Surface Water Management Plan - Hampshire County Council

7.2.1. AllbrookAllbrook is the smallest of the parishes within Eastleigh Borough located in thenorth of the Borough, adjacent to the River Itchen. Although there are largeareas of rural land within this parish there are also some densely populatedareas which, under heavy rainfall, could lead to flooding due to urban run-off.Within Allbrook, there has been flooding along Allbrook Hill which has affectedsome residential and commercial properties. This flooding is thought to be dueto the river overtopping and flowing down the hill. This can also impactPitmore Road although there is no record of property flooding. Flooding hasbeen minimal in recent years largely due to the provision of a grill on the mainriver culvert and its continual maintenance. It is not thought that any additionalwork is required in this area at present but it is recommended that this site ismonitored and if flooding re-occurs, there may be the need for furtherinvestigation.The Flood Map for Surface Water has been used to carry out the initialassessment of potential flood risk. It shows a small area thought to have apotential risk of surface water flooding located adjacent to the Lower Itchenmain river that flows alongside the north east boundary of the parish. Thewatercourse runs close to the rear of a number of properties on Pitmore Roadalthough, given the distance and elevation of these properties, flooding isunlikely to occur.This area is also adjacent to the Flood Warning Area known as ‘Shawford toBishopstoke on the River Itchen’ which is defined as a flood zone 3 area andat high risk of flooding.Other areas within the parish shown to be at a potential risk of surface waterflooding are sporadic and appear to be concentrated around the M3 junction12 interchange. Flooding is not known to be an issue in this area at present.However, this highlights the importance of maintaining the existing surfacewater and river systems to provide the maximum amount of drainage andensuring suitable maintenance.Any future development in this area should take the potential for flooding intoaccount and where feasible, should aim to meet or better greenfield run-offrates.The recommendations for Allbrook are: Hampshire County Council to continue to monitor the flood risksituation in the vicinity of Allbrook Hill The Planning Authority should ensure that future developments takeinto account potential flood risk and do not increase runoff rateswithin these areas13