Staveley Puddle Bank took the canal across the Doe Lea Valley just east of Staveley. The following is an extract from Next Navigation West, 2013 Revision, by Dr Geraint Coles. It describes the issues pertaining to restoration of this stretch of canal.

© Chesterfield Canal Partnership.

10.5    Options Appraisal:  The Doe Lea Valley and the Staveley Puddle Bank

10.5.1    Several alternative approaches to the crossing of the Doe Lea Valley and the possible reconstruction of the Staveley Puddle Bank were considered in detail. 
10.5.2    The Staveley Puddle Bank was an earth cored embankment which carried the canal across the valley of the river Doe Lea; the river itself passed under the embankment in a culvert.   There are several other earth cored structures of this type on the canal most notably at Renishaw, Worksop and Retford.  Staveley, however, was the largest free standing structure and was the last to be finished – its completion in the summer of 1777 marked the formal opening of the entire route.  The bank and its fellows are largely unnoticed and unrecognised today but as some of the earliest large structures of this type, they have a minor, but important, place in the history of British civil engineering.
10.5.3    The earth banks at Renishaw, Worksop and Retford still stand although the Renishaw bank is difficult to discern as the entire valley behind the bank has been infilled.  The Worksop and Retford banks lie on the Canal & River Trust section and are in everyday use.
10.5.3    The Staveley Puddle bank has fared less well and has been very badly damaged by mining subsidence, pipeline construction, the removal of the canal channel from the bank crest in a prior land reclamation project and the destruction of the culvert over the Doe Lea which has been opened into a broad cutting.
10.5.4    The Doe Lea Valley has a number of wildlife sites and the bank forms the northern limit of the Mastin Moor Flash County Wildlife Site and proposed Local Nature Reserve.   While not notified, the valley floor to the north of the bank also has considerable ecological potential.
10.5.5    Three options were examined in detail
* Reconstruction of the Puddle bank in-situ to its original form.
* Construction of a new puddle Bank on an alternative alignment.
* Construction of a new puddle bank on the original alignment.

Reconstruction of the Puddle Bank in-situ to its original form
10.5.6    Restoration in-situ would require the addition of considerable new material to compensate for subsidence.  In engineering terms the blending of old and new earth cored structures together – to ensure that they knit without slippage – is notoriously difficult.  On the Rochdale Canal, bank failures have occurred where repairs to the original structure did not fully integrate with the original structure.  Water percolated along the join line resulting in slippage.  To avoid this occurring at Staveley would require extensive micro piling which would effectively destroy what little is left of the bank and its heritage value.
10.5.7    Further, the culvert which carried the Doe Lea under the bank cannot be rebuilt in its original form.  As built, it was circa 4 foot 6 inches in height and this would prevent the movement of storm water and lead to local flooding.  Such a design would clearly not be acceptable to the Environment Agency.

Construction of a new Puddle Bank on an alternative alignment
10.5.8    Construction of a new puddle Bank on an alternative alignment was considered as a possible means of preserving the remains of the Puddle Bank in situ as a heritage feature.   Several objections were noted to this proposal: 
10.5.9    It would be very visually intrusive – where there had been one significant structure in the landscape there would now be two.  Further the proposed location (dictated by the position of high tension national grid overheard cables and pylons) would prevent the current long-view along the valley to the north of the existing Puddle Bank site.  It would thus change the visual relationship between the Puddle Bank and surrounding landscape.
10.5.10    It would increase the area of valley floor occupied by canal structures and thus conversely reduce the available area of valley floor, floodplain and wetland remaining after reconstruction.   This would impact upon both habitats and flood management.
10.5.11    It would impact most strongly on the valley floor, floodplain and wetland habitats which are of the greatest conservation interest at this location.  
10.5.12    Its approach works and embankments would have a very marked impact on current agricultural land use.  The footprint of the new works would occupy a significant area of agricultural land while not compensating the landowner and tenant farmer with alterative land for farming purposes.
10.5.13    It would make the junction between the new route and the existing foot and cycle path network difficult; requiring greater lengths of footpath to maintain the current level of connectively.   It would create a confused path network.
10.5.14    It would increase maintenance costs by increasing the area under DCC control.

