LIGHT PENETRATION DEPTH, TURBIDITY AND REFLECTANCE RELATED RELATIONSHIPS AND MODELS

Laboratory based studies related to the reflectance response of suspensions carrying different soil types and particle sizes of varying concentrations are presented. The studies indicate dependence of the reflectance measurements on the soil type characteristics and particle size. The reflectance for any soil and size increases with turbidity but decreases with increase in the modified secchi depth of the suspension. The reflectance also increases with a decrease in the particle sizes for any soil type. Models have been evolved for the prediction of turbidity and modified secchi depths from the measured reflectance values for a given soil type and size, and also with due involvement of the particle size in the predictive models. These predictions manifest best results at a wavelength of around 700 nm. The predicted and observed values of the turbidity and the modified secchi depth, from the various models presented show good agreement.