in property market data collection and management.

Furthermore, the institution should promote discussion and collaboration between all property market data stakeholders, such as valuation practitioners, public institutions, financial institutions, estate developers, estate agents and property owners. They should focus on the need to build a robust property market database that can support real estate business and market activities, effective data collection and the establishment of standards for and access to good-quality property market data.

The use of a suitable property market data template could also help standardise and guide meaningful data collection for valuation purposes. However, a systematic approach will require valuers to undergo regular relevant training to develop and enhance their knowledge, skills and capabilities to ensure good-quality data collection and high-standard valuations.

The availability of reliable property market data will not by itself address all the probable causes of variation identified by this study, so further research to identify these, their impact on client confidence, and practical and sustainable solutions to address excessive variation should be central to efforts to improve practice in Ghana.

Last but not least, the findings of this study, their implications and recommendations may be useful to – and applicable in – other African countries, given the similarities of the nature of valuation practice and the challenges it presents. b Dr Kwasi Gyau Baffour Awuah is an academic and practitioner currently at the Faculty of Environment and Technology of the University of West of England, Bristol kwasi.baffourawuah@uwe.ac.uk

Jones Lang Lasalle, ‘Twenty African cities emerge as next frontier for commercial real estate growth between now and 2020’ http://bit.ly/1OzUc7n FTSE Global Markets, ‘Sub-Saharan African real estate: a growing asset class?’ http://bit.ly/1NysFZ4 PwC, An African perspective: Valuation methodology survey, 6th edition http://pwc.to/1TYUGoZ An Evaluation of Property Valuation Practice in Sub-Saharan Africa: A Case Study of Ghana http://bit.ly/1TopymU

Related competencies include Valuation, Property finance and funding, Investment management (including fund and portfolio management)

J U LY/A U G U S T 2 0 1 6 2 3

RICS L A N D JO U RN A L

SOIL

Tim Farewell reflects on the many different ways soil has an impact on our daily lives

Getting down to earth

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Recently, I’ve had the pleasure of working alongside amazing people who are protecting and distributing our water resources, growing food for our tables, looking after our roads, preventing gas leaks and even with those who are insuring our properties.

I love the passion that these people have for their work. They put in the hours to keep us fed, watered and safe. More and more, I’m seeing the value of cross-sectoral working – how one set of experiences speaks so clearly to a completely different industry.

All these people have something in common. Their work, their assets, their risks are related to the soil. Some of the links are more clear than others – for example, certain crops will grow better on particular soils and under the right weather conditions, roads on unstable soils are likely to fail more quickly and iron pipes in corrosive soils are likely to degrade faster. More complex soil relationships include the pathways for agri-chemicals through the soil and into watercourses or the potential 2 4 J U LY/A U G U S T 2 0 1 6

for cavities or sinkholes to form under roads and houses.

One of my favourite examples of slightly obscure soil risks involves a burst water main. The first that people knew about it was when the road started to flood. Along came the maintenance van to repair the main when, to their surprise, it fell through the road into a cavity formed by the highly pressured water in this sandy, loosely structured soil.

Unfortunately, the van also broke a gas main in the hole, so the whole area was evacuated. The basement of the local authority offices also flooded – ruining thousands of official records. All because of a sandy soil.

My point is that understanding the soil is really helpful if you want to protect your assets, customers and reputation, to maximise the long-term profitability of your land or reduce maintenance costs.

The problem is that soil is a horribly complex thing. There are more than 1,000 types of soil in the UK, and each of these has different properties, so it responds in different ways to the weather and to

the stresses that we place on it.

Soil is the foundation for most of our infrastructure and is itself a highly complex and responsive ecosystem. When we think about life in soil, we tend to picture earthworms or moles, but actually the soil is teeming with life.

Imagine a field full of sheep. If you put all those sheep together on a big set of scales, they would only equal 1% of the mass of all the microscopic animals in the soil under their feet . And there may be three different soils in that field, each of different depths, textures – sand, silt, clay, peat – and associated risks.

Given that soils are complicated and highly spatially variable, is it any wonder so few people really understand them?

Making sense of stagnogley podzols Scientists haven’t helped.

