Estuaries are bodies of water along the coasts that are formed when fresh water from rivers flows into and mixes with salt water from the ocean. The density of seawater is greater than fresh water and it varies with salinity and temperature. Fresh water tends to float on top of seawater because of its lower density. Human-induced activities like the dredging of shipping lanes along the bottom estuarine, the dumping of industrial wastes into the water system, and shoreline development influence estuarine dynamics which include the mixing process. These activities lead to salinity changes and further adversely affect the estuarine ecosystem. The purpose of this research is to verify how salinity-morphology relations change in an estuarine system under various rainfall patterns, more specifically under extremely high rainfall conditions. The experiment that has been conducted studied the salinity-morphology relationships for a variety of rainfall patterns, most particularly for exceptionally high rainfall conditions, using an idealised channel. In the first part of this research, the morphology changes of the mixing between salt water (estuary) and freshwater (river) for different rainfall patterns, had been investigated in laboratory experiments. Fresh water was released from one end of the flume channel and overflowing over the weir at the other end. Meanwhile, salt water was represented by the red dye tracer released slowly through a weir and intruded horizontally to the upstream as a gravity current. In this experiment, an artificial roughened bed section was used as morphology change. The salinity pattern is plotted using Microsoft Excel. The salinity levels were measured at selected stations along the channel/longitudinal (x-axis), and also in transverse (y-axis) and vertical directions (z-axis) within the time duration. The observed salinity profile showed the difference in salinity level between heavy and light rain conditions with morphology effect where during heavy rain, the salinity level will decrease, hence, the existence of an artificial roughened bed section will affect the time taken for the process of mixing between salt water and fresh water.

Estuaries are one of the most productive ecosystems in the world, providing significant resources for humans and animals. However, the influence of various rainfall patterns due to climate change has affected the estuarine system, leading to changes such as salinity intrusion. This study aims to verify how river discharge changes affect salinity mixing within a meandering channel and the effect of flow patterns due to curvature. An experimental hydraulic investigation was conducted at Universiti Teknologi Malaysia (UTM) Johor Bahru. The cross-sectional profiles along the meandering channel are discussed in this paper. The findings prevailed as a typical characteristic of the salt-wedge estuary and indicated the process of estuarine mixing. As the saltwater flow upstream, the salinity level drops due to the dilution process. Additionally, the greater density of seawater compared to freshwater causes it to remain in the lower layers of the water column. The flow pattern in curvature is influenced by the velocity of the inner and outer banks, where velocity has been seen to be higher at the outer bank, allowing the salinity to flow quickly near the inner bank. The present study will be useful in predicting the estuarine salinity response to river inflow.

The water reticulation system for LRT3 Station 6, New Klang Valley Expressway is analysed and modelled in this research using EPANET 2.2 software. The study examines the difficulties posed by population growth and urbanization, which increase water demand and strain the distribution system. The objective is to create a Dead-End system model in EPANET 2.2 that provides crucial data for water reticulation design. The consulting firm in charge of the LRT3 project provides information, including water demand and elevation. Using a statistical test, the EPANET model is validated and compared to head loss equations (Hazen-Williams and Darcy-Weisbach’s). The validated model provides hydraulic information including pressure, velocity, conduit diameter, and total head loss. The study region has a daily water demand of 5,680 litres, revealing unique insights into water usage patterns and needs. The water pressure level study shows that most network sites maintain appropriate pressure levels over the 7.5-meter threshold, maintaining the water distribution system's operation and optimum performance to satisfy customer needs. This data assists water supply engineers, architects, planners, and technicians in analysing and optimizing LRT3 Station 6's water distribution network. The research contributes to the sustainable administration of water resources in urban development initiatives.

Estuaries, where freshwater rivers meet ocean saltwater, are vital coastal ecosystems characterized by water layer stratification. Human activities, including dredging, industrial waste disposal and coastal development, disrupt estuarine dynamics, leading to altered salinity levels and ecological threats. Sudden salinity changes, often driven by these activities, jeopardize estuarine species adapted to specific salinity conditions, potentially causing biodiversity decline and ecosystem collapse. This research focuses on two cases: Case 1 examines an unaltered estuary, replicating natural conditions, while Case 2 introduces a constriction pattern mimicking real-world estuaries influenced by geological or human-made features. Systematic salinity monitoring along multiple stations, including longitudinal, transverse and vertical directions, reveals a significant correlation between estuary shape and salinity distribution. In Case 2, a central constriction substantially impacts saltwater and freshwater mixing time, resulting in downstream salinity variations. These findings have broader implications, informing environmental conservation, climate adaptation, resource management and infrastructure design. Additionally, they advance fluid dynamics and environmental science, potentially fostering innovation across disciplines. In summary, this research offers practical solutions for the preservation and sustainable development of estuarine ecosystems.