1.1.2 The methodology set out in this TAG Unit provides an appraisal framework for taking the outputs of the environmental impact assessment process (which may be presented in an environmental statement) and analysing the key information of relevance to the water environment. The guidance does not provide information on undertaking the impact assessment process itself, rather it provides a method by which the significance of the identified potential impacts can be appraised consistently by decision makers. It is based on guidance prepared by the Environment Agency and builds on the water assessment methodology in DMRB 11.3.10.

1.2 Approach

1.2.1 The approach to appraisal is the same for all levels of study, and comprises four stages:

review of the activities proposed and the potential impacts identified;
appraisal of the importance of the water environment within the study area;
appraisal of the potential impacts of the proposal on the important attributes; and
final assessment score.

1.2.2 The methodology for describing the importance of the water environment (Stage 2) is the same at all scales (although the level of detail obtained will vary). However, the assessment of impact magnitude and significance (Stage 3) is conducted differently for route and area studies, reflecting the available data for each study type. The differing methods for assessing impacts make it necessary for different worksheets to be completed to record the appraisal information and for different criteria for generating a final assessment score (Stage 4). The appraisal for route based studies is recorded in Worksheet 1 (provided at the end of the TAG Unit) while that for area strategic based studies is recorded in Worksheet 2 (also provided at the end of the TAG Unit). This guidance initially provides guidance on Stages 1 to 4 for route based studies and then provides separate guidance for Stage 3 and Stage 4 for area based studies.

1.2.3 Stages 1 to 3 of the appraisal may have a risk component, where the exact impacts of the scheme are unknown because of uncertainties in exposure and effect. Where uncertainties of this sort are identified in the environmental impact assessment they should be made explicit in the appraisal process. As mentioned previously it is recommended that the precautionary principle be employed. However, it should also be remembered that at more strategic levels, where there is likely to be greater uncertainty regarding the potential impacts, there still remains the opportunity to incorporate mitigation measures when the proposals are considered in more detail. In these cases it will be necessary to determine whether the potential risks identified justify invoking the precautionary principle, or whether it will be sufficient to flag them up as issues for more detailed consideration at a later stage. The treatment of uncertainty is discussed further in Stage 3.

Stage 1: Review of the Activities Proposed and the Potential Impacts Identified

1.2.4 Stage 1 of the methodology is aimed at obtaining information relating to the potential impacts of the proposal and the scale over which they are significant. This enables the size of the study area, and the water features in this area that may be affected, to be determined. During Stage 1 it will also be possible to determine whether the study fits into the spatially detailed or spatially aggregate category and consequently the appropriate methodologies to be used in Stage 3 and Stage 4 of the appraisal.

1.2.5 The nature of the proposal may vary widely from the introduction of road traffic calming measures to the construction of a new transport route, for example. These measures will obviously have different potential impacts on the water environment. A useful distinction is made between impacts arising from construction of new transport infrastructure (e.g. an upgraded rail line, road widening or car parks), and changes in the use pattern of existing infrastructure (such as promotion of cycling or walking, improvements to bus services or traffic flow control technologies). Any transport proposal should fit into one, or both, of these categories.

1.2.6 The potential impacts arising from the proposals should be identified during the environmental impact assessment process. Once the potential impacts of the proposal have been identified its zone of influence can be determined. For releases to a watercourse, for example, this may be the length of river over which a noticeable change in quality is predicted, while for the creation of new hardstanding, it may represent the area which could be exposed to an increased flood risk.

Stage 2: Appraisal of the Value of the Water Environment within the Study Area

1.2.7 The value of the water environment within the study area is characterised by identifying and analysing its attributes. This process is consistent with an environmental capital approach because the water environment is being assessed in terms of the services it provides rather than on purely measurable criteria. No prescriptive guidance is given for determining the value of different attributes, because this will depend on the location of the proposal and factors such as quality, scale, rarity and substitutability (these are described in more detail below). However, because the majority of the available water data is based on its quality, these can help to indicate the value of the attributes or services provided by a water feature.

