The study area of Deep Bay in the Southern China has been recognized as ecologically important site. This study presents a wetland change detection analysis incorporating both geographic information system (GIS) and remote sensing techniques. Both natural and artificial wetlands are considered as part of the Deep Bay wetland system. For instance, mangrove forests, fish ponds and shrimp ponds (gei wai) are all considered as wetlands in this study. This study is to find out how much area of the wetland system has been lost due to the conversion of land cover types in recent decades. In particular, this study uses supervised classification and change detection analysis on the satellite images which were acquired in three different time periods (1975, 1994, and 2009). It is a quantitative result which was based on the numbers of pixel changed on the images. The result shows that 39.76 % of fishpond and 20.47% of mangrove in terms of pixels have been changed to urban or residential area between 1975 and 2009. The result implies both Shenzhen and Hong Kong side of Deep Bay has significant wetland loss in recent decades. Moreover, the Deep Bay in Hong Kong includes an Aerial Photos area change analysis. This study presents three different sets of land use data which was created according to the manual interpretation of aerial photos in three different time periods (1973, 1986, and 2011). The aerial photos mainly focus on the fishpond and mangrove change in recent decades. The qualitative results show that a lot of locations were no longer mapped as wetlands in recent decades. The quantitative results illustrate the total wetland areas in the Hong Kong side of Deep Bay were continuously decreased from 1973 to 2011 by 19.06%.
Additionally, the study also presents a change analysis of the nightlight imageries. Previous research found that urban development and the brightness value of nightlight imageries are highly correlated. The study uses two nightlight imageries which were acquired from 1992 and 2009 to examine whether Deep Bay has a rapid increase in urban developments. The result shows that the brightness value has continuously increased during the period with more changes in the western side of the study area. Moreover, the average brightness value of the study area has increased by 17.6%. It can show that there is an increase of urban activities in recent years.
Based on the change detection analysis, it can be concluded that urban development such as reclamation is the major threat to the Deep Bay wetland system. Furthermore, there are more changes occurred in the Wetland Conservation Area and Wetland Barrier Area in Hong Kong. Both of them are either close to or around the Ramsar site. The area may not be able to support further wetland loss in the future. This study can definitely provide some information to the government and policy-makers on strategic planning of land use in Deep Bay. Sustainable development in Hong Kong is crucial in balancing the ecology and development of the city. / published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
| Identifer | oai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/194567 |
| Date | January 2013 |
| Creators | Chum, Kai-fung, 覃繼鋒 |
| Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
| Source Sets | Hong Kong University Theses |
| Language | English |
| Detected Language | English |
| Type | PG_Thesis |
| Rights | The author retains all proprietary rights, (such as patent rights) and the right to use in future works., Creative Commons: Attribution 3.0 Hong Kong License |
| Relation | HKU Theses Online (HKUTO) |
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