3.1.2. Low Impact Development (LID) Practices

Rain Gardens and Bioswales: Shallow depressions planted with native vegetation filter and absorb stormwater.

Rain gardens and bioswales are specially designed areas that capture rainwater runoff from impervious surfaces like parking lots or rooftops. These depressions are filled with native plants that absorb excess water, helping to reduce flooding and improve water quality. The plants and soil in these gardens filter pollutants from the water before it seeps back into the groundwater or drains into nearby streams.

Imagine a sponge. Just as a sponge soaks up spilled water on the floor, rain gardens and bioswales soak up rainwater that would otherwise create puddles or cause flooding. By planting them with native vegetation, they not only absorb the water but also provide a beautiful habitat for local wildlife.

Green Roofs: Vegetated roof surfaces retain rainfall and release it slowly.

Green roofs are layers of soil and plants installed on rooftops. They help manage stormwater by absorbing rainwater, which reduces the amount of runoff that would enter storm drains. This also contributes to energy efficiency by insulating buildings, thus lowering heating and cooling costs.

Think of a green roof like wearing a thick winter jacket. Just as a jacket keeps you warm by trapping heat, a green roof helps keep a building's interior comfortable by acting as insulation due to the soil and vegetation, while simultaneously managing water efficiently.

Infiltration Trenches/Percolation Pits: Direct runoff underground, recharging groundwater.

Infiltration trenches and percolation pits are structures designed to capture and allow water runoff to seep into the ground. These features help replenish the groundwater supply while reducing surface runoff and flood risks. They are typically filled with gravel or sand to facilitate drainage and filtration.

Consider a sponge that has been filled with water. If you dig a small hole in the ground and place a sponge filled with water in it, the water slowly leaks out into the surrounding soil. Infiltration trenches work similarly, allowing stormwater to slowly filter into the ground, helping to replenish local aquifers.

Install rainwater harvesting systems to collect runoff for landscape irrigation or non-potable uses.

Rainwater harvesting systems involve the collection of rainwater from rooftops and other surfaces, storing it for future use, such as watering gardens or flushing toilets. This practice conserves potable water and reduces the demand on municipal water supplies.

Think about a bucket set outside during a rainstorm. The bucket collects the rainwater, and once the storm is over, you can use that water to wash your car or water your plants. Just like that bucket, a rainwater harvesting system collects rain for practical purposes, enabling us to use natural resources wisely.

Implement oil/grit separators or vegetated filter strips to remove contaminants before water leaves the site.

Stormwater treatment involves using methods like oil/grit separators and vegetated filter strips to clean the water before it is discharged. Oil/grit separators capture pollutants like oil and debris, while vegetated filter strips allow water to filter through soil and plants, removing contaminants effectively.

Imagine washing your hands at a sink. The soap and water work together to scrub away dirt and germs. Similarly, stormwater treatment measures cleanse rainwater of pollutants, ensuring that when it flows into streams and rivers, it's clean and safe for the environment.

Maintain or restore riparian buffers along streams or ponds to filter pollutants and provide habitat.

Riparian buffers are vegetated areas next to streams and ponds. They help filter runoff before it enters the waterbody, trapping sediments and pollutants. Additionally, these buffers provide important habitats for wildlife, promoting biodiversity and natural ecosystem functions.

Consider a natural sponge placed at the edge of a lake. As rainwater flows over the land, the sponge catches dirt and pollutants before they can enter the lake, keeping the water clean. Riparian buffers act like this sponge, protecting aquatic ecosystems.

Design Stormwater Flow Simulate pre-development hydrology (reduce peak flows).

Proper planning and implementation of stormwater management practices involve simulating how water naturally flows through a site before any development. This approach helps ensure that the developed site can manage stormwater efficiently while minimizing changes to the natural hydrology.

Think of it like planning a water park. Before building, you would consider where water flows to determine the best spots for slides and pools to avoid flooding. Similarly, in stormwater management, we must understand natural water flow to design effective systems that minimize disruption.

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