green-walk

THE GREEN WALK

Balby Carr (anti-clockwise). Length 1¼ miles

Bridge over Mother Drain at the start of the Green Walk © Allan Parker ARPS

The Green Walk starts on leaving the Reserve entrance. From here you can follow it either clockwise or anticlockwise – these notes describe the latter. The whole of the main part of the walk is on made paths suitable for wheelchairs. Four of the six hides have ramped accesses for wheelchairs.

On leaving the entrance building, cross the road access track and join the path which crosses over a bridge over the Mother Drain. ( This is the main drain across the carr and carries water from a waste water treatment plant, continues alongside Balby Carr Bank and across the carr to the River Torne. The drain was excavated in the mid 18th century to drain the former marshy area to enable it to be turned to farmland which proved to be very successful. However, over time the drains silted and reduced their efficiency leading to the drain regularly overtopped its embankments flooding what is now Old Eaa Marsh and Young Eaa Wood. As a part of the Flood Relief Scheme for south Doncaster in 1980, the drain was regraded to enable it to flow at a lower level through the western part of the Reserve. The pumping station (which you will encounter further on), lifts the water to a higher level in the stretch in the eastern part of the Reserve from whence it feeds into the River Torne. The flood relief scheme is designed so that in times of flood, water can be pumped into some of the water bodies on the Reserve to prevent serious flooding downstream. The water is then released once the main surge has subsided. )

Shortly the footpath divides, the right path passing a small pond which was intended for use by visiting schools for pond dipping but has become overgrown. The left path passes through a sensory garden, the main interest here being any butterflies that may be nectaring on the flowers. Shortly, the paths merge again. Immediately on the left is a path to a viewing hide which overlooks Decoy Lake and a bird feeding area. The hide has a ramped access suitable for wheelchairs and offers a view across this shallow lake. In winter there may be a range of water birds; in summer, look out for dragonflies on the lake margins – these could well be Black-tailed Skimmers which like bare margins on which to sun themselves. To the right, the hide provides a view over the Reed Bed Filtration system. ( The Reed Bed Filtration System is designed to improve the quality of water in the Mother Drain which is used to provide top-up water to parts of the Reserve using the pumps of the Potteric Carr Internal Drainage Board as well as the Reserve’s own pumping scheme. The system covers an area of around 2 ha, and was excavated in 1997/8 on former rough pasture between Mother Drain and Division Drain. There are five discrete cells, each containing, at the inlet end, a brick rubble filter designed to increase the sustainable retention of phosphorus within the wetland. The cells were planted, mainly with phragmites together with smaller areas of juncus, sparganium and iris and it is the microbiological action within the root matrix of this vegetation that effectively “cleans” the water. Between Mother Drain and Cell A, there is a large stilling lagoon designed to generate quiet conditions before the water enters the filtration cells. Essentially, once the stilling lagoon has been primed by pumping from Mother Drain, water passes sequentially through the cells, dropping 40 cm between each, through a system of cascades, to provide a degree of oxygenation. Each cell is clay lined to prevent ingress of ground water, with certain areas deepened and profiled to attract ducks, waders and other water birds. When fully operational, 4,000m3/day of water can be treated, with a threshold retention time of 12 hours, before being returned to Mother Drain at a lower level in its course. )

Decoy Lake Hide and view from hide © Allan Parker ARPS

The path continues alongside a hedgerow planted to screen out the A6182 road. However, the scrub on the embankment of the road, which often had singing warblers in spring notably both Common and Lesser Whitethroat, has been removed in part in preparation for road widening. On the left are two of the five cells of the reed bed filtration system.

Shortly, you pass over a bridge over Division Drain. This was regraded in 1980 as part of a flood relief scheme for Doncaster. Normally, unless there has been a lot of rain, the water level in the drain will be very low. However, agreement has been reached with the Potteric Carr Internal Drainage Board ( which is responsible for the water courses on the whole site ) to maintain a few inches of water in it and this is sufficient to allow some interesting water plants to grow and to maintain the plant succession.

Footbridge over Division Drain © Allan Parker ARPS

Shortly, the path once again divides. Straight on takes one towards Loversall Bank whilst the left turn diverts one through Loversall Field, the main interest here being the three ponds and the rough grassland beloved of some butterfly species, notable Meadow Brown and Small Skipper. The small pond on the left (Square Pond) was created artificially when the A6182 was built in 1979. It is not large enough to support many birds but in spring there is usually a pair of Moorhens and many birds may drop in to drink. The pond is also the haunt of dragonflies but it is quite shallow and tends to dry out on the margins where Soft Rush and Great Reed Mace dominate.

