Uncertainties in sediment quality assessments are discussed in five categories: (1) sediment sampling, transport and storage; (2) sediment chemistry; (3) ecotoxicology; (4) benthic community structure; and (5) data uncertainties and QA/QC. Three major exposure routes are considered: whole sediments, and waters in sediment pores and at the sediment-water interface. If these uncertainties are not...

The authors employed complex model for Cs-137 concentration in seawater and sediment to represent the spatially heterogeneous distribution in sediment. I don’t agree with their results of total amount of Cs-137 in sediment which is 10 times larger than previous estimated value based on observation. Main problem is that they only considered sedimentation and resuspension process in a similar man...

Here we provide global estimates of the seasonal flux of sediment, on a river-by-river basis, under modern and prehuman conditions. Humans have simultaneously increased the sediment transport by global rivers through soil erosion (by 2.3 +/- 0.6 billion metric tons per year), yet reduced the flux of sediment reaching the world's coasts (by 1.4 +/- 0.3 billion metric tons per year) because of re...

The methods available in the literature for sediment concentration estimation are complicated and time consuming and necessitate cumbersome parameter estimation procedures. In this study, artificial neural networks (ANNs) are used to forecast and estimate sediment concentration values. The forecasting results obtained using previously observed sediment values were close to the real ones. The se...

A key component of a sediment yield prediction is an estimate of the sediment deposition between erosion sources and a drainage basin outlet. This technical note presents methods requiring a minimum of data which can be used to assess the importance of sediment deposition within the river system of a basin. The methods were applied to a 4123 km basin in the Philippines. Results indicated that s...

Sediment transport under unsteady flow condition is studied experimentally. In the first step, sediment transport under different steady flow conditions was measured and an empirical equation was derived for its calculation. In the next step, two continuous and three stepwise hydrographs were generated in the flume, and their sediment transport rate was measured. The continuous hydrographs were...

Stream channel erosion has long been suspected as the major contributor to long-term sediment yield from urbanizing watersheds. For San Diego Creek in southern California, measurements from 1983 to 1993 showed that stream channel erosion furnished 10(5) megagrams per year of sediment, or about two-thirds of the total sediment yield. Thus, because channel erosion can be a major source of sedimen...

The long-term goals are 1) to assess the role of small gas bubbles in shallow sandy coastal sediment for sediment geotechnical properties, the transport of solutes across the sediment-water interface and the biogeochemical processes in the sediment surface layer 2) to develop and apply an acoustic technique for the detection and quantification of small gas bubbles in sandy sediment at a high sp...