A natural flood management gallery

From “leaky” ponds to flow restrictors, from re-meandering to tree planting schemes, a large amount of practical work has been carried out on the Eddleston Water over the lifetime of the Project. Below are a few examples of what the Project has put in place in the Eddleston Water catchment.

Re-meandering at Cringletie

Re-meandering increases river length, thereby reducing the slope and speed of flowing water and provides more space for flood waters, as well as creating new habitats and improving the landscape. At Cringletie, re-meandering was carried out as part of a suite of natural flood management (NFM) techniques deployed at the site. You can read more about the wider work at Cringletie (and Lake Wood) here.

Below: the Cringletie site prior to works commencing. Note the straightened “canalised” channel which is prevalent throughout the Eddleston catchment.

Below: the site immediately following re-meandering works in autumn 2013.

Below: a few weeks after the works have taken place.

Below: one year on, the site begins to naturalise.

Clockwise from top left: this detailed time-lapse of one small section of the re-meandered channel, shows how the channel is naturalising over time. In particular, the instream habitat is beginning to look very healthy, with sediment moving from a muddy morass, to a healthy mix of gravel and coarser material; typical for a river in this location.

Re-meandering at Lake Wood

Formerly the site of a mature Sitka spruce plantation, Lake Wood now boasts several NFM features including a re-meandered channel which has increased channel length by 30%.

Below: an aerial image of the site before re-meandering works took place.

Below: the site, following completion of the re-meandering works.

Below: the site one year on. Initial monitoring confirms that a healthy pool-riffle sequence has formed in-channel and there has been a 50% increase in the number of fish. Also, the presence (both here and at Cringletie) of multiple redds within the restored channel is testament to the suitability of the new habitat for spawning Atlantic salmon, a key species.

Pond creation

Below are some examples of the 28 “leaky” ponds that have been created over the lifetime of the project. Leaky ponds (also called storage ponds) store water during intense rainfall events. Although the most “engineered” tool in the NFM toolbox, they are still an important consideration in any NFM scheme. At times of high flow, water is directed out of the main watercourse into these ponds and then, following the intense rainfall event, water will drain back out through a regulated outlet.

Tree planting schemes

Riparian woodland planting helps increase rainfall interception, evapotranspiration, soil infiltration and decrease the speed of overland flow. Over 66 hectares of riparian woodland have been created in the Eddleston catchment.

Below: some examples of riparian woodland planting schemes within the Eddleston catchment.

Flow restrictors

Flow restrictors encourage out-of-bank flow and hold back water, thus “slowing the flow”. Typically of the type known as engineered log jams or large woody debris, these instream structures are typically formed from locally derived timber and are deployed in a number of different ways. In the Eddleston catchment we now have 40 flow restrictors in place.

Below: flow restrictors on the Middle Burn, the orange arrows indicate where they have been strategically placed.