ALBERT

Description: An intensive one-month long observational campaign of tides and currents during dry season were used to describe the tidal dynamics and the spatial evolution of tidal asymmetry in Cochin estuary. The estuary is described as hyposynchronous since tidal amplitude and currents get attenuated towards upstream through frictional dissipation. The results showed that the tidal momentum balance along the main axis of the channel was dominated by pressure gradient and friction. The influence of advection was prevalent near the inlets and friction was greatest in the shallow upstream regions. Higher harmonics were generated in the estuary through nonlinear friction and advection causing tidal distortions. Being a mixed predominantly semidiurnal tidal regime, tidal asymmetry was quantified in terms of sample skewness to examine the spatial evolution in the total asymmetry. The principal astronomical tides (M2, K1 and O1) interacted to engender flood dominance at the inlets. The compound tides and overtides generated inside the estuary were found to either augment or transform the asymmetry imposed by the principal tides. The study showed that friction causes flood dominance at the northern inlet (Munambam) and in the shallow regions of the upstream during dry season. In striking contrast, the Cochin inlet and the adjacent harbor area turned to be ebb-dominant. These findings have implications for management and sediment transport mechanisms within the estuary.

Description: This article offers an empirical example of how power and rationality interact in coastal resource planning and management and reveals their implications for meaningful public participation in such processes. Participation has gained significant popularity over the last decades especially regarding the need to develop appropriate and democratic opportunities for meaningful public involvement in resource planning and management. However, planning processes involve interactions between different actors with different levels and types of power and thus pose problematic contexts for democratic decision-making and public participation. Understanding planning processes as manifestations of the interactions between power and rationality provides a useful analytical lens to interrogate past and current planning procedures, and how such dynamics may impede the potential for more desirable modes of public participation. Drawing on ongoing research in the coastal community of Flagler Beach, Florida, I demonstrate, through qualitative analysis of public documents, legislation, interviews, and observations, how this plays out in a real-world planning context. I draw conclusions from the empirical case area relevant to the praxis of action-oriented researchers concerned with facilitating social change for sustainability. I propose three axioms relevant to power-laden resource planning and management processes and central to future critical planning research: power-rationality relations have historical roots; power-rationality relations are context-dependent; power-rationality relations affect the potential for public participation. Taken together, these indicate that any research intending to critically investigate planning processes with the goal of enhancing the potential for meaningful public participation should incorporate these axioms, maintain a responsibility to identify others, and adjust theory and research praxis accordingly.

Description: Lagoon-wetland systems are common along low-lying coastlines. They provide rich species habitats, multiple ecosystem services and socio-economic activities. They are particularly susceptible to the impacts of sea level rise (SLR), especially in less developed countries (LDCs) where economic and development constraints limit adaptation. The Muni-Pomadze lagoon is one of five coastal Ramsar sites in Ghana and one of many along the country’s coastline. It is an intermittently closed lagoon with extreme seasonal hydrological and physico-chemical variation. Field observation, digital mapping and GIS analysis of the shoreline has enabled an understanding of coastal change and SLR at the lagoon. From 1972 to 2014 the high water mark has shifted landwards with an average retreat rate of 0.22 m/year. Evidence of erosion and sediment washover indicate loss of and a shift landward of the sand barrier separating the lagoon from the ocean. Creation of an inundation map for a one-meter rise of sea level reveals fragementation and breaching of the barrier and an increasingly permanent connection to the ocean. A more open lagoon system stabilises hydrological and physico-chemical conditions, leading to increases in biodiversity and aquatic productivity. The lagoon currently has no consideration of SLR in its management plan. The results of this analysis and the limited development of the Muni-Pomadze lagoon support a no intervention approach to coastal management that allows SLR to transform the closed lagoon to an open estuary. A similar approach at comparable coastal wetland systems in Ghana and in other LDCs could prove an effective management option.

