Sustainable Landscape Design: Tackling Climate Change and Rain Gardens

With concerns growing over climate change and the environment, clients are asking landscape architects to incorporate sustainable landscape design into their residential and commercial landscaping projects.

The planning and design of rain gardens is a particularly popular project for firms involved in landscape architecture and environmental planning.

What is a rain garden?

A rain garden is a water capture feature designed to take advantage of rainwater runoff that flows from roofs, driveways, patios or lawns. Highly porous plants, such as native shrubs, perennials and flowers, are planted in a small depression filled with soil and sand. The depression captures the runoff, while the soil, sand and plants filter the pollutants that rainwater picks up along the way, such as fertilizers, oil, pet waste and other residential lawn contaminants.

What is their role in climate change?

Rain gardens help filter runoff rainwater and keep pollutants out of a community's storm drains and, eventually, area rivers and streams. According to the American Society of Landscape Architects, or ASLA, a properly designed rain garden can filter around 90% of copper, lead and zinc, 50% of nitrogen, and 65% of phosphorus from stormwater.

Rain gardens can also help prevent soil erosion and neighborhood flooding by redirecting runoff water and providing a temporary place for it to soak into the ground gradually and naturally. A rain garden can filter an inch of rainfall in 4 hours, the ASLA estimates.

Finally, rain gardens can improve the quality of the soil with microbes, recharge groundwater aquifers, and provide a habitat for insects and other wildlife.

How are rain gardens created?

An efficient and environmentally sustainable rain garden requires the expertise of a professional landscape architect. A professional landscape architect must be equipped to do a site and topography survey and drainage analysis to choose an area that can absorb the water.

They must have the tools and expertise to test the soil's compaction and percolation rate, determine the size and shape of the garden, and make sure there are no underground utilities in the way.

In addition, because a rain garden has specific zones based on each plant's tolerance to standing water, a professional landscape architect needs to be familiar with plants that will work in each zone. They must also formulate the right soil, compost and sand mixture for maximum filtration and to minimize erosion.

Finally, a professional landscape architect can recommend a landscape contractor to do the physical work of building the rain garden.

Investing in sustainable landscape design

Because it's a growing area of client demand, landscape architect firms that specialize in sustainable design and rain gardens can set themselves apart from their competitors while creating happier and healthier landscapes for their clients.

To reap the tax benefits of this lucrative specialty, landscape architects and environmental planning firms will need to line up financing or loans for tools that can make the job easier. On-site, they need computers and tablets to record the existing locations of trees, walls, paving, structures and vertical topography as well as testing equipment to conduct soil and drainage analysis.

Landscape architects also rely heavily on photographs, so they might consider investing in high-quality camera equipment or even a drone. From there, a landscape architect needs design software, such as building information modeling, or BIM programs, to draw up 3D renderings. Virtual reality is also making its way into the landscape design field and could be a good investment for early adopters.

For landscape architect firms that undertake the actual installation of a rain garden, they should consider financing for any rain garden-specific heavy equipment they don't already have on hand, such as excavators, sod cutters and rototillers for composting.

Is green landscape design in your future?

As residential and commercial clients become more environmentally aware and climate-conscious, sustainable landscape design is becoming a major consideration. Landscape architecture and environmental planning firms should consider investing in bioretention and rain garden-specific tools now to handle the demand for such sustainable projects in the future.