A Gardening Solution to Heavy Rainfall

You enjoy your gardening and are proud of what you’ve accomplished, but you’re also aware of the threat that heavy rainfall can have on your gardens structure. Brisbane’s climate receives heavy and repeated showers during the months of November through to March which can devastate a garden’s composition. A smart way to deal with such conditions is by incorporating a rain garden into your property this weekend.

Brisbane's Monthly Average Rainfall  

A rain garden redirects water runoff sources, particularly from a roofs downspout and or rain water tank, through a filtration system towards a garden bed. They can vary in size from a planter box setup all the way to a bioswale requiring excavation of your garden bed.

Benefits of a rain garden:

1. Through bioretention contaminants are removed from stormwater, acting as a hydrological buffer. Water can then be used for plants or funneled back to the drainage system;
2. Waterlogging plants mitigate flooding;
3. Conserve water, reducing the need for irrigation;
4. Provides a habitat for native birds, butterflies and insects;
5. Functions well in prolonged droughts;
6. Makes your property more attractive.

One of the easiest implementations of rain garden is accomplished with a planter box. Below is an ordered list of the materials and steps to be taken.

Materials:

1. Get yourself a pre-made planter box, alternatively you can construct your own from scratch with some wood and nails.
2. Stick some builders plastic to the sides of the planter box to prevent water moving laterally.
3. Install PVC or AGI drainage pipes and fittings to direct the downspout water flow to the planter box (if required).
4. Install an overflow pipe (PVC) in-case of flash flooding.
5. Get Drainage Gravel (10-20mm) to prevent the sand particles from entering the pipe. 
6. A layer of Coarse Sand will help to hold the water. Ensure enough room is left for a top layer of pebbles.
7. Pick some waterlogging and drought resistant plants, specifically fibrous rooted plants. The Brisbane Council offers residents a variety of free plants.
8. Top the planter box with medium sized pebbles to avoid any contents flowing away.