476 ENGINEERING GEOLOGY/Geomorphology its design lifetime (e.g., is the chance of being affected by a channelized debris flow, or being engulfed by blown sand, very low)? What will be the effect of climate change or sealevel rise on the project risks (e.g., will there be accelerated cliff recession or a higher chance of landslide reactivation)? Why has a problem arisen (e.g., are there leaking water pipes or is there disruption of sediment transport along a shoreline)? What effects will the project have elsewhere (e.g., will there be reduction in floodplain storage or changes in surface run off and erosion potential)? What magnitude event should be designed for to provide a particular standard of defence (e.g., what is the expected volume/depth of the 1- in 50-year debris flow event)? The answers to these questions can be both qualitative and quantitative; for example, recognition of pre-existing landslides with potential for reactivation can be related to rates of change and the magnitude/ frequency of events Most projects will involve a combination of approaches, including application of historical data, taking measurements, and making maps and models Historical records can be used to define the timing and frequency of past events, and historical maps, charts, and aerial photographs may aid in determining past rates of change Measurement and monitoring of change are accomplished using a variety of field-based or remote-survey techniques (e.g., aerial photography and satellite imagery) Mapping and characterization of the landscape (terrain evaluation and geomorphological mapping) can be applied in developing geomorphological models to provide a framework for the prediction of hazards and future changes Geographical information systems (GIS) are important tools for the storage, management, and analysis of the geomorphological information collected throughout a project Historical Records and Maps In many countries, there exists a wide range of sources that can provide useful information on the past occurrence of events, including aerial photographs, topographic maps, satellite imagery, public records, local newspapers, consultants’ reports, scientific papers, journals, diaries, and oral histories For example, a Figure Landslide model of the Ventnor Undercliff, UK, showing different landslide processes (T1 T9) Systematic study of local records revealed that the contemporary movements are largely confined to the superficial degradation of the ancient, deep seated landslide complex Reproduced from Lee EM and Moore R (1991) Coastal Landslip Potential Assessment: Isle of Wight Undercliff, Ventnor London: Department of the Environment, UK