Ness, (Potentially Vulnerable Area 02/01)

Local Plan District Local Authority Main Catchment 02 Comhairle nan Eilean Siar Coastal

Background

This Potentially Vulnerable Area (PVA) is The populated areas of the PVA are in located on the north-east of the Isle of the northern area at Tabost, focused Lewis (Figure 1). around the A857 which runs across the northern part of the PVA. The PVA The PVA extends from the includes several small burns which outfall at the most northern point of the island along the eastern and northern coast. and down the eastern coast to just north of Tolsta point. It has an area of The total Annual Average Damages approximately 53km 2. (AAD) for all flood sources are £1,000. The majority of the damages (92%) are from river flooding, with coastal flooding contributing 8% of the damages (Figure 2).

Figure 1: Ness, Isle of Lewis Potentially Figure 2: Annual Average Damages by Vulnerable Area Flood Source

This area was designated as a PVA due to flood risk to cultural heritage sites based on information available at the time of the National Flood Risk Assessment in 2011. Designation as a PVA means that further investigation of that flood risk was required. This has been carried out based on the flood hazard and risk maps published by SEPA in January 2014 together with input from the Local Plan District Partnership.

Summary of Impacts from all sources of flooding

Flooding to agricultural land contributes 87% to the total Annual Average Damages (AAD) and damages to roads contribute 13%. The roads affected include the A857. There are no properties at risk of flooding within the PVA. Coastal flooding only affects agricultural land.

A number of cultural heritage sites are identified as at risk, all of which are Scheduled Ancient Monuments and include prehistoric domestic and defensive sites and a church. Cultural heritage sites do not contribute to the AAD total as it is difficult to quantify a monetary value for them.

Areas of environmentally designated sites are identified as at risk. The sites affected include Ness and Barvas Special Protection Area (SPA) and Lewis Peatlands SPA.

Table 1 presents a summary of the receptors at risk from all sources of flooding in the different return periods (different probabilities of flooding in any one year). The contribution from the different receptors to the overall damages (by return period) is shown in Figure 3.

Figure 4 shows the location of receptors that are at medium to high risk of flooding from all sources in the PVA.

Table 1: Summary of Flood Risk from all sources High Risk Medium Risk Low Risk

1 in 10 year 1 in 200 year 1 in 1000 year Number of Residential 0 0 0 Properties at risk (out of 538) Number of Non-residential 0 0 0 Properties at risk (out of 132) Number of People at risk 0 0 0 Community Facilities at risk 0 0 0 Utilities at risk 0 0 0 Transport Links at risk Roads (6 locations) Roads (8 locations) Roads (9 locations) Designated Areas (km2) at risk 1 km 2 1 km 2 1 km 2 Number of Cultural Heritage 4 5 5 Sites at risk Agricultural Land at risk (km 2) 0.6 km 2 0.6 km 2 0.6 km 2

Figure 3: Damages by receptor and return period for flood risk from all sources

Summary of existing local actions to manage flood risk

There are hard coastal defences at the Port Nis harbour.

Comhairle nan Eilean Siar takes flood risk into consideration as part of decisions related to land use planning, as outlined in Scottish Planning Policy. This includes ensuring that new developments are not permitted in areas at risk of flooding and that all new developments do not increase flood risk elsewhere.

Floodline, SEPA’s flood warning service, provides flood alerts for the Outer Hebrides. Figure 4: Location of receptors at medium to high risk of flooding from all sources in the Ness, Isle of Lewis PVA

Summary of Objectives to manage flood risk in PVA

Local Plan District

Initial Objective Indicator Avoid an increasing the number of residential and From an estimate of 224 non-residential properties at risk from all sources of residential properties flooding. From an estimate of 152 non- residential properties

Ness, Isle of Lewis (PVA 02/01)

Accept risk of flooding.

Initial objectives for cultural heritage and environmental designated sites may be added when information is available from the relevant body at the end of the objectives sections.

Summary of Measures to achieve Objectives

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