Use of Turbidity Measurements to Estimate Suspended Solids and Nutrient Loads from Peatland Forestry Drainage

摘要

Continuous determination of suspended solids (SS) by turbidity measurements in drained peatland is expanding, increasing the demand for reliable calibration data for load calculations. Turbidity was used to estimate SS (n = 333) and particulate nutrient loads (n = 157) after peatland drainage for forestry in Central Finland for three study catchments. SS data from the drainage outlet correlated well with turbidity, demonstrating that turbidity can be used as an accurate measure of SS in drained peatland conditions. Measurement error was found to be approximately 8% (p < 0.01). The proportion of organic and inorganic fractions in SS seemed to affect calibration. Total phosphorus, total nitrogen, and particulate phosphorus showed linear dependency on turbidity values because a fraction of these nutrients occurs in particulate form or adsorbed to organic matter. Regressions during snowmelt periods were markedly different from those in other periods that were related to changes in the dissolved/total nutrient ratio. A close correlation between nutrient content of SS and turbidity provided a novel method to calculate phosphorus load from drained peatland areas, which can be used to conduct nutrient load estimations during summer peak flows.