Beira Lake, in the heart of Colombo City in Sri Lanka, is a prominent landmark, serving a variety of important services such as flood control, and providing habitat and nesting grounds for the city’s wildlife. During the past decades, Beira Lake has become highly polluted due to anthropogenic activities. The majority of the past restoration attempts failed, revealing a lack of understanding of the pollutant intricacies. The objective of this study is to investigate the trophic status of all four basins of the lake to investigate the pollution status. Thirty-nine sampling locations were randomly selected based on a 100 × 100 m grid covering the entire lake for water quality sampling. Water quality index (WQI) and trophic level index (TLI) were calculated to further investigate the pollution scenarios. WQI, total nitrogen, total phosphorous, Secchi depth, and Chlorophyll-a were considered to calculate the TLI of the lake. As per the WQI, more than 93% of the lake’s surface area is in poor condition. The TLI reveals the hypereutrophic status of the lake water. According to principal component analysis, eutrophication and algal bloom index observed can be due to the heavy anthropogenic activities and land use patterns around the catchment indicating a high possibility of untreated effluent entering the lake through the active inlets. The effluent entering the lake should be managed immediately to prevent further deterioration of the entire lake. Immediate restoration of the lake is recommended, as the hypereutrophic state may lead to irreversible an imbalance in the lake ecosystem.

贝拉湖位于斯里兰卡科伦坡市中心，是一个著名的地标，提供防洪等多种重要服务，并为该市的野生动物提供栖息地和筑巢地。在过去的几十年里，贝拉湖由于人类活动而受到严重污染。过去的大部分修复尝试都失败了，这表明人们对污染物的复杂性缺乏了解。本研究的目的是调查该湖所有四个流域的营养状况，以调查污染状况。以覆盖全湖的100×100 m网格为基础，随机选取39个采样点进行水质采样。计算水质指数（WQI）和营养级指数（TLI）以进一步调查污染情况。WQI、总氮、总磷、计算湖泊的 TLI 时考虑了 Secchi 深度和叶绿素 a。根据WQI，该湖93%以上的面积状况较差。TLI揭示了湖水的超富营养化状态。根据主成分分析，观察到的富营养化和藻华指数可能是由于流域周围的大量人类活动和土地利用模式造成的，表明未经处理的污水很可能通过活动入口进入湖泊。进入湖泊的污水应立即进行处理，防止整个湖泊进一步恶化。建议立即恢复湖泊，因为超富营养化状态可能会导致湖泊生态系统出现不可逆转的失衡。93%以上的湖面面积状况较差。TLI揭示了湖水的超富营养化状态。根据主成分分析，观察到的富营养化和藻华指数可能是由于流域周围的大量人类活动和土地利用模式造成的，表明未经处理的污水很可能通过活动入口进入湖泊。进入湖泊的污水应立即进行处理，防止整个湖泊进一步恶化。建议立即恢复湖泊，因为超富营养化状态可能会导致湖泊生态系统出现不可逆转的失衡。93%以上的湖面面积状况较差。TLI揭示了湖水的超富营养化状态。根据主成分分析，观察到的富营养化和藻华指数可能是由于流域周围的大量人类活动和土地利用模式造成的，表明未经处理的污水很可能通过活动入口进入湖泊。进入湖泊的污水应立即进行处理，防止整个湖泊进一步恶化。建议立即恢复湖泊，因为超富营养化状态可能会导致湖泊生态系统出现不可逆转的失衡。观察到的富营养化和藻华指数可能是由于集水区周围的大量人类活动和土地利用模式造成的，表明未经处理的污水很可能通过活动入口进入湖泊。进入湖泊的污水应立即进行处理，防止整个湖泊进一步恶化。建议立即恢复湖泊，因为超富营养化状态可能会导致湖泊生态系统出现不可逆转的失衡。观察到的富营养化和藻华指数可能是由于集水区周围的大量人类活动和土地利用模式造成的，表明未经处理的污水很可能通过活动入口进入湖泊。进入湖泊的污水应立即进行处理，防止整个湖泊进一步恶化。建议立即恢复湖泊，因为超富营养化状态可能会导致湖泊生态系统出现不可逆转的失衡。