Physical assessment of selected Groundwater-Related Ecosystem Services (GRES)

Description

Groundwater-related ecosystem services are the benefits that people obtain from an aquifer and from the ecosystems that depend on it. This approach assesses them physically, as flows and states of the system, so that environmental management decisions can be supported by measurements rather than by assumption.

The method selects the services of interest for a given groundwater body, defines for each the physical indicator that represents it, and establishes how that indicator responds to the pressures acting on the aquifer — abstraction, land use change, recharge variation and pollution. The result is a set of indicators that can be monitored and reported, and that translate directly into the terms in which water management plans are written.

It is the assessment approach used for the Medina del Campo groundwater body within NAIAD, where the relevant services include water supply, the maintenance of groundwater-dependent wetlands and the regulation of water quality.

Applications to decision making in the insurance sector

For a risk carrier, the value of this approach is that it separates the state of the resource from the services that depend on it, which is what makes it possible to describe the exposure that arises when the resource degrades. It is also the physical basis for any claim that a recharge or abstraction measure reduces drought exposure rather than merely redistributing it.

Added value of this modelling approach

It gives environmental management a physical indicator set that is specific to groundwater, where most ecosystem service frameworks are built for surface systems and translate poorly.

What decision can be improved with this modelling approach

Prioritising measures within a groundwater body; setting the indicators against which a river basin management plan reports; and judging whether a proposed intervention affects the services that matter most in the basin.