The value of multibeam bathymetry in marine spatial planning in South Africa: A review

Abstract

Given a growing global population and shift to embrace the blue economy, a need for marine spatial planning (MSP) has emerged in South Africa to sustainably resolve the rising conflicts over the use of marine and seabed resources and services. A well-developed marine spatial plan yields numerous ecological, social and economic benefits. These are achieved through mediating between spatially conflicting economic drivers’ interests (e.g. commercial fishing, tourism, mining), preventing their activities from compromising thresholds of an environment’s sustainability. Within the MSP framework, high-resolution geospatial datasets are required to document and describe the seabed in the highest possible detail. At any scale, integrated analysis of seabed geomorphology and habitats is anticipated to greatly improve the understanding of ecosystem functioning from a multidisciplinary perspective, whilst improving MSP procedures and management of marine space. South Africa is the first of few African countries to have an approved and implemented MSP framework, but is still somewhat behind globally in implementing large-scale regional hydroacoustic surveys to cover the country’s vast offshore territory. The deficiency of hydroacoustic surveys is perhaps due to a relative lack of funds and poor communication about the value of multibeam echo-sounder (MBES) derived data, whilst marine geoscience remains a scarce skill in the country. This review paper presents a geological perspective of MSP and explores (1) the value that seabed mapping offers MSP specifically and (2) the need to increase seabed mapping with MBES, using a recently initiated project from the South African east coast as a case study.

Multibeam Line Design Based on Geometric Analysis

“…Let the covering area of the strip corresponding to the measuring line of unit length be km, and the average effective area covered by the strip corresponding to the measuring line of unit length be k, where k is the ratio of the effective area to the total length of the measuring line. Effective area m1 is the area covered by its horizontal projection in the horizontal projection rectangle of the sea slope, and invalid area m2 is the area covered by its horizontal projection in the horizontal projection rectangle of the sea slope [9,10].…”