The Chase Through Time Project at Cannock Chase
Great War practice trenches, evidence of prehistoric enclosures and medieval mining pits are amongst the exciting archaeological remains revealed on Cannock Chase, Staffordshire, UK in a new lidar project.
Staffordshire County Council, in partnership with Historic England, is exploring this fascinating archaeological landscape as part of the Heritage Lottery funded ‘Chase Through Time’ project.
Cannock Chase was designated in 1958 on landscape grounds and today is the smallest of England’s 33 Areas of Outstanding Natural Beauty (AONB) covering 6,800 hectares (26 square miles). The AONB has a variety of landscapes including elements of the River Trent flood plain, rich agricultural land, deciduous woodland and the largest surviving area of lowland heathland in the Midlands. The AONB also contains areas of current and historic sand and gravel extraction and large tracts of coniferous plantation managed largely by the Forestry Commission (FC) following the end of the Great War.
The AONB has many other designations and parts are protected as a Special Area of Conservation (SAC), a Site of Special Scientific interest (SSSI), Conservation Areas, Scheduled Monuments, Registered Parkland and Listed Buildings. Areas of the surviving heathland and portions of the FC woodland were the focus of considerable military activity during the late 19th and 20th centuries. Principal among this activity was the construction of two divisional-sized Great War camps and an associated training landscape at the commencement of hostilities. While this aspect of the Chase’s cultural heritage has not been formally designated, it is recognized as being of national and, in places, international significance.
During 2017, a detailed ground surface model of the area was produced using lidar and now, the images are being analyzed by specialists, to reveal a host of previously unrecognized and hidden archaeological features.
Although lidar has been in use in various industries for many decades it is a relatively new tool for archaeological survey (Crutchley & Crow 2010). Since its initial use in the UK for this purpose early this century its application has expanded enormously, not least due to the availability of freely accessible data from the Environment Agency (EA), the UK Agency tasked with the protection and improvement of the environment. This data has been available for free since September 2015 and has seen an explosion in its use for archaeological investigation. However, the EA data is collected for a specific purpose, and as such the resolution and the date of capture are not always appropriate for archaeological purposes, hence the need for specifically targeted flights such as that over Cannock Chase.
Lidar was commissioned from Fugro BV who flew the area in May 2016. The survey was flown at an altitude of approximately 550 meters AGL using a fixed wing Pilatus PC6 aircraft. This allowed for the capture of a minimum point density of approximately 25 points per m² over the project area. The vertical accuracy was equal to or better than ±15cm and horizontal accuracy equal to or better than ±20cm. The laser scanner used was a Riegl LMS-Q780 sensor with a pulse repetition rate of up to 400,000Hz. Navigation was carried out using dedicated flight navigation software, which uses GPS to aid the pilot in following the planned flight lines. The data was processed and gridded to both 25cm and 50cm and provided as both DSM and DTM.
It was then further processed using the freely available RVT toolbox from the Slovenian Institute of Anthropological and Spatial Studies http://iaps.zrc-sazu.si/en/rvt#v to produce multiple visualizations including standard hillshaded images as well as more complex visualizations such as ‘openness’. These were viewed in CAD and GIS as well as being made available to volunteers via an ArcGIS on-line site. They were then used, alongside other sources such as traditional aerial imagery and historic and contemporary maps to help locate and interpret the various features visible over the Chase.
The images show an extensive Great War practice trench system larger than was previously thought to be there. There are also signs of medieval mining pits and possible Tudor roads. Further new discoveries include a circular ‘bank and ditch’ – which, while not hillfort size might be the remnant of a small prehistoric farmstead.
These are now being explored from the ground, assisted by volunteers to confirm and better understand what they are. The project has trained a team of volunteers to accompany the Historic England investigators in field work, to record the features identified on the lidar and further understand what is being recorded on the images. This field survey is being supported by a team of volunteers working with historians in the Staffordshire Record Office who are developing an understating of the chases’ recent historic development from written sources. Much of the fieldwork training has taken place on the Chase, and due to the nature of the work and sensitivities concerning nesting birds is mainly be carried out over the winter. The project has developed the skills, and confidence of the volunteer’s and they have gained experience in recognising earthworks in a variety of locations/topographies, using digital recording, photography, assessing extent, nature, condition and threats in a site-based situation and working in small groups. Field work has taken place across Cannock Chase and has been guided by the excellent lidar results to reveal a forgotten and often hidden history. The main aim of this work is to identify, record and assess all archaeological features visible on the lidar. The results (mapping and monument records) will be incorporated into the national and local historic environment record and will be summarised in a Historic England research report. This will help Staffordshire County Council to better manage this unique and sensitive historic resource for current and future generations.
Gill Heath, Staffordshire County Council’s Cabinet Lead for the Environment said:
This is a fascinating project that will tell us much more about the Chase’s past and we’re pretty excited about the initial findings.
“We’re now seeing evidence for things on the Chase we never realised were there before. And the beauty about this project is that using the lidar technology we can uncover some of the county’s lost history without digging up and damaging any part of what makes it special today. It’s a brilliant step towards protecting the Chase’s natural splendour, understanding more about the landscape and preserving its history for the future.”
Helen Winton from Historic England added:
The quality of the lidar data is excellent and confirms the extent and preservation of archaeological remains hidden beneath scrub and trees.
“The sheer scale of the First World War camps is particularly impressive. It will help us to understand and care for these remarkable archaeological remains and help preserve them for future generations to visit and enjoy.”