Sediment budgets are often constructed to assist with coastal management. A sediment budget allows an estimate to be made of the rate of accretion or erosion of sediment within a pre-defined area of the coastal zone (Rosati 2005). The main steps involved in constructing a sediment budget are:
- Set appropriate sediment cell boundaries for the sediment budget and for internal boundaries that separate sub-cells within the overall area to be considered;
- Identify sources, pathways, stores and sinks of sediment within the budget area;
- Calculate the rate of erosion from sources and stores and accretion in stores and sinks. These estimates may come from numerical models but are more likely to be derived from data;
- Calculate the sediment transport rates at the boundaries of the sub-cells and estimate the uncertainty in each transport rate. The calculations of transport rate may come from data but are more likely to be derived from numerical models; and
- Integrate the gains and losses within each section to obtain an overall sediment budget.
A good sediment budget will provide a useful indication of whether a beach in front of a coastal structure is likely to be subjected to beach lowering due to loss of sediment from the entire beach. Even if this is not the case and beach volumes have been constant or increasing, a coastal structure may be subject to beach lowering due to local effects.
- Rosati., J.D. 2005. Concepts in sediment budgets. Journal of Coastal Research 21(2): 307-322
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