On the right of the path are two more small ponds both of which are interesting primarily for dragonflies and damselflies. Here, at close quarters, it is often possible to see a range of these creatures and particularly female Brown Hawker and Emperor dragonflies laying eggs (ovipositing) in summer which they do by lowering their abdomen into the water and secreting the eggs into the stems of vegetation. Comparison between this technique and that of the chasers and darters can be seen; with these two groups the females, sometimes coupled with males, simply dip their abdomens to release the eggs into the water or onto mud. A careful watch on these ponds may also reveal some of the water creatures coming to the surface, including newts and water beetles and occasionally a Grass Snake, which are exceptionally good swimmers, or even a Water Shrew.

The hedgerows that surround this whole area are mainly Hawthorn and Blackthorn with, in early spring, hosts of white flowers. During April/May, these hedgerows hold lots of singing warblers and it is possible to hear both Blackcap and Garden Warbler and Whitethroat and Lesser Whitethroat and compare the similar songs of each pair of closely related species.

At the fork, the path to the left leads to a pond dipping area. Opposite this is an embankment which shields the area from northerly winds and has a southerly aspect, and often holds butterflies and other insects. Beyond this point there is an unmade path (wood chippings) as a shortcut to Loversall Delph .

The right turn leads one back to the main path. Shortly you emerge on Loversall Bank ( Until the 1980s, this was a railway track to the colliery at Edlington as part of the former Dearne Valley Railway but became disused when the colliery closed ). In spring along this stretch, and in the woodland to the right (Beeston Plantation), there will be warblers singing – Blackcap, Garden Warbler, Whitethroat, Willow Warbler, etc. On the left of the path there is a lot of ruderal plant regeneration, along with some more interesting plants such as White Bryony and Burdock. The former is a climber and struggles to find something to cling to, whilst the latter often attracts feeding butterflies in the late summer as well as producing burrs which stick to clothing.

After walking for about 150 m along Loversall Bank, the path forks and there is a choice of keeping on the “Green Walk” or diverting onto the “ Blue Walk ”.

Near the junction of the two paths, on the left, are some steps down to a series of small pools. These have been developed along the line of the old delphs which were created as shallow borrow pits at the time of the construction of the railway embankment in 1909 and have been in a semi-wet condition since that time. The main delph, Loversall Delph, was excavated in 1993 to create a more stable water body. The water body itself contains a number of uncommon plants. When the delph was created, one of the first plants to emerge was a Greater Spearwort a very uncommon plant in this area; two further plants which emerged after a time were Fen Pondweed, a brown submerged pondweed which is relatively rare outside the fens of Norfolk, and Water Soldier a strange plant which in some years will develop small white flowers – this too is an uncommon plant in this area, though it has now spread almost throughout this water body usurping the Fen Pondweed. It is possible that the seeds of these plants had lain dormant for many years until disturbed by the excavation work. There is a path around the main delph (Loversall Delph) but this may be a little overgrown at times; however, it is a very interesting area for invertebrates and in a by Derek Bateson in 2001, some 1400 plant and animal species were found in this small area.

Loversall Delph

Left, © Maureen Hancox and right © Michael Bird

Returning to Loversall Bank, this section of the embankment was, until the late 1960’s, an active railway comprising a running line and five sidings. When the railway lines were removed regeneration started to take place and the effect can be seen on the left hand side where Silver Birch was permitted to flourish along with other planted trees, the right section being retained for the path and a grassy margin. In about 150 m, on the left, is the access to the Loversall Pool hide. Loversall Pool, the small area in front of this hide, was originally intended to be maintained for waders but, with the development of the Huxter Well Marsh area, this pond is now more likely to hold a few duck and Coot and Moorhen. However, whilst in the hide, it is always well worth keeping a lookout for Kingfishers which sometimes use the drain in front of the hide as a flight line.

Loversall Pool from inside hide © Allan Parker ARPS

Looking to the right from the hide there is an area of trees (Young Eaa Plantation). This was a remnant area of woodland from the 1830s which died back as the result of flooding in the period 1965-1970 killing off all the trees, mostly Silver Birch and Oak. A new generation of trees, partly planted, partly self-set, has formed which mask the remnants of the dead trees from 40 years ago.

Returning to Loversall Bank, the view on the right opens up to reveal Willow Marsh, a large area of Common Reed ( Phragmites ) surrounded by willow scrub. Reed beds are favoured habitats for two closely related birds, Reed Warbler and Sedge Warbler, and in May and June the slow, deliberate chur-chur-chur song of the Reed Warbler can be compared with the faster more chattery song of the Sedge Warbler. Also, it is not unusual to hear the squealing calls of Water Rails in this marsh, particularly in summer when the young may be about.

