Longstanton, located as it is on the edge of the fens, has a complicated relationship with water.
Underlying much of Longstanton and Northstowe is a layer of gravel, the remnants of an ancient river. Water moves freely through this layer, known as an aquifer. Water also reaches us from the direction of Bar Hill. In the past, when it rained in Bar Hill, Longstanton had a flood. Nowadays this water is intercepted and held in the balancing ponds alongside the B1050. Rainwater also accumulates; where it falls over the gravel layer it is quickly absorbed, but where it falls outside the limits of the gravel, it forms ponds and puddles.
In the past, farmers and other inhabitants of the region have created ponds and wells. Many of these were dug directly into the underlying gravel; the level of the water in these reflects the level in the aquifer, but in normal use the aquifer is very stable and the level varies little with the seasons. Ponds dug into the clay surrounding or overlaying the aquifer are more variable: the level rises after rain and falls due to evaporation during hot, dry periods.
For complicated reasons, Northstowe Phase 1 was built on very low-lying land, parts of which were flooded throughout much of the winter (details: see our article). To make building work practicable, two measures were adopted. Firstly, large amounts of water were pumped out of the gravels and into the surrounding drainage systems and ultimately into the rivers. This is what is known as ‘dewatering’.
Secondly, the land was built up with imported soil to a level of 5 metres above mean sea level. For the gravel aquifer, the combined consequences of these two measures for were little short of catastrophic. Take a look at the map below. It shows various water features in and around Longstanton, and how they have been affected by dewatering.
Water Loss
Click a number for more information
Kingfisher Pond
The Kingfisher Pond provided one of the first indications of the severity of Longstanton's water loss. The sequence of pictures at the top of the page show the deterioration of the pond from 2014, when it was full, to the present day.
The pond was originally created to store irrigation water, but a thriving area of bio-diversity developed around it, including fish, water fowl and the kingfishers.
All are now lost and the waterless lake is covered in a thick mat of undergrowth.
Hatton House Pond
Hatton House pond belongs to one of Longstanton's most historic houses and before the groundwater loss was a stunningly beautiful large pond. Village residents of long standing tell us how vibrant the pond was, supporting different types of wildlife and vegetation.
A formerly thriving water feature full of wildlife, plants and fish, with healthy trees and a stable natural environment, it is now completely dry, the base is cracking, all wildlife has gone and trees are dying back.
This pond was featured on BBC Look East. Click here to view the programme extract.
Larksfield Nursery
Larksfield Nursery on Rampton Road has been a source of fresh fruit and vegetables in Longstanton for as long as most of us can remember.
Owner Clive Hayden has always irrigated his glasshouses with well water, from a source which accesses the RTD aquifer and for which he holds a legal abstraction licence. Since dewatering the well has mostly dried up. It is now possible to abstract - slowly - only a small amount of water, followed by a long wait while the well recharges. This seriously restricts the activities of the nursery and is rapidly making his business unprofitable.
The plight of this nursery has featured widely in the press. See our Press area for news items.
St Michael's Holy Well
St. Michael's church is the oldest building in Longstanton and is a rare example of a thatched church. It is no longer used for services but remains a building of great interest to historians and visitors to the region.
The well, known as the "Holy Well" is located just inside the main gate. It is believed to have been used for baptisms and in earlier times was probably a pagan shrine.
Since dewatering, it is dry.
Ladywalk Pond
This ornamental pond has been home for years to a thriving population of ducks,
Like the Kingfisher Pond, it is now dry and covered with a thick layer of reeds and undergrowth.
The ducks have emigrated.
Click here to read an extended article about the Ladywalk pond.
Fishponds
An ancient pond used for fishing by the Hatton family.
Believed to have dried up in 2015.
Private pond
A pond on private land adjacent to the footpath on the western side of Northstowe's Western Park.
Situated between the Kingfisher Pond and the Ladywalk Pond, like them it is now dry and overgrown.
Private Pond
A pond on private land, sometimes known as 'Bethan's Pond'
Since dewatering it is dry.
Primary School Pond
A bio-diversity pond in the grounds of Hatton Park Primary School.
This pond is clay-lined. During the summer drought, the water level has fallen, but it is still a viable pond, containing much of its water.
Dew Pond
A small, natural pond adjacent to the old course of the footpath beside the Northstowe playing fields.
Like the nearby school pond, it has a clay base and does not depend on the aquifer for its water. Although depleted by the drought and in very neglected condition, it still contains water.
Balancing Pond
One of two balancing ponds created next to the B1050 to hold excess water from the Bar Hill area which had previously caused flooding in Longstanton. Much of the soil excavated from these ponds is believed to have been used to raise the level of building land in Northstowe.
This pond and its neighbour do not rely on water from the aquifer.
Both are healthy.
Phase 1 Lake
Northstowe Phase 1 Lake. Formed as part of the dewatering process using water from the gravel aquifer.
The dewatering was supposed to be temporary, but what evidence we have suggests that water from the aquifer is still being allowed to flow into the Northstowe lakes.
This healthy lake supports a variety of bird life.
Phase 2 Lake
Northstowe Phase 2 Lake.
Like the Phase 1 lake, this appears to have derived its water from the dewatering process.
Not yet accessible to the public, but well-filled.
Phase 2 Lake
The lower part of the Northstowe Phase 2 lake.
This lake is to be designated a 'Water Park'. It already has a large population of wild birds and hides have been constructed on one side. It is well-stocked with water but not yet, it seems at its intended depth.
Like the other Northstowe lakes, its water appears to have come from the gravel aquifer. The presence of large inlet and outflow pipes at either side of this lake suggest that this process is likely to continue.
Nethergrove Pond
This is a private pond used by anglers.
It is known to be located on a clay base but the pond is currently inaccessible to the public and its condition has not been verified.
Being on clay, it is likely to have retained most of its water through the drought.
Greenway (Swale)
The swales were ditches on the old golf course, most containing a considerable amount of water and a lot of lost golf balls. Northstowe developers renamed them 'Greenways' and made a feature of them. They run across the full width of the site from west to east.
The marked swale is interesting in that it is dry at the Longstanton side but picks up groundwater as it crosses Northstowe. That water appears to end up in one or other of the Northstowe lakes. This process continued even at the height of this summer's drought.
All Saints' Church
All Saints' Church is showing recent signs of damage. Most visible is the cracking around the lintel above the entrance.
So far as we know, the cause of this cracking has not yet been confirmed, but damage to buildings is a common result of subsidence due to drying of the subsoil on which a building is constructed.
Please contact LEGG if you are aware of other instances of this sort of damage in the village.
The first signs in Longstanton that the aquifer was suffering was when the ponds started drying up, soon after dewatering started. On the map above, the cluster of red numbers denotes ponds and wells that directly access the aquifer.
The orange numbers (9 to 11) show the locations of ponds that are known to be based on clay or to have been repaired in the past by having a layer of clay added to them. These sites are all somewhat depleted due to this summer’s drought, but all contain water and are basically healthy.
The green group are healthy, well-watered ponds. Number 16 is the balancing pond that receives its water from Bar Hill. Numbers 13-15 are the Northstowe Lakes. These lakes are still receiving water via the swales, or greenways that cross the site in an east-west direction and the presence of large intake and outflow pipes suggest that it is intended to add more water.
We have now begun to add grey links to the map. These show buildings where visible damage may be connected to subsidence. Please contact LEGG if you are aware of other examples of this sort of damage.