Buying a property next to a small river/stream

I’m thinking of buying a property in France as a holiday home for a couple of years before retiring there (early retirement obviously, I’m not that old!).

Anyway the property I am drawn to has river frontage. I’m not bothered about flooding, I’ve looked in to it and all the experts tell me it is unlikely to be a problem at all.

So, flooding aside, what are the good and bad points of living near water.

We’re just about to do the same thing Ian although in Derbyshire, not France and our permanent home, not a holiday home so not quite the same thing…..
The stream is just across a very narrow quiet road from the house. We spoke with our (to be) neighbours before we committed to it and they said it’s lovely. Nice sound of running water when you’re sat outside, can’t hear it when your inside, no issues with rats or anything like that but it does attract other wildlife and birds although you have to sit still for a while before they’ll make an appearance.
It gets a bit more noisy when there is a few days of heavy rain and snow as the house is in a steep valley but the neighbours on each side had only good things to say about it.

We have a small river at the back of the house which can go from a nice quiet to a fairly fast torrent during heavy rainfall. Obviously you get used to the noise of the river once you’ve moved in. We have a 1 year old kid and I imagine in the future I’ll have to fence the river off from the property eventually so that might be a consideration if you’ve got grandkids. I suppose other good points could be it attracts wildlife and you could run some lights off the river using a turbine like the priest that lives next door to us does! Not any negatives I can think of but not many pure positives either.

Good – pretty

Bad – it might flood, garden may always be damp, infiltration to sewers

If the stream is small and there’s not much catchment upstream and the house is elevated above the stream by several feet (like 4+) I wouldn’t worry about flooding myself. Although as a hydrologist by training I’d have a good look round at the house and neighbouring areas to see if there are signs of past floods.

Sewers can be an issue though depending on how they are draining. You don’t want them filled with river or groundwater and backing up into the house.

Fishing.

water source heat pump

Clean feet!

Mosquitoes?

You might find it expensive to insure. Doesn’t matter if it’s actually likely to flood if someone in an office at the other end of the country has coloured the square near you in dark blue because you’re near a water course.

Have a friend who has retired to Brittany and lives next to the Brest – Rouen canal. He has had problems with flooding, I’l ask him about insurance. Aside from flooding my concerns would be whether structurally the house is on good foundations. As above insects could be a problem. Grandkids visiting could be a drowning hazard for them ? Aside from that fun potential with canoes and model boats 🙂

Have a friend who has retired to Brittany and lives next to the Brest – Rouen canal. He has had problems with flooding

On a canal? 😯
How does that work, then?

Thanks all. I had thought of mozzies but not rats and other creatures.

Good luck with your purchase Steve, I hope it goes smoothly for you.

Ian

This is a good idea, obviously do some sanity checking for flood risk, but its a wonderful thing.

We are just in the process of upgrading from a stream to a waterfall. The sound when you get home just washes the stress away. Can’t recommend it enough.

There will be creatures. They live in the river, in my experience they don’t come in doors. If you are lucky there will be bats too 🙂

Before buying I spent some time in the local archives. I found photo archives of recent spates and maps of areas concerned by floods back into the mid 19C. Roughly where in France?

It’s in Limousin, Haute Vienne region.

I don’t think the flooding is a huge concern as the house is quite elevated on the plot, it is quite a long way upstream and the catchment for the river is fairly flat.

I definitely want bats!

Ian

Worth looking in the loft. Bats are cool and everything, but you don’t really want a colony in your loft that you can’t shift, and a thick layer of guano and ammonia above your bedrooms.

Bats are a bit of a nuisance in the loft, we’ve them in our place in Ireland. Mainly because they make a lot of noise when they come back just before dawn and settle down for a kip. iirc there’s no health risk from their droppings and they eat midges which is good

In laws used to have a house (converted early Victorian cider barn) with a stream that ran under the house near Wells. First thing they did was to add a grid to prevent any small children being sucked under the house. It meant that after heavy rain they had to clear the grid but prevented any blockages under the property.

Flooding down the road was a problem (Somerset Levels, the new farm flooded, the old one near them didn’t) as was a blockage where the stream ran under the road downstream. Luckily the local farmer was up for impromptu use of a JCB in the middle of the night.

Nice having a gurgling stream in the garden.

In the Limousin you’re not in an area where you’ll be concerned by an Episode Cévenol which produces very high rainfall in a short time. You can therefore apply simple maths to the catchment area to work out how much water in m3 is going to go past if say 150mm falls in 12h on already saturated ground, and an average flow. How reactive the rive rwill be will depend on how high up the catchment you are – the further from the source you are the slower the response.

Once you’ve got an idea of how much water needs to flow you look at the valley profile, gradient and work where the critical points are which will cause water to back up. It’s usually pretty obvious just from using you eyes and common sense; bridges, walls, narrowings. Flat areas with a critical point at the end are bad news.

