OR/15/002 Appendix 3: Tables for vulnerability classification

Ó Dochartaigh B É,Doce D D, Rutter H K and MacDonald A M. 2015. User Guide: Groundwater Vulnerability (Scotland) GIS dataset, Version 2. Revised Report. British Geological Survey Internal Report, OR/15/002.

These tables are used, with the rules in Section 3, to define the assigned vulnerability class for each given combination of input parameters. They have been slightly modified from the tables used to derive Version 1 of the groundwater vulnerability dataset (Ball et al. 2004), as follows:

• Vulnerability Class 4 has been subdivided throughout into two sub-classes, Class 4a and Class 4b. Class 4a includes areas where superficial deposits have low permeability; Class 4b includes areas where superficial deposits have moderate or high permeability. The tables have been amended to reflect this.
• Because of this change, one table (the original Table 2) has been removed as no longer needed.

The following abbreviations and legend are used in the tables:

VH = Very High permeability

H = High permeability

M = Moderate permeability

L = Low permeability

n/a = not applicable

Vulnerability class:

Highest ......................................................................................................................................Lowest
5	4a	4b	3	2	1

Table A1 Bedrock Flow Type = Fractured; no soil or superficial deposits mapped (Rule 3).

	Fractured bedrock, no soil or superficial deposits
Fractured bedrock, no soil or superficial deposits	5

Table A2 Bedrock Flow Type = Fractured; soil present; no superficial deposits mapped (Rule 4)

		Superficial deposits thickness (m)
		<1
Soil permeability	H	5
	M	5
	L	4a

		Superficial deposits thickness (m)
		1-3	3-10	10-30	> 30
Superficial deposits permeability at surface	VH or H	4a	4a	3	2
	M	4a	3	2	1
	L	4b	2	1	1

		Superficial deposits thickness (m)
		<3	3-10	10-30	> 30
Superficial deposits permeability at surface	VH or H	n/a	1	1	1
	M	n/a	1	1	1
	L	n/a	1	1	1

		Depth to Water in Superficial Deposits (m)
		<3	3-10	10-30	> 30
Superficial deposits permeability at surface	VH or H	4a	4a	3	2

		Depth to Water in Bedrock (m)
		0-3	3-10	10-30	30+
Bedrock permeability	VH or H	5	5	4a	style="background-color:#9acd32 3
	M	5	4a	style="background-color:#9acd32 3	style="background-color:#9acd32 3
	L	5	4a	style="background-color:#9acd32 3	style="background-color:#9acd32 3

		Depth to Water in Bedrock (m)
		0-3	3-10	10-30	30+
Bedrock permeability	VH or H	5	5	4a	style="background-color:#9acd32 3
	M	5	4a	style="background-color:#9acd32 3	#9acd32 3
	L	5	4a	style="background-color:#9acd32 3	style="background-color:#9acd32 3

		Depth to Water in Bedrock (m)
		0-3	3-10	10-30	30+
Bedrock permeability	VH or H	4a	4a	3	3
	M	4a	3	3	3
	L	4a	3	3	3

Depth to Water in Bedrock (m)	Bedrock permeability	High permeability superficial deposits thickness (m)
		<3	3-10	10-30	>30	=>5m clay in sequence
<10 m	VH or H	4a	4a	3	2	1
	M	4a	3	3	2	1
	L	4a	3	2	2	1
10-30 m	VH or H	4a	3	3	2	1
	M	3	2	2	2	1
	L	3	2	2	1	1
>30 m	VH or H	3	3	2	2	1
	M	3	2	2	1	1
	L	3	2	1	1	1

Depth to Water in Bedrock (m)	Bedroc permeability	Moderate permeability superficial deposits thickness (m)
		<3	3-10	10-30	>30	=>5m clay in sequence
width="100pt" | <10 m	VH or H	4a	3	2	2	1
	M	4a	3	2	2	1
	L	3	2	2	1	1
10-30 m	VH or H	4a	3	2	2	1
	M	3	2	2	2	1
	L	3	2	1	1	1
>30 m	VH or H	3	2	2	2	1
	M	3	2	2	1	1
	L	3	1	1	1	1

Depth to Water in Bedrock (m)	Bedrock perm eability	Low permeability superficial deposits thickness (m)
		<3	3-10	10-30	>30	=>5m clay in sequence
p align="center"><10 m	VH or H	4b	2	1	1	1
	M	4b	2	1	1	1
	L	3	2	1	1	1
10-30 m	VH or H	3	2	1	1	1
	M	3	2	1	1	1
	L	3	1	1	1	1
>30 m	VH or H	3	2	1	1	1
	M	3	1	1	1	1
	L	3	1	1	1	1