Halcrow, Coastal Studies Forward Programme Data Compilation ...

There is some localised movement of gravels up and down the coastpredominantly during storm conditions, but with little or no net losses orgainsThere is considerable potential movement of sand; some bed loadtransport but also significant suspended load transport. Redistribution bycurrents means that large volumes could be moved about, particularlyduring storms, and deposition of this material will be dependent upon thestate of the tide and the undulating surface of the foreshore.Standard sediment transport models are generally limited to sand-sizefraction. An independent coarser-scale model developed by Dr Karla Rix(Halcrow 2004c) was applied to the LLWR frontage which reached thesame conclusions as summarised above.2.3 Landform characterisationA detailed assessment of the geomorphology and sedimentology of the shoreline isreported in Halcrow (2003b). The 2002 baseline survey data were used alongsideBGS geological data to characterise eighteen coastal landform units (Table 2.2).The sedimentological characteristics of the landforms were also described in thefield by assessing the cliffs and geological mapping.A second assessment of landform characterisation and dynamics was completed in2009 using data from the repeat baseline survey and field verification. Comparisonof the mapping highlighted the high mobility of sand bars, gravel movement in fandeltas of the rivers and accretion along the dune fronts from Seascale to Drigg.2.4 Sediment budget and boundary conditionsA review of the regional scale sediment budget, necessary to place the studycoastline in a broader context and to test the validity of the boundary conditionsused in the conceptual model, is provided in Halcrow (2005b). This work wasnecessary to amplify the regional information provided in shoreline managementplans for Cell 11 . The sediment budget was assessed at two scales:regional scale, including the Irish Sea coast between the Solway and theDee, defined by Sediment Cell 11 of the shoreline management plan(Figure 2.2)sub-cell scale, defined as sub-cell 11d, that extends between St Bees Headand the Duddon Estuary (Figure 2.2)Doc No 1 Rev 2: Date: May 2010 14