Loversall Bank looking east © Maureen Hancox

The bank on which you are walking is also a very good place to see butterflies on a warm day in summer. Its sheltered aspect, often in full sun, makes it attractive to them and amongst the species to be seen are the “browns”, Ringlets, Gatekeepers, Speckled Woods and Large Skippers, along with whites and the brilliant yellow Brimstones. The oaks on the right hold a population of Purple Hairstreaks this species is difficult to see as it spends most of it's time in the tree tops feeding on honey-dew and prefer warm, still days.

Loversall Bank looking back west © Maureen Hancox

The rough grassland has a number of Common Spotted Orchids in June/July. Other flowers include Perforate St. John’s Wort, Centaury, Ragwort ( look for the yellow and black caterpillars of Cinnabar Moths in late June/July ) and Knapweed, amongst others.

A number of embayments (areas cleared of trees on the north side) have been created. These are often used by dragonflies, particularly Migrant Hawkers in late summer, when they can be seen hawking insects.

In about 400 m on the left is the Field Centre with a café which is open for visitors daily and serves hot and cold drinks and meals.

Field Centre and Cafe © Allan Parker ARPS

Opposite the Field Centre, there are two hides.

Beeston Hide overlooks Willow Marsh where a reed fen rehabilitation scheme was undertaken in the mid 1990s, partly funded by ICI. This was carried out with design assistance from the RSPB and was designed to attract reed fen specialists such as Bittern, and Marsh Harrier. However, the new marshes at Huxter Well are much more extensive and more likely to attract such species, though both species do occur here, particularly Bitterns in winter. The water level in the marsh is maintained at optimum level all year round by means of a filtered supply from Old Eaa Marsh via Loversall Pool.

Willow Pool Hide attracts visitors because it overlooks an active feeding station – a good spot to see tits (including Willow Tit, which as declined in recent years and is now something of a rarity), finches, woodpeckers, etc., on the feeders which are kept filled with food. In winter, it is not unusual to get views of Water Rail which come out onto the ice. In summer, Kingfishers often feed in Willow Pool.

Returning to the path you reach a compound around a pumping station which was constructed in 1980 as a part of the Potteric Carr flood relief scheme for South Doncaster described earlier (here there is a junction with the Blue Walk, which gives access also to the Red Walk .

Continuing round the pumping station, follow the signs to turn right and then left to follow the Green Walk which leads back to the entrance ( Please do not walk down the tarmacadam track which is reserved for vehicular traffic, and staff and volunteers ). This path continues on along side a railway embankment. The bareness of the railway embankment is masked by the plants which have colonised it. Look out for the familiar Ox-Eye Daisy, Primrose, Cowslip, Dog Rose, Bladder Campion and Bird’s-foot Trefoil. In late winter the first flower to emerge is the attractive Coltsfoot, a sure sign that spring is just around the corner. In June look out for Bee Orchids which are sometimes present. Another plant which is present in large quantities is the primitive Horsetail.

On the left is another area of Phragmites where, once again there are Reed and Sedge Warblers as well as Reed Buntings. The reeds are also used for shelter by many small birds - Swallows roost in them in autumn and this is another place where the elusive Water Rail can sometimes be heard calling from dense cover.

On the left near a small grove of apple and pear trees (probably planted by railway employees) is a hide (Old Eaa Hide, suitable for wheelchairs) which overlooks Old Eaa Marsh. This raised hide gives an excellent view of the Marsh which was formerly polluted. The water is now improved and is attractive to a number of the usual water birds and a small colony of somewhat noisy Black-headed Gulls, whilst the reedy fringes, particularly near the hide, are home for a number of breeding birds, notably Reed and Sedge Warblers, which can often be seen at close quarters beneath the hide. A rarity which has recently colonised this area is the Cetti’s Warbler which bred here for the first time in 2010. Opposite the hide is the railway crossing with, adjacent to it a number of Buddleia (butterfly) bushes which may have a number of nectaring butterflies in late July/early August when the main brood of Peacocks in particular have emerged.

The crossing over the railway lines is the starting point for the " Yellow Walk ". Even if you don’t wish to walk the whole of the Yellow Walk it is worth diverting along it (100 m), if you have time, to visit Childers Hide which overlooks Low Ellers Marsh (this area is not suitable for wheelchairs).

Continuing along the path you pass along a section which adjoins commercial developments. The hedgerow here was planted with Blackthorn. In about 100 m, you reach a hide (suitable for wheelchairs) which overlooks Decoy Marsh ( this marsh is named because of its proximity to the original Duck Decoy constructed over 300 years ago . The marsh is a favourite spot for many water birds, including Little Grebe.

Continuing along the path, at the point where it turns left is a small plantation which includes many Alder trees and here, in autumn and winter it is sometimes possible to see small flocks of Siskins which feed on the seeds in the alder cones.

Continue along the path to return to the main entrance.