We are optimistic that 2025 will mark the year we can at last celebrate the completion of the Forge Dam renovation project.
We have been informing members about the problems that have kept the dam in its current condition since the main contractor abandoned the project a few years ago.
The story so far
We have aimed to address the wall leak and replace the spillway penstock that deteriorated more than 40 years ago. Progress has been slow with the council, however last year we managed to organise several meetings with them, which has resulted in what we consider to be considerable progress.
Progress
Towards the end of last year the council instructed a consultancy (JC Consulting Ltd), who managed to identify a practical range of options for managing water flow through the sluice channel, and remediating the leak.
Consequently, and following discussions, it was determined that the primary objective was to stop the leak from the sluice channel while continuing to use the millrace penstock to manage the water level in the dam, without replacing or renewing the spillway penstock. This decision was influenced by several factors, including the fact that opening it would adversely affect the downstream habitat. The millrace penstock, which was replaced during the main works, will be utilised to control the pond's height when required.
So, we are confident there is a realistic plan that will finally deal with the leak/s and prevent the pond from draining during the summer months, and the council have identified a contractor who can undertake these works (ESH Civils)
Plan
These works are undoubtedly complex, but to summarise, the plan involves exposing the sluice channel from above on the 'dry side' while keeping the dam wall intact, addressing any leaks before covering it back up. This method would also eliminate the necessity for a coffer dam within the pond during the process.
The ongoing issue of emptying the silt trap just above the pond has been a persistent challenge for us. The last time it was emptied was in March 2020, prior to the main works, and we aim to address this recurring issue with this final project. In our last meeting, it was suggested that the silt trap should be emptied twice a year, with the first occurrence happening during these works. Future maintenance of the silt trap will be managed by the Parks Department. Additionally, the manhole cover to the millrace penstock chamber will be raised to eliminate a potential tripping hazard.
Next Steps
We have now received cost estimates that allow the council to instruct ESH to undertake the exploratory works. This will involve some obvious works in front of the cafe from the end of February and into March, so we need to be prepared for a few restrictions in that area for a few weeks.
But what if?
Following the investigations the council should have a better idea of exactly where the leaks are, and of course the scale of that is yet to be discovered. However, based on these findings, final designs will need to be drawn up and, assuming no further issues are discovered, turnaround on design is anticipated to take several weeks.
And a bit of dissapointment!
Although this stage was reached in January, the final stages of the work cannot commence until September. This delay is due to various factors, such as the numerous legal hurdles ESH must navigate with The Environment Agency, the nesting season, and the need to protect Cray Fish below the spillway, which hinder such work from proceeding.
Sadly, we must therefore prepare ourselves for the disappointment of witnessing the pond's significantly reduced level for another summer, if we experience another extended dry spell.
Apologies for ending on a negative note, however, we will certainly keep you informed about progress as much as possible as we proceed through the Spring and early Summer.