We have great names for our soils, such as “stagnogley podzols” or “paleo-argillic stagnohumic gley soils”. But to be frank, soil maps with labels like these don’t really give people the information

“ There are more than 1,000 soil types in the UK, each of which has different properties

that they need to make a good decision.

When I started my job here at Cranfield University about 12 years ago, I was exactly the same as many of our clients. I was a geologist turned geographic information systems specialist, charged with helping clients use soil maps to solve their problems. I too got lost in the terminology and complexity and would go home most nights with a question or two for my wife, a geographer, as well as spending most of my coffee breaks quizzing my brilliant colleagues, many of whom had four or more decades of field experience.

But over time what I learned was that, if we could create versions of soil maps that I could understand, there was a good chance our clients could understand them as well. So we set out to convert the raw soil maps into ones that indicated subsidence risk, crop suitability, or how easy it would be for a pesticide to leach into the groundwater.

So, when we are now approached by a new land manager, town planner or infrastructure operator, we can provide them with maps to answer their specific questions. Once they have the evidence, they don’t need to waste their time guessing what environmental risks they might face – or worse, ignoring them altogether – but can get on with their jobs.

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Ageing pipes are more susceptible to failure under the tree canopy

Subsidence One of the soil risks that I find most fascinating is ground movement and subsidence. Clay soils, for instance, have a far greater volume when wet than dry.

Houses, pipelines or roads built on clay are thus subject to greater ground movements and stresses in the summer and autumn when these soils shrink and swell with changing moisture conditions.

Our clay ground movement map answers the following two key questions.

1. How much can the soil shrink and swell?

2. Is the summer going to sufficiently hot and dry to dry the soil out?

To answer these, we assembled two maps – one of soil volumetric shrinkage potential and the other of potential soil moisture deficit. By combining them we created climate-adjusted subsidence models, such as our Natural Perils Directory, which are now in use by many Image © Tim Farewell

insurers and the majority of water companies.

Climate change is highly topical – and rightly so, as weather is already a key driver of infrastructure degradation and failure. So with colleagues Steve Hallett and Oliver Pritchard, I modelled how the subsidence risk might change over the next 15–35 years.

We spent about a year running climate simulations, and from the 40TB of data in the directory data sets calculated the future soil moisture deficits across the UK. Then we replaced our existing climate models with these future scenarios. We found that the subsidence risk is set to increase towards the 2030s and 2050s, particularly in the South East of England.

These long-term views on risk enable infrastructure companies to plan their network maintenance to ensure the highest resilience.

Trees Trees can affect subsidence risks by acting like pumps in

the soil, drying it out more quickly and deeply than grass or small vegetation would. So when I found out that aerial mapping firm Bluesky had a National Tree Map showing every tree over 3m in the UK, my interest was piqued.

So we created a new version of our subsidence model that incorporated the effect of local trees. Those of you who work with spatial data can imagine some of the struggles we had integrating millions of tree polygons into a full national soil map – but the results were encouraging.

We tested our models by assessing the impact of trees on Anglian Water’s mains failure rate. We found that trees hardly increased the rate of failure, but when combined with highly shrinkable soils, they boosted it by up to 40%.

In practice, trees in the urban environment don’t pose a great risk to water infrastructure in most places – in fact, they provide a huge number of benefits – but in

certain places ageing pipes are more susceptible to failure under the tree canopy (see image above).

Soil solutions I’m always encouraged when people recognise that they need to identify and mitigate environmental risks. It’s great to be able to help them.

If you want to understand the soil and how it affects you look at our free soils map (www.landis.org.uk/soilscapes) and get in touch if you have an environmental risk you’d like us to consider. We love helping people to solve practical problems. b Tim Farewell is Senior Research Fellow at Cranfield University t.s.farewell@cranfield.ac.uk

Related competencies include Land use and diversification, Management of the natural environment and landscape, Sustainability

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RICS L A N D JO U RN A L

SINKHOLES

Not so unpredictable

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Checking records is essential to identify areas that are prone to sinkholes before development starts, as Clive Edmonds explains

The occurrence of sinkholes receives regular media coverage, and stories often mention that the public or councils are very surprised by what has happened. But should sinkholes really be as surprising as they first seem?

