Particle-driven gravity currents cause major geological problems. Turbidity currents are highly erosive and can be damaging to structures on the sea bottom such as telecommunication cables. Understanding the mechanisms of sediment transport and deposition is required to predict the erosive powers of turbidity currents (and of the distribution of turbidite deposits) which are fully dependent on the behavior of gravity currents. For this reason, the main question of this thesis was formulated: Which physical parameters of the gravity current are of importance for its behaviour?

The lock-exchange release experiment is a frequently used method to study gravity currents in a laboratory and was also used in this thesis. In order to answer the main question, the following parameters were investigated and their influence specifically on the 4 phases, the run-out length and the PSD: particle size, bed roughness and temperature. The influence of particles size was researched using mono-dispersed vs bi-dispersed experiments. In the bed roughness experiments, sandpaper was attached to the bottom and compared to smooth bed experiments. Finally, to investigate the influence of temperature on the gravity current, experiments with warm water were compared to experiments with colder water.

From these experiments, the most notable results are summarized below.
PSD : For all experiments applies that at low concentration the particles segregate over the run-out length of the gravity current. Smaller particles travelled further than the bigger particles with a higher settling velocity. This does not occur at higher concentrations and the PSD over the entire run-out length is similar.
Four Phases: In all experiments, the four phases could clearly be identified with one exception: the first phase in the rough bed experiments was difficult to distinguish.
Run out length: Some interesting findings were made that were in line with literature: adding fine particles to the mixture of the current cause the run-out length of the current to increase. However, it was also found that if the initial concentration is increased, this effect decreases.
Furthermore experiments showed that an increase in temperature can cause the current to travel less far when compared to experiments performed with water with lower temperature.

In the light of this research, the following recommendation are made:
Temperature should be taken into account for modelling gravity currents. Otherwise this can lead to an overestimation regarding the run-out length and an underestimation of the deposit density.
Furthermore, to get more insight in the effect of the particle sizes in the currents, it would be highly recommended to conduct more experiments with a greater difference between particle sizes. This would allow for a better assessment of the magnitude of the effect of hindered settling

Dam reservoirs form a crucial part for human society storing water, controlling floods, providing hydropower, water for irrigation and drinking. Annually 1% of the worldwide dam reservoirs storage capacity is lost, caused by sedimentation. The inflow of sediment and reduction of flow velocity and turbulence in the reservoir pro- vides favourable conditions for settling. Several sediment transport mechanisms are responsible for this, one of these is the turbid density current. The turbid density currents settle as the reservoir becomes wider, and it is affected by forces along the top and the bottom of the current. Recently, focus on reservoir engineering has shifted from primarily structural dam design towards complete sediment management strategies. In order to improve the sustainability of dam reservoirs, many management techniques are developed that inhibit or mitigate sedimentation. However, the effectiveness of these techniques is not yet known. This thesis provides an additional concept for sediment management in dam reservoirs consisting of channelling of turbid den- sity currents in dam reservoirs. The channel provides controllable parameters. The aim is to study the effects of channelling turbid density currents.
The study starts with a literature review, to describe sedimentation, sediment transport, and turbid den- sity currents in dam reservoirs, including their analytical and numerical descriptions.
Two computational models study the concept: a steady-state model and a numerical model. The steady- state solution and is based upon an equation for open channel flows modified for turbid density currents. This model is used to investigate the effects of hydraulic radii and slope of the channel on the turbid density current — secondly, the dynamic numerical solution. An analytical description is provided using the one- dimensional shallow water equations, consisting of the continuity, momentum and particle conservation equations. The solution includes four sources: deposition, erosion, gravity and friction. It omits water en- trainment and bed deformation. The model is discretised using the Generalised Lax Friedrichs method. First validation and investigation of the quality of the source terms are done. Subsequently, the model, including the four source terms, is used to study the effect of slope, hydraulic radii, concentration and sediment size in the channel. Expanding the numerical study by a Water Injection Dredging case in which local velocity, concentration and height are increased along a certain length to study possible effects.
To conclude, channelling turbid density currents is a viable solution to improve sediment transport. The slope and depth of the channel have the most significant effects. The generalised Lax Friedrichs method provides a valid and straightforward discretisation method for the numerical model. Furthermore, the model provides an easy, quick and simple to use tool to make first estimations of the effects of channel dimensions.