Box 3 – Estimating Groundwater Abstraction in the Paris Basin in 2010
The applied ‘national-to-aquifer-level transfer’ approach (NTALT) assumes that the distribution of groundwater abstraction over sub-areas is proportional to population size and the area irrigated by groundwater. The relevant map of France is shown in Figure Box 3-1.
National statistics of France for 2010 are:
- groundwater abstraction: 5.71 km3, of which 0.80 km3 is for irrigation (Margat and Van der Gun, 2013, Appendix 5 therein);
- population: 62,787,000 (Census 2010; Margat and Van der Gun, 2013, Appendix 5 therein); and,
- area equipped for irrigation using groundwater (AEI_GW): 1,213,543 ha (Siebert et al., 2010).
Figure Box 2–1 – Paris Basin and the regions it includes entirely or partly.
Selected statistics for zones located within the boundaries of the Paris Basin
| Regions | Share* | AEI_GW (ha) | Population 2010 | Area (km2) |
| Nord-Pas de Calais | 100% | 24,067 | 4,038,157 | 12,414 |
| Picardie | 100% | 92,007 | 1,914,844 | 19,399 |
| Haute Normandie | 100% | 12,451 | 1,836,954 | 12,317 |
| Basse Normandie | 40% | 2,492 | 589,398 | 7,036 |
| Pais de la Loire | 40% | 6,100 | 1,428,718 | 12,833 |
| Poitou-Charentes | 20% | 15,768 | 354,073 | 5,162 |
| Centre | 100% | 369,952 | 2,577,866 | 39,151 |
| Bourgogne | 75% | 17,321 | 1,231,586 | 23,687 |
| Ile de France | 100% | 41,559 | 11,786,234 | 12,012 |
| Champagne-Ardennes | 100% | 37,689 | 1,335,923 | 25,606 |
| Lorraine | 80% | 290 | 1,880,736 | 18,838 |
| Subtotal: | 619,696 | 28,974,488 | 188,454 | |
| % of France: | 51.1 | 46.1 | 34.5 |
* Share is the percentage of the region located within the Paris Basin. Other columns indicate values for the portion of each region within the Paris Basin.
Note that Supplement S2 of Siebert et al (2010) has been used to define the AEI_GW for the eleven regions. Based on these collected data, groundwater abstraction for domestic and industrial uses in the Paris Basin for the year 2010 is estimated as the product of the population ratio (Population Paris Basin / Population France) and the volume of water used for domestic and industrial purposes in all of France.
(46.1 / 100) * (5.71 km3 – 0.80 km3) = 2.26 km3
Similarly, groundwater abstraction for irrigation in the Paris Basin for the year 2010 is estimated as the product of the AEI_GW ratio (AEI_GW Paris Basin / AEI_GW France) and the volume of water used for irrigation in all of France.
(51.1 / 100) * 0.80 km3 = 0.41 km3
Hence, the estimated total groundwater abstraction rate from the Paris Basin is approximately 2.7 km3/year, which is equivalent to a water depth of 14 mm/year spread over the area of the Paris Basin.
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