Digging foundations next to a stream

Strapped

My neighbours have put in for planning permission to knock down their bungalow and build a replacement house which will occupy almost the full length of the plot, up to about a metre away from the devon bank at the back (north) of the plot. The site is on a slope (east to west), and they are planning to "dig down" on the higher (east) side. But as I said, there is a devon bank at the back, with a stream behind it (in fact, there's a small duck pond there where the stream runs through the garden of the big house behind). We're a bit nervous of what sort of things could go wrong in this scenario, as we are downstream/downhill and would be the ones flooded if the stream were to "escape" its current course! Also, there is a swimming pool on the other side of the east boundary, and I wonder whether this will "stay in place" if foundations are dug into the side of the slope below it?

Any engineers who could reassure me, or tell me what assurances we should seek from our neighbours if they get planning permission to go ahead? Thanks!

Errata

In your situation I'd be talking to the Planning Officer myself, and I wouldn't be discusssing anything with the neighbour in case of any future repercusions. I'd also not be talking to my insurance company along the lines of "what if........" at this stage. I'd also make sure I got everything in writing from all officials and any others involved.

Strapped

We will be objecting to the planning permission anyway, mainly on the basis that they want to turn the property around so it stares at ours, but I wasn't sure whether these sort of engineering issues were something that could be taken into account re. planning permission. Would this come under the broad umbrella of "good design" do you think?

Errata

I don't think the design is the problem, it's the nearness of the build to the stream and your house in the way of any possible flood. Don't be shy, talk to the Planning Officer and get some idea of which way the wind's blowing.
Along the lines of "I'm sick with worry and hope you can put my mind at rest".
Given that conservatories need to be sited at least a metre from a boundary I can't see how your neighbour will get away with a new building this close to a devon bank.

ormus

assuming they are mortgaging the new house, you can be sure that the lender will take great interest in any major change of levels, or changes to water courses.

Strapped

I'm not sure whether it will be mortgaged. I know that they bought the bungalow cash, as it's a concrete prefab. They don't intend to alter any water courses (in fact, they don't mention the stream at all!) but I'm a bit worried about any "oops, there goes the bank..." incidents occuring.

Mr_Warren_2

Errata wrote: »

Given that conservatories need to be sited at least a metre from a boundary ...

Our conservatory was build on the boundary itself using the "Party Wall Act 19 something" but of course, our neighbours were supportive of our new construction.

planning_officer

If the new house is to be built within 8m of a watercourse (i.e. this stream), then the planning department should have consulted the Environment Agency as part of the planning application - they will advise on this issue.

planning_officer

Errata wrote: »

Given that conservatories need to be sited at least a metre from a boundary I can't see how your neighbour will get away with a new building this close to a devon bank.

Conservatories don't need to be built 1m from the boundary - every planning authority has different planning policies for extensions and distances to the site boundaries. I've yet to see one where single storey extensions can't go right up to the boundary, although it is fairly common for two storey extensions to need a gap of at least 1m to the boundary at first floor level.

Errata

planning_officer wrote: »

Conservatories don't need to be built 1m from the boundary - every planning authority has different planning policies for extensions and distances to the site boundaries. I've yet to see one where single storey extensions can't go right up to the boundary, although it is fairly common for two storey extensions to need a gap of at least 1m to the boundary at first floor level.

Apologies, my mistake.