ctaaban / lagun-ex

LWaves: Applicability of LiDAR on wave measurements

Lagun-EX

This repository contains the developed software (LWaves) of an individual research objective related to a measurement campaign which goes under the name: Lagun-EX. This fieldwork is part of the course Fieldwork Hydraulic Engineering at the Delft University of Technology and took place in week 39 of 2018. The site of the fieldwork campaign is located at the Sand Engine between Kijkduin and Ter Heijde along the ‘Westland’ coastal cell of the Dutch coast.

Local (mega) nourishments are soft solutions regarding the deficit in the sediment budget of a certain coastal system and are expected to be more efficient, economical, and environmentally friendly in the long term than conventional beach and shoreface nourishments (Stive et al., 2013).The Sand Engine is an innovative and experimental example of such a coastal reinforcement which was constructed in 2011 in which 21.5 million cubic meters of sand is deposited between Kijkduin and Ter Heijde.

One of the morphodynamic features of the Sand Engine is the development of a lagoon inside the Sand Engine in which channels do connect the basin to the open sea. In order to get more insight in the hydrodynamic and morphodynamic character of such lagoons, a measurement campaign has been setup at the Sand Engine in which the central theme of the fieldwork was to research the exchange and development of (artificial) basins. A small, artificial lagoon has been constructed and the development of the lagoon has been be tracked by different students. A total of nine Hydraulic Engineering master students have contributed with individual research objectives and experiments to the general theme during the fieldwork.

One of the factors which affect the development of the artificial lagoon is the wave climate. Since the artificial lagoon is a disturbance in the morphodynamic equilibrium, the wave activity, amongst other influences (e.g. lagoon shape), will cause the lagoon to develop over time. The lagoon will either accrete with sediments, restoring the previous equilibrium, or erode to a larger lagoon and hence forming a new equilibrium. So tracking the wave activity nearby the lagoon during the development of the lagoon will give insight into the relation between the wave hydrodynamics and the development of the lagoon.

A potential new and innovative way of obtaining measurements of wave hydrodynamics is by applying a laser scanner (LiDAR). The use of remote sensing techniques has become increasingly popular during the past three decades since this remote techniques are non-intrusive, easily and safely deployed. This method should make the acquisition of wave measurements more easily in which smaller temporal and spatial scales can be obtained (Martins, Blenkinsopp, & Zang, 2016). This smaller scales might for example be useful to study higher frequency waves at the beach. Furthermore, the ability of obtaining measurements at multiple locations with just a single LiDAR survey would be more effective w.r.t. the measurements obtained by a large quantity of conventional, in situ instruments (e.g. pressure sensors or stilling wells).

So the research question for this research is as follows:

Can 3D laser scanning techniques be applied to acquire wave characteristics for studying the inner-surf and swash hydrodynamics?