Building standards - proposed changes to Section 3.3 Flooding and Groundwater: consultation analysis

3 Annex 3.B, Building Standards Advice on Flooding

3.1 Introduction

3.1.1 A new Annex 3.B is introduced which gathers and represents information drawn primarily from the previously published Planning Advice Notice (PAN) 69 on flood risk. Annex 3.B sets out background information on the water environment and the factors which contribute to flooding, including watercourses, coasts, sewer surcharging, groundwater and the influence of climate change.

3.1.2 The main purpose of Annex 3.B is to supplement the guidance in Section 3.3 by raising awareness and knowledge of flood risk and measures to mitigate flooding. It also presents a guide on the interaction of the building standards process with other statutory processes relating to flood risk management.

3.2 Annex 3.B

Question 9: Do you agree that the introduction of the guidance in Annex 3.B offers further useful information to support the informed practice in flood risk assessment and the application of flood risk principles?

3.2.1 Question 9 asked respondents if they agreed that the introduction of the guidance in Annex 3.B offers further useful information to support the informed practice in flood risk assessment and the application of flood resilience principles. Table 3.1 shows the quantitative responses to the question.

3.2.2 There was general support for the introduction of guidance in Annex 3.B with the majority of respondents (82%) agreeing that it provides useful information to support flood risk assessment practice and the application of flood resilience principles. There was overall support from all groups with only one respondent in each group disagreeing with the statement.

3.2.3 There were 14 comments made in response to this question. Responses are considered separately for those agreeing and those disagreeing with the quantitative part of the question.

Respondents Agreeing that Annex 3.B Offers Further Useful Information

3.2.4 Positive comments on the information contained within Annex 3.B fell into the following themes:

• Several respondents noted that the Annex is a practical resource to inform flood risk assessment practice and the application of property flood resilience principles. Having consolidated information in a single resource was felt to be helpful for both verifiers and designers and it is thought that it will aid consistency across Scotland.
• A few respondents highlighted the checklists as particularly welcome additions, noting that the Building and Flooding Checklist, Table 2 Building Components and Table 3 Good Practice Checklist provide a helpful quick reference for designers and verifiers. It was suggested that the Good Practice Checklist could be made available as an interactive online tool on Citizen Space.

3.2.5 In addition, whilst agreeing that the guidance in Annex 3.B offers further useful information, several respondents identified specific points of clarification including:

• One local authority respondent made the assertion that the guidance remains vague and lacks the necessary precision to support informed decision-making, and that clearer, more prescriptive guidance is required to ensure consistency and confidence in the verification process.
• A local authority respondent highlighted the need to update the statement “There has been a requirement in the building regulations since 1985 for all new buildings, other than dwellings, to be accessible to disabled people.” (p36 of Consultation) to clarify current requirements for dwellings.
• Another local authority respondent felt that whilst Annex 3.B provides useful background and context, particularly for verifiers and designers unfamiliar with flood risk issues, its alignment with planning policy and building standards could perhaps be improved.

