The British Geological Survey
Suitability of the subsurface for
infiltration SuDS in Great Britain
Infiltration
constraints
Drainage
Ground
stability
Groundwater
protection
What are infiltration SuDS?
Infiltration SuDS are sustainable drainage systems (SuDS) that allow surface water to infiltrate to the ground. Examples include
soakaways, infiltration basins, infiltration trenches and permeable pavements.
Can infiltration SuDS be installed anywhere?
Infiltration SuDS can be installed where the ground conditions are suitable. Consideration must be given to the drainage potential,
the stability of the ground and the potential impact of infiltrating surface water to the quality of the receiving groundwater. Where
ground conditions are optimal, infiltration may form the principal drainage solution, elsewhere, it may provide part of the solution.
What does this document contain?
This document provides an indication of the suitability of the subsurface for infiltration SuDS in each unitary authority area within
Great Britain. It gives percentage area estimates for where the subsurface is: highly compatible for infiltration SuDS; probably
compatible for infiltration SuDS; where there are opportunities for bespoke infiltration SuDS, and where very significant constraints
are indicated. These classifications are described in Table 1.
How was the data derived?
The data was generated from the ‘Drainage Summary’ section of the Infiltration SuDS Map, which is derived from ten national British
Geological Survey digital maps including: GeoSure soluble rocks, GeoSure landslide hazards, DiGMapGB50 artificial ground, mining
hazards (non-coal) for SuDS, susceptibility to groundwater flooding, permeability indices, geological indicators of flooding, depth to
groundwater and the superficial thickness model. The majority of these maps are derived from the 1:50 000 scale digital geological
map (DiGMapGB50). The methodology used to derive this product is provided in the user guide (http://nora.nerc.ac.uk/16618/).
How were the statistics calculated?
The maps allow estimation of the extent to which the geology and hydrogeology are suitable for infiltration SuDS. For each map,
geologists predicted how suitable the ground would be for infiltration SuDS on that factor alone. All maps were then combined by
Table 1 Description of suitability classifications.
Classification
Description
Highly compatible for infiltration SuDS
Suitable for free-draining SuDS
Probably compatible for infiltration
SuDS
The subsurface is probably suitable for infiltration SuDS, but the design of the system
may be influenced by the ground conditions
Opportunities for bespoke infiltration
SuDS
The subsurface is potentially suitable for infiltration SuDS, but the design will be highly
influenced by the ground conditions
Very significant constraints
There is a very significant potential for one or more hazards associated with infiltration
reporting the most limiting suitability, thereby producing a map
with four categories, as per Table 1. For each Unitary Authority
area (as derived from the Ordnance Survey’s Boundary Line
dataset, version October 2012) the percentage area covered by
each of the above four categories was calculated.
Are the statistics a fair representation of the suitability of
the subsurface for infiltration?
The methodology used to create the Infiltration SuDS Map has
been peer-reviewed and validated (Dearden et al., in press).
Known limitations include the following omissions:
• presence of contaminated land;
• presence of coal mining hazards;
• areas of small-scale artisan mining may be underrepresented in areas that have not typically been mined;
• previous and current land-use;
• presence of perched groundwater tables, and
• presence of made ground where not recorded.
What can these statistics be used for?
These statistics have been released for general information and
for high-level strategic planning purposes.
The data suggest that the Unitary Authority area where I live
is not very suitable for infiltration. What does this mean?
Where the subsurface is sub-optimal for infiltration SuDS,
other types of sustainable drainage systems are likely to be
more appropriate. For example, instead of infiltrating water
to the ground, surface water can be temporarily stored in
ponds, wetlands, or in constructed underground chambers, or
alternatively if no other options are available, permission may be
given for surface water to be discharged to the drainage network.
Where can further information be found?
For further information, please visit the BGS SuDS webpages
(www.bgs.ac.uk/suds) or contact [email protected].
Is the data that these statistics are derived from available?
Information about obtaining the Infiltration SuDS Map is
available from: http://www.bgs.ac.uk/products/hydrogeology/
infiltrationSuds.html, http://shop.bgs.ac.uk/georeports/home.
cfm or by emailing [email protected].
References
Dearden, R A, Marchant, A P, and Royse, K R. (in press) Development of
a suitability map for infiltration sustainable drainage systems (SuDS).
Environmental Earth Sciences.
Dearden, R A. (2011) User Guide for the Infiltration SuDS Map Detailed.
British Geological Survey, Open Report OR/11/061.