1.2.8 Table 1 provides information on the key features of the water environment, their attributes and the indicators to determine their 'quality' as a water feature. Table 2 provides guidance for estimating the importance of an attribute based on the indicators recorded in Worksheet 1 (quality, scale, rarity and substitutability etc.).

1.2.9 Indicators. The indicators used to make a judgement on the importance of an attribute under consideration include quality, scale, rarity and substitutability. Where all other factors are equal, and explicit, it may be possible to make judgements of value based on the quality indicators provided (e.g. GQA Grade A is more important than GQA Grade C). However, this level of consistency will rarely be possible, because in the majority of situations the other indicators described below (scale, rarity and substitutability) will also have important roles in determining importance. For large study areas quality data may be the only importance indicator available, because the large amount of qualitative data required to assess other indicators may not be practically obtainable.

Quality - this criterion provides a measure of the physical condition of the attribute. Table 1 provides guidance on available indicators of quality that can be used for specific attributes. The Environment Agency maintains data on these quality indicators at a national, or regional, level, usually in digital format.
Scale - this allows consideration of the geographical scale at which the attribute matters to both policy makers and stakeholders, at all levels. It is unlikely that any water features will have significance at a national or global scale (assuming that biodiversity interests are appraised independently), however major aquifers, floodplains, or fisheries may be important at a regional scale. It is important to consider the scale at which each attribute matters, rather than the feature as a whole, because subsequent appraisals of the rarity, substitutability, and importance will assess the attribute at this determined scale. Generally, the greater the scale at which the attribute is valued, the greater its importance. However, this will not always be the case. For example, where the feature is of great value to a community as the only source of potable water, or for providing significant proportion of local employment.
Rarity - allows consideration of whether the water attribute being evaluated is commonplace or scarce, at the scale at which it matters. For example an attribute that is abundant nationally (such as potable water) will be of high importance if it is locally rare.
Substitutability - allows consideration of whether water attributes are replaceable over a given time frame. The significance of the length of time before substitution could be achieved will be linked to the urgency with which the attribute is required (a long time frame may be acceptable for inessential attributes such as recreation, but less so for others, such as supply of potable water). Again the potential for substitution of the attribute should be considered in relation to scale at which it matters, but should also consider the risks of failure. Different attributes of the same feature may differ in their potential for substitution. Limited potential for substitution recognises that while it is theoretically possible for most water attributes to be substituted by some means, this will not always be viable within the funds of the proposal. Substitution should therefore be considered in terms of whether it is feasible rather than whether it is possible. Where no information is available relating to the substitutability of the attribute, it should be assumed that no substitution is possible.

