Implementation of a floating system as a form of environmental adaptation in Kuala Bubon Village, West Aceh

One of the important factors in supporting the sustainability of an architectural design is the ability to adapt to the environment. This adaptation can be observed, among others, from the accommodative level obtained from a building design to the needs of the community that uses the design. One form of design that is considered to accommodate the needs of the user community is the design of a floating system used by fishing communities. This paper wants to explore the adaptability of the floating system design which is judged by its ability to accommodate the dynamics of the wet environment and the needs of the fishing community. The research method is descriptive and logically explains the causal relationship between the design of the floating system building and the environmental and socio-cultural aspects of the community. Observations show 2 things: a) the legged building system (pit foundation and 2 meter stilt building) is highly adaptive to wetland conditions with tidal characteristics of water at the mouth of the river; b) architectural design of residential units which are about 4 meters apart, allowing the development of residential units into 4 sides, to accommodate the increase in daily activities of fishing communities so that community productivity increases. The conclusion of the study shows that the floating system is very flexible and adaptive to the dynamics of the environment and people’s lives (socio-cultural and economic aspects).

Modeling Tidal Characteristics in a Creek-Marsh Drainage System: Implications for Stormwater Management

The traditional goal of stormwater management is to reduce the threat of flooding to life and property, and so most landscapes are engineered to maximize the speed at which the unwanted water leaves the watershed. This has been effective in landscapes with some topographic gradient. This often involves the installation of drainage ditches that disperse runoff from urban areas to receiving water bodies; in coastal areas this means a tidal creek, estuary, bay, sounds, or the coastal ocean. This practice reduces flood hazards in some cases but results in unintended effects on the natural hydrology in the watershed and downstream tidal dynamics. For low-gradient watersheds in humid climates, ditch systems also lower the water table of an area, increasing infiltration to recharge and groundwater discharge to streams (baseflow), and larger volume of freshwater delivered downstream yearround. Ditches also create unintentional avenues for the incoming tide from a tidal creek or tidally-influenced waterway to reach further inland, thus reducing the hydraulic gradient between the inland areas and the receiving water body. The combination of these effects can exacerbate compound flooding events, increasing the flood probability if high tide and storm events coincide. Additionally, coastal communities face the challenge of mitigating more complicated flood hazards while land development increases to meet the needs of a growing population. This study analyzed the tidal influence within an inland drainage ditch in the central coast of South Carolina USA that is representative of thousands of artificially-drained coastal watersheds. The ditch-creek system investigated here is 12 km long in a 753-hectare (1860-acre) watershed of Church Flats Creek, a first-order tidal system. We monitored for 13 months a 0.75-km reach of the lower ditch portion of the system, just above the relatively undisturbed tidal creek and marsh. Prior to ditching in the 1960s this system had a wetland-rich floodplain but is now partially tidal. Field data collected were stream stage (depth), discharge, tidal range, tidal volume, incoming (flood) and outgoing (ebb) tidal durations, and water table hydrograph at a location about 50 m of mid-reach of the ditch. Multiple linear regressions were performed to best predict the flood and ebb tidal durations of the system based on tidal characteristics within the ditch. The mean values were 229 ± 2.5 and 182 ± 2.1 minutes for flood and ebb tide durations, respectively and the models explained 84% (residual standard error (RSE) of 25 minutes) and 80% (RSE of 23 minutes) for the flood and ebb conditions, respectively. The models were simulated for sea levels in 1993 and 2050, and results indicate that the flood tide within the drainage ditch is predicted to increase an average of 66 minutes and the total tidal duration (flood and ebb) an average of 139 minutes by 2050. These results suggest a loss in drainage functionality as sea level rises. Increases in the duration of tidal influence will induce a lower capacity for stormwater volume than the drainage infrastructure was constructed to manage, therefore resulting in an increased frequency of compound flooding events because of the lower storage volume and decreased hydraulic gradient in the system. This study fills a knowledge gap of tidal dynamics within coastal ditch-creek systems and we urge stormwater managers to consider the unintended consequences of using traditional stormwater methods in a region that does not benefit from gravity drainage practices like in other regions.

