Major, minor, trace element and suspended sediment variations in the River Tweed: results from the LOIS core monitoring programme

“…Suspended sediment concentrations are typically`10 mg l À1 during baseflow, but concentrations may exceed 500 mg l À1 during high discharges associated with storm events (unpublished data; Neal et al, 1997). (Available data on annual suspended sediment loads are presented in Table III.…”

mentioning

confidence: 99%

Deposition and storage of fine-grained sediment within the main channel system of the River Tweed, Scotland

Owens

Walling

Leeks

1999

Earth Surf. Process. Landforms

View full text Add to dashboard Cite

This paper assesses the importance of deposition and storage of fine-grained (c.`150 "m) sediment on the floodplains and beds of the main (non-tidal) channels of the River Tweed (4390 km 2 ), Scotland, and two of its tributaries (River Teviot and Ettrick Water). Caesium-137 analysis of floodplain sediment cores has been used to estimate average rates of overbank sedimentation during the last 30 to 40 years. Average values for individual transects ranged from 0Á16 to 2Á18 kg m À2 a À1(0Á13 to 2Á2 mm a À1 ). The mean for the 10 transects investigated was 1Á29 kg m À2 a À1 (1Á3 mm a À1 ). The total amount of fine sediment deposited was estimated to be about 44 000 t a À1. The fine-grained sediment stored in the channel bed was quantified using resuspension techniques. Average values for individual sites ranged from 0Á12 to 0Á96 kg m À2. The mean for the 10 sites investigated was 0Á56 kg m À2. The total amount of sediment stored on the channel bed of the main channel system at the time of sampling was estimated to be about 4300 t. Comparison of these estimates of floodplain and channel storage with the estimated suspended sediment load for the River Tweed at the downstream gauging site at Norham, indicates that floodplain sedimentation and channel bed storage represent about 40 and 4 per cent, respectively, of the annual load of fine sediment delivered to the main channel system. Erosion of channel banks will reintroduce the equivalent of about 30 per cent of the floodplain-deposited sediment back into the channel. The residence time of the fine-grained sediment stored on the channel bed is probably less than one year, but that of sediment deposited on the floodplain is likely to be considerably longer. Conveyance losses associated with overbank deposition have important implications for the routing of sediment through fluvial systems and the interpretation of downstream sediment yields.

show abstract

“…This was because nearly 60% of the whole reservoir basin is covered by a variety of forest types, which generally contain higher content of organic matter as reported (93.6%) for a given species of plant litter (Dawson and Billett 1998). In another study, Neal et al (1997) examined the composition of suspended sediments at three sites in the basin of the River Tweed and the mass percentages of POC were determined as 35.6, 27.1 and 13.4%, respectively. The POC values obtained in our present study (1.2-3.1% at all three sites) were significantly lower than their values but resembled the literature value of 3.3% reported by Dawson and Billett (1998) for the River Dee mentioned earlier.…”

Section: Water Content and Organic Matter In Sedimented Mudmentioning

confidence: 98%

Vertical Distribution of Nonylphenol Ethoxylates and Their Derivatives in Sediments of a Freshwater Reservoir

Tsumori

Suzuki

et al. 2007

Water Air Soil Pollut

View full text Add to dashboard Cite

The distribution of nonylphenol ethoxylates (NPEOn) and their derivatives of nonylphenol (NP) and nonylphenoxy ethoxy acetic acids (NPEnC) in the sediments of a relatively closed freshwater reservoir was investigated using sediment layers sliced from undisturbed sediment cores collected with a gravity core sampler at three sampling sites (St. 1, St. 2 and St. 3) along the water flow direction. The relationships between the bound content of these compounds and the sediment organic matter as well as the likely transformation pathways were evaluated. The total content of NPEOn (n=1-15) fell in 84.6-336.5, 59.9-135.5 and 77.0-623.4 μg/kg-dry for all sliced layers at St.1, St.2 and St.3, respectively, with the content of individual NPEOn species showing a general decreasing trend with the attached molar number of the ethoxy (EO) chain. Compared to each detected NPEOn species, the bound content of NP was much higher, falling in 73.2-248.4, 79.9-358.2 and 25.5-1,988.4 μg/kg-dry at St. 1, St. 2 and St. 3, respectively. A general increasing trend of the NP content along the water flow direction of the reservoir was revealed. NPEnC (n=1-10) varied in 1.93-4.12, 2.85-9.84 and 1.05-19.1 μg/kg-dry for sediment at the respective site of St. 1, St. 2 and St. 3, with the averaged values at these sites (2.91, 4.71 and 6.72 μg/kg-dry) showing an increasing trend from the upstream to the downstream.For NPEnC, a parametric trend of increases in the content of NPE 1 C, NPE 2 C and NPE 3 C with the bound sediment organic matter (9.06-11.8%) seemed to be existent. Furthermore, the computed magnitudes of NPEO 1-2 / NPEO 1-15 , NP/NPEO 1-15 and NPEC 1-10 /NPEO 1-15 suggested that non-oxidative hydrolytic transformation was probably prevailing within the sedimented mud phase of the reservoir, with the oxidative hydrolytic transformation pathway being less involved.

show abstract

Major, minor, trace element and suspended sediment variations in the River Tweed: results from the LOIS core monitoring programme

Cited by 50 publications

References 21 publications

Lowland river water quality: a new UK data resource for process and environmental management analysis

Lowland river water quality: a new UK data resource for process and environmental management analysis

Deposition and storage of fine-grained sediment within the main channel system of the River Tweed, Scotland

Vertical Distribution of Nonylphenol Ethoxylates and Their Derivatives in Sediments of a Freshwater Reservoir

Contact Info

Product

Resources

About