Table 1 Water Features, Their Attributes and Indicators of Quality

Feature	Attribute/Service	Indicator of quality	Possible measure
River	Water Supply	Use for water supply (potable, industrial or agricultural)	- Location and number of abstraction points - Volume of water abstracted - Use of water (potable most important)
		Chemical water quality	- Existing chemical GQA grade (A/B=good, C/D=fair, and E=poor, F=bad) - Likelihood of a change in grade arising (+ve or ve)
	Transport and dilution of waste products	Presence of surface water discharge points	- Location and number of discharge points - Volume of effluent discharged
		Contribution of discharges to total river flow	- Proportion of flow made up by effluent at different times of the year
	Biodiversity	Biological water quality	- Existing biological GQA grade (A/B=good, C/D=fair, and E=poor, F=bad) - Likelihood of a change in grade arising (+ve or ve)
		Fisheries quality	- EC Fishery designation (Salmonid, Cyprinid or undesignated)
		Conservation value of river corridor¹	- Results of River Habitat Survey - Presence of designations (e.g. SSSI, NNR, LNR, SINCs) - Presence of protected species or BAP species
	Aesthetics	Contribution to landscape character and quality²	- Results of river landscape assessment
	Cultural heritage	Presence of historic features associated with river³	- Results of heritage assessment - Presence of designations (e.g. SAMs, listed buildings)
	Recreation	Riverside access	- Presence of route and importance (i.e. is it a nation or strategic route, such as the Thames Path)
		Use of river for recreation	- Presence of facilities and clubs for using the river environment - Use for angling (number of clubs / membership)
	Value to economy	Value of the uses of the river (e.g. commercial fishing, abstractions, discharges, navigation, leisure and riverside development land)	- Value to local economy (e.g. employment, relative property prices, cost of alternatives, etc.)
	Conveyance of flow and material	Presence of watercourses	- Number and size of watercourses - Existing flood risk
Floodplain	Conveyance of flood flows	Presence of floodplain	- Existing flood risk/flood return period
		Flood flow routes	- Location / importance of flood flow routes
	Biodiversity	Conservation value of river corridor¹	- Results of River Habitat Survey - Presence of designations (e.g. SSSI, NNR, LNR, SINCs) - Presence of protected species or BAP species
	Aesthetics	Contribution to landscape character and quality²	- Results of river landscape assessment
Groundwater	Water supply	Use for water supply (potable, industrial or agricultural)	- Location and number of abstraction points - Volume of water abstracted - Use of water (potable most important)
		Groundwater vulnerability	- Location and grade of source protection zone - Classification of aquifer vulnerability
	Transport and dilution of waste products	Presence of discharge points	- Location and number of discharge points - Volume of effluent discharged
	Value to economy	Value of the uses of the groundwater (e.g. abstractions and discharges)	- Value to local economy (e.g. employment, cost of alternatives, etc.)
	Biodiversity	Conservation value of areas fed by groundwater¹	- Results of River Habitat Survey - Presence of designations (e.g. SSSI, NNR, LNR, SINCs) - Presence of protected species or BAP species
	Conveyance of flood flows	Flow routes	- Location and importance of flow routes
		Groundwater levels	- Charges in levels and recharge
Sea and Estuaries	Water supply	Use for water supply	- Location and number of abstraction points - Volume of water abstracted
	Transport and dilution of waste products	Presence of discharge points	- Location and number of discharge points - Volume of effluent discharged
	Biodiversity	Water quality	- Chemical and biological quality (data availability will be variable)
		Fisheries quality	- Results of surveys etc (numbers / biomass of species and individuals)
		Invertebrate populations	- Results of surveys etc (numbers / biomass of species and individuals)
		Conservation value of marine/estuary environment¹	- Presence of designations (e.g. MNR, SSSI, NNR, LNR, SINCs) - Presence of protected species or BAP species
	Aesthetics	Contribution to landscape character and quality²	- Results of river landscape assessment
	Cultural heritage	Presence of historic features associated with sea/estuary³	- Results of heritage assessment - Presence of designations (e.g. SAMs, listed buildings)
	Recreation	Bathing beaches	- Compliance with EC water bathing standards
		Other recreation uses	- Presence of facilities and clubs - Use for angling (number of clubs / membership)
	Value to economy	Value of the uses of the sea/estuary (e.g. commercial fishing, abstractions, discharges, navigation, leisure and waterside development land)	- Value to local economy (e.g. employment, relative property prices, cost of alternatives, etc.)
Stillwaters (Lakes and Ponds)	Biodiversity	Water quality Conservation value of stillwaters¹	- Classification system to be developed - Presence of designations (e.g. SSSI, NNR, LNR, SINCs) - Presence of protected species or BAP species
		Fisheries quality	- Results of surveys etc (numbers / biomass of species and individuals)
		Invertebrate populations	- Results of surveys etc (numbers / biomass of species and individuals)
	Aesthetics	Contribution to landscape character and quality²	- Results of river landscape assessment
	Recreation	Use of still water for recreation	- Presence of facilities and clubs for using lake/pond - Use for angling (number of clubs / membership)

Notes: 1 Include in Biodiversity sub-objective, 2 Include in Landscape sub-objective, 3 Include in Heritage sub-objective

