Tag Archives: Drainage

Hertford gets the Wild Trout Trust treatment

John Shannon from the East Yorkshire Rivers Trust inspecting the Hertford Cut drainage channel before work begins.

John Shannon from the East Yorkshire Rivers Trust inspecting the Hertford Cut channel before work begins.

A demonstration day on the Hertford Cut, organised for the Environment Agency and Vale of Pickering Drainage Board was deemed a success as two hundred metres of the drainage channel received the Wild Trout Trust treatment. (Read more about the Wild Trout Trust’s recent work on Pickering Beck here) The work carried out in May was made possible in no small part thanks to the willing help of Scarborough Conservation Volunteers who donned chest waders and took up brash bundles to learn about low-tech restoration techniques. They were able to install a decent trial stretch of in-channel features in The Hertford to show how simple intervention using local materials such as birch brash and ash stakes can enhance habitats for fish such as brown trout and grayling.

The principle is to create a two stage channel where vertical scouring and speeded flow in the centre make up for the reduction in width of the low flow channel. The narrower channel is better at regulating itself and should not be as prone to silting up. The ecology of the river benefits too from invertebrates to fish from the variety in the channel shape and flow regime.

The demonstration day was organised by The Wild Trout Trust in collaboration with East Yorkshire Rivers Trust and the Environment Agency on 22nd May. Thanks are also due to the landowner at Manor Farm Staxton, Mr Hill for accommodating the access and parking on the farm and of course to the Vale of Pickering IDB, who own and control the Hertford banks and are responsible for the maintenance of the drainage cut.

Volunteers constructing paired deflectors from brash bundles.

Volunteers constructed paired deflectors from brash bundles.The brash features are staked and wired firmly allowing flow over the top when levels rise, but in normal flows focus energy in the centre of channel to prevent silt and form some pools for fish.

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Working on a paired deflector

The features installed include 5 or so ‘paired current deflectors’ – looking like upstream pointing V’s with a narrow gap in centre. They create pinch points and deflect current inwards to the centre.

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Bundles after wiring down

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Just below the bridge is an offset brash feature, which both narrows the over-wide low-flow channel and creates sinuosity.

 Also there is a version of a ‘tree-kicker’, using felled or pleached limbs or bankside trees to create the same effect of pinching the channel.

Also there is a version of a ‘tree-kicker’, using felled or pleached limbs or bankside trees to create the same effect of pinching the channel.

Invited staff from the EA and IDB learn about the demo features and how the trail will work

Invited staff from the EA and IDB learn about the demo features and how the trial stretch may be monitored.

Three new gaugeboards were put in by the rivers trust, in order that one may monitor the impact over that stretch. All three boards were zero-ed to water level on the first day, so relative differences upstream and downstream of the demo stretch would be apparent. The EA will collate readings of the three measuring boards, collected at different flow states as the channel adjusts to the new features. More pictures of the event are on the Carrs Wetland Project facebook page.

 

An excellent starting point to find out more about river restoration is the Wild Trout Trust’s own website, and a simple pictorical guide to rivers restoration for fish such as trout

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Investing in Peatlands

Delegates from around the world convened in York for a three day summit in Sept 2013: ‘Investing in Peatlands’. Was ever so much passion gathered together in one venue discussing moors, mires, bogs, fens and mosses?  The county of Yorkshire was splendidly represented among organisations and projects pioneering new ways to restore and protect peat landscapes and attract new investment for influencing land management.

The central theme of the conference was about new ways to secure investment partnerships that recognize the massive economic benefits provided to society by peatlands – and the massive future costs of ‘business as usual’ scenarios, especially in relation to greenhouse gas emissions, water quality and biodiversity. Peatlands are at the vanguard of the drive to establish robust economic basis for PES (Payment for Ecosystem Services) schemes.

Ploughed peaty soils in the Vale of Pickering

Ploughed peaty soils in the Vale of Pickering

A key announcement by the IUCN UK Peatland Programme was the challenge to bring a million hectares of peatlands into beneficial management by 2020. If that sounds a lot it’s because it equates to roughly a third of the UK’s entire peatland area.

Here are some more astonishing Peatland Facts from the conference.

1. Globally Peatlands cover just 3% of the land surface but store twice as much carbon as all the worlds forest biomass.

2. In the UK alone peatlands store 3 billion tonnes of Carbon, which is twenty times that of all the UK’s forests.

3. UK is ranked among the top twenty nations in terms of our total peatland area, out of 175.

4. In the EU 70% of all greenhouse gas emissions from arable farmland, comes from cropped peat soil which is kept drained for the purpose.

The IUCN launched an ambitious challenge to restore one million hectares (about a third of the UK peatlands) to good condition or restoration management by 2020. They call upon landowners, government and society at large to recognize the value of peatlands as brought together in the findings of the IUCN UK Commission of Enquiry on Peatlands. They also unveiled their draft Peatland Code an effort to establish quality standards for peatland restoration schemes.

If one needs further convincing that this is a global issue, take a glance at the report from no less an authority than the Food and Agriculture Organisation of the United Nations, which  has clearly identified in its global good practice guide on peatlands the role of agriculture in mitigating climate change. The main strategies they advocate are: Secure undrained peatlands to prevent emissions; Rewet drained peatlands to reduce emissions; Adapt management of peatlands that cannot be rewetted. It is now recognized that these activities make by far the best long-term investments for carbon emissions-reduction. Never mind about planting trees, investing in hydropower, biofuels and countless other green or renewable technologies in developing countries – we have huge investment potential here in the UK.

