Before (above) and after (below) the new ‘rain garden’ created at Pollerton Road/Green Lane, Carlow

By Suzanne Pender

A NEW ‘rain garden’ created at Pollerton Road/Green Lane, Carlow not only enhances the area but offers a green alternative to flooding.

A first of its kind, this retro bioretention area (rain garden) is built with permeable surfaces that allow water to flow freely.

Traditionally, the run-off from hard, landscaped areas would be collected by roof gutters, downpipes and road gullies and directed into a piped sewer network. However, these piped drainage systems have a limited capacity, and when that capacity is exceeded, flooding occurs.

These Sustainable Urban Drainage Systems (SUDS) offer a real solution to this problem.

Green Lane/Pollerton Road’s rain garden features kerbs with strategically located inlets, allowing water from the carriageway to enter the rain garden and infiltrate the soil.

The plants, aggregates and soil in the rain garden filter out pollutants and take up, or cycle, nutrients in the water. The rain garden therefore improves stormwater quality as well as dampening peaks in stormwater flows and passively watering the plants.

Importantly, the rain garden features a variety of trees, grasses and perennials to absorb water, which enhances the street scape with some fun landscaping features and provides habitats for wildlife.

Carlow Municipal District has already begun investigating the next possible locations for bioretention areas to create a greener and more liveable town.