Table 2 Guidance for Estimating the Importance of Environmental Attributes

Importance	Criteria	Examples
Very High	attribute with a high quality and rarity, regional or national scale and limited potential for substitution	Aquifer providing potable water to a large population EC designated Salmonid fishery
High	attribute with a high quality and rarity, local scale and limited potential for substitutionattribute with a medium quality and rarity, regional or national scale and limited potential for substitution	GQA Grade A reach of riveraquifer providing potable water to a small population EC designated Cyprinid fishery
Medium	Attribute with a medium quality and rarity, local scale and limited potential for substitutionattribute with a low quality and rarity, regional or national scale and limited potential for substitution	GQA Grade B / C reach or river Aquifer providing abstraction water for agricultural or industrial use
Low	attribute with a low quality and rarity, local scale and limited potential for substitution	Floodplain with limited existing development

1.2.10 Stage 2 enables the completion of the environmental capital sections (features, attributes, and importance criteria) of Worksheet 1 for project and spatially detailed based corridor studies and Worksheet 2 for strategic and spatially aggregate based corridor studies.

Available Data

1.2.11 The geographic scale of the proposal will determine the availability of data more than the strategic scale. Nationally the Environment Agency has digital datasets available for Chemical GQA, Rivers and Catchment Areas, Groundwater Vulnerability, Source Protection Zones, EC Designated Fisheries, and Floodrisk zones.

1.2.12 It should be possible to use these at both a small and large scale in conjunction with GIS data on the proposal. The degree to which qualitative interpretation of water feature data (such as rigorous identification of attributes and their scale, rarity and substitutability) can be made will vary with the size of the study area. Because strategic studies are more likely to cover a large area, they will be less amenable to interpretation of this sort. However, where the study area is small it should be possible to comment on the importance of specific attributes of the water features identified.

Stage 3: Appraisal of the Potential Impacts of the Proposal on Valuable Attributes

1.2.13 The potential impacts of a transport proposal should be considered for each valuable water attribute identified. The impacts of a specific scheme will be identified during the environmental impact assessment process and these will then be used in the appraisal. Potential impacts are appraised in two steps, estimation of impact magnitude and estimation of impact significance.

Magnitude

1.2.14 At these levels it should be possible to identify the potential impacts (both positive and negative) of the route based proposals to a reasonable level of detail. Their magnitude can be determined by appraising the effects predicted for exposed attributes. Table 3 provides guidance on the magnitude criteria for potential impacts, with some examples. The magnitude of the potential impact is completely independent of the value of the attribute affected and therefore gives no indication of significance when considered alone.

Table 3 Criteria for Determining Impact Magnitude

Magnitude	Criteria	Example
Major	Results in loss of attribute	loss of EC designated Salmonid fishery change in GQA grade of river reach compromise employment source loss of flood storage/increased flood risk pollution of potable source of abstraction
Moderate	Results in impact on integrity of attribute or loss of part of attribute	loss in productivity of a fishery contribution of a significant proportion of the effluent in the receiving river, but insufficient to change its GQA grade reduction in the economic value of the feature
Minor	Results in minor impact on attribute	measurable changes in attribute, but of limited size and/or proportion
Negligible	Results in an impact on attribute but of insufficient magnitude to affect the use/integrity	discharges to watercourse but no significant loss in quality, fishery productivity or biodiversityno significant impact on the economic value of the feature no increase in flood risk

1.2.15 For each attribute identified the magnitude of the impact should be recorded in the magnitude column of Worksheet 1.

1.2.16 The significance of a potential impact is estimated by its magnitude and the importance of the affected attribute. Table 4 provides guidance for determining the significance of a potential impact based on its magnitude and the importance of the attribute.

Table 4: Criteria for Estimating the Significance of Potential Impacts

	Importance of attribute
Magnitude of potential impact	Very High	High	Medium	Low
Major	Very Significant	Highly Significant	Significant	Low Significance
Moderate	Highly Significant	Significant	Low Significance	Insignificant
Minor	Significant	Low Significance	Insignificant	Insignificant
Negligible	Low Significance	Insignificant	Insignificant	Insignificant

1.2.17 Where the predicted potential impact is highly uncertain as a result of lack of information or insufficient design details, this should be considered as part of the appraisal. If a more significant, but less probable impact is identified, then this may warrant a higher classification to take account of the potential for a more significant impact. Uncertainty will require the use of best judgement by the appraiser, based on the relative probability of the possible outcomes and their significance.