My parent’s house is by a river (in the UK), only downsides really are the size of the rats the cats would sometimes bring back as presents and fishermen managing to go up the wrong side of the river and ending up trespassing through the garden trying to get back to a road (usually harmless but there were some dicks that caused damage to fences and gates).

Limousin, Haute Vienne you say? One word – Ragondin – Google it. They are known as Coypu or beaver rats. They are literally rats the size of beavers. I’ve seen them on the Creuse a little further north. Some friends bought a summer house there near a river, when they came back on holiday a colony of Ragondins had moved in. They eventually sold the house.

On a canal?
How does that work, then?

@Count canals often include stretches of river and typically have rivers / streams flowing into them – perhaps I should have said “navigation” rather than canal. We used to live overlooking the river Wey navigation and in the winter there is a big field / flood plane which took excess water, after really heavy rain they used to shut the bridge in Guildford town centre.

bad points of living near water

Do the French have midges like in Scotland?

Nowhere has midges like Scotland. 🙂 They’re called moucherons, there are various types but I’ve never experienced anything like Scotland’s west coast. Mosquitoes are bad in all the flat wetlands of France south of the Loire.

We have a brook running in a culvert under our house. It has flooded twice, when the water just ran around the house and carried on down the street. Our floor level is 12″ to 18″ above the garden so for it to flood the house would be a flood of catastrophic volume. The insurance co. are not interested because their maps don’t show us as being in a flood prone area.

edukator – do you have no faith in the local flood search report/maps? We got a big pile of reports for the flat about avalanche/rockfall/seismic/flood risks with colourful maps etc. Are they not very useful in real life?

Mosquitoes x1000

The OP has just posted a new thread which reminded me about this one. So I’ll reply to Stoner. Those colourful maps are very general and the flood ones in particular only a rough guide. Taking local examples:

The seismic risk here is high due to the North Pyrenean fault. However, if you check historical records you find there are sections on the fault which move regularly with minor earth quakes and others that move rarely but violently.

We’re in a flood risk area on the map but I’ve gone through historical records and the flood water has never got anywhere near us in 150 years. The river would have to get 3m above anything historic in a valley shape where every extra metre above historic flood levels increases channel capacity many times.

The avalanche risk maps are pretty good.

We have a brook running in a culvert right under our house. It has only flooded once, about 3 weeks after we moved in when a load of debris came down and blocked the bridge in my neighbour’s garden upstream, meaning the water flooded out and ran into our garden and around the house. Since our DPC and floor level is 18″ to 24″ above the surrounding garden it didn’t threaten the house at all and a flood that did get into the house would be a catastrophe, probably resulting from the reservoir dam bursting upstream.

Our insurance company isn’t interested because we are not in a flood area. The river valley slopes steeply so water runs under our house very fast. The only bad aspect of it is that when the water is high, boulders tumble down the stream bed making a thump-thump-thump noise, which I hate.

In the recent floods the water level reached the bottom of my neighbour’s bridge but still had two feet to go before it would have reached the underneath of the massive concrete and steel bridge on which our house is built, separate from the culvert. Still, it was a worrying morning.

The benefit is that we get herons fishing in the brook and under our house is a huge space, well ventilated, so the structure of the house is nice and dry.

Ed – yes, I think the avalanche ones are going to be a bit more accurate, mainly because they have a greater number of events from which to determine the risks.

Fortunately our flat is outside of all risks, but sometimes when looking at how much is built on the moraines in the Valleé d’Aulps you cant help but feel some of the properties are highly precarious.

After the April storms last year, the river Dranse took huge chunks out of some moraines, leaving some chalets only 1 more “1 in 50” event from being down in the valley bottom.

I’m a Geologist, our ski flat is on bedrock and not threatened by any landslides short of the whole mountain moving. There are many flats in the resort I wouldn’t buy and in the time we’ve been there two chalets and a stone house have been demolished by landslides.

The col d’Aubisque had to be diverted by a huge landslide which is still slowly moving down.

That French landslip looks quite like the one in Derbyshire.

Even solid rock isn’t guaranteed solid, as residents of the valley below Zermatt discovered in May 1991:

https://en.wikipedia.org/wiki/Randa_rockslides

We’re on Cretaceous limestone, the landslide down the valley was Devonian schist, like the landslide you link. The orientation of the cleavage and state of weathering of the rock are to be considered – “solid rock” is not always solid. The limestone in this part of the world moves when more easily eroded rock under is removed allowing blocks of limestone to fall off, the whole mountain moving is unlikely.

I’m unlikely to be proved wrong in my lifetime even if an increase in exceptional rainfall events is making landslides more likely. The degree of water saturation and pore fluid pressure are critical to movement by deep rotational slip which is the way most landslides move.