Modeling curtain weirs for controlling algal blooms in the largest tributary of the Three Gorges Reservoir, China

Abstract

Curtain Weirs (CWs) are hydraulic structures that act as a barrier to the flow and diffusion of heat across the width of a water body. Algal blooms occur frequently in Xiangxi Bay (XXB), which is one of the largest tributaries of the Three Gorges Reservoir (TGR). Numerical modeling has become a widely accepted tool for predicting and diagnosing hydrodynamic problems. A laterally averaged two-dimensional hydrodynamic and water quality model (CE-QUAL-W2) was used to simulate the CWs and the hydrodynamics, temperature and chlorophyll-a concentrations for XXB. The developed model was calibrated using data collected in XXB from January to December in 2010. The results indicated that the maximum chlorophyll-a concentrations was observed 154 mg/m3 at sampling sites XX09, XX06 and XX01. The CWs led to a marked reduction of the overall chlorophyll-a concentrations 30–85% because of the CWs height and locations. Therefore, the proposed CWs represent a potential method of reducing algal blooms and improving water quality in XXB of the TGR. Keywords: Curtain weirs (CW), Xiangxi Bay (XXB), CE-QUAL-W2, Algal blooms, Three Gorges Reservoir (TGR)