Making surface water stop on roads.

[rachandsarai]

With heavy rain sometimes surface water and floods can happen from drains on the roads. What I'm thinking to stop this happening would be like what the A9 has just after the B874 road turn off to halkirk there is small gaps for water to go into. They could have that on all the roads and maybe it can stop surface water and floods that are likely to cause accidents.

[Big L]

Picture? Google link?

[JohnnyMo]

If I understand what you are saying, this is illegal now under pollution control regulations.

Over time small amounts of hydrocarbons, oil dripping or un-burnt fuel, will get deposited on the road surface. This get washed off when it rains so the rain water flowing off a road is considered polluted and therefore can not be allowed to enter the natural water course.

[KeithW]

The problem with small slots and gulleys is that unless regularly cleared they clog and make matters worse. What you do surely depends on the local geology and geography. If the road is running along a slope often the best thing is just to let the water run across the road and drain away naturally. In many flat rural areas you will see drainage ditches down one side but these are not very friendly if you put a wheel in something like this one where several vehicles have come to grief over the years especially at night.
https://www.google.co.uk/maps/@52.11940 ... 6656?hl=en

Another option on minor roads is a soft gravel rich shoulder, still easy to get stuck in but less likely to leave you upside down in a field.

Another issue is that where possible you do not want pollutants such as spilled fuel to get into the natural water channels where it could cause major damage to wildlife and agriculture. Diesel is not good for the ecology and is a big concern on trunk roads.

Highways England cover the subject of drainage in their Design Manual.
http://www.standardsforhighways.co.uk/h ... hd4916.pdf

[KeithW]

If I understand what you are saying, this is illegal now under pollution control regulations.

Over time small amounts of hydrocarbons, oil dripping or un-burnt fuel, will get deposited on the road surface. This get washed off when it rains so the rain water flowing off a road is considered polluted and therefore can not be allowed to enter the natural water course.

It may be illegal but I will wager that over 95% of classified roads do not meet that requirement.

I know that in certain locations where either the potential environmental impact is very high (close to a salmon fishery for example) is high or the risk is high drainage water has been directed to ponds and other lined traps but that is simply not the case for most roads.

I guarantee that it is what happens on this road as I used to drive it every day and the drainage method is simply a rather unfriendly deep ditch.
https://www.google.co.uk/maps/@52.16558 ... 6656?hl=en

[JohnnyMo]

If I understand what you are saying, this is illegal now under pollution control regulations.

Over time small amounts of hydrocarbons, oil dripping or un-burnt fuel, will get deposited on the road surface. This get washed off when it rains so the rain water flowing off a road is considered polluted and therefore can not be allowed to enter the natural water course.

It may be illegal but I will wager that over 95% of classified roads do not meet that requirement.

The cost of retro fitting would be very high but all new/upgraded roads I expect will need to comply

[orudge]

With heavy rain sometimes surface water and floods can happen from drains on the roads. What I'm thinking to stop this happening would be like what the A9 has just after the B874 road turn off to halkirk there is small gaps for water to go into. They could have that on all the roads and maybe it can stop surface water and floods that are likely to cause accidents.

Do you mean kerbs with drainage built in, like this? I'm not an engineer and don't know if these are any 'better' than traditional drains, but perhaps they're lower maintenance. They also look to the untrained eye as though they might provide better drainage as they are more frequent.

[KeithW]

Do you mean kerbs with drainage built in, like this? I'm not an engineer and don't know if these are any 'better' than traditional drains, but perhaps they're lower maintenance. They also look to the untrained eye as though they might provide better drainage as they are more frequent.

They should work well in that location but somewhere with a lot of deciduous trees could end up with problems due to leaves blocking drains. As I know from personal experience wet leaves dont decompose quickly. Despite having covers and wire mesh on the downcomer outlets I still have to clear my garden soakaways every autumn or end up with standing water on the drive. The first time was a pain as the previous owner had just lived with a wet drive but getting into the habit of doing it every year made life easier.

[Skinnylew]

With heavy rain sometimes surface water and floods can happen from drains on the roads. What I'm thinking to stop this happening would be like what the A9 has just after the B874 road turn off to halkirk there is small gaps for water to go into. They could have that on all the roads and maybe it can stop surface water and floods that are likely to cause accidents.

Do you mean kerbs with drainage built in, like this? I'm not an engineer and don't know if these are any 'better' than traditional drains, but perhaps they're lower maintenance. They also look to the untrained eye as though they might provide better drainage as they are more frequent.

They are called Beany blocks and they do offer a relatively good solution and are relatively high capacity, albeit they will still need to flow to some form of chamber/dumbwell/soakaway (unlikely owing to pollutant issues)

[rachandsarai]

Picture? Google link?

Haven't gotten a photo of it yet and not on maps yet.

[Dougman]

I think you're talking about a 'grip' or what I've also heard referred to as an offlet? It's a small channel cut in the verge to direct water into an adjacent drainage ditch. You can get preformed pieces to form them now like this

[rachandsarai]

I think you're talking about a 'grip' or what I've also heard referred to as an offlet? It's a small channel cut in the verge to direct water into an adjacent drainage ditch. You can get preformed pieces to form them now like this

Yeah it was more stone than that though

[nowster]

Why not put roofs over the roads, and maybe put solar panels on top?

[Alderpoint]

Why not put roofs over the roads, and maybe put solar panels on top?

Some houses have both of those. Doesn't stop them flooding which is generally cause by rivers rising, not (directly) by the rain falling.

[Johnathan404]

Why not put roofs over the roads, and maybe put solar panels on top?

Some houses have both of those. Doesn't stop them flooding which is generally cause by rivers rising, not (directly) by the rain falling.

Surface water is very different to floodwater. Houses do indeed have roofs and that's why they are generally dry in the rain.

[Alderpoint]

Why not put roofs over the roads, and maybe put solar panels on top?

Some houses have both of those. Doesn't stop them flooding which is generally cause by rivers rising, not (directly) by the rain falling.

Surface water is very different to floodwater. Houses do indeed have roofs and that's why they are generally dry in the rain.

Surface water on roads can come from other places that the sky. Initial post said:

With heavy rain sometimes surface water and floods can happen from drains on the roads.

[Dougman]

I think you're talking about a 'grip' or what I've also heard referred to as an offlet? It's a small channel cut in the verge to direct water into an adjacent drainage ditch. You can get preformed pieces to form them now like this

Yeah it was more stone than that though

That's the modern version in the link, they're usually just cut through the verge with nothing to line them at all

[skiddaw05]

The problem is, as usual, lack of maintenance. Over time even a preformed channel could fill up with earth and suchlike and may get buried altogether, or get annihilated by the grass cutter

[Fenlander]

The problem is, as usual, lack of maintenance. Over time even a preformed channel could fill up with earth and suchlike and may get buried altogether, or get annihilated by the grass cutter

Spot on. There's also the issue that over time the ground at the side of the road slowly gets higher and if left alone creates its own physical barrier to runoff where there wasn't one before, at the same time the road itself might be slowly sinking due to constant use making the height difference even more pronounced.