2011, Subacoustech, Zone 1 - Moray Firth, Noise Modelling Survey series https://portal.medin.org.uk/portal/start.php?tpc=015_2388369a-8a82-4575-9483-33033cb6e3f2 Modelling was undertaken to provide a prediction of the likely extent of impacts on marine fauna. The impacts are calculated as a result of underwater noise generated during the predicted events during construction and operation of the Moray Offshore Windfarm. The general approach to estimating the levels of subsea noise from offshore wind farm developments has been undertaken in two phases. In the first a broad-brush modelling approach has been used to rank order a wide range of offshore wind farm-related sources of underwater noise. This was done using the proprietary Simple Propagation Estimator And Ranking model (SPEAR) developed specifically for the Moray Firth developers. In the main, the information used to validate this model has come from the very substantial database of recordings of various noise sources compiled by Subacoustech Environmental over the last 20 years. Phase 2: (Recordings at six locations at MORL development) Impact piling is known to generate high levels of underwater noise. It is therefore important to make an accurate estimate of its likely level so that its impact can be accurately assessed. There are a variety of acoustic models for the estimation of underwater noise propagation in coastal and offshore regions, mainly developed as a result of military interests. However, the authors are not aware of any underwater broadband noise propagation models suitable for the much shallower environments typical of wind farm construction, or for the highly impulsive time histories encountered from impact piling. In these environments and with these source types there is a greater capacity for underwater sound to be affected by absorptive processes in the seabed, resulting in propagation losses which typically increase with frequency but decrease with depth. The series present a full set of dBht contours and noise allocations per 4x4km grid square for the marine mammal impact assessment: · Scenario 1 is just piling at location 1 · Scenario 2 is piling at location 1 and 5 · Scenario 3 is piling at all 6 MORL locations · Scenario 4 is piling at all 6 MORL locations and locations A and B for BOWL. 'Extent' is for the piling locations for the study. 20260910T10:43:45