simulations will be referred to as “1900s” and “2100s” in the remainder of the paper.
Results from the SAFRAN reference simulation will be referred to as “2000s” or
“reference situation”.
5.1 Estimating Land Cover Changes
The land cover and soil texture define the hydrological response unit on which the
water balance is calculated. A crucial step for the simulation of scenarios is therefore
to estimate the changes in the land cover for the three main types of land use: urban
areas, agricultural lands and forested lands (Table 1).
At the scale of all 24 administrative districts of the basin, 1901 and 2009
population census data provided by the National Institute of Statistics and Economic
Studies (INSEE
2 ) have allowed evaluating urban areas for the 1900s scenario, using
equation (1), which relates the surface of artificialised area S a (in hectares
for 10
3 inhabitants) and the population density p (in inhabitants/km
2 ) [99]:
S a ¼ 1; 475 p
À0:6 ,
ð1Þ
In the case of the 2100s run, a similar method was implemented using results from
the Explore 2070 project [100], which provides projection data on how the population is expected to evolve by the year 2070. This was considered steady until the
year 2100.
Regarding forested areas, data between 1950 and 2010, also provided at the
administrative district scale, were extracted from the annual agricultural statistics
Table 1 Key figures on
distributions of land cover and
withdrawal types in
groundwater as well as
population rates at the scale of
the Seine basin for the 2000s
simulation. Other values
identify respective relative
variations (%) for the 1900s
and 2100s scenarios when
compared to the 2000s
reference
Scenario
1900s
2000s
2100s
Withdrawal types (in Mm
3 a
À1
)
Drinking water
À100%
731
À12.9%
Industrial processes
À100%
169
À52.6%
Irrigation
À100%
96
À2.5%
Total
À100%
996
À16.7%
Land use (in % of the surface domain)
Urban areas
À3.3%
7.9
+0.1%
Forested lands
À2.7%
23.2
0%
Agricultural lands
+6.0%
68.9
À0.1%
Demography (in 10
6 inhabitants)
Population rate
À47%
16.7
+26%
2 https://www.insee.fr/en/accueil.
72
N. Flipo et al.
Results from the SAFRAN reference simulation will be referred to as “2000s” or
“reference situation”.
5.1 Estimating Land Cover Changes
The land cover and soil texture define the hydrological response unit on which the
water balance is calculated. A crucial step for the simulation of scenarios is therefore
to estimate the changes in the land cover for the three main types of land use: urban
areas, agricultural lands and forested lands (Table 1).
At the scale of all 24 administrative districts of the basin, 1901 and 2009
population census data provided by the National Institute of Statistics and Economic
Studies (INSEE
2 ) have allowed evaluating urban areas for the 1900s scenario, using
equation (1), which relates the surface of artificialised area S a (in hectares
for 10
3 inhabitants) and the population density p (in inhabitants/km
2 ) [99]:
S a ¼ 1; 475 p
À0:6 ,
ð1Þ
In the case of the 2100s run, a similar method was implemented using results from
the Explore 2070 project [100], which provides projection data on how the population is expected to evolve by the year 2070. This was considered steady until the
year 2100.
Regarding forested areas, data between 1950 and 2010, also provided at the
administrative district scale, were extracted from the annual agricultural statistics
Table 1 Key figures on
distributions of land cover and
withdrawal types in
groundwater as well as
population rates at the scale of
the Seine basin for the 2000s
simulation. Other values
identify respective relative
variations (%) for the 1900s
and 2100s scenarios when
compared to the 2000s
reference
Scenario
1900s
2000s
2100s
Withdrawal types (in Mm
3 a
À1
)
Drinking water
À100%
731
À12.9%
Industrial processes
À100%
169
À52.6%
Irrigation
À100%
96
À2.5%
Total
À100%
996
À16.7%
Land use (in % of the surface domain)
Urban areas
À3.3%
7.9
+0.1%
Forested lands
À2.7%
23.2
0%
Agricultural lands
+6.0%
68.9
À0.1%
Demography (in 10
6 inhabitants)
Population rate
À47%
16.7
+26%
2 https://www.insee.fr/en/accueil.
72
N. Flipo et al.