Flood Risk Management Strategy Ayrshire Local Plan District Section 3
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Flood Risk Management Strategy Ayrshire Local Plan District This section provides supplementary information on the characteristics and impacts of river, coastal and surface water flooding. Future impacts due to climate change, the potential for natural flood management and links to river basin management are also described within these chapters. Detailed information about the objectives and actions to manage flooding are provided in Section 2. Section 3: Supporting information 3.1 Introduction ............................................................................................ 23 7 3.2 River flooding ......................................................................................... 23 8 • Doon catchment group ..................................................................... 239 • Irvine and Ayr catchment group ........................................................ 24 6 • Isle of Arran catchment group .......................................................... 25 5 3.3 Coastal flooding ...................................................................................... 26 0 3.4 Surface water flooding ............................................................................ 27 0 Ayrshire Local Plan District Section 3 236 3.1 Introduction In the Ayrshire Local Plan District, river flooding is reported across three distinct river catchments. Coastal flooding and surface water flooding are reported across the whole Local Plan District. A summary of the number of properties and Annual Average Damages from river, coastal and surface water flooding is outlined in Table 1. Total Annual number of Average Local authority properties 1 Damages at risk River catchments Dumfries and Galloway Council, Doon catchment group 730 £1.6 million East Ayrshire Council, South Ayrshire Council. Dumfries and Galloway Council, East Ayrshire Council, Irvine and Ayr catchment East Renfrewshire Council, 5,900 £10 million group North Ayrshire Council, Renfrewshire Council, South Ayrshire Council South Lanarkshire Council. Isle of Arran catchment 110 £170,000 North Ayrshire Council group Coastal flooding East Ayrshire Council, Ayrshire coastal area 1,500 £1.3 million North Ayrshire Council, South Ayrshire Council. Surface water flooding Dumfries and Galloway Council, East Ayrshire Council, Ayrshire Local Plan East Renfrewshire Council, 3,100 £3.2 million District North Ayrshire Council, Renfrewshire Council, South Lanarkshire Council South Ayrshire Council. Table 1: Summary of flood risk from various sources within the Ayrshire Local Plan District 1 Total number of residential and non-residential properties at risk of flooding. 237 Section 3 Ayrshire Local Plan District 3.2 River flooding Ayrshire Local Plan District This section provides supplementary information on river flooding at the catchment level. It provides an overview of the catchment’s natural characteristics, flood risk and the existing actions to manage flooding. It outlines the likely impact of climate change and the potential for natural flood management. Detailed information about the objectives and actions to manage flooding are provided in Section 2. In the Ayrshire Local Plan District, river flooding is reported across three distinct river catchments, shown below. Figure 1: River catchments within the Ayrshire Local Plan District Ayrshire Local Plan District Section 3 238 River flooding Doon catchment group Catchment overview The River Doon catchment group is located in the Ayrshire Local Plan District and covers an area of over 1,080km2. The catchment area is over 97% rural with less than 3% of the area identified as urban and an approximate population of 46,000. This catchment group includes areas of three local authorities; Dumfries and Galloway Council, East Ayrshire Council and South Ayrshire Council. There are three main river catchments within the area: the River Doon, the Water of Girvan and the River Stinchar. The River Doon catchment is located in the north of the area where it flows through a number of small settlements and towns including Dalmellington, Patna, Dalrymple, and Alloway before discharging to the sea at Doonfoot. The Water of Girvan catchment is central in this catchment group, where it receives a number of tributaries and flows through Straiton, Kirkmichael and Dailly, before entering the sea at Girvan. The River Stinchar catchment dominates the south of the Doon catchment group, where it flows in a south westerly direction through Barr, Pinwheery and Colmonell before entering the sea at Ballantrae. The average annual rainfall in the area broadly typical for Scotland, with values ranging between 1,359mm and 1,566mm in the lowland areas to 1,636mm and 1,803mm in the upper parts of the catchment. Flood risk in the catchment Approximately 600 residential properties are predicted to be at risk of river flooding, 64% of which are located within a Potentially Vulnerable Area and an additional 10% in candidate Potentially Vulnerable Areas. Approximately 130 non-residential properties are predicted to be at risk of river flooding, 41% of which are located within a Potentially Vulnerable Area. There are seven Potentially Vulnerable Areas within this catchment area and one candidate Potentially Vulnerable Area as shown in Figure 1: • Ayr east (12/12) • Ayr south (12/13) • Dalrymple to Patna (12/15) • Straiton (12/16) • Dailly (12/17) • Girvan (12/18) • Dalmellington (12/19c). 