Description: The identification of temporal change in the extent of coral reefs and mangroves patches along the Narara and Kalubhar islands was performed using multi-temporal data from 1999 to 2010 (LISS III and LISS IV (MX)). For extracting coral reefs, the reflectances of the feature were studied and using a few sample locations identified by sea-truthing, the reflectances of the corals were observed in different bands. Since these values were not normally distributed, it was considered best to use the modal value of the dataset. The final range was taken as ±1 from the mode, which was used for the extraction of coral pixels. The findings suggested that the coral cover depleted from 19.35 to 9.11 km 2 in the study area. The second objective of extracting the mangroves was accomplished by employing the technique of Principal Component Analysis (PCA). This technique gave better results as it not only identified the mangrove swamps but also differentiated between the dense and sparse. The greatest variance in the dataset could be identified by this method, thereby making it easier to outline the variations existing within the mangroves. The findings highlighted that out of the total area mangroves covered 38.81 km 2 in 2010 while in 1999, they covered only 30.69 km 2 ascertaining the impact of mangrove restoration projects functioning in the area.

Description: Waterlogged and salt-affected soils are serious environmental hazard indicators for wasteland problems in arid and semi-arid regions of the World. Similarly human activities in agricultural and urban sustainable developments have also led to the development of waterlogging and subsequent salinization of soils leading to many geo-environmental problems. Thus, it is important to be able to monitor, assess and map waterlogged and salt-affected areas at an early stage to develop an effective soil reclamation programme that helps to reduce and prevent a future increase in areas of wasteland. Remote sensing and GIS tools and techniques have been found to outperform more traditional methods for assessing the impact of soil salinity and waterlogging, thereby providing extremely useful, informative, and professional rapid assessment techniques for monitoring and accurate mapping and the quantification of waterlogged areas and salt-affected soils. This study applies digital image processing and GIS tools to monitor, assess, and map the waterlogged and salt-affected areas, to establish the main causes that lead to widespread wastelands, and to suggest approaches to mitigation in the eastern Nile Delta region in Egypt. Multi-temporal Landsat 5, 7 and 8 data for 1984, 2000, 2006 and 2013 and ASTER GDEM were selected to monitor, assess and map the waterlogged and salt-affected areas, and to determine and map the rate of change of land-use/land-cover, the status of wasteland, and the use of geomorphological terrain analyses based on enhanced digital images processing and field verification. Image band combinations, PCA, change detection, and image classification techniques, together with many indices such as NDVI, NDSI, NDWI and NDBI were applied, together with statistical analysis, to construct various thematic and spatial distribution change maps of the wasteland hazard indicators. Spatial distribution maps of waterlogging, salt-affected areas, permanent and temporarily waterlogged areas, surface changes, and their rate of change in addition to integrated relationships between terrain analyses, water table, depth to water and landform maps over a timespan of 29 years based on the analysis and interpretation results of image processing, field investigation and ancillary geological and hydrogeological data. The results reveal that changes to land-cover caused by human activities - particularly irrigated agriculture and land reclamation as well as urban expansion - will lead to a serious deterioration in the environment through waterlogging and salinization presenting future difficulties for any sustainable development of the study area. In addition; the existence of natural factors such as areas of low-lying land, topographic depressions, and rising water tables will increase the threat of waterlogging and salinization. It is concluded that it is essential for planners and decision makers to seriously consider taking appropriate action now concerning the recommended mitigation measurements from this study to avoid serious future problems in these areas.

Description: Intense transport of sediments occurs along the eastern coast of the Gulf of California, interacting with several coastal lagoons like Santa María-La Reforma. This sediment dynamics plays an important role in the conservation issue of marine species. The effect of tidal currents on the bed load sediment transport has been investigated for this lagoon, emphasizing the mechanisms of the geomorphologic development of the sea bottom. The flow dynamics has been studied applying the vertically integrated shallow water equations through a modified two dimensional non-linear finite difference model. A parameterized formula for the bed load sediment transport and a sediment conservation equation were applied to investigate the morphodynamics of the sea bottom of the lagoon. The predicted currents pattern allowed identifying a zone where tidal waves, entering into the lagoon throughout the northern and southern openings, meet. This process had consequences on the bed load transport of sediment. The results revealed areas where the currents induce noticeable erosion and accretion processes. The complex geometry of the lagoon seems to determine the accretion and erosion areas. Important changes of the order of 0.04 m per year were predicted nearby the Northern inlet and around the Talchichitle Island. The lagoon system exports sediment through the two inlets. This research work contributes to the understanding of the sediment dynamics in an extensive region with a series of coastal lagoons located on the eastern side of the Gulf of California.

