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Lueck R.,Rockland, Inc. | Wolk F.,Rockland, Inc. | Hancyck J.,Rockland, Inc. | Black K.,Partrac Ltd.
2015 IEEE/OES 11th Current, Waves and Turbulence Measurement, CWTM 2015 | Year: 2015

The Nemo turbulence measurement system is an anchored, buoyant float designed to measure time-series of current velocity, velocity shear, and turbulent kinetic energy (TKE) dissipation rates in swift tidal channels. The system consists of a 4.5 m long streamlined float made from syntactic foam, with cutouts to house various instrument components: a 600 kHz downward-looking acoustic Doppler current profiler (ADCP); an acoustic Doppler velocimeter (ADV); and a turbulence module equipped with velocity shear probes and fast-response thermistors The system was successfully deployed over a two-week period in Islay Sound, a tidal channel between Islay and Jura Islands, Scotland, where flow speeds exceed 3 m/s. The depth of the channel was 53 m and the system was deployed such that it remained within the depth aperture of a proposed tidal energy extraction rotor. This environment represented significant challenges for the design of the mooring and the turbulence instrumentation. We describe the measurement system and its performance in terms of attitude and flight dynamics including a synopsis of time series of current velocities and shear probe turbulence data. Scientific interpretation will be presented in subsequent publications. © 2015 IEEE. Source

Black K.,Partrac Ltd. | Leggett D.,DLEnviro Ltd | Read K.,Dredging International NV
International Ocean Systems | Year: 2015

Dredge monitoring and oceanographic specialist Partrac Ltd was commissioned by Dredging International to deliver one of the largest marine monitoring networks associated with environmental compliance for the development of the London Gateway Port. One of the environmental mitigation measures was to place a network of 11 buoy monitoring stations around the dredging and reclamation activities, placed in-between the dredging and reclamation operations, and identified sensitive areas to landward. To seawards, measurements were made one meter above the bed to reflect the potential of sediment disturbance there, to detect any increase in SSC due to discharges from the reclamation moving along the bed, and to measure the higher values in SSC found in that part of the water column. To control the works, an approach to thresholds was identified to be applied in real-time. The setting of a Caution level aimed to allow sufficient time to be able to react to any changing SSC events whilst not being so sensitive that an unnecessary amount of cautions were triggered. The measurements made between March 2009 and March 2014 have demonstrated, in spite of slightly elevated SSC during Year One dredging, compared to the predredge baseline year, that the levels of change in the environment fall within or below those identified as 'potential impacts' through the extended environmental impact assessment process. Source

Collins A.L.,Environment Group | Yusheng Z.,Environment Group | Walling D.E.,University of Exeter | Kevin B.,Partrac Ltd.
IAHS-AISH Publication | Year: 2010

A novel tracing framework combining conventional sediment source fingerprinting and a dual signature tracking method has recently been tested in a grassland catchment in Cumbria, northwest England, UK. The former component of the framework provided information on the relative importance of generic sediment sources characterised as pasture (75±1%) or arable (9±1%) surface soils, damaged road verges (6±1%), channel banks/subsurface sources (9±1%) and the local sewage treatment works (1±1%), whereas the latter component was used to apportion sediment loss from grass fields between poached gateways (1±1%) or cattle tracks (28±1%) and wider areas of general pugging and poaching damage (46±1%). Uncertainty and prior information are explicitly recognised by the novel source tracing framework. Copyright © 2010 IAHS Press. Source

Source control i.e. the reduction of contamination from upstream or diffuse sources, is a critical element in any management plan for contaminated waterways. If source control measures are not successfully implemented, then a situation exists in which contamination will continue through time, and the cleanup of waterway segments becomes increasingly problematic. To provide greater understanding of the issues surrounding source control, it is essential to have some knowledge of contaminant sources and transport pathways of contaminated particulates. In port areas a plethora of factors interact to control contaminant transport pathways. These include: rain and river flow; tidal circulation, surface waves and wind drift, and temporally changing water column stratification. Particle tracking offers a practical means to map the transport pathways of contaminated sediments under these collective influences. This paper introduces a new and novel "dual signature" tracer product, and describes the particle tracking technique on a practical level through a study example in the Lower Duwamish Waterway, Washington, USA. © Owned by the authors, published by EDP Sciences, 2013. Source

Black K.,Partrac Ltd.
Coasts, Marine Structures and Breakwaters: Adapting to Change - Proceedings of the 9th International Conference | Year: 2010

Following introduction of the concept of Renewable Energy Zones (REZ) by the UK government, licensed marine windfarm developments are being sited in shallow coastal regions where the seabed sediments are potentially highly mobile. These present acute challenges to developers in terms of the stability, serviceability and longevity of the piles and turbines in these areas. A detailed knowledge of the sediment transport spatially at a proposed windfarm site is required in order to understand the risks presented by the sediment mobility. Current industry practice is reliant almost entirely on numerical models which are often calibrated for the hydrodynamics but are not validated. However, recent technological developments in marine instrumentation capable of gathering field data on the rates of seabed mobility, coupled to acquisition of wave, tide and wind data on a scale applicable to wind farm developments can for the first time permit geospatial, direct field measurement of sediment transport in support of site assessments for offshore windfarm developments. This presentation provides an overview of these technologies and presents a strategic framework within which data can be acquired and combined in order that informed decisions can be made regarding site selection, thus reducing the risk of turbines being located in areas not suitable due to high scour or mobile sand banks. Source

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