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Plants and delaying groundwater.

NorthernJoeNorthernJoe Posts: 656
Are there plants that are better at delaying groundwater or rainfall run off? Steep garden above limestone base rock that's possibly not too far below the soil in places. Or so I've been told by neighbours. I don't think the soil is that high in pH because it has got a lot of variety in the garden, I think some don't like alkali too.

There's space for trees,  shrubs and ground cover plants.  I'd prefer no more trees or at least nothing that grows too high or wide or gives you too much shade. We've bit enough shady bits would be nice to have sunny spots too.

Anyone got planting ideas? We're looking at more landscaping solutions too like French drains or even berms. This is planting to help out a bit,  if that's achievable. 

Posts

  • raisingirlraisingirl East Devon, on the Edge of Exmoor.Posts: 5,575
    trees do, for sure - that's been studied - but I would have thought large woody shrubs will as well. 
    If you plant a shrub on a slight ridge of rocks and soil, you create a shallow dish above it. Water running down the slope will pool in the dish, and it will soak down into the ground around the shrub's roots, rather than running off the surface. Plants with woody stems break up the surface, which lets the water soak down more readily. The deeper the roots go, the stronger that effect, which is presumably why trees are good at it.
    Hedge banks, even shallow ones, are quite effective at slowing run off and reducing hill wash
    “Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first” 
  • NorthernJoeNorthernJoe Posts: 656
    Could this cause water to head deeper and skip surface plant roots or generally speed it down to the house and causing a problem? I think keeping it surface is better as I have a surface drain lower down.  Although I was thinking trees and woody shrubs, shrub form of trees even coppiced would have deeper roots soaking up lower groundwater. I suspect its groundwater and base rock just below the garage ditching it up through the concrete garage floor. The water bubbling up from under the garage is why I'm looking at planting as well as other options (another thread about this).
  • ErgatesErgates Devon, east of ExeterPosts: 1,508
    I don’t think any amount of planting is going to sort out water bubbling up under the garage floor. Maybe better to get that properly investigated first in case any drastic building work needed. Might there be a spring coming to the surface?
  • DovefromaboveDovefromabove Central Norfolk UKPosts: 77,498
    edited 7 February
    It sounds to me as if the level of the garage floor is below the water table … that’ll require remedial drainage work and the garage will need ‘tanking out’ to solve the problem. 

    Is this a new build or has some building work been done in the vicinity recently? Could some recent work have damaged previously installed ‘tanking’. 

    I suggest you get professional advice … this doesn’t sound like a DIY task.  Have you checked to see if your buildings insurance covers such problems?
    “I am not lost, for I know where I am. But however, where I am may be lost.” Winnie the Pooh







  • 'Bubbling up' suggests its under pressure. If rock head is shallow you may have broken into artesian ground water.
    Or you've bust a pipe 😬
  • NorthernJoeNorthernJoe Posts: 656
    It's not a burst pipe it's heavy rain. Seriously heavy rain.  Neighbour has it too but not as bad. He has water issues elsewhere due to issues at the back of the house.

    Water table? Possible but we are higher than houses over the road and I know at least one had a apace under the house that in really wet conditions had standing water in it. That was likely water table level and unlikely to rise several metres.  Especially since the flooded house I know about stopped getting it 5 years at least before the owner moved out and that at least 5 years ago so 9 years since water table was several metres lower. 

    Of course water table can follow slope in circumstances it really shouldn't  be the issue.

    Artesian spring? Old maps pre 70s when these 8 houses were built show nothing like a spring historically in this area. 

    Bubbling up doesn't need pressure  just a flow. This happens with surface run off and groundwater I reckon. Can't see water flowing anywhere that could lead into the garage. I need to investigate the drain between the patio and the house.  It could be leaking into the house. There's a breeze block wall to the hill side of the garage.  Behind it I expect a slope of concrete. If its leaking through from the drain onto this surface then under the wall to bubble up from under concrete flags we have freezer, dryer, shelves,  etc on. There's an undercroft the other side of the house separated by another breeze block wall at the end of the garage.  This goes full depth of the house from front wall to back. The back wall is basically a concrete slope to the underside of the floor above. This is dry but in reckon the hidden part under the house at the garage side should be similar. 

    This is seriously only an issue when the heavens open.  The sort of rainfall that happens maybe twice a year.  If you are out in it when it starts you get wet through in seconds it's that heavy. In those cases it's spells of very heavy then a little respite. Slowing water running down the hill can only help which is what I'm looking at.   Not a solution by itself just another piece in the solution. Planting, garden landscaping and a drainage option. Tanking out is possibly going to send the problem elsewhere. 

    Is there anywhere you can get to see local drainage system in a plan? Would that show house drainage points? Points where run off enters the drainage system? I need to identify where one drain goes.  I've not been able to identify the flow direction.

    We read that ferns hold water, more than other ground cover plants, is that right? Tres, shrubs and ferns. Might make a decent show, any suggestions?
  • Lizzie27Lizzie27 SomersetPosts: 9,271
    Your local water board should be able to send you a map showing water and sewer pipes, not sure if they'd show anything else.
  • raisingirlraisingirl East Devon, on the Edge of Exmoor.Posts: 5,575
    Lizzie27 said:
    Your local water board should be able to send you a map showing water and sewer pipes, not sure if they'd show anything else.
    IME the water companies charge for them, they come with a load of caveats about accuracy and for drains they are generally next to useless, unless there's been recent work done and the records updated. You're better walking the streets looking for manholes and making some educated guesses about how they are joined up
    “Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first” 
  • DogmumDogmum DerbyshirePosts: 72
    edited 7 February
    We had water bubbling up through cracks in our concrete path when it rained heavy.  We were worried that we had a collapsed drain but it turned out that our soak away rain water drains, built in the 1950s weren’t actually working anymore and heavy rain had no where to go.
    It might be worth checking what kind of rain water drains you have and if soak away, where they are trying to soak away to.
    Tomorrow is another day
  • NorthernJoeNorthernJoe Posts: 656
    I think I do need to track one drainpipe's drain at the corner above the garage. That drain has the linear drain running into it. Plus a water butt that has a diverter that causes a blockage with leaves. This causes a gutter overflow. No idea how we get so many leaves.  It blocks up so much that I think we might take the but out.  
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