The Intra-Tidal Characteristics of Tidal Front and Their Spring–Neap Tidal and Seasonal Variations in Bungo Channel, Japan

The intra-tidal variations of a tidal front in Bungo Channel, Japan and their dependence on the spring–neap tidal cycle and month were analyzed utilizing high-resolution (~2 km) hourly sea surface temperature (SST) data obtained from a Himawari-8 geostationary satellite from April 2016 to August 2020. A gradient-based front detection method was utilized to define the position and intensity of the front. Similar to previous ship-based studies, SST data were utilized to identify tidal fronts between a well-mixed strait and its surrounding stratified area. The hourly SST data confirmed the theoretical intra-tidal movement of the tidal front, which is mainly controlled by tidal current advection. Notably, the intensity of the front increases during the ebb current phase, which carries the front toward the stratified area, but decreases during the flood current phase that drives the front in the opposite direction. Due to a strong dependence on tidal currents, the intra-tidal variations appear in a fortnight cycle, and the fortnightly variations of the front are dependent on the month in which the background stratification and residual current changes occur. Additionally, tidal current convergence and divergence are posited to cause tidal front intensification and weakening.

Seasonal variability of tides in the Russian Arctic seas

<p>In this research, the sea level variability in the Russian Arctic seas caused by the Moon and the Sun tidal forces is considered. For a long time, it was thought that the tides can be easily calculated based on a small series of observations made in summer, but as shown in a few recent publications, describing tides in the different parts of the Arctic Ocean, tidal characteristics change significantly during the year. The main attention is paid to their seasonal variability in the seas of the Russian Arctic. The most interesting results have been obtained for the east sector of the Russian Arctic seas, where the tides were poorly known, and the long-term data from the tide gauges have been processed for the first time. We have used the long-term hourly sea-level data from several stations in the White, Kara, Laptev and Chukchi seas. The temporary coverage for the White Sea stations includes rather continuous sea-level records from 2004 to 2014 yrs. The maximum length of records made from 1981 to 2005 at the stations of the east sector of the Arctic was found at the Tiksi station. In this work we also analysed unique data obtained from the bottom pressure loggers installed on the Laptev-sea shelf in the period 2018-2020. The results of this study allow us to conclude that the classical harmonic analysis applied to the precomputation of tides does not provide an accurate estimate of the tidal characteristics in individual water areas in the Arctic. Accounting of the seasonal variability in the tidal characteristics will make it possible to clarify tidal maps important for navigation and coastal construction in the Arctic Region.</p>

OVERVIEW OF CLASSIFICATIONS OF THE DEGREE AND TYPES OF HAZARDS INHERENT IN COASTAL TERRITORIES

The article provides a brief overview of approaches to classifying the degree of danger of natural phenomena and the types of possible hazards for coastal territories. It is shown that some approaches are universal and can be applied to almost any category of the coast to improve decision-making tools when planning the development and modernization of coastal infrastructure, including in Russia. Such approaches can be considered as a methodological basis for a simple assessment of the hazards inherent in the coastal environment in a changing climate. The paper also considers the system of comprehensive classification of coastal areas, which uses as a basis a geological classification, which is superimposed on the main dynamic forces and processes acting in the coastal environment and on the geological framework itself. Using this methodology, a total of 113 typical coastal environments were identified, and attempts were made to keep the number of typical environments as low as possible, while maintaining the usefulness of the classification system considered from the point of view of decision support. This system allows for practical classification by collecting data on the ground and using remote sensing of the Earth, or mainly using remote means. The system includes the following components: geological and chemical structure, wave parameters, tidal characteristics, flora/fauna, sediment balance and storm climate. Each common coastal system has a specific combination of these variables. The geological plan includes the following categories: coastal plain; barrier; islands; rocky coast; coral islands; tidal inlet / spit / estuary.