Managing ditches for farming and conservation

Reed-fringed ditch near Seamer Carr

Reed-fringed ditch near Seamer Carr

The open-ness of The Carrs floodplain near Scarborough is what attracts many of our farmland bird species to nest here, but boundary features are important habitats too, none less so than the network of drainage ditches which form a distinctive element of the Vale of Pickering landscape.  These wet ditches are an important heritage feature in their own right and have been managed routinely since they were dug over two hundred years ago.

Ditch management, by which we mean the regular maintenance regime, carried out in autumn, winter or early spring, consists of cleaning out accumulations of silt, weed and vegetation in order to keep the water flowing. This is not merely a necessary operation for ditches which carry water from the land to the river system but it also performs a valuable role in managing them as wildlife habitats.

Some, which are important drainage arteries, may need to be maintained frequently – sometimes every year if the silation, debris or vegetation build-up is rapid. Those that are best for wildlife are managed on a rotational basis every few years, perhaps one in five or one in eight. Diversity and timing are key. Ideally a farm area would have a range of ditch habitats at different stages of succession – some just freshly cleaned and others at various stages of re-growth – hence diversity of habitats. Sometimes even longer rotations can be accommodated. In this way species which prefer clear, open sites and those which need choked well vegetated ditches will always have somewhere to thrive. Management in the winter has less impact upon ecology as a lot of wildlife is dormant. It is also helpful to wildlife if ditches which are immediately adjacent are not all done at once, potentially removing food plants and shelter. Cutting the banks or cleaning out only one side of a ditch one year and the other side the next, leaves undisturbed refuges.

Some of the best ditches for plants and invertebrates on The Carrs though are those which have an unusual origin – and the clue may be in the shape of the ditch. look on a map of The Carrs and you will readily identify lots of straight blue lines where artificial drainage ditches were cut when the large scale land drainage began after the 1800 Muston and Yedingham Drainage Act. This is the act of Parliament which paved the way for ‘the draining of the low grounds’ and the straightening of the Hertford and the part of The Derwent. At that time many subsidiary ditches were cut, draining into the New Cuts of the rivers. However in a few places there can still be found sinuous ditches which are relics of the former natural course of the Hertford. These older watercourses harbour some of the more notable wild plants and animals and may have greater ecological variety. Plants such as Water Violet, Water Whorl Grass and the primitive stoneworts are found in such places.

An Internal Drainage Board oversees the water level management of The Carrs including The Hertford Cut. Currently there are three IDBs in the Vale of Pickering (with Muston & Yedingham IDB being our local one) but they are preparing to amalgamate

Vanishing peat

At this time of year arable farmers in the Vale of Pickering can be found cultivating for spring crops. This is often on the land that sits too wet to plough it in autumn when modern cereal and oilseed crops are planted. After an exceptionally wet year many areas remain too soggy to drive machinery over without damaging the soil or getting bogged.

Let us not forget however that at critical growth stages a shortage of water can be equally damaging to crop yields. We had official drought orders in place in Yorkshire only a year ago. Lighter soils, such as sands and peats, both found in quantity in the Vale of Pickering are very prone to blowing away when dry. If strong winds coincide with dry conditions just after cultivation this can cause mass wasting of soils by wind erosion. It is not uncommon for farmers to have to re-drill crops on blow-away soils if rain fails at the critical time. Scenes like the one here near Killerby Carr, emphasise the vulnerability of peat soils not only to land drainage and subsequent shrinkage but also to wind erosion.

Soil is  a precious and limited commodity. Peat soils on The Carrs are especially precious, due to the carbon they hold, the heritage record within and their biodiversity potential. Yet how many of us give soils a second thought? Are they another aspect of our overlooked heritage in Yorkshire’s Hidden Vale?

A dust cloud of peat  tells a dramatic story of peatland erosion during a dry spring on The Carrs

A dust cloud of peat tells a dramatic story of peatland erosion during a dry spring on The Carrs

Rivers in the Vale of Pickering

The Vale of Pickering is a place of many watercourses. Some are ‘proper’ rivers, in name and in habit – all wiggly meanders, pools and riffles, natural banks. Others rather blur the distinction between a river and a drainage channel. A cursory glance at a map will reveal there are many alternative names for watercourses and drainage ditches in the Vale, including Becks, Dykes, Cuts, Drains and Delphs. In Yorkshire a beck is another name for a river or stream. Many of the settlements peripheral to the Vale of Pickering have their own beck, indeed it may have played a defining role in the formation of settlements in ancient times. How many rivers do you know in the Vale? Can you name any of the becks? What about the drainage channels? Some carry as much flow as a river and are just as important for drainage.

Here are a few examples:

‘Rivers’ – River Hertford, River Derwent, River Rye, River Seven, River Dove, River Riccal…

‘Becks’ – Pickering Beck, Costa Beck, Thornton Beck, Scampston Beck, Rillington Beck, Wintringham Beck, Holbeck, Hodgebeck, Brompton Beck, Ruston Beck, Beedale Beck, Weldale Beck, Cripple Beck, Difford Beck, Ellis Beck, Marrs Beck…

‘Drainage ditches’ – Loder’s Carr Drain, Pry End Drain, Black, Dike, New Dike, Double Dikes, Red Bridge Sewer, Sherburn Cut, Twelve Foot Cut, South Delph…

I suspect that whilst many people are aware that the Vale of Pickering is a floodplain, few are aware just how many watercourses there are, natural and made by human hand.