| “Ocean sprawl” is the global phenomena involving the expansion of anthropogenic activities and structures along the coast and into the ocean. This includes the modification of coastal areas into hardened structures. Examining the drivers and impacts of these large-scale phenomena is the science of seascape ecology. However, while the local negative ecological effects of hard coastal structures are well-studied, their much wider, global or regional impacts remain poorly understood, partly due to a lack of appropriate complexity metrics for quantifying rapidly changing seascapes at large spatial scales. This thesis has therefore chosen the rapidly developing island-state of Singapore as a case study, for implementation of three methods of coastline-catchment complexity quantification on historical maps, to evaluate their potential usefulness for decision-making. The three indices, namely (1) Fractal Dimension Index, (2) Simple Ratio Index and (3) Straight Section Index, are a combination of previously used and novel methods. Each index was applied to four selected years of historical maps of Singapore (1983, 1993, 2005 and 2010) and four different scenarios of coastline-catchments for each year, (1) Full Data, (2) Coastline Only, (3) 3 km from River Mouth, (4) 3 km from Estuary Centroid. Results were consistent across indices, showing 2005 as the year with an unexpectedly high coastline-catchment shape complexity, resulting in a fluctuating trend over the study period. It was deduced that new ports and a partial fusion to a cuboidal island in 2005 increased Singapore’s shape complexity. Unfortunately, due to the summarised nature of the indices and the fast pace of coastline-catchment changes, finer scale and further studies are required to confirm this. Different coastline-catchment scenarios, however, had minimal impact on the results, but catchments should not be completely excluded from analyses. The advantages and disadvantages of the three indices were compared and discussed, with reference to their practical applications from both technical and policy-making perspectives. The Fractal Dimension Index gave relatively similar qualitative results to the Simple Ratio Index, both being sensitive to scaling effect and considering overall shape complexity. However, the former was considerably harder to explain conceptually and difficult to compare across studies. The ratio index had the greatest flexibility as the scale of study could be explicitly selected. The Straight Section Index, being the first quantification of its kind, was unable to consider complexity, but utilised simple geometric rules to give a clearly defined, scale-independent and familiar results that are easy for policy makers to interpret. This study therefore concluded that the Simple Ratio Index be used concurrently with the Straight Section Index, to assist with further urban seascape studies and for deciphering scaling generalities in this understudied field. |