About

This blog is about the Hampstead Heath Ponds Project and will track progress throughout the construction phase.

Following advice from a government appointed panel engineer, the City is undertaking safety works on two chains of ponds on Hampstead Heath. This work will be mitigated by important ecological improvements and will ensure the dams on Hampstead Heath can withstand extreme rainfall events.

For background information on this project please visit: www.cityoflondon.gov.uk/pondsproject

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2 Responses to About

  1. Nigel Shindler says:

    Now that the project is virtually finished (and looking very impressive I must say!) It would be interesting to see a more detailed plan and explanation, of how it is intended to work in practice. In other words, exactly how and where does the water enter and leave the two chains of ponds, how does it normally run from one pond to the next, and what is supposed to happen in the event of serious flooding.
    If this is already shown somewhere on the site, perhaps you could kindly indicate where it is?
    Thanks very much!
    Nigel

    Like

    • Hello Nigel, thanks for your comment – we are glad you like the look of the finished scheme. The information you are looking for can all be found in the Preferred Solution Report: http://www.cityoflondon.gov.uk/things-to-do/green-spaces/hampstead-heath/ponds-project/Documents/hampstead-heath-ponds-project-preferred-solution-report-rev2.pdf
      The section ‘Design Principles’ on page 5 may answer some of your questions. In simple terms, during normal conditions, water runs down the chain of ponds through interconnected pipes, as it always did, before discharging into the sewar system. We have improved the capacity of some of these pipes as part of the project. In a very large storm, these pipes alone cannot hold the quantity of water so the ponds may overtop or spill-over and water will travel across the ground into the pond below. We have built spillways at the ponds so that water can safely overtop without damaging the integrity of the dam. These spillways look like grassy channels in most cases (Model Boating Pond, Stock pond, Vale of Health Pond, Viaduct Pond) and in some places are concrete structures (Hampstead No. 1 and No. 2). These needed to be concrete as there was not the space to construct a grass spillway without removing more trees. We have also built in additional storage on each chain of ponds – with a dry dam at the Catchpit, and by raising the dam at Model Boating Pond by a significant height. This means that a large quantity of water can be temporarily stored on the Heath during a large flood before then being discharged down the chain through the pipes at a slower rate, therefore missing the peak of the potential storm. The water does all end up being discharged as it did before, but in a controlled way without any risk of dam collapse. Hope that makes sense!

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