MAgPIE - An Open Source land-use modeling framework

4.6.0

created with goxygen 1.3.1

Water availability (43_water_availability)

Description

The water availability module determines the water that is available in MAgPIE. The following water sources are currently implemented: surface water, groundwater, technical (like desalination etc.). Additionally, this module includes the main water constraint that requires water withdrawals to be smaller or equal to available water. Information is passed to and received from the 42_water_demand module.

Interfaces

Interfaces to other modules

Input

module inputs (A: total_water_aug13)
  Description Unit A
sm_fix_cc year until which all parameters affected by cc are fixed to historical values \(year\) x
vm_watdem
(wat_dem, j)
Water demand from different sectors \(10^6 m^3/yr\) x

Output

module outputs
  Description Unit
im_wat_avail
(t, wat_src, j)
Water availability \(10^6 m^3/yr\)

Realizations

(A) total_water_aug13

The calculation of available water as described below happens in the MAgPIE preprocessing. This realization only considers renewable water resources, i.e. runoff generated from precipitation. All runoff is assumed to enter rivers, neglecting groundwater recharge. Other water resources such as fossil groundwater, discharge from melting glaciers or desalination are also not considered. The calculation of available water per grid cell is based on LPJmL (Bondeau et al. (2007)) simulations. For each river basin, total annual runoff in the basin constitutes the amount of water available in one year. In order to account for the fact that water can only be supplied to the plants during the growing period, the mean growing period over all crops based on LPJmL sowing and harvesting dates (Bondeau et al. (2007)) is calculated in MAgPIE. Some data has been excluded from the calculation:

Therefore, water available for irrigation in each basin only consists of the total runoff occurring in the mean growing period in all basin cells except for cells where water storage in terms of dams is present (taken from Biemans et al. (2011)). In this case, total annual runoff is available.

The distribution of basin runoff in the growing period to the individual grid cells is done using LPJmL (Bondeau et al. (2007)) discharge as a weight.

There is an interface to the 42_water_demand module. If exogenous non-agricultural water demand exceeds available water the missing amount is available from groundwater to avoid infeasibility.

\[\begin{multline*} \sum_{wat\_dem}vm\_watdem(wat\_dem,j2) \leq \sum_{wat\_src}v43\_watavail(wat\_src,j2) \end{multline*}\]

The water constraint, q43_water, assures that, in each cluster, the sum of water withdrawals in all sectors vm_watdem does not exceed available water from all sources v43_watavail. The local seasonal water constraints is the sum of the amount of water needed in the sectors defined by wat_dem (agriculture, manufacturing, electricity, domestic and ecosystem). This value must be lower than the sum of the Amount of water available from different sources in the sectors defined by wat_src (surface, ground, technical and renewable groundwater).

Limitations There are no known limitations.

Definitions

Objects

module-internal objects (A: total_water_aug13)
  Description Unit A
f43_wat_avail
(t_all, j)
Surface water available for irrigation per cell from LPJmL \(10^6 m^3/yr\) x
q43_water
(j)
Local seasonal water constraints \(10^6 m^3/yr\) x
v43_watavail
(wat_src, j)
Water available from different sources \(10^6 m^3/yr\) x

Sets

sets in use
  description
cell(i, j) number of LPJ cells per region i
j number of LPJ cells
j2(j) Spatial Clusters (dynamic set)
t_all(t_ext) 5-year time periods
t(t_all) Simulated time periods
type GAMS variable attribute used for the output
wat_dem Water demand sectors
wat_src Type of water source
watdem_exo(wat_dem) Exogenous water demands

Authors

Anne Biewald, Markus Bonsch

See Also

09_drivers, 42_water_demand, 43_water_availability

References

Biemans, H., I. Haddeland, P. Kabat, F. Ludwig, R. W. A. Hutjes, J. Heinke, W. von Bloh, and D. Gerten. 2011. “Impact of Reservoirs on River Discharge and Irrigation Water Supply During the 20th Century.” Water Resources Research 47 (3). https://doi.org/10.1029/2009WR008929.

Bondeau, Alberte, Pascalle C. Smith, Sönke Zaehle And Sibyll Schaphoff, Wolfgang Lucht, Wolfgang Cramer, Dieter Gerten, Hermann Lotze-Campen, Christoph Müller, Markus Reichstein, and Benjamin Smith. 2007. “Modelling the Role of Agriculture for the 20th Century Global Terrestrial Carbon Balance.” Global Change Biology 13 (3): 679–706. https://doi.org/10.1111/j.1365-2486.2006.01305.x.