Selecting Appropriate Plant Species for Basin Retrofit Projects

Stormwater basins serve an important purpose and provide a unique landscape opportunity in neighborhoods and communities. They are designed to provide a location to capture excess stormwater runoff due to changes in land cover after construction and development. For this reason, stormwater basins experience prolonged periods of inundation, and the plant species planted in the basin need to be carefully selected to withstand rainfall events, but also persist through periods of dry weather. Facultative plant species, or plants that are equally likely to occur in wetlands and non-wetlands areas, are better able to tolerate the harsh growing conditions of stormwater basins compared to wetland obligate plant species.

Depending on the site-specific conditions of the basin, native grasses and wildflower seed mixtures were selected for these retrofit projects. Native grasses and wildflowers have long root systems that penetrate deep into the soil. The long roots help prevent compaction, increase aeration, and augment the soil’s capacity to store water and prevent flooding – essentially turning the soil into a sponge. In addition, native grasses and wildflowers provide nectar and pollen for bees and beneficial insects, as well as host habitat for butterflies and moths. Once appropriate species were selected, the seed mixture was planted utilizing the no-till Kasco Versa-Drill or conventional hand-seeding method. Over 3 acres of land was retrofitted with seed supplied by Pinelands Nursery, subsequently enhancing the local environment and watershed by reducing pollutant loads to the Metedeconk River and its tributaries.

These “before” and “after” photos show the stormwater basin serving the residential community near Sunset Road. Before implementing the retrofit, the soil was compacted below the surface, providing inadequate drainage. After the seeding took place and the grasses and wildflowers grew, the long penetrating plant roots helped to remedy the soil compaction. The roots also serve a thriving underground ecosystem that maintains a healthy substrate for the native plants.