THE POTENTIAL OF FIELD TURBIDITY MEASUREMENTS FOR THE COMPUTATION OF TOTAL PHOSPHORUS AND SUSPENDED-SOLIDS LOADS

The computation of loads of material transported in streams is general ly based on relationships between river discharge and concentration fo r particular sites. These correlations are often poor and are frequent ly based on samples which are unrepresentative of the range of flows o ccuring in the stream. These problems result in considerable uncertain ty in the subsequent load estimates. Turbidity is a property that is s imple to measure and can be cheaply collected continuously using an el ectronic data logger. It is proposed that (i) held turbidity measureme nts are well correlated with the concentration of some transported mat erial, in particular total suspended solids and total phosphorus and ( ii) that these correlations can be used along with logged how and turb idity data to compute load estimates which are less uncertain than usi ng traditional methods. Data for turbidity versus total suspended soli ds concentration and turbidity versus total phosphorus concentration a re presented for samples taken throughout a 5000 km(2) catchment under a full range of flow conditions. (C) 1996 Academic Press Limited.