Influência da orientação de praia na retração da linha de costa induzida por marés de tempestade: Armação e Canasvieiras, Ilha de Santa Catarina - SC

Os processos de recuo da linha de costa em praias arenosas oceânicas estão comumente relacionados à ocorrência de marés de tempestade e agravados pelas construções sobre o limite superior de praia. Neste contexto, o trabalho apresentado quantificou a variabilidade da linha de costa de duas praias urbanizadas, Armação e Canasvieiras, situadas no sul do Brasil, que possuem orientações distintas ao clima de ondas, e relacionou sua exposição às marés de tempestade registradas entre os anos de 2009 e 2018. Para isso foram datadas e caracterizadas as marés de tempestade quanto às ondas, maré e ventos durante sua ocorrência. A variação da linha de costa foi calculada por meio do Método do Polígono de Mudança e do DSAS, que representam as variações a partir de modelos espaciais distintos. Os resultados mostram que houve recuo do limite superior nas duas praias e que o mesmo está relacionado às ocorrências de marés de tempestade. A praia da Armação apresentou recuo de até -4 m/ano e na praia de Canasvieiras registrou-se recuo de até -1m/ano. Constatou-se que na praia mais exposta, Armação, as marés de tempestade estão associadas às ondulações de SE e ventos de S. Por outro lado, os eventos na praia de Canasvieiras estão associados às ondulações de NE e ventos de N, tendo em ambas sido registrados durante as marés de sizígia. Nesta praia mais abrigada os eventos ocorrem sob condições meteo-oceanográficas particulares e podem igualmente causar impactos. Influence of beach orientation on shoreline retreat induced by storm surges: Armação and Canasvieiras, Ilha de Santa Catarina – SC A B S T R A C TCoastal retreat processes in oceanic sandy beaches are commonly related to storm surges and intensified by urbanization on the upper beach limit. In this research, shoreline variability was quantified in an interannual basis between 2009 and 2018 in two urbanized beaches in southern Brazil. Both Armação and Canasvieiras beaches have different orientations and exposures to the regional wave climate, but historically present severe wave-induced damage reports. The study was carried out based on the Change Polygon Method and the Digital Shoreline Analysis System (DSAS), two distinct shoreline change approaches based on different spatial models. The identified historical storm surges were discriminated according to waves, winds and tidal characteristics during their occurrence. It was concluded that the observed upper limit retreats in both beaches were, in fact, induced by storm surges. Due to its orientation, Armação beach is exposed to storm surges with SE waves and S winds. During the analyzed period, this beach showed a retreat up to -4 m/year. On the other hand, the events at Canasvieiras beach were associated with NE waves and N winds, showing a retreat up to -1 m/year. All the analyzed storm surge events occurred during spring tides and were concentrated in autumn. Although Armação beach is more exposed to storm surges due to its orientation, Canasvieiras beach, even with its sheltered shoreline orientation, can also be impacted depending on the storm surges characteristics.Keywords: Wave climate. The Change Polygon Method. Digital Shoreline Analysis System.

Comparing the ionospheric response to the 2008/2009 and 2018/2019 SSW events

<p>It is now well accepted that the ionosphere and thermosphere are sensitive to forcing from the lower atmosphere (troposphere-stratosphere) owing mainly to the progress that have been made in the last decade in understanding the vertical coupling mechanisms connecting these two distinct atmospheric regions. In this regard, the studies linking the upper atmosphere (mesosphere-lower thermosphere-ionosphere) variability due to sudden stratospheric warming (SSW) events have been particularly important. The change of stratospheric circulation due to SSW events modulate the spectrum of vertically upward propagating atmospheric waves (gravity waves, tides, and planetary waves) resulting in numerous changes in the state of the upper atmosphere. Much of our understanding about the upper atmospheric variability associated due to the SSWs events have been gained by studying the 2008/2009 SSW event, which occurred under extremely low solar flux conditions. Recently another SSW event in 2018/2019 occurred under similar low solar flux conditions. In this study we simulate both these SSW events using Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X) and present the findings by comparing the ionospheric and thermospheric response to both these SSW events. The tidal characteristics of the semidiurnal solar and lunar tides and the thermospheric composition for both these SSW events are compared and the causes of varying responses are investigated.</p>