.HGS Active Sites.

The Bourne Gutter is a unique winterbourne valley, where the river rarely rises and has in the past been called a woe stream because its flow coincided with major disasters in English history.

At it's current maximum extent, the visible flow rises at Corner Spring and can be seen to it's confluence with the River Bulbourne at Bourne End. See map below.

The water levels and flows have been monitored since 2014.

Discharge measurements using a current meter at set stations along the course of the stream is a standard method of data acquisition, providing results that can be used to estimate watershed outflow. This technique also allows for the identification of stream sections that are hydraulically gaining, where the stream is fed by groundwater from the catchment as well as sections that are losing flow invisibly, where water infiltrates into the ground and recharges the local aquifer. Data collection was carried out in 2014, 2021, and 2024. The results are presented in Transactions of the Hertfordshire Natural History Society.

Background
HGS became involved with Geoconservation of the site in early 2018 at the invitation of Hertfordshire Countryside Management Services team. A plan was developed, and in March 2019, with funding from the GA Curry Fund, a small excavator was brought onto the site to remove loose rubble from the chalk face and to excavate into the underlying Chalk Rock (Hitch Wood Hardground) section. All the material excavated from the site was piled up so that visiting geological parties and groups of local school children can collect fossils safely.

For more information, visit the RIGS page and scroll down to the section on Hill End Chalk Pit This includes a video visit to the site, the Information Board at the site, and a brief history of the site via a pdf download.

Geoconservation Activity
Initial clearing of vegetation and improved access was done after the excavation. However, over time the growth of vegetation and erosion of the exposure has required the need for working parties to maintain the site.

This page has a description of our most recent activity. Click to read about Previous Activity 

2025

On the 22nd March, a bright but cloudy day, a group of nine of us met up at the Hitch Wood car park ready to spend the morning working.

The site had degraded since we were last there with brambles covering parts of the exposure and a significant build up of talus material covering a large proportion of the face.

Great teamwork meant we were able to clear all the brambles, a tricky operation on the steep slope. Also, we managed to expose a good part of the face using pickaxes and spades, with the loose material moved to the adjacent spoil heap so available for any keen fossil hunters.

Thanks to everyone involved we were able to leave the Hill End site in a much-improved condition for visitors. 

Background
The site was excavated in 2012 under the leadership of John Catt, assisted by Clive Maton. It had the agreement of the owners, the National Trust, and the consent of Natural England, who have responsibility for SSSI’s.  A 10m wide face was exposed which allowed  a detailed view of the sedimentology and the collection of samples to use in the dating of the deposits by Cosmogenic Isotope Analysis. The excavation originally dug down to the chalk 9m below the surface, but the lowest 4m were back filled for safety.

For more information see Videos and Trails and Information Boards.

Geoconservation Activity
The site was left in good condition so that visitors could view the exposed section, but gradually the vegetation began to take over. Therefore, with the agreement of the National Trust and Natural England, in 2017 we held our first working party to clean up the site.  We have continued to do this on an annual basis.

This page has a description of our activity in the last year. Click to read about Previous Years Activity 

2026

February

We were particularly fortunate to pick the 14th February for this year’s Working Party. It had been very wet through January and early February, but we were blessed with the first lovely sunny day.

Nine of us (two had to leave just before we took the team photo) arrived at 10:00 ready for action. We were also very pleased to get the help again this year from Ashridge National Trust Management Team, by Jenny, one of the Rangers, armed with a hedge trimmer to speed some of the clearance.

The 2025 refurbishment gave us a good starting point this year. In particular, the newly created steps on the left and side of the main face were a real boon providing good access to the three levels of the main exposure.

Through the morning, all the vegetation cleared and deposited in the nearby designated pit where it will compost down over the twelve months. We also cleaned the exposure of vegetation and eroded sand. The sand was heaped at the opposite end of the pit, as that area is of no geological value as agreed with Natural England.

Another great day’s work thanks to everyone involved.  

March

A new Information Board was installed at Little Heath Pit as part of the 2025 refurbishment project. We provided the text and sourced the photos, and the National Trust Design Team created the image. It was funded by Natural England.

Hertfordshire Puddingstone boulders were placed at this location in the early 1990s, having been found by builders working on the foundations of a nearby house. They were prized by the local community and often visited on geological excursions, but no information board had been installed. Following a visit led by HGS in 2015, the HGS Committee agreed that we would run a project to put one in place.

A successful application was made to the Curry Fund of the Geologists Association to access funds to provide onsite information for this RIGS site.

The next step involved simultaneous consultations with interested stakeholders which included the local residents association, Berkhamsted Town Council, Dacorum Borough Council Highways Department who maintain the footpaths and grass verges on behalf of the County Council.

An assessment of plaque styles and prices led us to select a contractor based in Rochester, Kent.

Finally, after eight months from stating the project, we were ready to install the plaque. So, on a sunny morning in July 2016 a small team did the installation in a couple of hours:-