Landscape and morphometric controls on water quality in stormwater management ponds

Abstract

Stormwater management ponds (SWMPs) are used to mitigate the adverse effects of urbanization on water quality, and are increasing in numbers in the urban landscape. Given that these novel urban environments are becoming more ubiquitous and are being used as habitat by myriad flora and fauna, it is important to understand what controls water quality in SWMPs. We sampled 50 SWMPs and associated forebays in Southern Ontario, Canada for water quality to investigate the role of morphometric and landscape characteristics in determining water quality under baseflow conditions. SWMPs were characterized by extremely variable water quality, which was highly degraded compared to natural ponds. We found significant differences in water quality among varying ponds types, including ponds with different forebay designs and those without forebays. Ambient pond water quality was correlated with variables such as watershed imperviousness contributed by roads, sewershed area, and rainfall amount. We found that pond morphometry influenced nutrient concentrations, and that pond length, width, length: width ratio and surface area: perimeter ratio had the highest correlation with water quality. Over 80 % of SWMPs were found to show thermal structure, which often resulted in low dissolved oxygen, particularly at the sediment-water interface. These results will improve understanding of these new urban aquatic systems, including their suitability as habitat, and help managers improve pond nutrient removal efficiency.

Drivers of Sediment Accumulation and Nutrient Burial in Coastal Stormwater Detention Ponds, South Carolina, USA

“…Though there has been extensive research into the impacts of urbanization on the biogeochemical cycles of lotic systems others 2005,2012;Booth and others 2016), urban ponds have not received the same level of attention. There is still only a limited understanding of the role stormwater ponds play in urban biogeochemical cycles (Williams and others 2013;Chiandet and Xenopoulos 2016;Cheng and Basu 2017). This is especially true in coastal urban centers where stormwater runoff and pond discharges directly enter estuarine and marine receiving waters.…”

Planktonic algae abundance and diversity are similar in urban stormwater ponds of different geographic locations and natural shallow lakes

“…Phytoplankton communities and their dynamics in urban ponds are likely to be influenced by urban stormwater flow which is expected to be of lower chemical quality compared to lakes. To our knowledge, only a few authors (e.g., Olding et al (2000), Vincent and Kirkwood (2014), and Chiandet and Xenopoulos (2016)) have to a larger extent examined phytoplankton composition in stormwater ponds. These studies documented dominance of cyanobacteria and euglenophytes in most of these man-made ecosystems.…”

“…Less effort has been put into describing these as ecosystems from a biological or ecological point of view (Olding 2000;Vincent and Kirkwood 2014;Williams et al 2013). It is becoming well acknowledged that urban stormwater ponds serve as habitats for a variety of biota (Bishop et al 2000;Chiandet and Xenopoulos 2016) and could potentially contribute to the regional biodiversity (Le Viol et al 2012). This seems to be the case even though the ponds are intended as treatment facilities and can receive a significant pollutant load covering a wide range of toxic substances (Pitt et al 1995).…”

“…Only a limited number of studies describing phytoplankton communities in stormwater ponds have been published. It appears that the dominant groups of phytoplankton found in stormwater ponds is Cyanobacteria as demonstrated through microscopic counts (Vincent and Kirkwood 2014) or pigment analysis (Chiandet and Xenopoulos 2016), some of which might be responsible for the production of toxins. Given the dynamic nature of these communities, more studies are needed to understand their links with the hydraulic regime of the pond , stratification patterns of ponds (Song et al 2013), and internal biogeochemical dynamics .…”

Urban Stormwater Characterization, Control, and Treatment

“…Pond geometry is one parameter that can potentially be controlled and optimized to improve performance. Pond length, width, depth and surface area-to-perimeter ratio were shown to be correlated to water quality in 50 stormwater management ponds and 10 associated forebays (Chiandet and Xenopoulos, 2016). In addition, pond lengthto-width ratio and outlet depth were identified as key factors in controlling pond temperature using gene expression programming and ANN models (Sabouri et al, 2016).…”