Effects of water turbidity and salt concentration levels on penetration of solar radiation under water

Two large, outdoor tanks were constructed in order to investigate the effects of water turbidity and salt concentration levels at various depths of water on penetration of solar radiation. These experiments were followed by a laboratory investigation that measured spectral transmittance and the extinction coefficient of water at different salt concentrations and turbidity levels. Both the outdoor and laboratory results indicate that the salt concentration level does not significantly affect solar radiation penetration. However, water clarity, quantified in terms of the turbidity level, plays a critical role on the magnitude of the solar radiation penetration, with the effect of turbidity on penetration increasing with the depth of water. A best-fit model is developed that gives the solar radiation penetration as a function of turbidity level and depth of water.