However, the urban landscape lakes have not received widespread attention, and a few simulation cases focused on the hydrodynamics and water quality ( Yang et al.
#Hydrodynamic models mike 21 code#
(2017) coupled the Environmental Fluid Dynamics Code (EFDC) with the Water Quality Analysis Simulation Program (WASP) to analyse the influence of combined sewer overflows on the hydrodynamics and water quality of the Chicago Area Waterway System. The MIKE 21 FM model was applied to investigate the effects of water diversion on water quality ( Yang et al. (2020) used a high-fidelity hydrodynamic-eutrophication-sediment model to investigate spatiotemporal variation in sediment phosphorus retention and release in Danjiangkou Reservoir. Numerical simulation is a useful tool to test hypotheses, simulate various scenarios, analyse the influence of hydrodynamic condition on the water quality, and evaluate the regulation alternatives before project implementation ( Dunn et al.
Therefore, the study of hydrodynamic analysis has attracted more and more attention. (2018) discovered that water transfers could accelerate water movement and improve water quality.
(2014) has proven that the water quality was better in the lakes with good hydrodynamic conditions than in those with bad hydrodynamic conditions. The organic detritus deposited in the sediment would be re-suspended under turbulent condition, the organic detritus residence time would be prolonged, and the aerobic degradation would be more complete. (2019) found that the increasing shear velocity accelerated the release of total phosphorus from sediment. The hydrodynamic condition cannot only dilute pollutant concentrations, accelerate water exchange and the re-oxygenation rate, and improve the self-purification capacity but also resuspend the sediments to release large amount of nitrogen and phosphorus into the overlying water ( Kang et al. Numerous scientific studies have focused on the factors affecting the water quality, such as the salinity, light, temperature, nitrogen, phosphorus, redox, and watershed landscape ( Mahanty et al. Improving the hydrodynamic conditions was proposed for enhancing water quality in urban landscape lakes. The circulation system could slow the water quality deterioration but cannot eliminate the eutrophication risk. The high concentrations nitrogen and phosphorus in the reclaimed water would accelerate the deterioration of water quality, and the concentrations of TP, NH 4 +-N, and TN in the lake increased from 0.080 mg/L, 0.53 mg/L, and 1.53 mg/L to 0.090–0.096 mg/L, 0.71–0.81 mg/L, and 1.89–2.08 mg/L, respectively. Circulation system was the main force that expedited water changes and pollutant movement, increased the lake average water speed from 0.003 m/s to 0.008 m/s, and could effectively reduce the COD, NH 4 +-N and TN concentration nearly by 35, 32, and 5%. Moreover, an engineering experiment was carried out to confirm the comprehensive degradation coefficients of chemical oxygen demand (COD), total phosphorus (TP), nitrogen ammonia (NH 4 +-N), and total nitrogen (TN) (0.014 d −1, 0.024 d −1, 0.019 d −1, and 0.005 d −1, respective). In this study, a 2D hydrodynamic and water quality model was built based on MIKE 21 to investigate the relationship between hydrodynamic condition and water quality, and then applied in an urban landscape lake in Tianjin, China.