According to Wikipedia, a French Drain is a trench filled with gravel or rock or containing a perforated pipe that redirects surface water and groundwater away from an area.
Rain garden / Rock garden refers to a garden that takes the advantage of the water from the rainfall in growing plants. The garden is designed to withstand a great level of moisture and concentration of nutrients.
A lot of people in Ontario will probably recommend the construction of french drains as the only sole available method of fixing water drainage issues, often, forgetting other methods like the
building of Rain gardens.
Let us look at how people can repair still water problems in their homes through the building of rain gardens that can store water in the ground and improve soil health. Read through widely.
How To Create an Effective Rain Garden
Heavy storms may threaten infrastructure in urban areas such as Ontario as the storms mostly end up causing disastrous floods that impact communities-homes negatively.
Rain gardens can bring positives for communities that are upstream from low-lying areas that are susceptible to damaging storms.
Planning a rain garden is an exercise in balance. Specifically, you are trying to balance the amount of rain that falls on a property with the amount of rain that stays on the property long enough to be absorbed.
Choosing a Location
A rain garden location can be decided by the following factors:
- your construction budget
- storm water managing needs
- accessibility to the public
The rain garden should be located in a place where it will receive runoff. Check to make sure runoff flows to your site or could flow with minor modifications, such as cutting a space out of a curb.
STEP 1: FIND A PERFECT SPOT USING THESE GUIDELINES
- A location that uses the downspout from your roof
- The area should stop and hold the water before it enters a sewer, road, or sidewalk.
- A site that is approximately 100 to 300 square feet (9.3 and 27.9 square meters).
- An ideal location for adding forb-rich, broad-leafed flowering perennial plants (such as black-eyed Susans or milkweed), as there is evidence to suggest these provide the best retention and detention services in rain gardens.
- A site that avoids large trees with complex root systems or utility lines that could be damaged when digging out the garden.
- Choose a location in full sun for six or more hours a day.
STEP 2: CHOOSING A SHAPE FOR THE GARDEN AND TEST YOUR SOIL.
Mark out the shape of the garden using rope, twine, extra garden hose, flour, or other materials that can be placed on top of the surface where the garden will be. This will provide a visual outline for your project.
A bean-like shape with a gradual slope towards the centre is common for rain gardens. Similar to a catcher’s mitt, the garden will be elevated on one side (the finger cushion area) and slope towards the middle (palm) to help water move to the deeper centre of the garden to maximize infiltration.
To test the soil, locate the middle of your garden and dig an 8-12 inch hole and fill it with water. Monitor this hole over 24-48 hours for drainage.
Step 3: DIGGING OUT THE GARDEN AND ADDING SOIL
Following the established outline for the garden, dig down and remove six to eight inches of the soil with the deepest part of the garden located in the centre. If the soil is compact, a pick-axe might be best used to break up the soil before removing it with a shovel and wheelbarrow.
The removed soil can be used to provide the base of the berm or the elevated side of the rain garden. The berm acts to help direct the water towards the deeper centre of the rain garden.
50% SAND + 25% TOP SOIL + 25% COMPOST
If your original soil is rich in sand you can get away with adding a higher compost amount. Or, if you have very compact soils you may want to add more of 60% sand, 20% topsoil and 20% compost. Use your best judgement based on your soil conditions. Premixed soils can often be purchased in large amounts from local landscaping companies.
Step 4: PLANTING YOUR RAIN GARDEN–USE NATIVES
Native plants are not only adapted to your area but provide better habitat for wildlife, which doubles your rain garden’s positive impact. Choose flowering plants, grasses, and shrubs that provide resources at different times of the year.
Plants that require drier soils should be planted in the berm, with water-loving plants in the lowest part of the garden. Using perennial flowering plants and shrubs in your rain garden will minimize the amount of annual work, as these plants will come back year after year.
Make sure to provide enough “growing room” for each plant you add to the rain garden, generally 8-12 inches between native perennials.
A layer of mulch applied to the top after planting will help to give the garden a strong start by minimizing weeds and helping to hold in the moisture while the roots establish themselves. Make sure to thoroughly water the site right after planting to avoid plant shock.
Benefits of Rain Garden
- Water Conservation- Rain gardens capture and hold rainwater and allow that water to soak slowly into the ground. This reduces, actually eliminates, the need to ever water a rain garden once it is established and conserving municipal water use for the garden and surrounding landscape.
- Flooding Protection- By positioning a rain garden, at least, 10 feet from your home or other structures and directing rainwater runoff into the rain garden, it is possible to reduce the amount of rain that flows into your basement and toward the sewer.
- Pollution Control- Rain gardens filter out sediment and other pollutants (like animal waste, brake dust, oils and automotive chemicals) by capturing the first flush of rain (or a first inch or so of rainwater runoff) which tends to contain the highest concentration of pollutants. When localized runoff flows into a rain garden the water slows down because it is filtered by the soil and the plants.
