Long-term water quality records for assessing natural variability, impact of management, and that guide regulatory processes to safeguard water resources are rare for California oak woodland rangelands. This study presents a 20-yr record (1981-2000) of nitrate-nitrogen (NO(3)-N) and suspended sediment export from a typical, grazed oak woodland watershed (103 ha) in the northern Sierra Nevada fo...

Remedial dredging of contaminated bed sediments in rivers and lakes results in the suspension of sediment solids in the water column, which can potentially be a source for evaporation of hydrophobic organic compounds (HOCs) associated with the sediment solids. Laboratory experiments were conducted in an oscillating grid chamber to simulate the suspension of contaminated sediments and flux to ai...

In a watershed, sediment arises due to the erosion and some factors such as pastures destruction,change users, no reasonable cultivation. That causes problems such as sedimentation in reservoirs andreduces their useful volume, reducing water quality in agricultural consumption; reduce the efficiencyof hydraulic structures and some other environmental problems. Changes in sediment load in a rive...

Sorption of pyrethroid insecticides to solid materials will typically dominate the fate and transport of these hydrophobic compounds in aquatic environments. Batch reactor isotherm experiments were performed with bifenthrin and λ-cyhalothrin with suspended material and bed sediment collected from the Sacramento River, California, USA. These batch reactor experiments were performed with low spik...

This paper proposes and explains a data treatment technique to improve the accuracy of a neural network estimator in regression problems, where multi-dimensional input data set is highly skewed and non-normally distributed. The proposed treatment modifies the distribution characteristics of the data set. The prediction of the suspended sediment, which is an important problem in river engineerin...

Although sound has been applied to the study of sediment transport processes for a number of years, it is acknowledged that there are still problems in using the backscattered signal to measure suspended sediment parameters. In particular, when the attenuation due to the suspension becomes significant, the uncertainty associated with the variability in the scattering characteristics of the sedi...

The Minnesota River Basin (MRB), situated in the prairie pothole region of the Upper Midwest, contributes excessive sediment and nutrient loads to the Upper Mississippi River. Over 330 stream channels in the MRB are listed as impaired by the Minnesota Pollution Control Agency, with turbidity levels exceeding water quality standards in much of the basin. Addressing turbidity impairment requires ...

[1] A mechanistic model is derived for the rate of fluvial erosion into bedrock by abrasion from uniform size particles that impact the bed during transport in both bed and suspended load. The erosion rate is equated to the product of the impact rate, the mass loss per particle impact, and a bed coverage term. Unlike previous models that consider only bed load, the impact rate is not assumed to...

This laboratory work examines the relationship between turbidity (NTU) and total suspended sediment concentration (TSS, mg/L) for a Cecil Ap soil, a common Southeastern Piedmont soil type. We show a 1:1 correlation between NTU and TSS for the silt and clay fractions, but a smaller ratio for clay and bulk-soil samples. These results suggest that NTU measurements can be used to estimate sediment ...

This research studied the occurrence of estrogens in the Upper Satilla watershed, Georgia, USA, which was impacted by poultry litter land application and discharge from a sewage treatment plant (STP) receiving poultry wastes. Over 14 months, four estrogens in stream water, sediment, suspended particles, and STP samples were quantified by LC/MS. Estrogens were consistently found in the STP influ...