Flooding from paving yards

Paving a yard is a landscaping technique that involves covering the compound with a hard, flat, and durable surface, such as concrete, asphalt, bricks, pavers, or other similar materials. The purpose of paving a yard is to create a solid and stable surface for various activities, such as walking, driving, or placing outdoor furniture. Paved yards are often used in urban and suburban environments where green spaces may be limited or where property owners want to create functional outdoor spaces.

Despite its various merits, paving your yard can increase the risks of flooding, especially if proper drainage measures are not taken into consideration. When you have a large portion of your yard, you create an impermeable surface that prevents rainwater from being absorbed into the ground. Instead, the water flows over the surface, potentially overwhelming the existing drainage systems and leading to various issues:

1. Runoff: Paved surfaces prevent water from soaking into the ground, causing rainwater to accumulate and flow quickly over the surface. This increased runoff can lead to localized flooding as well as overwhelming local stormwater management systems.
2. Reduced Infiltration: Natural soil acts as a sponge, absorbing water and slowly releasing it into the ground. Paving your yard reduces this natural infiltration process, contributing to increased runoff and reduced groundwater recharge.
3. Overburdened Drainage Systems: Paved yards can strain existing drainage infrastructure, such as gutters, storm drains, and sewers. These systems may not be designed to handle the increased volume of water, leading to backups and flooding.
4. Erosion: Excess runoff from paved surfaces can erode soil and create channels that further exacerbate flooding issues. This erosion can affect neighboring properties and even cause damage to your property over time.
5. Water Quality: When rainwater flows over paved surfaces, it can pick up pollutants like oil, chemicals, and debris. Without natural filtration through the soil, these pollutants can end up in local water bodies, impacting water quality.

To mitigate the risks of flooding when paving your yard, you should consider implementing proper drainage solutions:

Rainwater Harvesting: While not a direct drainage solution, rainwater harvesting involves collecting rainwater from paved surfaces and storing it for later use, which can help alleviate the burden on drainage systems during heavy rainfall events. One way of doing it is through the installation of rainwater gutters.

Permeable Paving: Permeable or porous paving materials allow water to pass through the surface and infiltrate the ground. These materials include permeable concrete, permeable pavers, and gravel. They help to reduce runoff and promote groundwater recharge. Rainwater can be absorbed by the soil below, which helps alleviate flooding issues.

Rain Gardens: A rain garden is a planted depression in the ground that collects and absorbs rainwater runoff from paved surfaces. Native plants are selected for their ability to tolerate both wet and dry conditions. Rain gardens slow down the flow of water, allowing it to infiltrate the soil gradually.

French Drains: A French drain is a trench filled with gravel or rock that contains a perforated pipe. It is designed to redirect water away from an area prone to flooding. The water enters the pipe and is carried away from the paved surface to a designated drainage area. Read more about French drains by clicking here.

Swales: Swales are shallow, vegetated channels designed to direct and manage rainwater runoff. They are typically used to channel water away from paved areas and into appropriate drainage points. Swales can be combined with grass or plants that help slow down the flow of water and facilitate absorption.

Retention Basins/Detention Ponds: Retention basins and detention ponds are larger-scale solutions that temporarily hold excess water during heavy rainfall. They are designed to release the water slowly over time, reducing the risk of flooding downstream. These basins and ponds can be landscaped with vegetation to enhance their visual appeal.

Dry Wells: Dry wells are underground structures designed to collect and hold rainwater before gradually releasing it into the surrounding soil. They are particularly useful for areas where surface drainage is difficult to achieve.

Sloping and Grading: Proper grading of the paved surface and surrounding areas is crucial to ensure that water naturally flows away from structures and toward designated drainage points. Creating a gentle slope away from buildings and paved surfaces helps prevent water from pooling.

Channel Drains: Channel drains, also known as trench drains, are long, narrow drains that are typically installed at the edges of paved surfaces. They collect water and direct it to a suitable drainage outlet, helping to prevent water accumulation.

When planning and implementing drainage solutions, it’s important to consider factors such as the local climate, soil type, slope of your property, and existing infrastructure. Consulting with a professional landscaper, civil engineer, or drainage specialist can help you design and implement effective drainage solutions tailored to your specific property and needs.