# Evaluation of Algal Control Measures in Eutrophic Reservoir Based on Aquatic Ecosystem Models
###### Abstract
The model has been widely used in the control and management of water eutrophication, mainly including assessing the algal proliferation in lakes and reservoirs under different scenarios, such as changes in nitrogen and phosphorus inputs in the watershed, nitrogen and phosphorus release from sediments, and hydrodynamic changes, etc. It plays an important role in evaluating the expected effects of eutrophication control technologies in lakes [19; 20; 21; 22]. Aquatic ecological models describe the inherent mechanisms of change between individuals or populations in aquatic ecosystems, linking hydrology, water quality, meteorology, and other factors. They are mainly used to study eutrophication, biological enrichment, and food chains in aquatic systems [23]. Modern aquatic ecosystem models take into account the interaction between multiple factors in nature and spatiotemporal changes. At present, some large-scale ecological dynamics integration models are quite mature, and some have been commercialized, such as EFDC, CE-QUAL W2, WASP, DELFT3D, AUATOX, and MIKE. EFDC, DELFT3D, and MIKE are widely used for simulating eutrophication in reservoirs. In recent years, many domestic studies have been conducted on this topic. For example, [PERSON] et al. used the EFDC model to predict the trends in chlorophyll and algal blooms and provided the criterion for the evaluation of algal bloom levels [23; 24]. [PERSON] et al. developed a DELFT3D model and analyzed the impact of temperature, wind forcing, and nitrogen-phosphorus inputs on algal blooms, and they concluded that the simultaneous reduction in nitrogen and phosphorus is more effective in controlling algal growth [25]. [PERSON] et al. considered the impact of hydrodynamic conditions, specifically flow velocity, on algal growth. They coupled the velocity function with the MIKE21 Ecolab model and obtained simulation results that were more consistent with observations. The optimal flow velocity for algal growth within the pond was determined to be 0.055 m per second [26]. Comparing these mainstream models, each has its own strengths. The Ecolab module in the MIKE model allows researchers to freely add the processes of phytoplankton and zooplankton growth, as well as interactions with light, temperature, and nutrients based on personal experience and understanding [27]. It possesses good modifiability and expandability, making it advantageous for exploring the effects of different environmental factors on algal growth [28]. This study aims to develop a lake and reservoir aquatic ecological model based on the ecological cycle mechanism [29; 30; 31; 32], using MIKE Ecolab as the development foundation and comprehensively considering all relevant factors. The focus will be on incorporating the nodes of aquatic organisms and microorganisms within the water ecological model, simulating the complete life cycle of algae, and ultimately developing a risk assessment and early warning system for algal blooms under the control of various ecological factors in lake reservoirs [33]. This system will serve as a predictive tool to evaluate the expected effects of various algal control technologies. Analyzing and validating the application of biological, chemical, and physical technologies to control oxygen, nitrogen, and phosphorus in lake reservoirs is crucial for the effective prevention and control of algal reproduction [34; 35; 36; 37]. This research holds significant importance for the sustainable and healthy development of the ecological environment of lakes.