Report 2005
On the first of June 2005 the Report "Monitoring the effects of soil subsidence on East Ameland, Evaluation after 18 years of gas extraction" was presented at Ameland by the Supervisory Committee Monitoring Soil Subsidence Ameland.
History of the research
Gas extractions on East Ameland started in 1986. In that same year, on the instruction of the NAM, WL|Delft Hydraulics, in conjunction with Alterra (RIN at the time), produced a forecast of the possible effects of soil subsidence, after which the monitoring process was started at the end of 1988.
The first two reports are based on data up to 1994 and 1999 respectively and describe the effects covering a period of 8 and 13 years respectively after gas extraction activities commenced. This third report is based on data up to 2003/2004.
In 2000, the results were presented during a public debate. Various improvements have since been implemented. The highlights of the past 5 years are the publication of the 2000-2010 research programme, the bird study, the extensive measurements on the mudflats and the newly developed technology of pin measurements. In addition, the new programme for the wet dune slack received ample attention with surprising results. The new prognosis of NAM has been discussed in the Committee and, as a result thereof, a new assessment of the possible consequences for the salt
meadow has been made.
Results of the research
The soil subsidence took place in the form of a large basin with a diameter of around 15 km and could be measured as from 1987. In the subsequent period, up to around 2000, the soil in the centre of the basin subsided by approximately 1.8 cm per year. After that, as a result of the falling pressure in the field, the subsidence speed reduced somewhat to up to 1.2 cm per year. In 2003, the soil subsidence in the centre of the soil subsidence basin amounted to 27 cm. It is expected that the soil subsidence will continue to diminish up to 2020, when it will have come to a full stop.