Description: The coastal zones management not only relies on a profound knowledge of the shoreline but also on a good assessment of morphodynamics, sediments transport and coastal interventions required. Many coastal studies, such as beach slope estimates, equilibrium beach profile definition or sediment transport analysis, depend on the sediment grain size at the site. This paper aims to gain a better understanding of grain size distribution along the cross-shore profile and variation of d 50 , allowing to define a representative d 50 to characterize the beaches. On the study site chosen, Barra beach, Aveiro, an extensive field campaign was performed, from October 2010 to May 2011. In a weekly basis, samples from 5 points along a cross-shore profile were collected. During this period, data related to wave climate was collected from the Portuguese Hydrographic Institute in temporal series of 10 min. Tidal projections from Hydrographic Institute were also identified for the period of the field campaigns. The sediment grain size distributions showed that, although the mass-median-diameter does not usually pass the 1 mm, d 50 presented a great variation during winter, in the intertidal zone. On the other side, the first and last points of the cross-shore profile, located far from the intertidal zone, presented the smaller d 50 and variation through time. The significant wave height presented a mean value of 2.16 m. The most energetic wave climates happened in November, January and February. During those months, an increase of d 50 in the wave breaking zone was noticed. Generally, the expected behavior of the cross-shore sediment grain size distribution is in line with the data collected in this paper and it was verified that the grain size is coarser on the intertidal zone and after storm periods. Also, despite the complexity of defining a characteristic d 50 due to its great temporal and spatial variation, sensitivity analysis on the data obtained helped the identification of the upper foreshore limit, at high tide, as the better location for a sediment sample collection representative of a cross-shore profile.

Description: The marine park of Hoi Ha Wan was established in 1996 and functions as a public leisure and educational facility that also protects a rich marine biodiversity. This study examines a sequence of historical aerial images dating back to the 1950s as Hong Kong recovered from World War II. These expose an hitherto unrecognised 〉60 year–long pattern of environmental change and, ultimately, decline in head-of-bay beach form related to a variety of long- and short-term anthropogenic-induced impacts upon the village of Hoi Ha and its bay – Hoi Ha Wan. How these perturbations have collectively impacted beach form in Hoi Ha Wan to reduce it to, probably, something like its pre-human and post ice age form is described. The long term consequences of this reduction in beach size will have implications with regard to the sustainability of the marine park itself in the light of continuing infra-structural changes to the surrounding village and country park and in relation to climate change resulting in locally higher temperatures, higher volumes of rainfall and raised sea levels.

Description: The Frisian islands (Southern North Sea) have extensive island tails, i.e. the entire downdrift side of an island consisting of salt marshes, dunes, beaches and beach plains, and green beaches. Currently, large parts of these tails are ageing and losing dynamics, partly due to human influence. This may mean a loss of young stages on the long term, and current management is not enough to counteract this. To aid the development of new interventions aiming at (re)introducing natural dynamics, a conceptual model of island-tail development under natural and disturbed conditions was developed, based on existing data, field visits and literature. The development of an island tail follows the general pattern of biogeomorphic succession. The first phase consists of a bare beach plain. In the second phase, embryonic dunes form. In the third phase, green beaches, dunes and salt marshes form, including drainage by creeks and washovers. In the fourth phase, vegetation succession continues and the morphology stabilises. Human interference (such as sand dikes and embankments) reduces natural dynamics and increases succession speed, leading to a reduction in the diversity in landforms and vegetation types. Both for natural and human-influenced island tails, succession is the dominant process and large-scale rejuvenation only occurs spontaneously when large-scale processes cause erosion or sedimentation. Island tails cannot be kept permanently in a young successional stage by reintroducing natural dynamics through management interventions, as biogeomorphic succession is dominant. However, such interventions may result in local and temporal rejuvenation when tailored to the specific situation.