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
Water is a crosscutting issue across many of the Sustainable Development Goals (SDGs). However, there is one goal that is focused explicitly on water – Goal 6. Sustainable management of water implies that, as part of water resources management activities, sufficient water is left for ecosystems so that they can continue to provide services to society into the future. This, essentially, points to the need to ensure environmental flows (EF) in order to meet the SDGs. However, in most countries, there is a lack of awareness of EF at multiple stakeholder levels, and a lack of consistent, easy-to-use, readily available EF data to feed into the SDG process. If countries are to implement EF-related SDG targets over the next 15 years, baseline EF information is a prerequisite, and a process to incorporate such information into the targets needs to be developed.
This research study focused on making data on EF, and sustainable surface water (SR) and groundwater (BF) abstractions available at a global, regional and subregional level. The first EF assessment at global scale, carried out by the International Water Management Institute (IWMI) in 2004, was modified to provide EF information for the calculation of SDG target indicators. The spatial resolution of the analysis was improved from 0.5 to 0.1 degrees, and environmental water ‘needs’ were estimated for both surface runoff and \ groundwater. The desired flow and environmental conditions of rivers are defined by four environmental management classes (EMCs). The percentage of flow required relative to pristine conditions, and the volume of groundwater and surface water that may be withdrawn without impacting EF are calculated for each EMC globally. The EF for each EMC are based on modifying synthetic, pre-development natural flows derived from the global hydrological model PCR-GLOBWB. Since the actual river flow and environmental condition of rivers vary across the world, the study also provides an estimate of the most likely current EMC for each grid cell globally, based on a modified “Incident Biodiversity Threat”.
Finally, an online, publicly available, interactive tool, the ‘Global Environmental Flow Information System’ developed by IWMI, enables users to select areas either at a country or river basin level (or any area of choice), identify existing and/or desired EMC, and get estimates of associated EF, baseflow (BF) contribution, and corresponding sustainable surface water and groundwater abstractions. These estimates can then be compared either directly with the information on actual water withdrawals in the selecte