239 Section 3 Ayrshire Local Plan District Figure 1: River catchment for the Doon catchment group Ayrshire Local Plan District Section 3 240 Main areas at risk The main areas at risk of river flooding can be seen in Table 1, which shows the number of properties at risk and the Annual Average Damages caused by river flooding. This includes damages to residential and non-residential properties, transport and agriculture. Ayr and Dalrymple are the main areas at risk from river flooding. Residential and non-residential Annual Average properties at risk of river Damages flooding Ayr 170 £370,000 Dalrymple 140 £170,000 Girvan 130 £220,000 Dalmellington 80 £110,000 Kirkmichael 40 £64,000 Barr 20 £60,000 Barrhill 10 £46,000 Table 1: Main areas at risk of river flooding Economic activity and infrastructure at risk The Annual Average Damages caused by river flooding in the Doon catchment group are approximately £1.6 million, which accounts for almost 13% of the estimated Annual Average Damages from river flooding within the Ayrshire Local Plan District. The damages are distributed as follows: • 75% residential properties (£1.2 million) • 8% non-residential properties (£120,000) • 6% emergency services (£98,000) • 4% roads (£65,000) • 4% agriculture (£63,000) • 3% vehicles (£40,000). Figure 2 shows the distribution of Annual Average Damages throughout the catchment group. The highest concentration of damages can be seen in south of Ayr, Barr, Barrhill and Dalrymple. Please note that economic damages to rail were not assessed as information on damages at a strategic scale is not available. Table 2 shows further information about infrastructure and agricultural land at risk of flooding within this catchment. 241 Section 3 Ayrshire Local Plan District Number at Further detail risk Includes: educational buildings and <10 Community facilities emergency services Includes: electricity substations and 10 Utility assets Scottish Water assets Notably: Roads (km) 6.6 A77 between Prestwick and Girvan, A713 Railway between Minishant, Girvan and 1.0 Railway routes (km) Wallacetown Agricultural land (km²) 27 Table 2: Infrastructure and agricultural land at risk of river flooding Designated environmental and cultural heritage sites at risk Within the catchment group it is estimated that approximately 25 designated cultural heritage sites are at risk of river flooding. These sites include; scheduled monuments, gardens and designed landscapes and listed buildings. Approximately 13 km2 of environmental designated area is at risk of river flooding. This includes Special Areas of Conservation (<1km2), Special Protection Areas (<1km2) and Sites of Special Scientific Interest (11km2). History of flooding There is a long history of flooding within the Doon catchment group which tends to have localised impact on properties with more widespread flooding in agricultural areas. The River Doon has been known to flood land and roads in Dalmellington and Patna, most recently in November 2009 with flooding also occurring from the Muck Water resulting in road closures. Levels on the River Doon in October 1977 were identified as the highest recorded levels on the river at that time. The earliest and most significant flooding recorded in the area occurred in 1814 when snow melt coincided with an already swollen River Doon to cause flooding to properties in Dalrymple with depths greater than one metre reported in some places. Further detail about the history of flooding in this area is available in the relevant Potentially Vulnerable Area chapters of this document. Ayrshire Local Plan District Section 3 242 Figure 2: Annual Average Damages from river flooding 243 Section 3 Ayrshire Local Plan District Managing flood risk A range of public bodies have responsibility for managing flood risk in Scotland and they are working closer than ever before to target action in the areas where the greatest benefit can be gained. Members of the public also have a role to play and are the first line of defence against flooding by taking action to protect themselves and their property from flooding. Further information about roles