Measure and reduce pollution, Act in favour of Environment : Nice Airport

An in-depth analysis of surveys taken over twenty years at the platform by the Department of Town and Country Planning. This involves synthesising the main indicators recorded over time; providing a global evaluation of overall activity on the South embankment in relation to theoretical forecasts; and identifying the main hard spots.
Subsequently updating the current inspection programme and monitoring the airport platform in order to optimise credits granted by the State,
Defining an earthquake alert threshold (or a series of successive thresholds) with a view to drawing up emergency procedures at a later date, making it possible to raise the eastern and western extremities of the South runway once and for all.

Physiographical reconnaissance (lateral sonar),
Monitoring reference points on dykes, jetties, etc. (terrestrial topographical surveys) (concrete posts on rocks forming dykes),
Bathymetric surveys of sea bed (underwater profile)
Defining characteristic profiles
Monitoring the pressure of groundwater and aretesian water (monthly piezometer readings)

Bathymetric surveys (using an echo sounder) and physiometric surveys highlight minor movements that are occasionally reversible but never significant:

as for bathymetry in general, depth curves hardly change between 1989 and 1994 (stability of seabed). The only phenomena of note involve the occasional hollowing and refilling of specific profiles.
as for physiography, the various granulometric facies have been examined (pebbles, gravel, blocks of rock, etc.) without any significant movement being brought to light.

Topographical surveys on the surface highlight normal activity at the airport with slight compression - lower than theoretical forecasts. The extend of compression increases regularly towards the extremities of the runway: 0.90m to the east and 1.20m to the west. There are also signs of compression towards the south, but to a lesser extent.

north dyke: compression increases towards the west from 0.19m to 0.74 m; the rate of compression is between 1 and 8mm per year towards the west
west dyke: homogenous compression between 1.18 and 1.30m; the rate of compression is between 6 and 8mm per year towards the south
south west dyke: compression between 0.38 and 0.54m; the rate of compression is between 10 and 12mm per year (to be confirmed by future monitoring)
western extremity of the axis of the southern runway: greater compression towards the west. Compression between 0.10 and 0.50 m; the rate of compression on the edge of the runway is 10mm per year from north to south.
east dyke: compression decreases from north to south. Compression of 0.55mm. The rate of compression is between 3 and 8mm per year from north to south
south dyke: regular progression since 1979. Compression of 0.30 to 0.90m from west to east; rate of compression of 2 to 7 mm in 98/99 at the eastern extremity of the runway
eastern extremity of the axis of the south runway: compression from 0.10 to 0.29m from west to east; rate of compression of 5mm per year at the eastern extremity of the runway.

Monitoring confined and free ground water reveals their relative stability with slight movements only, not of a nature to destabilise the airport platform. Average levels are 0.80m for ground water and 4.60m for artesian water.

Physiographical surveys (lateral sonar). These surveys provide a general picture of the part of the dyke that is below water, making it possible to detect whether blocks of rock have moved. The surveys are too imprecise for decision-making purposes and must be complemented by visual inspections by divers. The recommended frequency is annual. A diver undertook such a visit in October 2001. He inspected 3.5km of dyke and took 68 photos.

Divers inspect the submerged part of the dykes. FONDASOL recommends that divers carry out visual inspections to complete the physical geography. These are local inspections. Dykes are completely inspected over a period of 7 to 10 years. The opreation is vital to complete physiographical surveys.

Bathymetric surveys Useful at a scale of 1/2000 to highlight sizeable zones of instability. Specific profiles at 1/200 show evolutions on a small scale, to be complemented by an EW profile along the axis of the thalweg located to the north-east of the airport. Recommend frequency: annual.

Terrestrial topographical surveys Significant reduction in the number of points monitored (from 227 to 42) because only a few are relevant. Recommended frequency: annual.

Piezometric readings Current arrangements must be maintained (2 ground water piezometers, 6 aretesian piezometers). Continuous monitoring with monthly readings continue to suffice. Also, monitoring at the level of the sea is recommended with a view to setting off an alarm (specific study required) if a situation similar to 1979 were to reoccur.

Three alarm thresholds have been determined in terms of acceleration of movement - weak, intermediate and borderline. The thresholds correspond to the breakpoints of different classes of construction. A contract was signed in 2002 for a seismograph and emergency procedures.