Page - 401 - in Biodiversity and Health in the Face of Climate Change

401 results showed no significant difference between control and intervention sites with regard to river water quality, periphyton and macroinvertebrate metrics. However, it did show a small significant decrease in runoff volume in intervention areas. Kondo et  al. (2015) investigated the effects of a range of green storm water infra- structures across 52 sites in Philadelphia on health and social outcomes using a difference-in-difference design. Installed infrastructure included 152 tree trenches, 46 infiltration/storage trenches, 43 rain gardens, 29 pervious pavements, five storm water basins, and one wetland. The comparator groups were matched control sites where no construction took place. Results showed significant reductions in narcot- ics possession (18–27% less; p  <  0.01), narcotics manufacture and burglaries. There were non-significant reductions in homicides, assaults, thefts and public drunken- ness. In addition, there were negative, non-significant effects on stress levels and increased reporting of high blood pressure and cholesterol. Jarden and Jefferson (2016) found a significant reduction in storm water flow at the intervention sites with reductions of up to 33% of peak discharge and 40% of total run-off volume. The intervention involved provision of 91 rain gardens (< 25  m2), street-connected bio-retention cells (~26–44  m2) and rain barrels on two streets. Each intervention street had a matched control street (n  =  4) of similar size, drainage area and characteristics. Van Seters et  al. (2009) found that the green roof on a building in Toronto, Canada (241  m2) retained 63% more rainfall than the conventional (bitumen) roof over an 18-month monitoring period. In a similar study in Michigan, USA, Carpenter and Kaluvakolanu (2011) investigated the effects of an extensive green roof (325.2  m2 and 929  m2) on a university building compared to a stone-ballasted roof and an asphalt roof. Results showed that the green roof retained 68% of rainfall volume and reduced peak discharge by an average of 89%. Also, there were signifi- Table 17.4 (continued) Reference Study design Intervention Outcome Jarden and Jefferson (2016) Ohio, USA Before–after– control– intervention (BACI) experimental design Installation of 91 rain gardens, street-connected bio-retention cells and rain barrels at 2 treatment streets. Rain gardens (< 25  m2) were installed in front yards and backyards; bio-retention cells (~26–44  m2) were installed between the sidewalk and street +ve: Reduction in storm water flow at the treatment streets with reductions of up to 33% of peak discharge and 40% of total run-off volume Peng and Jim (2015) Hong Kong, China Quasi- experiment, controlled, pre and post design A 484  m2 extensive green roof was retrofitted on a 2-story railway station +ve: Green roof displayed cooling effects in spring, summer, and fall, with slight warming effects in winter BACI Before-after-control-intervention, US United States, +ve positive intervention effect, −ve no intervention effect 17 Environmental, Health and  Equity Effects of  Urban Green Space Interventions