Understand the site to sustainably manage stormwater

Follow this guide to learn how water moves through your landscape and how to best manage it.

The key to creating a truly resilient and sustainable storm water management plan for your home environment is understanding your site. Explore how water works in the landscape and how it fits into the bigger picture. Identify existing problems and opportunities for improvement and respond to your site’s storm water needs in the most climate-appropriate way. Here’s how to get started:

Look at the big picture

When analyzing how water moves, it is helpful to look at the landscape as a whole. Monitor your yard during heavy rain and see where and how water moves and puddles. How do the different surfaces and areas of your garden interact? Looking at the landscape during a storm can help you think about the bigger picture about stormwater design.

Find out your climate. Find out the annual rainfall in your area and when it usually occurs during the year. When is too much or too little water, and what does this have to do with your garden? For example, in dry climates, long periods of drought are common, but also heavy rains can occur. Water storage and harvesting are good ways to respond to these situations. In other climates, rain occurs regularly throughout the year, so residents must develop strategies to move and infiltrate water in showers throughout the year. Understanding rain in your climate can help you plan stormwater management strategies.

Know your soil. Soil has an amazing ability to purify water while filtering it. This is one of the main reasons why penetration techniques are important. Allowing dirty runoff from your driveway to seep through the soil can purify the water before returning it to groundwater.

However, to keep the soil clean, it must be able to effectively absorb rainwater. If water can already beasily infiltrate the soil, you have less work to do because you can take advantage of the soil’s unique properties to manage runoff. If your soil is compacted or has a high clay content and low permeability, you will need to put more effort into managing water effectively.

Identify problems and opportunities

Most homeowners don’t know they have a water problem until their basement floods or a drought kills all their garden plants. Before this happens, look around the site and look for clues about water movement.

Below is a list of questions to help you identify challenges and opportunities for improved stormwater management in your environment.

Which surfaces affect runoff? Calculate the area of your roof, driveway, patio, walkways, and other impervious surfaces. Consider runoff as an opportunity to incorporate water movement into your landscape design. Swales and rain gardens can be beautiful features.

Where is water pooling or sitting for prolonged periods of time? During heavy rain, it is normal for water to pool in one place, but it will drain within 24 hours. Depending on the situation, areas where water accumulates may be an opportunity for reevaluation. Grading changes the shape of the land, helping to manage water and connect garden areas to each other.

Where does soil erode? Soil erosion is a major concern and will accelerate over time if not stopped. Even minor erosion can become more severe over time. Areas with soil erosion are good places to plant vines and ground covers that stabilize the soil.

Are there areas vulnerable to drought? On a warm, sunny afternoon, check to see if your plant’s leaves are drooping or sunburned. Does your plant look wilted? Do leaves get burned when exposed to sunlight? This is a sign that the plant is now drying out and needs too much irrigation to survive. The opportunity here is to plant species that require hot, full sunlight to bloom. Depending on the climate, these may be succulents or native perennials.

Respond in a way that best suits your landscape

Store runoff and allow it to spread and sink slowly. Storing water is a good way to reduce irrigation demands and contain runoff. In this space, roof downspouts channel roof water into rain barrels for storage.

Slowing and diffusing runoff through swales and rain gardens helps prevent flash flooding downstream. Green roofs and permeable paving are another great way to keep rainwater from reaching water sources.

Allowing water to infiltrate the soil also known as sinking water whenever possible is the best thing you can do for your landscaping and the environment.

Tip: Check local laws before purchasing or installing a rain barrel. Some states have announced rainwater harvesting restrictions.

It moves and infiltrates pool water. Standing water for more than 24 hours after a storm can be a sign of poor soil infiltration or too much runoff that has nowhere to go. If the soil cannot absorb rainwater efficiently, the water can migrate to rock swales, runoff channels or points in the storm water chain where the soil can absorb the rainwater. If your soil cannot manage water effectively on its own or if you do not have room to carve out a swale in your landscape, you can also manage water effectively by combining subsurface drainage with swales and rainwater planters.

Stop soil erosion. If you see decomposed soil being washed away or soil being swept away from foundations or tree roots, you may have a soil erosion problem. This means that water is moving too quickly through that part of the landscape, as evidenced by fast-flowing streams and soil cuts.

There are many solutions to this problem. The sustainable stormwater technologies mentioned here can reduce the overall volume and velocity of water on site. Also, look at how the water meets the ground at your roof downspouts and try to slowly spread and sink any rainwater flowing from that point. Additionally, erosion control measures should be implemented in areas with steep slopes and soils prone to erosion.

For dry areas, use drought-tolerant plants. The home landscape has a hot, sunny microclimate that can get quite dry even in rainy climates. Instead of wasting potable water trying to keep your plants’ roots moist, use drought-tolerant native plants or other suitable drought-tolerant plants. Plants that thrive in hot sun can withstand drought and require much less irrigation than plants that require a lot of water.

Plant shade trees as another strategy to cool overexposed areas. Trees benefit your home’s landscape by lowering the city’s overall ambient temperature. When cities are warmer than non- urban areas, trees can play an important role in regulating the temperature around your home.Increased shade from trees helps your garden retain moisture, which means less irrigation in the long run.