Summary This is the first in a series of papers devoted to the ecology of the sandy beaches of the Cape Peninsula. Conditions on these beaches are described, with special reference to the beaches of Hout Bay, Llandudno, Milnerton and Muizenberg. Tidal conditions, wave-action, beach profiles and sand movements are discussed, while attention is also given to the particle-size distribution of the substrata forming the beaches. The organic content of the sand, its permeability and porosity, and the disposition of the water-tables are all discussed briefly and some data concerning salinities, temperature and pH are presented. Mention is made of the fauna and a list of the more important members of the resident fauna of the beaches accorded special attention is given. There is some attempt to show how the physical factors are interrelated.

The ecology of the sandy beaches of the cape peninsula, south africa. part 1: introduction

This report presents a sediment and nutrient budget for the Mitchell River catchment, located
on the western flanks of Cape York and draining to the Gulf of Carpentaria. A catchment
sediment (or nutrient) budget accounts for the major sources, transport pathways and sinks
of sediments and nutrients within a catchment. It is difficult to measure all of the relevant
components of a catchment sediment budget across space and time. Consequently a modelling
framework is useful to bring together the individual components of the budget in a coherent
manner, whether derived from local empirical data or theoretical models. The SedNet and
ANNEX models have been used in this study; these models have been widely applied in tropical
Queensland settings and elsewhere in Australia. Each sediment budget term comprises its own
sub-model and here, a combination of national-scale models (terrain, hillslope erosion, colluvial
gully density and surface soil nutrient concentrations), state-wide data sets (foliage projected
cover) and locally-derived models (alluvial gully erosion, floodplain extent) have been used for
input data. For some aspects of the model, such as the dissolved nutrient concentrations in
overland flow, no local data were available and values have been derived from reference to
the literature. Some budget components (particularly floodplain deposition, and also partially
hillslope erosion) have been derived as “residual value” terms; that is model parameters and/or
terms have been adjusted to match other data with limited independent constraint on the exact
magnitude of that budget term. These residual terms contain not only the data attributed to
them, but also unmeasured components of the sediment budget and the associated error from
the known or directly measured components, such as total load at gauges and alluvial gully
erosion.

A catchment sediment and nutrient budget for the Mitchell River Queensland. A report to the Tropical River and Coastal Knowledge (TRaCK) reesearch program

Biodiversity patterns in False Bay: an assessment using underwater cameras

Summary A siltation problem at Gordon's Bay harbour is presented and the methods used to collect field data for a proposed model analysis are described. Characteristics of bed form and littoral materials within and around the harbour are dealt with, followed by an analysis of the possible modes of sediment transport; namely wave action, transient and steady-state currents and wind action. The results of direct bed drift measurements, as yet incomplete, are correlated with all other data in a tentative ‘sediment balance’.

G. de F. Retief

Papers

Sediment transport in gordon's bay