Construction of a new Puddle Bank on the original alignment
10.5.15    The final alternative considered was the complete reconstruction of the Puddle Bank along the original alignment to a modern specification and meeting the requirements of the Environment Agency with respect to flood control.
10.5.16    This will entail the removal of the remains of the majority of the original bank and its reconstruction from land surface upwards.   The bank will be reconstructed to compensate for mining subsidence on a line which will incorporate the original bank footprint.  It will differ from the original in having a long central gap spanned by an aqueduct.  This will meet the flood control requirements of the Environment Agency and will permit much greater movement of flora and fauna along the river margins.  The latter may enable the linking up of separate wildlife sites south and north of the Puddle Bank to form a larger river margin reserve.
10.5.17    The largest draw-back to this option of radical reconstruction is the damage to the surviving archaeology within the Puddle Bank.  While recent survey of the earthwork has shown that it is very severely degraded and that few, if any, of the original surface features relating to the canal survive, it is possible that the interior of the structure contains valuable evidence as to the working methods and practices of the early canal engineers – about which we know very little.  Paradoxically the recording of the interior structure of the Puddle Bank may help to better inform the maintenance and upkeep of the surviving banks at Renishaw, Worksop and Retford.
10.5.18    Any reconstruction of the Bank would therefore require detailed excavation of sections through the structure to determine its formation and to recover samples for palaeoenvironmental analysis from any buried land surfaces discovered beneath it.  As proposed (below) some areas of original bank would remain as voucher samples for the future.  Removal of the remaining Puddle Bank would be accompanied by an archaeological watching brief.
10.5.19    The new bank will occupy a footprint only marginally larger than the existing bank.   In consequence it will have little impact on the valley floor and will preserve the existing valley floor habitats.  It will also have only limited impact on agriculture as it is re-using the existing brownfield land corridor.  The greatest possible impact is during construction when particular care will have to be taken to reduce possible impact on the valley floor.
10.5.20    The new Puddle Bank, by using the original line, will secure the historically validated visual relationship between the Staveley Puddle Bank and the Doe Lea Valley.  It will provide an element of continuity in the landscape and a link to the origins of the canal.
10.5.21    It was concluded that in terms of engineering design, safety and the visual, ecological and heritage impact, the most satisfactory option is the construction of an entirely new structure on the alignment of the original embankment.

Further Work Following Site Investigation
10.5.22    On the basis of this assessment, further detailed work was carried out on the original Puddle Bank.  Site investigations including geotechnics boreholes and archaeological studies were undertaken by contractors in 2010.
10.5.23    These studies confirmed that the Puddle Bank has been severely damaged with several breaches resulting from removal of the original culvert as an anti-flooding measure and from pipeline crossings (themselves now disused).  Most importantly the study confirmed local stories that the entire channel section, including towpath, had been bulldozed down the slope of the bank.  Artefacts found in the dumped puddle clay included Victorian pottery and bottles and a late Georgian or early Victorian iron pig suggestive of some historic accidental loss or an attempt at theft. 
10.5.24    The site investigation did, however, reveal that the bank had been constructed almost entirely of clay (likely the origin of the name) on a ground surface which had been completely stripped of overburden and alluvial soils to the underlying bedrock.  It was possible to identify the spade and pick marks at the interface. The bank material was extremely solid with no voids suggestive of internal water flow or erosion.  When the bank material was sectioned and cut back it was possible to identify the individual spade clods of clay from which it was built.  The internal consistency was very high and the material – as confirmed by the geotechnical study – was well compacted and uniform.
10.5.25    Re-assessment of the evidence led to the conclusion that reconstruction would not be as difficult as first thought.   Following consultation with local stakeholders and landowners a decision was taken by the design team to revise the design to incorporate as much of the original structure as was possible.  While the embankment would not be entirely original it would more closely reinstate the appearance of the original route and would retain the key relationship between the canal structure and the surrounding landscape.  
10.5.26    The key change is that the culvert carrying the River Doe Lea will be replaced with an aqueduct.  This resulted from the stipulation of the Environment Agency that culverts could not be used as these might lead to flooding of the land and housing which lies south and upstream of the embankment.
10.5.27    These initial designs were submitted to structural engineers Scot Wilson’s who were commissioned to provide detailed structural design for the new aqueduct.   
10.5.28    The principle of reinstating the Puddle Bank is incorporated in the Chesterfield Borough Council Local Plan and will be carried forward into the Local Development Framework.

An 1892 map of the Puddle Bank.

The Puddle Bank.

The current bridge over the Doe Lea seen from the top of the Puddle Bank.