The over-exploitation of mangrove forests since the 1980s has led to biodiversity loss and coastal erosion in several parts of the world. Still, about 80-90% of mangrove restoration projects have been reported to fail. The main reasons are related to a poor understanding of the eco-geomorphological dynamics and mangrove species-specific ecological requirements. Although several guidelines are available, they are mostly site-specific, with a management focus on coastal protection schemes. A better system understanding of the feedback processes between mangrove forests and mudflat dynamics is required.
The thesis objective is to gain a better insight into complex eco-geomorphic interactions and feedback processes in coastal mangrove environments to the benefit of developing trustworthy tools for predicting their dynamics. To achieve the objective, the thesis describes the development of hybrid modelling by coupling the landscape-scale processbased hydro-morphodynamic model Delft3D-Flexible Mesh (DFM) and the individualbased MesoFON mangrove model (MFON). This coupled model (DFMFON) resolves the feedback process between seasonal and decadal environmental changes (waves, tides, river flow, sediment supply, salinity, and morphodynamics) and mangrove life-stages ranging from (dispersal of) propagules to development of seedlings and sapling into mature trees.
Since it covers a unique, rapidly progressing delta setting with concomitant mangrove expansion, Porong Estuary in Indonesia is used as a case study to validate the newly developed modeling tool (DFMFON). Imagery from off-the-shelf unoccupied aerial vehicles (UAV’s) and atellites was used and groundthruthed to retrieve accurate mangrove structural attributes and mangrove belt dynamics. The DFMFON model successfully reproduced observed spatiotemporal (seasonal-decadal) mangrove development, like the age-height relationship, as well as morphodynamic delta features.
DFMFON was then used to explore optimizing mangrove restoration strategies and carbon sequestration capacity in coastal systems. Best results were obtained for higher level (above mean sea level) and patchy mangrove restoration schemes.
The observations and tool presented in this thesis open up possibilities to assess and gain a better system understanding of the interactions between mangroves and environmental drivers. DFMFON will be a helping hand in directing mangrove management schemes for climate change mitigation and adaptation.@en

As climate-change-driven extremes potentially make coastal areas more vulnerable, mangroves can help sustainably protect the coasts. There is a substantial understanding of both mangrove dynamics and hydro-morphodynamic processes. However, the knowledge of complex eco-geomorphic interactions with physical-environmental stressors remains lacking. We introduce a novel coupled modelling approach consisting of an individual-based mangrove (mesoFON) and a process-based hydromorphodynamic model (Delft3D-FM). This coupled model is unique because it resolves spatiotemporal processes, including tidal, seasonal, and decadal environmental changes (water level, flow, sediment availability, and salinity) with full life-stages (propagule, seedling, sapling, mature) mangrove interaction. It allows us to mechanistically simulate forest expansion, retreat, and colonisation influenced by and with feedback on physical-environmental drivers. The model is applied in a schematized mixed fluvial-tidal deltaic mangrove forest in dominantly muddy sediment inspired by the prograding delta of Porong, Indonesia. Model results successfully reproduce observed mangrove extent development, age-height relationship, and morphodynamic delta features.

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To date, the potential development of 3D laser scanning has enabled the capture of high-quality and high-precision reality-based datasets for both research and industry. In particular, Terrestrial Laser Scanning (TLS) technology has played a key role in the documentation of cultural heritage. In the existing literature, the geometric properties of point clouds are still the main focus for 3D reconstruction, while the surface performance of the dataset is of less interest due to the partial and limited analysis performed by certain disciplines. As a consequence, geometric defects on surface datasets are often identified when visible through physical inspection. In response to that, this study presents an integrated approach for investigating the materials behavior of heritage building surfaces by making use of attribute point cloud information (i.e., XYZ, RGB, reflection intensity). To do so, fracture surface analysis and material properties are computed to identify vulnerable structures on the existing dataset. This is essential for architects or conservators so that they can assess and prepare preventive measures to minimize microclimatic impacts on the buildings.@en

This article presents a novel approach to explore mangrove dynamics on a prograding delta by integrating unmanned aerial vehicle (UAV) and satellite imagery. The Porong Delta in Indonesia has a unique geographical setting with rapid delta development and expansion of the mangrove belt. This is due to an unprecedented mud load from the LUSI mud volcanic eruption. The mangrove dynamics analysis combines UAV-based Structure from Motion (SfM) photogrammetry and 11 years (2009–2019) satellite imagery cloud computing analysis by Google Earth Engine (GEE). Our analysis shows unique, high-spatiotemporal-resolution mangrove extent maps. The SfM pho-togrammetry analysis leads to a 3D representation of the mangrove canopy and an estimate of mangrove biophysical properties with accurate height and individual position of the mangroves stand. GEE derived vegetation indices resulted in high (three-monthly) resolution mangrove coverage dynamics over 11 years (2009–2019), yielding a value of more than 98% for the overall, producer and consumer accuracy. Combining the satellite-derived age maps and the UAV-derived spatial tree structure allowed us to monitor the mangrove dynamics on a rapidly prograding delta along with its structural attributes. This analysis is of essential value to ecologists, coastal managers, and poli-cymakers.

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Accurate and repetitive observation and quantification of the shoreline position and the coastal feature are essential aspects of coastal management and planning. Commonly, the dataset associated with coastal observation and quantification is obtained with in-situ coastal surveys. The current methods are mostly quite expensive, time-consuming, and require trained individuals to do the task. With the availability of the off-the-shelf low cost, lightweight, and reliable Unmanned Aerial Vehicle (UAV) with the advances of the algorithms such as structure-from-motion (SfM), UAV-based measurement becomes a promising tool. Open SfM initiative, open topographical database, and UAV communities are the enablers that make it possible to collect accurate and frequent coastal monitoring and democratize data. This paper provides a review and discussions that highlight the possibility of conducting scientific coastal monitoring or collaborating with the public. Literature was examined for the advances in coastal monitoring, challenges, and recommendations. We identified and proposed the use of UAV along with the strategies and systems to encourage citizen-led UAV observation for coastal monitoring while attaining the quality.

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Quantitative assessment for sustainable watershed management is essential. Hydrological parameters such as stream discharge, surface runoff, infiltration, groundwater recharge, and water quality are susceptible to the changes of the components in the river basin ecosystem. Numerous studies have shown that the Land Use Land Cover (LULC) changes such as deforestation, extensive agriculture, urbanization, and mining are recognized as the main factors to changes in LULC, which are related to the changes of the hydrological components of the river basin of all scale. This paper particularly shows the spatiotemporal variability of LULC in the Upper Brantas Basin and the effects on the river discharge variation. We showed that the changes in LULC, particularly cultivated and managed vegetation and urban/built-up area, contributed significantly to the river discharge. Particularly in the Upper Brantas Basin, it was indicated that almost half of the increased river discharge was explained by the increase of urban/built-up and the decrease in cultivated and managed vegetation area.

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