1.2.18 The significance of the impact on each attribute should be recorded in the Significance column of Worksheet 1.

Stage 4: Overall Assessment Score

1.2.19 The overall impacts of the proposal are summarised by a qualitative comment and an overall assessment 'score' entered in the relevant worksheet. For route based studies, the assessment score is on a textual seven-point scale (Slight, Moderate, and Large, positive and negative impacts; and Neutral).

1.2.20 It is unlikely that the construction of a new transport route (rail or road) will have a net positive impact on the water environment, although it may help to achieve benefits (e.g. upgraded pollution prevention measures on the new route, or carrying river restoration as part of a scheme). Proposals aimed at modal or route shift have greater potential for beneficial impacts by reducing or redistributing traffic in areas where it is currently causing adverse impacts.

1.2.21 Where a proposal affects a number of sites a judgement will need to be made concerning the cumulative impacts of the proposal. The proposal should be classified as a whole and the potential impacts on individual features, or attributes, combined in the overall classification. In some cases the impacts on one important attribute will be sufficient for a moderate or severe adverse impact classification for the whole proposal, while for others a series of cumulative or conflicting impacts will need to be considered.

1.2.22 It is not useful to provide prescriptive guidance for determining an assessment score, because each combination of positive and negative impacts will be different. Where more than one feature is involved, judgements about the overall assessment score will be required, to compare the relative significance of one group of impacts with another. The indicative criteria below can be used for guidance, but experience and an understanding of the proposal will also be required. The qualitative comment box should be used to provide further information on the basis for reaching the assessment score for that option.

1.2.23 Where a proposal is under continuing development and refinement it is possible (or even probable) that the assessment score will change. This may be a result of changes in the proposal, or the agreement of certain mitigation options to moderate any impacts identified at an earlier stage. Therefore the assessment score given for the proposal should be based on current understanding of its content, or expected mitigation, rather than on assumption that measures to counter any adverse impacts identified will be incorporated if this has not been agreed.

1.2.24 The scoring categories described below should not be considered as comparable with those determined for other environmental sub-objectives, due to qualitative differences between them.

1.2.25 The qualitative box on the Appraisal Summary Table should state whether features and elements present in the water environment are typical of the locality and summarise the overall effect of the project or proposal on the water environment.

1.3 Methodology for Strategies

1.3.1 Stages 1 and 2 of the methodology for area studies will be the same as that for appraisal of studies where route information is known. However, the level of detail available on the potential impacts will be considerably less when no route specific information is available. Although data on the importance of environmental attributes may be relatively detailed, the available impact data may be limited to changes in vehicle kilometerage and gross landtake within an area. In these cases it may only be possible to say whether an option has a positive or negative effect within the sub-area being considered.

Stage 3: Appraisal of the Potential Impacts of the Proposal on Valuable Attributes

1.3.2 Impact significance is determined using a series of environmental objectives for the region affected by the proposal. These objectives are determined in two ways; firstly, using national and regional environmental policy objectives; and secondly, using sub-area specific objectives determined from the review of the environmental capital in the area.

1.3.3 Because of the lack of impact detail available at the strategic level, impact significance can only be presented as supporting or contradicting the objectives which apply to it. Examples of objectives based on a review of environmental capital are:

the prevention of additional hardstanding in an area where there is an existing flood risk;
reduction in traffic flows in areas with particularly important surface waters; and
redirection of hazardous waste movements away from areas of high groundwater vulnerability.

1.3.4 Where an option being considered contradicts a national, regional or environmental capital derived objective this is recorded in Worksheet 2 as a negative impact. Where it supports an objective this should be recorded as a positive impact, while if there is no discernible impact arising from the proposal this should be recorded as neutral.