For more information please contact:
Enquiries
British Geological Survey, Keyworth, Nottingham NG12 5GG
tel: 0115 936 3143 email: [email protected] www.bgs.ac.uk/suds
© NERC 2013. All rights reserved
Aberdeen City
Aberdeenshire
Angus
Argyll and Bute
Barking and Dagenham
Barnet
Barnsley
Bath and North East Somerset
Bedford
Bexley
Birmingham District
Blackburn with Darwen
Blackpool
Blaenau/Gwent
Bolton District
Bournemouth
Bracknell Forest
Bradford
Brent
Bridgend
Bromley
Buckinghamshire
Bury
Caerphilly
Calderdale District
Cambridgeshire County
Camden
Cardiff
Carmarthenshire
Casnewydd/Newport
Central Bedfordshire
Ceredigion
Chester East
Chester West and Chester
City of Brighton and Hove
City of Bristol
5
2
5
1
2
1
28
16
2
27
22
14
2
29
6
37
21
19
0
39
31
18
20
46
20
7
9
10
6
9
13
1
9
10
61
16
16
7
25
13
13
56
26
24
22
12
12
35
27
20
49
15
32
41
44
19
11
14
37
25
37
11
45
27
29
23
13
43
22
21
7
13
48
67
40
70
40
38
23
40
55
31
47
23
27
8
18
35
37
12
48
20
28
41
18
15
18
64
43
32
45
54
46
37
18
34
17
44
Very significant
constraints
indicated
Opportunities for
bespoke
infiltration SuDS
Probably
compatible for
infiltration SuDS
Compatible for
infiltration SuDS
Table 2 Suitability of the subsurface for infiltration SuDS within unitary authority areas (%) calculated from the ‘Drainage
Summary’ layer of the Infiltration SuDS Map: Aberdeen City to City of Bristol.
31
24
31
16
45
4
23
20
22
29
19
29
44
42
28
13
10
28
8
22
30
27
25
14
25
18
4
31
21
14
28
19
51
35
14
27
City of Derby
City of Edinburgh
City of Leicester
City of London
City of Nottingham
City of Peterborough
City of Plymouth
City of Southampton
City of Stoke
City of Wolverhampton
Clackmannanshire
Conwy
Cornwall
County Durham
Coventry District
Croydon
Cumbria
Darlington
Denbighshire
Derbyshire
Devon
Doncaster
Dorset
Dudley District
Dumfries and Galloway
Dundee City
Ealing
East Ayrshire
East Dunbartonshire
East Lothian
East Renfrewshire
East Riding
East Sussex
Enfield
Essex CC
Falkirk
2
5
1
10
22
8
4
2
7
12
7
3
3
13
13
26
8
5
5
28
19
18
31
18
2
2
1
3
3
8
0
20
26
1
4
2
3
40
18
17
9
5
3
45
36
22
46
26
40
50
33
5
30
36
35
24
24
10
12
23
49
50
26
45
50
51
56
14
17
36
43
40
64
10
47
50
37
60
75
21
6
26
10
47
48
20
35
23
42
33
33
26
45
57
32
19
29
11
54
32
14
9
28
49
47
35
37
10
Very significant
constraints
indicated
Opportunities for
bespoke
infiltration SuDS
Probably
compatible for
infiltration SuDS
Compatible for
infiltration SuDS
Table 3 Suitability of the subsurface for infiltration SuDS within unitary authority areas (%) calculated from the ‘Drainage
Summary’ layer of the Infiltration SuDS Map: City of Derby to Falkirk.
31
44
34
23
32
28
18
32
52
40
36
24
9
17
19
46
20
26
27
23
12
15
25
40
21
37
19
21
33
32
16
17
10
28
16
48
Fife
Flintshire
Gateshead
Glasgow City
Gloucestershire
Greater London Authorities
Greenwich
Gwynedd
Hackney
Halton
Hammersmith and Fulham
Hampshire
Haringey
Harrow
Hartlepool
Havering
Herefordshire
Hertfordshire
Highland
Hillingdon
Hounslow
Hull
Inverclyde
Isle of Anglesey
Isle of Wight
Islington
Kensington and Chelsea
Kent
Kingston upon Thames
Kirklees
Knowsley
Lambeth
Lancashire
Leeds
Leicestershire
Lewisham
4
7
14
5
31
8
16
3
4
12
0
34
1
0
5
5
13
19
1
1
1
0
7
2
21
6
2
19
1
29
4
1
10
26
5
4
45
29
36
38
10
20
9
20
22
21
2
21
37
41
35
32
45
34
11
24
2
4
49
14
28
32
9
10
5
28
26
6
29
33
22
6
15
20
20
6
40
39
45
49
40
54
64
24
55
55
50
23
22
23
66
41
47
93
23
51
34
49
45
48
70
17
59
56
40
17
51
59
Very significant
constraints
indicated
Opportunities for
bespoke
infiltration SuDS
Probably
compatible for
infiltration SuDS
Compatible for
infiltration SuDS
Table 4 Suitability of the subsurface for infiltration SuDS within unitary authority areas (%) calculated from the ‘Drainage
Summary’ layer of the Infiltration SuDS Map: Fife to Lewisham.
