An investigation of the environmental factors that affect water quality and the occurrence of harmful cyanobacteria in stormwater management ponds

Abstract

Stormwater management ponds (SWMP) have an important role in flood mitigation and basic water quality treatment via sedimentation. As aquatic ecosystems, less is known about their role as habitats for aquatic organisms and their potential to transform pollutants. This study focused on twelve SWMP in Oshawa, Ontario, Canada to assess the impacts of flow conditions and pond characteristics on SWMP water quality treatment and algal growth, including toxic cyanobacteria. Net release of total phosphorus (TP) and net retention of total nitrogen (TN) by SWMP were observed. Flow conditions had little affect on the overall functioning of the study SWMP. Large pond designs and recent dredging were observed to positively influence the reduction of total suspended solids (TSS), TN, and TP net release from SWMP. Algae and cyanobacteria were observed to be generally N-limited. The presence of the cyanobacterial toxin gene mcyE was positively associated with chloride and heterocyst-forming cyanobacteria.