Aerial Photography 30th September 2004 Helen Dalton Environment Agency Project Manager

Content Historical aerial surveys Aerial survey within current programme Continual developments

Background Sussex Offshore dredging in 1960’s Concern over sediment budgets Partnership Pilot aerial surveys launched 1971 The growth in the number of offshore dredging activities being undertaken in the 1960’s raised concerns over the potential impacts on sediment transport and sediment budgets along the Sussex coastline. This prompted a partnership of organisations including the Sussex River Authority, the Crown Estate Commissioners and maritime local authorities to set up a regional monitoring survey along the Sussex coastline. Pilot schemes using aerial survey and photogrammetry were launched in the early 1970’s at a variety of contact scales ranging from 1:2000 to 1:10,000.

First Surveys In 1973 the following methodology was adopted for the first full survey of Sussex: Stereoscopic photography at 1:5000 One low spring tide sortie (May - August) Foreshore leveling measured along pre-defined profile lines Following the results of the pilot surveys and the impracticalities experienced with flying at certain scales, the following methodology was adopted for Sussex in 1973. Stereoscopic photography was to be flown at a contact scale of 1:5000, one flying sortie was to be undertaken per year at low spring tide and over the summer months. Information on foreshore levels was to be obtained from photogrammetry along pre-defined profile lines, which would enable future data comparison. It is interesting to see that despite several changes to the programme and improvements that have taken place since 1973, these three parameters remain predominantly the same in today’s survey.

Programme Development 1973 - 1983 included Kent, Hampshire and the Isle of Wight Ground control network revision in 2000 Landward extension of profiles (10m - 250m) BUT Data Quality issues Over the following 10 years the aerial survey programme was expanded to include Kent, Hampshire and the Isle of Wight making it a truly regional survey programme. Over the 30 years of the programme the method of establishing ground control points has changed significantly from using OS base maps to establish height and positional data to using more sophisticated GPS techniques. Changes have also taken place to the positions of the start points of the profiles. During the 2001 survey over 2000 profiles were extended landward between 10m and 250m. The reasons for this were to include hard defences (seawalls, rock revetments etc), soft defences such as shingle banks and saltmarsh and the position of permanent features such as footpaths houses etc. Where areas lying immediately landward were identified as dynamic and susceptible to change they were also included.

Coverage - Portland Bill to Isle of Grain Survey Extent The incorporation of the EA’s beach monitoring work into the strategic regional coastal monitoring programme has led to further improvements and extension of the scope of the survey. As you can hopefully see, the geographical extent of the coastal monitoring programme covers the coastal cells 4a to 4d and 5a to 5g, including part of Dorset. The harbours and estuaries along the coastline have now been added to the programme. These areas are important components of the coastal system as they tend to be areas of significant accretion and erosion and therefore have significant impacts on sediment transport. Coverage - Portland Bill to Isle of Grain

Survey Programme SCOPAC SDCG SECG SPRING 1:3000 1:3000 (Ranges) 1:5000 SUMMER This slide shows the existing annual aerial programme. Low level aerial survey flights (1:3000) have previously been undertaken in SDCG by Arun District Council to obtain detailed topographical information for their frontages. These flights are now part of the SRCMP aerial survey programme and are being undertaken in Spring (March) and Autumn (October). In addition to the flights being undertaken in SDCG, we are also capturing the Lydd and Hythe MOD ranges in the SECG area by this method. As SCOPAC and the SECG are using land based topographical methods for their surveys, we should be able to have a significant amount of data to compare the two methods at the end of the five year programme. The advantage of incorporating these surveys within this contract is that we can obtain financial efficiencies (by using one contractor) and project management efficiencies. However there are also disadvantages of this method, as they are reliant on weather and tidal windows. However I will let Kampsax discuss these issues. The region-wide aerial survey is undertaken during the summer months. One of the further adaptations that has taken place within the aerial programme is that the summer aerial flight for the SDCG has been changed from a contact scale of 1:5000 to 1:3000. We have decided to make this improvement in scale to the SDCG flight in order to obtain 3 comparable datasets throughout the year to improve the data analysis. This also enables beach management plan data to be obtained from aerial techniques in this area. It is possible that in the future the entire region-wide flight will be undertaken at this finer resolution, however this would have to be investigated nearer the time. 1:3000 1:3000 (Ranges) AUTUMN

Deliverables Aerial photography 1:5000 & 1:3000 scale - Contact prints and digital scanned images Photogrammetric analysis Profiles Cliff top and toe Saltmarsh Digitally orthorectified aerial photos (every 5 years) The deliverables from the programme will be...

Data Accessibility Photography - digital scans archived at CCO Photogrammetry - data updated into SANDS by Lead Authority Orthophotos - ECW format held as a backdrop to SANDS The mechanism for circulating the data will be….

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Any queries: helen.dalton@environment-agency.gov.uk 01903 832077