Contrasting Eutrophication Risks and Countermeasures in Different Water Bodies: Assessments to Support Targeted Watershed Management

Abstract

Eutrophication is a major problem in China. To combat this issue, the country needs to establish water quality targets, monitoring systems, and intelligent watershed management. This study explores a new watershed management method. Water quality is first assessed using a single factor index method. Then, changes in total nitrogen/total phosphorus (TN/TP) are analyzed to determine the limiting factor. Next, the study compares the eutrophication status of two water function districts, using a comprehensive nutritional state index method and geographic information system (GIS) visualization. Finally, nutrient sources are qualitatively analyzed. Two functional water areas in Tianjin, China were selected and analyzed: Qilihai National Wetland Nature Reserve and Yuqiao Reservoir. The reservoir is a drinking water source. Results indicate that total nitrogen (TN) and total phosphorus (TP) pollution are the main factors driving eutrophication in the Qilihai Wetland and Yuqiao Reservoir. Phosphorus was the limiting factor in the Yuqiao Reservoir; nitrogen was the limiting factor in the Qilihai Wetland. Pollution in Qilihai Wetland is more serious than in Yuqiao Reservoir. The study found that external sources are the main source of pollution. These two functional water areas are vital for Tianjin; as such, the study proposes targeted management measures.

Mapping Algal Blooms in Aquatic Ecosystems Using Long-Term Landsat Data: A Case Study of Yuqiao Reservoir from 1984–2022

“…Specifically, the freezing period with minimal vegetation occurs from December to February of the following year, while the initial stage of plant growth typically spans from March to April. The peak growth period for most AV species typically extends from May to October, with degradation of AV commencing from November onwards [47]. Therefore, the period from May to October is selected for extracting AV in this study due to its maximal growth and stability during this period.…”

“…Therefore, the accuracy of AV extraction can be improved by using the measured water level data to invert the historical water level and then removing the high water level images. The mudflat located in the northwest of Yuqiao Reservoir (Figure 1c) exists year-round with higher AV growing on it, and the overall water quality is good with few ABs occurring around it [47][48][49]. The historical water level can be inverted by establishing the relationship between the flooding area and the water level in this area (Figure 3b).…”

Characterization of Water Quality in Xiao Xingkai Lake: Implications for Trophic Status and Management

“…Eutrophication is a major problem globally that has to be addressed by the definition of water quality targets, and establishment of monitoring systems and intelligent watershed management plans (Abell et al, 2020). Although it is critical to prevent water quality deterioration in lake catchment environments (Li et al, 2017c); conflict between environmental protection and economic development makes the task challenging (Mueller et al, 2019). Nevertheless, to improve lake water quality, and in turn aquatic ecosystem health, numerous strategies could be adopted.…”

Toward a Brighter Future: Enhanced Sustainable Methods for Preventing Algal Blooms and Improving Water Quality

“…Their smaller size and lower density usually result in lower sedimentation coefficients, which affect their settling rates in water columns [18,60]. Researchers discuss strategies for POM and HAB mitigation, such as using physical (e.g., filtration and sedimentation), chemical (e.g., coagulants and oxidants), and biological methods (e.g., bioremediation and phytoremediation), and emphasize the careful selection of treatment methods to avoid unintended ecological impacts [18,[61][62][63][64][65][66][67][68][69].…”