Green Stormwater Infrastructure: Does it Work?
Green Stormwater Infrastructure (GSI) is typically built for multi-purposes: reducing peak runoff volume of stormwater runoff, removing pollutants, and providing the benefits of green space as well as for recreational purposes. Vegetation is used in GSIs to achieve these functions. It is also called Low Impact Developments (LID). By definition and by the term, LID should allow land development projects to reduce their impact on the environment. Vegetation that includes grasses, trees, shrubs, and other types of plants is often used to achieve the desired goal by mimicking what happens in natural environments.
However, plants are often under stress and consequently die. Replacing dead plants has been the standard operation. When LID/GSI components are proposed to be included in projects, the design team tends to use the mature state of the selected plants in their calculations of benefits and functions. The benefits may include the reduction of stormwater runoff due to the retention and absorption by leaves, bark and roots, the amount of pollutants that plants pull out of the stormwater, the amount of pollutants break down by microorganisms in the soil, the rate of evapotranspiration, the infiltrated rate through the healthy soil that is home to plant roots, soil microorganisms and beneficial insects, etc. If the plants are constantly being replaced and never reach their mature state, then LID/GIS cannot work for the designed purposes. In contrast to the designed benefits of reducing environmental impacts, many of these projects actually increase the environmental burden and carbon footprint with added pollution/emission during replacing dead plants.
This presentation will guide the audience to look into the fundamentals of the LID/GSI systems, identify the main stresses: water stresses during droughts, heat island effect, deicing salt for northern climates and coastal areas, irrigation salinity from reclaimed wastewater sources, human errors, soil compaction, and organic matter depletion. Then we will introduce a cutting-edge technology of soil genomics to examine the impact of some pollutants on the soil microbiome, provide a solution that can reduce the casualties of the plants in these systems, and actually reduce the impact of LID/GSI projects.
Learning Objectives:
- Learn the importance and the challenges encountered in green stormwater infrastructures
- Discuss the stresses in GSI: soil moisture fluctuation, presence of salt, compacted soils, heat island, drought or any other brought up by the audience
- Review methods and technologies that can help solve the problems and how soil genomics can help parks to be more resilient.
- Review case studies in different regions, different climates and environments with newest data on soil genomics and discuss what worked and what not worked
