Run ReWaterGAP with Karst (Under Construction)#

This tutorial introduces the modifications in ReWaterGAP for handling karst regions and explains the required input files, as well as the assessment methods.

Introduction#

[Insert Introduction here]

Implemented Modifications#

The following extensions and changes need to be made to the code:

Fraction of karstification#

A fraction of the continental area is defined as karst. For this fraction, the runoff component (R3) is treated as groundwater recharge.

Groundwater recharge factor (fg)#

The original calculation of fg has to be replaced by an externally provided input factor.

Semi-arid coarse-texture adjustment#

A grid-cell-specific indicator allows special handling of (semi-)arid regions. If a semi-arid grid cell has R<sub>gmax</sub> > 5 mm/d (indicating coarse texture), groundwater recharge occurs only when precipitation exceeds 12.5 mm/d (instead of being triggered solely by coarse texture).

Maximum groundwater recharge dataset#

A dataset specifying the maximum possible groundwater recharge rate (mm/d) needs to be implemented

Input Files#

ReWaterGAP requires additional input files for the karst extensions:

G_ARIDCOARSE.UNF2#

  • The input file for indicating coarse arid gird cells

  • Value: 1

  • Unit: [-]

../../_images/G_ARIDCOARSE.png

G_GWRFACTOR.UNF0#

  • The input file for groundwater recharge factor

  • Range: 0 – 1

  • Unit: [-]

../../_images/G_GWRFACTOR.png

G_KARSTFRAC.UNF0#

  • The input file for karst fraction

  • Range: 0 – 0.9

  • Unit: [-]

../../_images/G_KARSTFRAC.png

G_GWRMAX.UNF2#

  • Specifies the maximum groundwater recharge rate.

  • The input file for gwr max

  • Range: 3 – 7

  • Unit: [mm/d]

../../_images/G_GWRMAX.png

Assessments#

To evaluate the impact of the modifications, the following assessments are recommended:

Water balance#

Streamflow evaluation#

Validate model outputs against observed streamflow