Hydrology, Ecology and Water Chemistry of Two Suds Ponds: Detailed Analysis of Ecosystem Services Provided by Blue-Green Infrastructure

Abstract

Stormwater retention ponds are an important part of blue-green infrastructure, providing multiple benefits associated with flood resilience, water quality improvements, wildlife habitat creation and increases in amenity and biodiversity values. Here we compare two ponds in Edinburgh (Scotland): Oxgangs and Juniper Green. These were both established 10-15 years ago during construction of housing estates and are 3.5 km apart. The volumes of the ponds were calculated using detailed hydrographic data (obtained as part of this study). Delineation of catchments was performed using fine resolution DEM data together with details of the storm water sewer network. Hydrological and hydrodynamic modelling was carried out using the SHETRAN and CityCAT models. The presence of the ponds not only delays peak discharge after an extreme precipitation event but also reduces it rather considerably. Reductions in peak discharge and delay are much bigger for the larger Oxgangs pond, giving a 45% reduction in discharge and a 5-minute delay for a 15-minute one-in-100-year event. Data obtained on water chemistry, abundance of planktonic organisms and abundance of macroinvertebrates suggest that the increase in pollutant levels affects biological water quality and the ecosystem structure. Oxgangs pond has much higher electrical conductivity, corresponding to higher concentrations of specific elements and lower macroinvertebrate indices than Juniper Green. However, the water in Juniper Green is enriched in Ag, Pb and a number of REE, which may be related to discarded electronics. In addition to the flood resilience and water quality benefits, both ponds provide considerable amenity and biodiversity value. To date, there are 103 and 22 species of vascular plants, 20 and 16 species of bryophytes, 5 and 2 species of non-lichenised fungi and 11 and 4 species of epiphytic lichens recorded, respectively, at Oxgangs and Juniper Green. The results presented here have implications for further research and stormwater pond design and management practices.

Mitigating Polluted Runoff from Industrial Estates by SUDS Retrofits: Case Studies of Problems and Solutions Co-Designed with a Participatory Approach

“…In industrial settings, it may also have an indirect positive influence on the employees' productivity. SUDS/BGI features considered in this paper, such as biodiversity swales [6], raingardens [11], and retention ponds [12,13,45], are particularly relevant in that respect. The existing SUDS ponds at Company B provide a valuable example of how BGI installations can be used effectively not only to alleviate the flood risk and mitigate polluted runoff, but also to provide efficient grey water reuse (GWR) and optimize the supply of valuable water resources for technological processes.…”

“…The existing SUDS ponds at Company B provide a valuable example of how BGI installations can be used effectively not only to alleviate the flood risk and mitigate polluted runoff, but also to provide efficient grey water reuse (GWR) and optimize the supply of valuable water resources for technological processes. Further studies should examine the contribution of these ponds to the local biodiversity value, which is expected to be significant based on studies of BGI ponds elsewhere [11][12][13]46]. Further research should also address the possibilities of increasing GWR through economic and policy instruments using participatory system dynamics modelling [38,39], and should examine potential tradeoffs between specific retrofits [45].…”

“…Combining SUDS assets with Green Infrastructure (GI) in a well-developed BGI network is essential for alleviating the risk of pollution damage and is therefore an important prerequisite for sustainable water management in the context of the Blue-Green Cities (BGC) theoretical and practical framework [5,7,[9][10][11][12][13][14]. SUDS are a statutory requirement for new developments in Scotland [15].…”

Comparative Ecosystem Analysis of Urban Ponds: Implications for Synergistic Benefits and Potential Trade-Offs Resulting from Retrofitting of Green Roofs in Their Catchments

“…This is a conservative estimate reflecting the uncertainty of slope and construction details. Further details on the catchments' properties and description of the software used are documented in our previous publication [13].…”

“…Here, we address this research gap by investigating what would happen to the ecosystem services related to hydrology, water quality and biodiversity of SuDS ponds following the retrofitting of GRs on buildings situated in the ponds' catchments. These research questions are investigated for two case study sites whose functioning has previously been discussed [13] in relation to the 'No GRs' scenario (i.e. the current situation).…”