Comprehensive Circulation and Water Quality Investigation of the Coastal Lagoon: Puerto Galera, the Philippines

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Implementation Specification of Channel Reflector

In this document, we detail an implementation specification of ``Channel Reflector''. Channel Reflector (CR) offers an effective policy and scope control technique for multicast channel announcement without use of a traditional SAP advertisement. It appears as a hierarchical directory system and each end user accesses this system as a regular Web server and retrieves available channel information via his Web browser. According to this property, we have designed the CR implementation which can work with a common and well-known http server and database implementations. More precisely, our CR has been implemented as modules used with an Apache http server. In addition, while the channel information including the policy configuration is defined in XML format in CR, all the information are converted and stored in MySQL efficiently. Such the implementation strategy reduces the operator's maintenance cost and finally contributes to the easy deployment

Hydrodynamics Modeling of Khung Krabaen Lagoon, Chanthaburi Province, Thailand

Khung Krabaen Lagoon (KKBL) is a small low-inflow water body. There are vast areas of tidal flat occupied nearly 60% of the lagoon that host some of the most productive seagrass habitats in the region. The lagoon is surrounded by mangrove forest and intensive shrimp farms behind it. The KKBL was used as an intake and recipient water for the farms. However due some shrimp disease epidemics and possibly deteriorated water quality, the farms are now taking the intake water from the outer sea through very expensive (to construct and to maintain) irrigation system. Objective of this study is to investigate the KKBL’s hydrodynamics using a numerical simulation model validated with measured data. The simulation model was setup two-dimensionally based on the Delft3D model. Results suggested that water currents inside, at the mouth and at the outer sea of the lagoon are mainly governed by tide and wind. Offshore of the lagoon, there are strong tidal currents flowing along northwest and southeast direction. The tidal currents flow into the lagoon through its mouth before dispersion rapidly inside the lagoon. Mean circulation largely varied seasonally and had direct correlations outer sea seasonal mean currents and the monsoons

Hydrodynamics Modeling of Khung Krabaen Lagoon, Chanthaburi Province, Thailand

Khung Krabaen Lagoon (KKBL) is a small low-inflow water body. There are vast areas of tidal flat occupied nearly 60% of the lagoon that host some of the most productive seagrass habitats in the region. The lagoon is surrounded by mangrove forest and intensive shrimp farms behind it. The KKBL was used as an intake and recipient water for the farms. However due some shrimp disease epidemics and possibly deteriorated water quality, the farms are now taking the intake water from the outer sea through very expensive (to construct and to maintain) irrigation system. Objective of this study is to investigate the KKBL’s hydrodynamics using a numerical simulation model validated with measured data. The simulation model was setup two-dimensionally based on the Delft3D model. Results suggested that water currents inside, at the mouth and at the outer sea of the lagoon are mainly governed by tide and wind. Offshore of the lagoon, there are strong tidal currents flowing along northwest and southeast direction. The tidal currents flow into the lagoon through its mouth before dispersion rapidly inside the lagoon. Mean circulation largely varied seasonally and had direct correlations outer sea seasonal mean currents and the monsoons

Distribution and flux assessment of microplastic debris in the middle and lower Chao Phraya River, Thailand

Microplastic (MP) debris is now a global concern. The Chao Phraya is the largest river in Thailand and transports MPs from terrestrial areas to the ocean. MP debris in its water and sediment were measured in March 2021, September 2021, and March 2022 in five provinces along the watercourse. Hydrological data were also collected to estimate the MP riverine flux between provinces. Size, shape, color, and types of MP polymers were observed, with sedimentation data collected for MP content. Results showed that MPs were found at all sample stations, with average abundance in all province water samples ranging from 0.54 ± 0.05 to 1.07 ± 0.28 pieces/L, while in sediment sample, numbers ranged from 183.84 ± 38.76 to 546.18 ± 86.84 pieces/kg dry weight throughout all seasons. Overall contamination and accumulation were similar between provinces but significantly different between seasons. Sizes of MPs in water varied between seasons with MPs in sediment mostly 330–5,000 μm (Kruskal–Wallis, P < 0.05). Sedimentation of MPs was different between seasons (Kruskal–Wallis, P < 0.05). The highest MP flux values discharged from Samut Prakan Province to the inner Gulf of Thailand were 1.83 × 105 and 1.60 × 105 million items/day in September 2021 and March 2022, respectively. HIGHLIGHTS Highest microplastic (MP) riverine flux discharged into the sea was recorded as 183,000 million items/day.; Fiber MPs were abundant in both water and sediment samples, with fragment MPs significantly higher in sediment samples than in water samples.; Significant seasonal variations were found in water and sediment samples.; Water discharge and current velocity play important roles in MP contamination in riverine ecosystems.

Environmental Habitat Mapping of Green Mussel: A GIS-Based Approach for Sustainable Aquaculture in the Inner Gulf of Thailand

The green mussel (Perna viridis) is one of the most commercially-important cultured species along the coast of Thailand. In this study, a suitable aquaculture site-selection model (SASSM) was developed to identify the most suitable areas in the inner part of the Gulf of Thailand (InnerGoT) for green mussel culture. Satellite-derived chlorophyll-a (Chl-a) and hydrodynamic model outputs for sea surface temperature (SST), salinity, maximum water current (MWC), and bathymetry between 2018 and 2019 were used as input to the SASSM. The results show that suitability scores in mussel aquaculture areas were lowest (1&ndash;3) during the Southwest (SW) monsoon, rainy season (July&ndash;August), and highest (6&ndash;7) during the Northeast (NE) monsoon, cold season (November&ndash;December). Moderate suitability scores (4&ndash;5) were obtained during the monsoon transition from the NE monsoon to the SW monsoon, summer (April&ndash;May). The study area was further divided into three zones: the western, central, and eastern regions. The western and eastern parts showed high suitability scores (5&ndash;7) while the central zone exhibited low suitability scores (2&ndash;4). The model results show a similar pattern to the actual mussel production in the study area. Seasonal events (i.e., flood and dry seasons) were incorporated into the model to examine the seasonal effects on the suitable mussel aquaculture areas. The suitability scores during the SW monsoon in 2018 were more sensitive to changes in SST and salinity relative to 2019. The higher freshwater discharge and lower temperature in 2018 relative to 2019 resulted in the accrual of suitable aquaculture areas. This pattern is consistent with the productions of the green mussel, where higher production was recorded in 2018 (2002.5 t) than in 2019 (410.8 t). However, correlations among atmospheric (air temperature, rainfall, and wind) and oceanographic factors (SST and MWC) were significant in the western and central regions, suggesting that the suitability of green mussel aquaculture in these regions is vulnerable to environmental disturbances. Thus, the SASSM can be a powerful tool in providing useful information on spatial management for marine aquaculture in environmentally-dynamic coastal systems