Scenarios in FHI Main Driving Forces Infrastructure on water bodies

Infrastructure on water bodies has some of the most direct impacts on the future state of a basin. Freshwater infrastructure includes dams for hydro power or water consumption, pumping stations for rivers and aquifers for supply of water, outlets returning wastewater to these systems and dredging, channelization or straightening of rivers for navigation. All of these can have effects on Ecosystem Vitality and Ecosystem Services indicators. With the Ecosystem Services component, infrastructure can have detrimental effects on flood regulation, water quality and sedimentation, but it can also improve intra-annual variability of supply relative to demand. It can affect water quantity and quality, drainage basin condition and biodiversity indicators under Ecosystem Vitality. The suite of indicators that might change under an infrastructure planning scenario will be highly context dependent.

One of key areas under this is expected to be water allocation and trade-offs. Since freshwater is often limited, and numerous needs exist within a basin, water of sufficient quality must be allocated to different uses such as municipal human consumption, agriculture, industry, energy, environmental flows, etc. Water needs to be allocated in a manner that achieves economic, social and environmental goals. Water allocation, therefore, makes trade-offs between the priorities of stakeholders, reliability of water supply, equity, economic growth and maintenance of ecosystems. Water allocation can change for a variety of economic, social or environmental reasons, including greater need for municipal water due to population growth, industrial or agricultural expansion, or drought, as well as water diversion or transfer projects to deliver water into or out from a basin.

Existing water allocation models, like, the REALM (REsource ALlocation Model) (Perera et al. 2005) or the Water Evaluation and Planning (WEAP) water allocation model (Yates et al. 2005) can be used to structure the water allocation scenarios and provide input on water quantity and quality for the Ecosystem Vitality component and provisioning and regulation/support for Ecosystem Services component for the Freshwater Health Index. Other indicators also may be relevant for different water allocation scenarios, e.g. Conservation/Cultural/Heritage sites. The values of the Freshwater Health Indices can then be used to rank alternative water allocation scenarios as additional information in the decision-making process.