Respondents Disagreeing that Annex 3.B Offers Further Useful Information

3.2.6 A few comments were provided by respondents who disagreed with the quantitative part of the question.

• One individual respondent stated that while they agreed that the Annex offers useful guidance in terms of flood resilience, it was felt that it does not address the contradiction in the planning 'requirement' to not build or redevelop or convert where there is a flood risk.
• One local authority respondent expressed concern around the presumption that building standards verifiers would interact with other sections of the local authority stating that there was no mechanism in place for this outside the planning application process. Capacity issues within flooding teams to take on this additional role were highlighted.
• One respondent in the other group expressed concern that Annex 3.B is reliant on withdrawn and outdated Government guidance, most notably Planning Advice Note (PAN) 69 from 2004, which has been superseded^[1]. It was felt that the Annex is not reconciled with current best practice.
• A Local Authority response highlighted a few specific points relating to the text in Annex 3.B in Section 3.B.2 Sources of flooding as follows:
  • Section 3.B.2 (Fluvial): overall, the text is too simplistic and is not using correct aggravation points as it omits the roles and responsibilities explanation in flood risk management.
  • Section 3.B.2 (Pluvial): the text fails to note the simple inability of the drainage system to take extreme rainfall events into the system (exceedance events). The FloodMaps link is for all reasonable sources, not just Pluvial.
  • Section 3.B.2 (Sewer): contains text for the pluvial section and incorrectly states sewerage system is Combined – it can be, but there are many areas that are separate. Combined Sewer Overflows (CSOs) are ‘normal’ and can exist without operating. The respondent challenges the statement that infiltration of surface water can contribute flows beyond design capacity.
  • Section 3.B.2 (Groundwater): Groundwater is not explicitly considered as part of FRM(S)A 2009. In fact, the Groundwater maps are missing from the current production of SEPA Flood Maps. On the original maps, the groundwater layer was to indicate the potential to influence the duration and extent of flooding from other sources only, and not where groundwater could cause flooding directly.
  • Section 3.B.2 (Coastal): text fails to consider comments on joint probability where river and coastal effects combine.
  • Section 3.B.2 (Drainage Assessment): it is in principle correct that moisture from ground and groundwater may need to consider a drainage assessment, however, this fails to highlight the potential barrier that is discharge of the collected water to somewhere other than ground (i.e. into a Scottish Water asset). There is reference to the sentence “NPF4 advises that “Development proposals will:…”. It was suggested that this should say “NPF4 requires that “Development…”. The drainage assessment undertaken to support applications covered by NPF4 does not typically include groundwater or soil moisture.
  • Secondary Effects of Flooding: the section makes note of contamination by sewage. Should this occur, it would be necessary to have Scottish Water become involved in the assessment of flood mechanism / clean up.

Question 10: Are there any other issues that you consider Annex 3.B could address to further improve knowledge and understanding of the topic?

3.2.7 Question 10 asked respondents if there were any other issues that they consider Annex 3.B could address to further improve knowledge and understanding on this topic. Table 3.2 shows the quantitative responses to the question.

3.2.8 More than half of the respondents (59%) suggested other issues that could be addressed by Annex 3.B. Respondents across all three of the groups suggested potential issues that could be considered. There were 10 comments made in response to this question which have been analysed by theme.

Suggestions for Other Issues to Include in Annex 3.B

3.2.9 The suggestions offered by respondents for potential additions to Annex 3.B include:

• A few respondents across all three of the groups suggested the addition of case studies or worked examples would be valuable, perhaps showing successful PFR measures for both new build and retrofit.
• A few respondents suggested specific edits to the guidance including:
• the wording around the annual probability of flooding greater than 0.5% should be changed to ‘equal to or greater than’ to avoid ambiguity;
• checklists:
  • accounting for potential extensions (increases in habitable space in a property that would not require planning permission), that may result in different levels of PFR within the building;
  • the Building and Flooding Checklist could be divided into distinct sections with a building warrant assessment resource and guidance on appropriate inspections to include in a Construction Compliance and Notification Plan (CCNP); and
  • the Good Practice Checklist should note that groundwater flooding is not available on SEPA Flood Maps and is not considered explicitly in the planning process.
• A few respondents in the individual and other groups highlighted the need for greater consideration of PFR retrofit on existing buildings, including historical environment and conservation areas. It was noted that PFR measures are currently difficult to progress in older buildings due to planning constraints around NPF4 and it was suggested that flood resilient conversion should be welcomed by planning authorities. The need for the guidance to provide clear standards to property owners and communities on implementing cost effective flood resilience to protect homes was also noted.
• One respondent in the individual group thought that the Annex could signpost designers and verifiers to training or competency schemes for PFR and that guidance on engaging stakeholders and presenting PFR strategies would be useful.
• A local authority respondent raised the issue of potential delays to the building warrant process arising from a reliance on external professional services to provide specialist flood risk assessments. It was suggested that the guidance should acknowledge operational realities and provide mechanisms to mitigate delays, for example through clearer expectations, streamlined processes or improved access to competent assessors.