2 Nightingale Way, Catterall, Garstang, Preston, PR3 1TQ Tel 01995 600733 email [email protected] Flood Risk Assessment For Application at: Gibstick Hall Farm Island Lane Winmarleigh Preston PR3 0LB email [email protected] Contents 1. Introduction 2. The Site 3. Flood Risk 4. Existing drainage 5. Proposed Development 6. Mitigation Measures email [email protected] Introduction ML Planning Services Ltd have been instructed by client Mr Hull to prepare a Flood Risk Assessment for the application site at Gibstick Hall Farm, Winmarleigh, in support of a planning application for the erection of a ring type slurry store. The Site The application site is located approximately 4.2km to the south of Pilling Sands and some 9.8km east of the River Wyre. Application Site Approximately 25 years ago a new sea wall was constructed at Pilling, which is the first line of defence from tidal flooding, the old sea wall forming a second line of defence should the former be breached. Local research supports the views of the former owner of the site who has stated that the first line of defence appears not to have been breached since construction. The applicant has lived on site for years and has experienced no flooding issues. email [email protected] Flood Risk From the Environment Agency’s Flood Map shown below it can be seen that the application site is within Flood Zone 3. Flood Zone 3 is a high risk area with an annual probability of flooding of 1% or greater from rivers and 0.5% or greater from the sea. (If no defenses are in place). However, the map also shows that the application site is in an area currently covered by flood defenses. This is indicated by the area hatched in blue on the map. The Environment Agency has a Section 105 Model for the River Wyre. The aforementioned flood defenses around the application site have been constructed to reflect the results in the Section 105 Model and protect the land accordingly. Application Site Existing Drainage Water will drain into the existing network on site. There is no where within the site that water could collect due to the natural topography. There will be a minimal increase in surface water as a result of this planning application. email [email protected] Proposed Development The proposed development includes the erection of a ring type slurry store. Mitigating Measures Although the site lives within flood risk zone 3, the flood defense measures provide protection against the risk of flooding on the site. It is unlikely that any fast flowing water will affect the application site in the event of a flood, due to its location within the flood defense area. Due to the nature of the flood risk, good warning is likely to be available prior to any serious flooding and evacuation of people will be possible via the network of adjacent roads. Registration with the Environment Agency’s Early Flood Warning system is possible in this area and subscription to that service would be recommended to the applicant. In the unlikely event of a flood, the site can be easily evacuated via Island Lane until the waters recede. Tidal Flood Level The highest recorded flood level for the site, as specified by the environment agency, is 2.58m above a site datum of 1.71AOD. Therefore the proposed level of the development should ideally be above this level. email [email protected] This means the highest recorded flood reached a height of 4.29AOD. Climate Change It is important when determining potential flood risks to a development to take into account potential climate change activity which may add to the risk over the lifespan of the development. email [email protected] Results The highest recorded flood plus a contingency for climate change in the next 100 years results in a required floor level no lower than 5.22AOD. The existing ground level of the site is 2180mm higher (7.3m AOD) currently, and it can be therefore it can be proven that the site will not be at risk from flooding. However, based on findings in the section 105 model detailed above, the 1 in 100 year modeled flood level for the area is 6.9AOD. This means the development will not be at risk from flooding. The finished internal level of the ring type slurry store shall be set no lower than the existing ground levels on site. email [email protected]