storm frank floods, impacts upon the river dee, aberdeenshire - jamie urquhart, river dee trust

Storm Frank FloodsImpacts upon the River Dee, Aberdeenshire

Jamie Urquhart River Dee Trust Biologist

Background• River Dee finally burst its banks on 30th

Dec 2015.

• 1 in 500 year event.

• River levels reached 15ft 6in at its peak.

• 6in off largest spate event recorded in 1829.

• 1,300 cumecs estimated flow at peak.

Video Credit: Ewan Brown YouTube

Impacts - Habitat• Significant changes to parts of the River,

new channels/braids formed/banks burst.

• Erosion and deposition of substrate.

• Channel still very mobile, with areas yet to be surveyed.

• Has habitat heterogeneity increased or decreased?

• Sections of habitat surveys from 2013-15 will be repeated in 2016 to compare.

BeforeAfter

Impacts - Fauna• Fish and invertebrates

stranded/displaced/crushed.

• Won’t fully understand impacts until summer surveys.

• Positives; Increased survival – density dependence.

• Fish rescued just last week - illustrates their resilience.

• Prospects for 2016-17 ample good quality habitat available for juveniles and adults.

Impacts - Infrastructure• Severe constraints on access across

catchment.

• Local communities.

• Beat access tracks, huts (50% lost).

• Considerable economic impact to local businesses.

• Despite all this the River is open for business.

• Message from the Riverbank is that the Ghillies and anglers are positive and eager to start fishing.

Before DuringAfter

Restoration• Emergency works instream – SEPA

consented.

• RDT infrastructure – Largely unscathed UDRS, Fish Passes (1 of 27 damaged).

• Riverbank Clean Ups - 100 vols over 3days 4 km cleared, 30 tonnes of debris removed.

• Early days restoration work will continue for several months.

• Challenging times but attitude from across the catchment is upbeat.