Flood Risk Assessment Erection of Masjid/ Place of Worship, extended car parking following demolition of 11a Grafton Street & boundary treatment Land adjacent 11/ 11a Grafton Street, Preston, PR1 8JB 0723/ FRA revised 03/11 January 2011 The information contained in this document has been obtained from the Environment Agency website: http://maps.environment-agency.gov.uk/wiyby/wiybycontroller#x=353209&y=429059&lg=1,&scale=11 The following page indicates the Flood Map for a given postcode and it allows the user to identify a particular area on the Flood Map and obtain the Environment Agencies zoning for a specific location. The application site is on the edge of flood zones 1 and 2 with flood zone boundary cutting across part of the southern boundary of the site. The subsequent pages indicate the actual information which the Environment Agency provides for the specific location; The first for the area within zone 1 which is noted for number 11 Grafton Street and which forms part of the site The second for the area within zone 2 which is noted for number 19 Grafton Street which is the adjacent property along the southern part of the site. In each instance, the flood risk assessment by the Environment Agency is low and the guidance note for each of the zones taken from their website is noted below: Flood likelihood explained What we mean by the likelihood or probability of flooding The probability or likelihood of flooding is described as the chance that a location will flood in any one year. If a location has a 1.3% chance of flooding each year, this can also be expressed as having: a 1 in 75 chance of flooding in that location in any year odds of 75 to 1 against a location being flooded in any year However, this doesn't mean that if a location floods one year, it will definitely not flood for the next 74 years. Nor, if it has not flooded for 74 years, will it necessarily flood this year. When we describe the chance of flooding, we give it one of three descriptions or put it into one of three categories: Significant: the chance of flooding in any year is greater than 1.3% (1 in 75) Moderate: the chance of flooding in any year is 1.3% (1 in 75) or less, but greater than 0.5% (1 in 200) Low: the chance of flooding in any year is 0.5% (1 in 200) or less The lower the percentage then the less chance there is of flooding in any one year; the higher the percentage then the more chance there is of flooding in any one year. The conclusion is that location of the application site is considered at low risk of flooding within Flood Zone 1 and furthermore, it is not in an isolated location where it could be vulnerable as a dry island adjacent to Flood zones 2 or 3. The site is to be drained to the main drains and part of the site to the south has been laid out to allow percolation of surface water in to the ground to minimise the discharge from the site. 1
The following measures should help to mitigate the potential risk of damage from flooding; 1. Ground levels on adjacent land, Grafton Street (west) and Halifax car park (east), are below the lowest part of the application site 2. Path levels around the new building relate to existing ground levels 3. The finished floor/ slab level of proposed building (9.80m) will be set higher the lowest part of the site (8.90m) 4. The surfacing treatment adjacent the building toward the south west, south and south east consists of permeable landscaped areas along with paths consisting of soil stabilisation trays with a granular infill 2
Map of PR1 8JB at scale 1:10,000 - Map Legend Click on the map to see what is the Risk of Flooding at a particular location. Flood Maps Flooding from rivers or sea without defences Extent of extreme flood Flood defences Areas benefiting from flood defences Main rivers Environment Agency copyright and database rights 2010. Ordnance Survey Crown copyright. All rights reserved. Environment Agency, 100026380, contains Royal Mail data Royal Mail copyright and database right 2010. 3
Flood Risk Information for location; 11 Grafton Street, Preston, PR1 8JB Interactive Maps Flood Risk for X:353124, Y:428953 The information below provides an indication of the likelihood of flooding in your area. This information comes from the Environment Agency's Flood Risk Assessment, which uses ground levels, predicted flood levels, information on flood defences, and our local knowledge. The likelihood is described in one of three categories, low, moderate or significant, as used by the insurance industry. The Environment Agency has provided this information to the financial services industry, as required by Government to ensure that as many people in flood risk areas are able to access flood insurance for their home. For more information, follow the link to Flood risk and home insurance on the left of the page. What is the likelihood of flooding from rivers or the sea in my area? What does 'low' mean for me? The location you have selected is in an area that is unlikely to flood except in extreme conditions. The chance of flooding each year is 0.5% (1 in 200) or less. This takes into account the effect of any flood defences that may be in this area, whether or not these are currently illustrated on the Flood Map. Flood defences reduce but do not completely remove the likelihood of flooding and can be over topped or fail in extreme weather conditions. Get a fuller explanation of flood likelihood. 4
Flood Risk Information for location; 19 Grafton Street, Preston, PR1 8JB Interactive Maps Flood Risk for X:353140, Y:428929 The information below provides an indication of the likelihood of flooding in your area. This information comes from the Environment Agency's Flood Risk Assessment, which uses ground levels, predicted flood levels, information on flood defences, and our local knowledge. The likelihood is described in one of three categories, low, moderate or significant, as used by the insurance industry. The Environment Agency has provided this information to the financial services industry, as required by Government to ensure that as many people in flood risk areas are able to access flood insurance for their home. For more information, follow the link to Flood risk and home insurance on the left of the page. What is the likelihood of flooding from rivers or the sea in my area? What does 'low' mean for me? The location you have selected is in an area that is unlikely to flood except in extreme conditions. The chance of flooding each year is 0.5% (1 in 200) or less. This takes into account the effect of any flood defences that may be in this area, whether or not these are currently illustrated on the Flood Map. Flood defences reduce but do not completely remove the likelihood of flooding and can be over topped or fail in extreme weather conditions. Get a fuller explanation of flood likelihood. 5
In addition to the Environment Agency s assessment for the site, the following measures should help to mitigate the potential risk of damage to the buildings from flooding; 1. Ground levels on adjacent land, Grafton Street (west) and Halifax car park (east), are below the lowest part of the application site resulting in the water draining away from the site 2. The finished floor/ slab level of proposed building (9.80m) will be set higher the lowest part of the site (8.90m) minimising the potential for damage from rising water levels 3. Path levels around the new building relate to existing ground levels minimising the risk of surcharging from the site to neighbouring premises 4. The surfacing treatment adjacent the building toward the south west, south and south east consists of permeable landscaped areas along with paths consisting of soil stabilisation trays with a granular infill reducing the potential run-off from the site in to the existing drainage system 6