Stage 4: Overall Assessment Score

1.3.5 For area based proposals of this scale, the assessment score will necessarily be much less precise than for studies where specific route options have been defined. The assessment score derived is based on the degree to which the proposal supports or contradicts the environmental and specific water related objectives that are relevant to the study area. The proposals are assessed using a four-point scale (significant positive, significant negative, mixed and insignificant contributions). The uncertainty in impact evaluation makes it more appropriate to use a mixed contribution 'score' rather than slight, or moderate positive and negative scores, because it avoids making an unrealistically confident prediction of impacts which might be taken out of context. In the case of a mixed contribution score, the qualitative comment box will be important for identifying the positive and negative impacts considered.

1.3.6 Clearly, in many cases the proposal will have mixed impacts and it will be necessary to compare the relative and cumulative importance of different impacts. This requires the appraiser to use judgement based on their experience and understanding of the proposal. Some indicative criteria are presented below to assist in appraisal. The qualitative comments box should be used to provide further information on the basis for reaching the assessment score for that option.

Significant Positive Contribution - where the proposal may result in a positive impact on the water environment, because it either:
- supports the water relevant objectives which apply to the study area; or
- has mixed positive and negative impacts, but the positive impacts are much more significant than the negative impacts (this requires judgement and should be justified in the qualitative comments box).
Significant Negative Contribution - where the proposal may result in a negative impact on the water environment, because it either:
- contradicts the relevant objectives which apply to the study area; or
- has mixed positive and negative impact, but the negative impacts are much more significant than the positive impacts (this requires judgement and should be justified in the qualitative comments box).
Mixed Contribution - this score should be used where the project has positive and negative impacts, which cannot be considered insignificant, but do not clearly indicate that the overall impact will be significantly positive or negative.
Insignificant Contribution - where the project has no significant impacts on water related objectives for the study area.

Table 5 Water Environment - Definitions of Overall Assessment Scores

Score	Comment
Large Beneficial Impact	It is extremely unlikely that any proposal incorporating the construction of a new transport route (road or rail) would fit into this category. However, proposals could have a large positive impact if it is predicted that it will result in a very or highly significant improvement to a water attribute(s), with insignificant adverse impacts on other water attributes.
Moderate Beneficial Impact	Where the proposal provides an opportunity to enhance the water environment, because it results in predicted: significant improvements for at least one water attribute, with insignificant adverse impacts on other attributes; very or highly significant improvements, but with some adverse impacts of a much lower significance. The predicted improvements achieved by the proposal should greatly outweigh any potential negative impacts.
Slight Beneficial Impact	Where the proposal provides an opportunity to enhance the water environment, because it provides improvements in water attributes which are of greater significance than the adverse effects.
Neutral	Where the net impact of the proposals is neutral, because: they have no appreciable effect, either positive or negative, on the identified attributes; the proposals would result in a combination of effects, some positive and some negative, which balance to give an overall neutral impact. In most cases these will be slight or moderate positive and negative impacts. It may be possible to balance impacts of greater significance, however, in these cases great care will be required to ensure that the impacts are comparable in terms of their potential environmental impacts and the perception of these impacts.
Slight Adverse Impacts	Where the proposal may result in a degradation of the water environment, because the predicted adverse impacts are of greater significance than the predicted improvements.
Moderate Adverse Impacts	Where the proposal may result in a degradation of the water environment, because it results in predicted: significant adverse impacts on at least one attribute, with insignificant predicted improvements to other attributes; very or highly significant adverse impacts, but with some improvements which are of a much lower significance and are insufficient positive impacts to offset the negative impacts of the proposal.
Large Adverse Impact	Where the proposal may result in a degradation of the water environment, because it results in predicted: highly significant adverse impacts on a water attribute; significant adverse impacts on several water attributes.
Very Large Adverse Impact	Where the proposal may result in a degradation of the water environment because it results in predicted: very significant adverse impacts on at least one water attribute; highly significant adverse impacts on several water attributes.

