Comparison of Different Methods of Measuring Turbidity for Estimation of Total Suspended Sediments (Poster)
Franklin, Dorcas H.
Steiner, Jean L.
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Turbidity in streams has long been thought of as an important indicator of stream health. The standard methods for measuring turbidity in streams today are nephelometric methods (NTU). However there are a variety of relationships and correlations between nephelometric units and total suspended sediments (Tss). Colorimetric methods (FAU) of measuring turbidity may reduce the number of instruments needed while stream sampling and may also have a more reliable relationship with total suspended sediments than nephelometric units in Southern Piedmont streams. We sampled stream base flow (n = 224) and storm flow (n = 145) and runoff (n = 141) from grazing lands within two Southern Piedmont watersheds and determined relationships of Tss with NTU and FAU. Using linear regression to predict Tss from either NTU or FAU, we found r² of 0.89 and 0.80 for base flow, 0.94 and 0.92 for storm flow and 0.93 and 0.94 for runoff, respectively. However, when turbidity units were < 25 NTU or 25 FAU, relationships with Tss were much weaker.