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"For the Federal Water Quality Administration, Department of the Interior and twenty-five local governmental jurisdictions." ; Mode of access: Internet.

Antarctic Bottom Water (AABW) and North Atlantic Deep Water (NADW) control the abyssal limb of the global overturning circulation and play a major role in oceanic heat uptake and carbon storage. However, current general circulation models are unable to resolve the observed AABW and NADW formation and transport processes. One key process, that of overflows, motivates the application of overflow parameterisations. We present a sensitivity study of both AABW and NADW properties to three current parameterisations using a z*-coordinate ocean-sea ice model within a realistic-topography sector of the Atlantic Ocean.Overflow parameterisations that affect only tracer equations are compared to a fully dynamical Lagrangian point particle method. An overflow parameterisation involving partial convective mixing of tracers is most efficient at transporting dense NADW water downslope. This parameterisation leads to a maximum mean increase in density in the north of 0.027kgm-3 and a decrease in age of 525years (53%). The relative change in density and age in the south is less than 30% of that in the north for all overflow parameterisations. The reduced response in the south may result from the differing dense water formation and overflow characteristics of AABW compared to NADW. Alternative approaches may be necessary to improve AABW representation in z*-coordinate ocean climate models. ; BMS was supported by the Australian Government Department of the Environment, and CSIRO through the Australian Climate Change Science Programme. AMH was supported by an Australian Research Council Future Fellowship FT120100842. SMH was supported by the ARC Centre of Excellence for Climate System Science (Grant CE110001028)

Antarctic Bottom Water (AABW) and North Atlantic Deep Water (NADW) control the abyssal limb of the global overturning circulation and play a major role in oceanic heat uptake and carbon storage. However, current general circulation models are unable to resolve the observed AABW and NADW formation and transport processes. One key process, that of overflows, motivates the application of overflow parameterisations. We present a sensitivity study of both AABW and NADW properties to three current parameterisations using a z*-coordinate ocean-sea ice model within a realistic-topography sector of the Atlantic Ocean.Overflow parameterisations that affect only tracer equations are compared to a fully dynamical Lagrangian point particle method. An overflow parameterisation involving partial convective mixing of tracers is most efficient at transporting dense NADW water downslope. This parameterisation leads to a maximum mean increase in density in the north of 0.027kgm-3 and a decrease in age of 525years (53%). The relative change in density and age in the south is less than 30% of that in the north for all overflow parameterisations. The reduced response in the south may result from the differing dense water formation and overflow characteristics of AABW compared to NADW. Alternative approaches may be necessary to improve AABW representation in z*-coordinate ocean climate models. ; BMS was supported by the Australian Government Department of the Environment, and CSIRO through the Australian Climate Change Science Programme. AMH was supported by an Australian Research Council Future Fellowship FT120100842. SMH was supported by the ARC Centre of Excellence for Climate System Science (Grant CE110001028)

The Environment Agency has analysed Event Duration Monitoring data on storm overflows associated with bathing waters across England for 2023. This data, provided to the EA following the end of the bathing water season (May to September inclusive), is a …

We consider some simple Markov and Erlang queues with limited storage
space. Although the departure processes from some such systems are known to be
Poisson, they actually consist of the superposition of two complex correlated processes, the
overflow process and the output process. We measure the
cross-correlation between the counting processes for these two processes. It turns out
that this can be positive, negative, or even zero (without implying independence). The
models suggest some general principles on how big these correlations are, and when
they are important. This may suggest when renewal or moment approximations to similar
processes will be successful, and when they will not.

SummaryIn this paper some known formulae concerning overflow traffic have been derived in a simpler way than is generally done in literature, i.e. by using simple results obtained from elementary renewal theory.After the model has been introduced, the distribution of intervals between overflows is calculated by means of a recurrence relation. A generalization of Erlang's formula for the call congestion follows almost immediately. The last section the special case of Poisson input is discussed.

AbstractThis paper reviews some of the physical model studies which have been carried out in the UK to determine the performance of combined‐sewer overflow chambers. The topic of computational fluid dynamics is introduced and identified as a viable alternative to physical modelling. The limitations of both modelling approaches are discussed. It is concluded that the future of chamber modelling will be a combination of computational fluid dynamics and physical techniques.

AbstractThe paper describes a unit hydrograph method, calibrated using the WALLRUS modelling suite, which was employed to simulate the long‐term behaviour of storm overflows in combined sewerage systems. It is shown that this procedure synthesizes overflow operation characteristics to acceptable engineering accuracy, measured relative to WALLRUS predictions. This is achieved at only a small fraction of the computer run‐time, and therefore makes practicable a wide range of overflow performance and river impact studies using local rainfall records of unlimited extent.