The interactive maps provide information related to Environmental Flows for current conditions and different Environmental Management Classes (EMCs) of a river system. The current condition of rivers is based on the river health indicators developed by Vorosmarty et al., 2010. EMCs are defined as the state of the river for certain criteria of river health. They are defined in four classes (from A to D) with "A" being "natural" to "D" being "significantly modified" (Smakhtin and Eriyagam, 2008):

For details of the methodology, please refer to theIWMI Research Report.

The maps presented here are:

1. Natural Annual Runoff (Modelled)(mcm)*: Mean annual runoff for natural conditions as generated by global hydrological model PRC-GLOBWB (Wada et al., 2014).
2. Present Day EMC: Represents the current condition of the river.
   1. Environmental Flow Percentage: Percentage of natural flow required to maintain the current condition of river.
   2. Environmental Flow (mcm): Flow in mcm required to maintain the current condition of river.
   3. Sustainable Groundwater Abstraction (mcm): Groundwater that can be abstracted without impacting the EFs for the current condition of river.
3. EMC: Environmental Management Class (select one out of "A","B","C","D")
   1. Environmental Flow Percentage: Percentage of natural flow required to maintain the EFs for the selected EMC.
   2. Environmental Flow (mcm): Flow (in mcm) required to maintain the EFs for the selected EMC.
   3. Groundwater contribution to Environmental Flow (mcm): Contribution of groundwater (in mcm) in the EFs for the selected EMC.
   4. Sustainable Groundwater Abstraction (mcm): Groundwater that can be abstracted without impacting the EFs for the selected EMC.

mcm - Million Cubic Meters

These data can be downloaded either as spatial, gridded data or as aggregate values at country/basin/customized polygon level.

References:

Sood, A. Smakhtin, V. Eriyagama, N. Villholth, K. G. Liyanage, N. Wada, Y. Ebrahim, G. Dickens, C. 2017. Global environmental flow information for the sustainable development goals. Colombo, Sri Lanka: International Water Management Institute (IWMI). 37p. (IWMI Research Report 168). doi: 10.5337/2017.201

Smakhtin, V. and Eriyagama, N. (2008). Developing a software package for global desktop assessment of environmental flows. Environmental Modelling & Software, 23: 1396-1406.

Vorosmarty CJ, McIntyre PB, Gessner MO, Dudgeon D, Prusevich A, Green P, Glidden S, Bunn SE, Sullivan CA, Liermann CR, Davies PM.(2010). Global threats to human water security and river biodiversity. Nature, 467(7315):555-61.

Wada, Y., D. Wisser, and M. F. P. Bierkens (2014). Global modeling of withdrawal, allocation and consumptive use of surface water and groundwater resources, Earth System Dynamics, 5: 15-40.

• For further details please contact: IWMI Hydroinformatics: (iwmi-hi-support@cgiar.org)
• To view the earlier version of IWMI's environmental water requirements and scarcity assessment, please click here