Understanding Sources of Phosphorus and Trophic State in the Forbes Lake Water Supply

近年来，加拿大大西洋的几个湖泊和水库出现蓝藻水华，引起了公众的极大关注和关注。蓝藻水华频率的明显增加可能是由于许多因素，包括气候变化和酸沉降水平的下降。然而，营养负荷的增加仍然被认为是影响水华潜力的中心因素。磷通常是淡水系统中的限制性营养物质，识别和控制湖泊流域内的磷源是防止蓝藻水华的关键第一步。新格拉斯哥水务公司的饮用水来自一个72公顷的福布斯湖水库。该湖从未经历过藻类水华，但最近水处理厂运营的变化导致磷基缓蚀剂重新回到湖中。公用事业公司和达尔豪西大学正在进行这项研究项目，以更好地了解添加到湖泊中的额外磷的风险，以及是否需要采取缓解措施来消除这种磷来源。这项研究将涉及一个实地采样计划，旨在描述福布斯湖目前的磷水平和营养状态，并开发一个流域模型，以了解该湖的各种磷来源。这项研究的结果将指导公用事业公司做出与水源、湖泊和水处理过程管理相关的关键决策。

The occurrence of cyanobacteria blooms in several lakes and reservoirs in Atlantic Canada in recent years has generated significant public awareness and concern. The apparent increasing frequency in cyanobacteria blooms could be due to a number of factors, including climate change and decreased levels of acid deposition. However, increased nutrient loading is still recognized as a central factor influencing potential for blooms. Phosphorus is typically the limiting nutrient in freshwater systems, and identification and control of phosphorus sources within the lake watershed is a critical first step in preventing cyanobacteria blooms. The Town of New Glasgow Water Utility sources their drinking water from a 72 ha reservoir called Forbes Lake. The lake has never experienced an algal bloom but recent changes to water treatment plant operations have resulted in the recycling of phosphorus-based corrosion control agents back into the lake. The Utility and Dalhousie University are undertaking this research project to better understand the risk associated with this extra phosphorus addition to the lake, and if mitigative steps need to be taken to remove this source of phosphorus. The research will involve a field sampling program aimed at characterizing current phosphorus levels and trophic state of Forbes Lake, and the development of a watershed model to understand the various sources of phosphorus to the lake. Outcomes from this research will guide the utility in making critical decisions related to management of both the source water lake and water treatment process.