Abstract

Estuaries are seen as one of the most productive ecosystems in the world and crucial to the life history and development of many aquatic groups. The shorelines of these estuaries and coastal regions are often comprised of large areas of intertidal mudflats and saltmarshes which are areas of significant land–ocean interaction. They are important coastal geomorphological systems providing habitats for wildlife, resources for land reclamation and protection for the coast against extreme storm events. These systems are currently under enormous pressure owing to climate change such as rising sea level and human activities such rapid development in coastal regions. There is therefore a need to understand how development around coastal regions are impacting these ecosystems. This research aims to contribute to the knowledge of sediment dynamics on intertidal mudflats and propose a novel method for implementation in numerical models using Portsmouth harbour as a case study. To achieve this research aim, a combination of field sampling and data collection, empirical analysis and numerical simulations have been used. Results show that intertidal flat areas have very low dissolved oxygen due to the substantial amount of sediment and nutrients supplied by bed forms such as creeks into receiving waters which is associated to freshwater discharge and draining of intertidal areas on the ebb tide. Time of exposure of mudflats which is a function of the tidal cycle has an exponential relationship with the net flux of sediment. Gradual increase in the time of exposure of mudflats leads to substantial increase in sediment net flux. Analysis of sediment dynamics within creeks on intertidal flats showed that increasing freshwater discharge led to seaward transport of sediment. However, more sediment is transported landward due to inundation of the intertidal area. This study has shown how freshwater discharge changes sediment dynamics in intertidal areas. With the increasing need for global communities to live close to coastal areas, particular attention should be given to the impact of increasing developments on intertidal habitats in sheltered environments.

Course: Master of Philosophy - MPhil

Date Deposited: 2022-12-14

URI/permalink: https://library.port.ac.uk/dissert/dis14088.html