Ecological Sustainability Assessment of Water Distribution for the Maintenance of Ecosystems, their Services and Biodiversity

Abstract

Water provision and distribution are subject to conflicts between users worldwide, with agriculture as a major driver of discords. Water sensitive ecosystems and their services are often impaired by man-made water shortage. Nevertheless, they are not sufficiently included in sustainability or risk assessments and neglected when it comes to distribution of available water resources. The herein presented contribution to the Sustainable Development Goals Clean Water and Sanitation (SDG 6) and Life on Land (SDG 15) is the Ecological Sustainability Assessment of Water distribution (ESAW-tool). The ESAW-tool introduces a watershed sustainability assessment that evaluates the sustainability of the water supply-demand ratio on basin level, where domestic water use and the water requirements of ecosystems are considered as most important water users. An ecological risk assessment estimates potential impacts of agricultural depletion of renewable water resources on (ground)water-dependent ecosystems. The ESAW-tool works in standard GIS applications and is applicable in basins worldwide with a set of broadly available input data. The ESAW-tool is tested in the Danube river basin through combination of high-resolution hydro-agroecological model data (hydrological land surface process model PROMET and groundwater model OpenGeoSys) and further freely available data (water use, biodiversity and wetlands maps). Based on the results, measures for more sustainable water management can be deduced, such as increase of rainfed agriculture near vulnerable ecosystems or change of certain crops. The tool can support decision making of authorities from local to national level as well as private enterprises who want to improve the sustainability of their supply chains.

Keywords: Biodiversity; Ecosystem Services; GIS; SDGs; Sustainability assessment; Water distribution.

Fig. 1

Workflow of the development and application of the multiscale ESAW-tool including the main data inputs, processes, outcomes, and user applications

Fig. 2

Location of the Danube river basin in Europe and riparian states of the Danube basin (Based on: ESRI World terrain Base; TM_WORLD_BORDERS-0.1, Lehner and Grill 2013)

Fig. 3

WSI results for the sub-basins of the Danube basin from April to September 2015. Green and yellow indicate sustainable index values, orange and red indicate unsustainable index values

Fig. 4

Summary of four-year period (2015–2018) for the WSI. Map shows all sub-basins that have an unsustainable water use for at least three months in each of the four vegetation periods

Fig. 5

WDI results for the vegetation period 2015 in the Danube basin. Green and yellow indicate sustainable index values, orange, red and purple indicate unsustainable index values

Fig. 6

Results for compliance with e-flows from April to September 2015 the Danube basin. Green and yellow indicate compliance with e-flows, orange and red indicate no compliance with e-flows

Fig. 7

Risk of agricultural water use to impair GDEs in the Danube basin. Overview and detailed view with intersection with ecosystem map

Fig. 8

Hot Spots of unsustainable water use in July 2015–2018 in the Danube basin. Overview on the entire Danube basin and detailed view on a sub-basin overlaid with the WSI result for the respective month. The detail view shows that large areas of the sub-basin are Hot Spots of unsustainable water use