Greywater impact on green roofs’ provision of ecosystem services

Abstract

Previous research showed that some herbaceous perennial species could offer summertime cooling better than succulent species on green roofs (GRs), if supplementary irrigation is available during times of drought. In light of increasing water shortages, use of greywater (GW) instead of mains tap water (TW) for this purpose comes into focus. A glasshouse experiment was conducted in summer 2015 at the University of Reading (UK) to assess the impact of GW irrigation on the health, growth and functioning (in terms of leaf stomatal conductance (gs) and associated water uptake) of four plant genotypes (Salvia, Stachys, Heuchera and Sedum), and their ability to deliver ecosystem services, particularly cooling. Twenty-two replicates of each genotype, plus controls of bare, unvegetated substrate, were irrigated with fixed volumes of TW or synthetic GW for 6 weeks. Plant growth and visual quality, and gs were measured. In Week 7, daily water loss from each container following saturation was determined. For the first 6 weeks, plant growth, visual quality and gs were similar for both TW and GW treatments for all genotypes, indicating no negative impact of short-term GW irrigation and no apparent impact on cooling when plants were well-watered. However, in Week 7 water uptake (and thus presumably gs) was significantly lower for plants irrigated with GW compared to TW for some genotypes (Salvia and Heuchera), especially as substrate became drier, suggesting a reduction in evapotranspiration and potentially reduced cooling service when the soil is dry.

Exploring Influencing Factors and Innovative Solutions for Sustainable Water Management on Green Roofs: A Systematic Quantitative Review

“…However, the negative impact that the water consumption of green roofs may have on water resources is a concern [15][16][17]. During periods of drought or in regions with limited water resources, the water consumption of green roofs can become a significant issue and Architecture 2023, 3 295 may affect other water uses, such as agriculture, industry, and residential needs [15][16][17]. Therefore, it is essential to carefully manage the water consumption of green roofs to ensure they do not exacerbate existing water scarcity issues.…”

“…However, the negative impact that the water consumption of green roofs may h on water resources is a concern [15][16][17]. During periods of drought or in regions w limited water resources, the water consumption of green roofs can become a signifi issue and may affect other water uses, such as agriculture, industry, and residential ne [15][16][17]. Therefore, it is essential to carefully manage the water consumption of green r to ensure they do not exacerbate existing water scarcity issues.…”

Study of Greywater Reuse System With Local Material Filter

“…The rapid growth of large cities' population must be supported resources, one of them clean water (Stec et al, 2017). History The city's development is always considered in water resources (Kemp et al, 2017). Water is a natural resource necessary for the livelihood of many people.…”