Worksheet 1 Environment: Water Environment - Plan Level

Worksheet 2 Environment: Water Environment - Strategy Level

2. Application of TAG to Highway Schemes

This section provides advice on the links between TAG's treatment of the water environment sub-objective and the advice given in Volume 11 of the Design Manual for Roads and Bridges (DMRB), which deals with the environmental assessment of highway projects. An explanation of the correspondence between the advice set out in TAG and DMRB is given in Applying the multi-modal new approach to appraisal to highway schemes (TAG Unit 2.6).

2.1 Methods and Worksheets

2.1.1 The TAG appraisal is based on data collected under the DMRB 11.3.10 assessment. It takes this information and classifies and analyses it in a logical and transparent manner. Note that, at all Stages, the assessment score and its basis must be discussed with the Environment Agency and their views taken into account.

2.1.2 Worksheet 1 shows the information that should be reported for this sub-objective.

2.1.3 Water features identified in DMRB are listed in the worksheet together with their attributes. The value of each water feature is recorded in terms of four indicators: quality, scale, rarity and substitutability, based on data held by the Environment Agency and guidance set out earlier in this TAG Unit. The magnitude and significance of the potential impact on a water feature is then assessed using Tables 3 and 4. This leads to an Overall Assessment Score on a 7-point scale, based on criteria given in Table 5.

2.1.4 The results of detailed modelling exercises (mentioned in DMRB 11.3.10) - flood risk, hydrological models etc - will provide the technical back up and justification for the entries in the Worksheet 1 and AST and this material can be provided in supporting reports.

2.2 Data Transformation from DMRB to GOMMMS

ata Requirements	Modify DMRB Output?	Data Sources
Worksheet Description of study area features Appraise potential impacts Impacts on 7-point scale	Re-order Re-order Yes	DMRB 11.3.10 DMRB 11.3.10 Follow advice set out in this TAG Unit
AST Summary of character and effects Assessment score	Yes Yes	Summarise worksheet Transfer from worksheet

ata Requirements

Modify DMRB Output?

Data Sources

Worksheet

Description of study area features

Appraise potential impacts

Impacts on 7-point scale

Re-order

Yes

DMRB 11.3.10

Follow advice set out in this TAG Unit

AST

Summary of character and effects

Assessment score

Yes

Summarise worksheet

Transfer from worksheet

2.3 DMRB Stages 1 and 2/ TAG

2.3.1 The DMRB assessment at any stage (Stages 1, 2 or 3) can provide information for a TAG appraisal, at a level of detail commensurate with the stage in the scheme process.

3. Further Information

The following documents provide information that follows on directly from the key topics covered in this TAG Unit.

For information on:	See:	TAG Unit number:
Appraisal Summary Table	Transport Appraisal and the New Green Book	TAG Unit 2.7 TAG Unit 2.5
The Environmental Capital Approach	The Environmental Capital Approach	TAG Unit 3.3.6
The Appraisal Summary	Table Transport Appraisal and the New Green Book	TAG Unit 2.7

For information on:

See:

TAG Unit number:

Appraisal Summary Table

Transport Appraisal and the New Green Book

TAG Unit 2.7

TAG Unit 2.5

The Environmental Capital Approach

TAG Unit 3.3.6

The Appraisal Summary

Table Transport Appraisal and the New Green Book

TAG Unit 2.7

4. References

Highways Agency Design Manual for Roads and Bridges (DMRB)

DETR (2000) Guidance on the Methodology for Multi-Modal Studies

5. Document Provenance

This Transport Analysis Guidance (TAG) Unit is based on Chapter 4, Section 11 of Guidance on the Methodology for Multi-Modal Studies Volume 2 (DETR, 2000).

Technical queries and comments on this TAG Unit should be referred to:

Integrated Transport Economic Appraisal (ITEA) Division
Department for Transport
Zone 3/08 Great Minster House
33 Horseferry Road
London
SW1P 4DR
itea@dft.gsi.gov.uk
Tel 020 7944 6176
Fax 020 7944 2198

Updated: April 2009

Documents

Guidance documents - Expert

3.3: The Environment Objective

Unit 3.3.11: The Water Environment Sub-Objective

WebTAG

Department for Transport

Transport agencies

Transport bodies

UK Government

Key