Appendix: Supplementary Materials of the LID technology hubs Table S1 to Table S4 present a suite of LID technology hubs for better understanding this paper. Table S1. Summary of point-based LID technologies Low Impact Development Description Ecosystem Services Retention basin http://www.stormwaterpa.org ▪ A recessed area within the landscape that is designed to store and retain a defined quantity of runoff, allowing it to percolate through permeable soils into the groundwater. ▪ Reduces stormwater volume, which reduces the average annual pollutant loading that may be discharged from the system. ▪ Suspended solids, heavy metals, bacteria, pesticides, and nutrients are removed as runoff percolates through the soil profile. Wet detention basin http://www.facilities.vt.edu ▪ Wet detention systems are permanently wet ponds which are designed to slowly release a portion of the collected stormwater runoff through an outlet structure. ▪ Provides removal of both dissolved and suspended pollutants by taking advantage of physical, chemical, and biological processes within the pond. ▪ They are simple to design and operate, provide a predictable recovery of storage volumes within the pond, and are easily maintained. Underground storage https://en.wikipedia.org ▪ Underground storage and retention systems are special types of retention systems that capture the required treatment volume in an underground storage system. ▪ Used where land values are high, and the owner/applicant desires to minimize the potential loss of usable land with other types of retention BMPs. ▪ Does not require human access for maintenance. Vegetated natural buffers (VNBs) http://ci.owatonna.mn.us ▪ VNBs are defined as areas with vegetation suitable for sediment removal along with nutrient uptake and soil stabilization which are set aside ▪ An effective best management practice for the control of nonpoint source pollutants in overland flow by providing opportunities for
the annual mass of pollutants discharged. Managed aquatic system (MAPS) http://www.clemson.edu ▪ Aquatic plant-based BMPs remove nutrients through a variety of processes related to nutrient uptake, transformation, and microbial activities. ▪ Examples include planted littoral zones and floating treatment wetlands. ▪ They can be incorporated into a wet detention BMP treatment train to provide additional treatment and nutrient removal after the wet pond has provided reduction of pollutants through settling and other mechanisms that occur within the wet pond. Table S4. Summary of another LID technologies Low Impact Development Description Ecosystem Services Stormwater harvesting http://blog.farmsreach.com ▪ Uses treated stormwater for beneficial purposes before it is discharged to surface waters, thus reducing the stormwater volume and mass of pollutants discharged. ▪ It is most often used with wet detention as part of a BMP treatment train. ▪ Stormwater harvesting offers an alternative freshwater resource, which may alleviate demand on typical freshwater sources. ▪ Can be used to provide water for irrigation and other applications, thus reducing strain on groundwater aquifers, rivers, and lakes. Natural area conservation http://moverdubai.net/ ▪ Protection of natural areas helps maintain the undeveloped hydrology of a site by reducing runoff, promoting infiltration and preventing soil erosion. ▪ Examples of conservation areas include areas of undisturbed vegetation preserved at the development site, such as forests, floodplains and riparian areas, ▪ The undisturbed soils and native vegetation of conservation areas promote rainfall interception and storage, infiltration, runoff filtering, and direct uptake of pollutants. ▪Natural areas are eligible for stormwater credit if they remain undisturbed during construction and are protected by