Cottingham and Orchard Park Flood Alleviation Scheme

The scheme is to provide a large Flood Alleviation Scheme that reduces the flood risk in an economically achievable standard with ranges established by sensitivity testing.

The Target standard will be 1% Annual Exceedance Probability with a 30% allowance for climate change (1:100 year + 30% CC Standard of Protection). This will be refined with sensitivity testing that shall take into account climatic antecedents and other factors.

Subject to detailed options appraisal in line with the Detra approved national standards using the ‘Flood Hazard Research Centre- Flood and Coastal Erosion Risk Management- A Manual for Economic Appraisal of Flood Risk.’ The preferred option will include one or all of the following components:

1. Construction of a series of large flood storage areas, approximately 300,000m³
2. Construction of new ancillary engineering works
3. Construction of real time flow control apparatus

The intervention area centres on the rainfall run-off from the geographical features known as the Raywell Valley. This is an area of approx 1500 Ha that presents peak flood flows to Cottingham and the City in excess of 6,000 l/s as was seen in 2007. Because the urban drainage system in the city has a finite drainage capacity this becomes quickly overwhelmed causing significant flooding to properties and business. This scheme will take approximately 4000 properties out of flood risk to the target design standard.

This scheme is complimentary to two other neighbouring flood alleviation schemes, being the Willerby Derringham Flood Alleviation Scheme and the Anlaby and East Ella Flood Alleviation Scheme. All three schemes working in unison have a combined beneficial effect on the urban drainage system that has a finite capacity as it relies on pumped operation.

CASE STUDY – COPFAS PHOTOS – COPFAS