Maintaining/Improving Status in Large Schemes: Skipton FASBuilding River Restoration into Flood Management

Authors: I. Lexartza-Artza, S.E. German, K. Colledge

The town of Skipton, North Yorkshire, has experienced a significant degree of flooding in recent years. In order to improve flood protection, a number of options have been identified and assessed. The scheme proposals include:

- Two flood storage reservoirs proposed upstream of Skipton

- Eller Beck - construction of a high embankment upstream of the A65. The watercourse will be re-routed through a culvert (approx. 108m long) - Waller Hill Beck - construction of a high embankment at Elsey. The watercourse will be re-routed through a culvert (approx. 96m long)

- Defence wall enhancements in Skipton townAlthough the WFD assessment found that the scheme will not cause deterioration of the water bodies, it was deemed appropriate to undertake enhancement of other reaches to compensate for the impacts of the two lengths of river that will be culverted.

Eller Beck- from source to Haw BeckGood Ecological StatusGood mixture of substrate types, good flow diversity, active sediment transfer, good connectivity between channel and floodplain, good habitat conditions.Eller Beck- from Haw Beck to River AireDownstream of A65- Artificially straightened channel, incised, reinforced banks, low flow variability.

This case study shows the potential for integration of flood protection, river restoration and wider WFD objectives. It presents a strong case for making use of the opportunities to introduce improvements to river systems as part of large schemes. Working with natural processes to integrate river restoration into flood protection schemes can contribute to increase the resilience of the system, with multiple social, economic and environmental benefits.

In summary: - Flood protection objectives can be achieved while providing environmental improvements; - Opportunities to contribute to the improvement of the ecological status/potential of water bodies; - Integration of flood protection and river restoration objectives will provide multiple benefits.

irantzu.lexartza-artza@arup.comsally.german@arup.comwww.arup.com

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Skipton FAS

River Restoration

Conclusion

Contains Ordnance Survey data © Crown copyright and database right 2013

0 0.5 10.25km

Integrate river restoration, catchment management and river basin planning Work with natural processes Enhance floodplain connectivity /

make use of active floodplain Futureproofing

In addition, provision of realignment and 2ha of BAP habitat creation has been proposed along two sections of river upstream of the flood storage reservoir. These proposals aim to provide enhanced habitat conditions and improved floodplain connectivity. The proposed BAP habitats to be created include:

- Wet woodland - Floodplain grazing marsh - Reed beds

The proposed restoration and enhancements can also be an important contribution to the improvement of the ecological potential of Eller Beck - from Haw Beck to River Aire in the future.

Waller Hill BeckThe scheme design includes 350m of river restoration in the channel downstream of the flood storage reservoir to compensate for impacted habitat on both Eller Beck and Waller Hill Beck. The river restoration considers existing hydraulic conditions to propose improvements that will contribute to enhanced morphological variability and habitat quality in an area where diversity is limited at present. The proposed restoration includes a variety of elements, such as:

- Channel realignment - Creation of backwater habitats - Introduction of in-channel features - Improved flow diversity - Improved habitat condition and diversity

Waller Hill Beck realignment and BAP habitat

Backwater Pond

Coir roll

River gravels

Riffle

Pool

Existing channel

Realigned channel

Backwater Pond

Coir roll

River gravels

Riffle

Pool

Existing channel

Realigned channel

Reed bed/Wetland creation

Coir roll

Riffle

Pool

Existing channel

Realigned channel

Wet woodland creation

Wetland/BAP habitat extent

Reed bed/Wetland creation

Coir roll

Riffle

Pool

Existing channel

Realigned channel

Wet woodland creation

Wetland/BAP habitat extent

Waller Hill Beck realignment

Eller Beck- from Haw Beck to River AireHeavily Modified Water BodyModerate Ecological PotentialEller Beck through Skipton: channel fairly uniform, confined by walls, with limited marginal habitat. Water body also includes Waller Hill Beck: Mixed substrate, limited diversity in flow types, relatively straight channel, banks heavily grazed, significant fine sediment input.