Pickering Beck Case Study

Pickering is market town with 7000 people. It has flooded in 1999, 2000 and 2007. 

In 2007, 85 properties flooded and £7million of damage was caused. 

Hard engineering to prevent flooding is not viable as it would have a negative effect on Malton downstream. 

-Urbanisation = The devlopment of Pickering has increased the impermeable surfaces (Lidl, car parks, train station). This reduces infiltration and surface runoff increases. However, Pickering is a relatively small urbanisation with only 7000 people.

-Heather burning = Game keepers on the moors burn heather in order to keep it in control. This means the soil is degraded, infiltration and interception are reduced. 

-Grips = Farmers drain the saturated peat soil on the moors using channels called grips. This increases the rate at which water reaches the river. However, sediment and heather can naturally build up in these and slow the flow. 

-Climate Change = Anthropogenic climate change increases global temperatures which means the warmer air holds more water and more severe rain events occur. 

-Relief = Pickering is a relatively low-lying area with the steep North York Moors surrounding it. This means water is pulled rapidly down hill by gravity, giving it less time to infiltrate. 

-Drainage Basin = The Pickering drainage basin is circular, meaning all water falls roughly equidistant from the river and so reaches it at the same time. 

-Season Variations = Flooding is more likely to occur in winter as rainfall is heavier. However, the unusual summer flooding in 2007 was caused by movements of the Jet Stream.

-Climate Change = Climate change can also be natural, and it causes more frequent storm events. This can lead to antecedent rainfall which means stores are already saturated when more precipitation happens. 

This project was the first of its kind; led by the Forestry Commision and Environment Agency, it attempted to reduce flooding in Pickering through natural management instread of hard engineering. It cost £750,000

- 160 Debris Damns = These block the river, slowing the flow and traps sediment to prevent it building up and causing flooding downstream.

- 120,000 Metres of Flood Storage = When debris dams force water out of the channel, it can be held safetly on these flood plains instead of surging into Pickering.

- 180 Heather Bales in Grips = The grips are blocked with bales of heather to slow the flow and trap sediment to prevent it causing flooding downstream. 

- 10m No Burn Zones = These are being inforced along channels to prevent heather burning and to keep the soil quality healthy (better for infiltration).

-40,000 Trees Planted = Planting riparian woodland around the river means that the flow is slowed and the soil is kept healthy. Hydrophilic plants like willows are favoured. 

Floods on Boxing Day in 2015 showed that the measures had slowed the flow by 2 cumecs (compared to predictions) , equal to 15-20%. 

Half the reduction was because of dams and half due flood storage. 

Prevented flooding in the Beck Isle Residential area and museum, which usually flood. 

Flooded areas as a whole were in open areas, not in urbanised ones. 

However:

Material shifted in 11 dams and 2 were structurally weakened. This allowed improvements to be made in the future.