5 landscape ideas to prevent flooding

Happy dog sitting on a flooded lawn

The end of summer weather hasn’t been too kind to us in little old New Zealand. Experiencing two tropical cyclones in a short space of time, many parts of the country have suffered severe flooding. They say when it rains, it pours, and the past couple of weather patterns have done just that. If you’re fed up with your backyard filling up with water, and the lawn needing a lot more care, then we have a few creative landscape ideas to help you.


Identify the problem areas

You will need to observe how water enters your lawn, where the gravity pulls it, and where it ends up. Flooding only happens when the soil can’t absorb any more water, so it may take a few heavy rains for you to see. When the soil can’t drain away any more water it will run to the lowest point in the lawn which will be where the drainage needs to be. 

Other signs your backyard is prone to flooding:

  • Pooling of water on the driveway
  • Water stains in the bottom level of your home
  • No roof top gutter system
  • Lawn sloping towards the house

You may find that a bit of water actually trickles in from other parts of your property, like the driveway or downpipes. If this is the case you will need to find a way to divert this extra water. 


1. Diverting extra water

If you have no guttering or spouting systems, sure your lawn might be slanting the right way but it will be no match for the roof run off come a few days of rain! Consider installing a few gutters to collect the rain off the roof. 

Diverting downspouts away from your house and lawn in heavy rain will prevent water pooling near your house. The easiest way to do this is by using a downspout extender. These can be easily found at your local hardware store along with an elbow corner pipe. This can be easily attached at the base of the downspout and the water diverted away from the house into dry areas, or into any drains. 

Remember to check and clear blockages in your downspout extender prior to heavy rain to prevent overflowing. Just make sure you don’t divert your drain towards your neighbours or  somewhere else it will become a problem. 


French drainage system in New Zealand garden

2. French drain

A french drain is an ideal way to control excess water without be too much of an eyesore. It works like an underground creek, a drainpipe below the soil that diverts water to areas that are dry. French drains are ideal to be constructed where the water is pooling, around gutters, garden beds or uneven driveways. There are so many ways to create these french drains, so here is the basic guide so you know what labour is involved, and if it would be an option for you:

  • Get all the necessary materials (pipe/gravel/plastic) for the method you choose. 
  • Dig the trench to fit the pipe leading towards the space you want to divert excess water.
  • Line the trench with plastic or gravel.
  • Fit the pipe to the trench.
  • Fit the entry point for water, whether it be stones or a drain like top. 
  • Test it!
  • Cover the trench with stones/soil or grass. 


There are professionals that are experienced in french drainage, so have a look into those options if you are not so keen to start hacking away at your lawn. A DIY french drain can be done easily enough, just make sure you check with your council as to whether you are allowed to dig or not. There are so many ways you could construct your drain all using different materials. 


3. Rain garden

If you have a spot in your lawn constantly taking on a bit of water - this could be the simple solution for you. 

  • Select a spot on your property where water will run into it and plan out an appropriate shape for your rain garden. 
  • Plan out the shape of your rain garden and research some native plants, flowers and grasses that do well with large amounts of water. Plan to plant the ones needing a more drier climate on the outer edge. 
  • Dig up the turf of your grass at least 20cm deep. Create a berm on the edge as a border and remember to add an overflow, a break in the berm where excess water can flow through. 
  • Plant the grasses and natives and add a heavy mulch a few inches thick that won’t blow away. Feel free to add stones or other grasses on the outer edges. 


4. Swales

If water is running down your driveway, or down any hills in your property - this may be the answer for you. The basic function of a swale is to redirect water to other places, and soak into the soil along the way. So it is perfect to incorporate where there will be lots of water hitting as it can delay and soak up the water running to the bottom of any gradients. You might have seen these on large hills, or farms looking like a staircase. It prevents the water from rushing to the bottom and creating gullies - and from taking all the nutritious top soil with it. 

All you need to do is dig a long shallow trench along the contour of the land, and the water will flow where directed, spreading out the impact of the water. Swales can definitely be incorporated into your residential home by yourself, or if the job might be a bit bigger, consulting a landscaping professional is a good idea.  


The process:

  • Locate the water run off areas, where it rushes to as that will be where you need to prevent it from going to as quickly. 
  • Locate were you could dig the trench to direct the water, maybe a rain garden, drain or other part of lawn. 
  • Dig a trench 25cm deep or more along the contour of land, and adjust the width to your preference. 
  • Place the excess soil on the side of the berm, downward hill side. 
  • If building multiple swales, have an overflow spout running between them. Lastly, plant grass or plants on the berm to hold in place. 


5. Kit out your backyard

A key part of preventing flooding is preparing for bad weather to come. You can do this by:

  • Using heavier mulch on plants so that it that won’t float away come some rain. 
  • Planting more water loving grasses and plants in areas that take on water. 
  • Using rain barrels under spouting to collect water in heavy rain. These can then be used after wild weather. 



So there we have five ways you can prevent your lawn and garden flooding. Get creative and give it a go! Many of these methods can be done yourself, and now is the perfect time before winter sets in. Remember to do a few more preparations for wet weather and keep up with your lawn mowing even in winter. You could even consider working together if a few neighbouring properties are in the same boat with flooding issues. 

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