People living in river valley floors or beside the coast are aware of the risk of flooding in bad weather. Similarly, people living in coalfields know there is some risk of land instability over old mines. Beyond this, though, such hazards are less thoroughly understood, although more information is available than ever before.

The vast majority of collapses are triggered either by rainfall or by the sudden release of large volumes of water into the ground from leaking or broken utility pipes.

The water saturates the ground, which increases the unit weight of a soil bridge over a void in the ground, changes the pore pressure and causes the internal erosion of fine particles.

Sinkholes and crown holes The cumulative effect is to destabilise the soil bridge, so it collapses downwards and triggers upward void migration to the surface, where it is referred to as a sinkhole.

Strictly speaking, however, the term should only be used for a surface collapse over an 2 6 J U LY/A U G U S T 2 0 1 6

The crown hole at Hemel Hempstead upward migrating void created by the natural dissolution of a soluble rock at depth, such as limestone, chalk, salt or gypsum. If the void is artificial – that is, a mining void – then the surface collapse is referred to as a crown hole.

It follows that knowing where there are soluble rocks underground or where mining has historically taken place can offer an indication of where sinkholes and crown holes are likely to form. Details of mapped geological strata can be obtained from online resources, such as those of the British Geological Survey, to determine where soluble rocks are present.

Data on old mine workings is more difficult to source; although there are specialist websites such as Subterranea Britannica and the National Association of Mining History Organisations, as well as helpful books, caving guides, council archives and historical maps. Alternatively, data on the occurrence of naturally formed and artificial voids can be obtained from commercial national databases, including the natural cavity and mining cavity databases held by Peter Brett Associates LLP. Recent, notably large crown holes occurred at Hemel Hempstead in February 2014 (see image above) and at

St Albans in October 2015, being about 10m and 13m in diameter respectively and around 5–6m deep.

Both collapses occurred at locations where Palaeogene Lambeth Group deposits – clays and sands – overlay Cretaceous-age chalk. With reference to historical maps, it is also apparent that both locations had been the site of former brickworks with kilns, dating from the early to mid-1800s onwards and falling into disuse by the 1890s.

In this period, it was common to use a ground mix of 75% clay and 25% chalk to produce durable bricks.

The chalk was obtained by sinking a shaft below the clay and extracting it by mining.

Once the brickworks became disused the shaft was sealed or infilled, but mine workings were often left open at depth.

Over time, such workings degrade, the old shaft becomes increasingly unstable and eventually the ground above falls into the mine, producing a collapse or crown hole at the surface.

Based on knowledge of the geology and historical land use, it is possible to foresee the potential of these collapses occurring.

While an RICS member carrying out a building inspection or an inspection Image © Peter Brett

for building control purposes may have local knowledge of past land instability, their training does not give them the specific understanding of geological and historical factors that actually determine the potential for ground movement in an area.

It may also be that new development extends across previously undeveloped areas with different geological conditions, so local knowledge is not necessarily applicable.

While it would be good practice to become broadly familiar with areas prone to subsidence, it would be best to direct housebuyers and developers to national databases so they themselves can check what is recorded and what the foreseeable geohazard risks are.

These resources will never pinpoint the exact position of the next sinkhole or crown hole, but they can at least indicate the areas that are most prone to subsidence, forewarning owners of existing development and alerting those who need to mitigate risks to new development. C Dr Clive Edmonds is a partner at Peter Brett Associates cedmonds@peterbrett.com

www.peterbrett.com www.bgs.ac.uk www.subbrit.org.uk www.namho.org.uk

Related competencies include Construction, technology and environmental services, Building pathology

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Valuation of land for affordable housing Explore the principles, methodology and process of how to value land for affordable housing through a review of VIP12, the Practice Statement, and the various factors affecting the assessment of value.

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• Describe the context in which affordable housing is delivered • Identify the regulation applicable to affordable housing • Analyse the impact of the accommodation mix and tenure • Comprehend and assess the inputs to a development appraisal

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BRIDPORT WASTE MANAGEMENT & RECYCLING CENTRE -

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RICS South West Awards 2016 - Highly Commended

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