Long term and high frequency monitoring of beam attenuation coefficient as a proxy for suspended particulate inorganic matter: use in the calibration of a sediment resuspension model

摘要

The concentration of suspended particulate matter (SPM) is important for water quality in lakes and reservoirs. High concentration of SPM will affect the light climate for phytoplankton and reduce the quality of drinking water supplies (GAUTHIER et al. 2003). The light extinction coefficient of water (Kd) is an important factor when estimating the underwater light climate. Light extinction in water is caused by yellow substance, phytoplankton, SPM, and the properties of pure water. Suspended particulate matter can further be divided into suspended particulate inorganic matter (SPIM) and suspended particulate organic matter (SPOM). The SPIM fraction affects Kd due to its light scattering properties (PIERSON et al. 2003). The amount of SPM in lakes is related to wind speed (SOMLYODY & KONCSOS 1991), internal seiches (PIERSON & WEYHENMEYER 1994, MAN et al. 1997), bioturbation (SCHEFFER et al. 2003), and transport from discharging rivers (BLOESCH 1994, MARKENSTEN & PIERSON 2003). Many numerical models predicting SPM in lakes have included the effect of wind speed (BLOESCH 1994, TEETER et al. 2001), but only rarely has it been combined with the effect of river flow (MARKENSTEN & PIERSON 2003). We used underwater beam attenuation coefficient measurements collected at frequent intervals to calculate and verify the performance of a wind-speed and river-flow driven SPIM model (MARKENSTEN & PIERSON 2003). We tested the performance of this model using 24 months of measured beam attenuation data, as compared to the initial testing of the model, which was made using only 3 months of data ( MARKENSTEN & PIERSON 2003).