The reliability of suspended sediment load data

The growing significance of suspended sediment load data has directed attention to the reliability of measurement procedures and published data. The efficiency of sampling equipment and laboratory techniques has been studied by many workers, but much less attention has been given to the problems of assessing long term loads. In the absence of detailed records of suspended sediment concentration, a number of indirect methods of estimating such loads based on interpolation and extrapolation procedures have been employed. These may lead to serious under- or overestimation of the actual loads. A detailed assess­ ment of both the accuracy and precision of load estimates produced for the River Creedy in Devon, UK, using these procedures is presented. La validite des donnees relatives aux charges solides en suspension RESUME L'importance croissante des donnees relatives aux sediments en suspension a attire l'attention sur la validite des techniques pour la mesure. L'efficacite de l'equipement pour la prise d'echantillons et des techniques de laboratoires ont ete etudies par plusieurs chercheurs mais moins d'attention a ete apportee aux problemes concernant l'evaluation a long terme des debits solides. Faute des donnees detaillees sur les concentra­ tions des sediments en suspension, plusieurs methodes indirectes, fondees sur les techniques d'interpolation et d'extrapolation, ont ete employees. Ces methodes peuvent sousestimer ou surestimer serieusement les donnees veritables. Une evaluation detaillee de l'exactitude et la precision des evaluations effectuees pour la riviere Creedy en Devon, RU, en utilisant ces techniques est presentee dans cette communication.