36
44
30
51
20
33
30
27
34
13
35
22
6
3
11
41
20
24
22
35
49
3
20
33
17
12
44
22
24
26
12
37
21
23
22
30
Lincolnshire
Liverpool
Luton
Manchester District
Medway
Merthyr Tydfil
Merton
Middlesbrough
Midlothian
Milton Keynes
Monmouthshire
Moray
Na H-Eileanan an Iar
North East Lincolnshire
Neath and Port Talbot
Newcastle Upon Tyne
Newham
Norfolk
North Ayrshire
North Lincolnshire
North Somerset
North Tyneside
North Yorkshire
Northamptonshire
Northumberland
Nottinghamshire
Oldham
Orkney Islands
Oxfordshire
Pembrokeshire
Perth and Kinross
Poole
Portsmouth
Powys
Reading
Redbridge
11
15
24
6
11
30
1
1
10
4
17
7
0
6
33
2
0
17
7
10
28
1
16
13
11
16
23
6
22
9
3
22
8
4
9
2
10
17
19
25
9
24
9
27
52
37
43
8
0
26
20
33
5
27
34
12
5
29
28
27
44
10
29
44
14
22
17
19
5
34
24
29
57
50
32
50
51
12
38
36
11
35
20
60
96
55
19
30
41
46
33
34
55
29
35
45
29
48
25
30
40
55
53
29
39
42
25
29
Very significant
constraints
indicated
Opportunities for
bespoke
infiltration SuDS
Probably
compatible for
infiltration SuDS
Compatible for
infiltration SuDS
Table 5 Suitability of the subsurface for infiltration SuDS within unitary authority areas (%) calculated from the ‘Drainage
Summary’ layer of the Infiltration SuDS Map: Lincolnshire to Redbridge.
22
18
26
19
29
34
52
36
28
24
19
25
3
13
28
35
53
10
26
44
12
41
21
15
16
25
23
19
24
13
26
31
48
20
42
39
Redcar and Cleveland
Renfrewshire
Rhondda
Richmond upon Thames
Rochdale
Rotherham
Rutland
Salford
Sandwell
Scottish Borders
Sefton
Sheffield
Shetland Islands
Shropshire
Slough
Solihull
Somerset
South Ayrshire
South Gloucestershire
South Lanarkshire
South Tyneside
Southend-on-Sea
Southwark
St Helens
Staffordshire
Stockport
Stockton-on-Tees
Suffolk
Sunderland
Surrey
Sutton
Swansea
Swindon
Tameside
Telford and Wrekin
Thurrock
6
2
30
6
28
34
22
9
18
3
5
26
3
10
1
8
19
2
17
6
4
2
0
7
18
8
3
13
8
23
25
22
28
16
13
4
40
47
25
14
27
27
17
17
18
64
8
30
6
36
3
18
13
33
14
51
11
17
1
34
19
44
35
40
28
11
3
27
8
42
19
16
18
17
17
40
14
20
47
45
17
13
57
26
73
29
41
55
51
48
61
20
68
67
66
35
37
34
44
41
51
43
29
16
51
20
31
30
Very significant
constraints
indicated
Opportunities for
bespoke
infiltration SuDS
Probably
compatible for
infiltration SuDS
Compatible for
infiltration SuDS
Table 6 Suitability of the subsurface for infiltration SuDS within unitary authority areas (%) calculated from the ‘Drainage
Summary’ layer of the Infiltration SuDS Map: Redcar and Cleveland to Thurrock.
36
34
28
40
31
19
14
29
47
20
31
18
19
25
56
18
17
17
9
23
16
14
33
24
26
14
18
7
12
23
43
35
14
22
37
50
Torbay
Torfaen
Tower Hamlets
Trafford
Vale of Glamorgan
West Berkshire
West Midlands
Wakefield
Walsall
Waltham Forest
Wandsworth
Warrington
Warwickshire
West Dunbartonshire
West Lothian
West Sussex
Westminster
Wigan
Wiltshire
Windsor and Maidenhead
Wirral
Wokingham
Worcestershire
Wrexham
York
35
25
7
8
18
28
16
24
13
1
6
5
6
11
2
26
6
4
45
12
10
13
9
8
4
39
26
13
11
45
22
20
25
27
32
5
26
14
37
42
8
23
38
7
19
19
24
15
35
9
16
17
47
43
19
16
37
27
26
46
49
53
61
15
18
45
50
32
32
33
48
32
55
25
80
Very significant
constraints
indicated
Opportunities for
bespoke
infiltration SuDS
Probably
compatible for
infiltration SuDS
Compatible for
infiltration SuDS
Table 7 Suitability of the subsurface for infiltration SuDS within unitary authority areas (%) calculated from the ‘Drainage
Summary’ layer of the Infiltration SuDS Map: Torbay to York.
10
32
33
38
18
34
27
23
34
21
39
16
18
38
37
21
21
26
16
36
23
31
22
33
7