DefinitionImportance for Understanding Hydropower ImpactsMetrics related to the types of plant and animal species found in the watershed, as well as their absolute abundance and relative abundance to each other.
Shifts in aquatic, riparian and terrestrial populations and communities have been linked to several aspects of hydropower construction and operation, including decreased longitudinal connectivity and changes in flow velocities in rivers, inundation of uplands upstream of dams, changes in ground water depth both up and downstream of dams, and changes in sediment and flow regimes. Accurate assessments of population and community changes reflect the overall health of the ecosystem.
Welcome to the Hydropower Environmental Decision Support Toolkit
The Hydropower Environmental Decision Support (EDS) Toolkit has been developed by Oak Ridge National Laboratory (ORNL) with the support of the U.S. Department of Energy Water Power Technologies Office (WPTO). This toolkit is designed to facilitate discussions among stakeholders involved in hydropower project planning by offering a systematic and transparent platform to consider potential environmental impacts.
Key Features
- Helps in identifying environmental impacts from hydropower projects.
- Tailored for new projects or adding hydropower to existing non-powered dams, including, but not limited to, Federal Energy Regulatory Commission (FERC) hydropower licensing proceedings.
- For existing dams, the EDS Toolkit focuses only on the environmental impacts created by the proposed hydropower addition. The current EDS Toolkit is not intended to address pumped storage or conduit projects.
How to Use the EDS Toolkit
To use the EDS Toolkit, one should start with the Impacts module and work through the remaining menu items from left to right.
1: Impacts Module
To identify potential environmental impacts from the proposed hydropower project, the River Function Indicator (RFI) Questionnaire within the Impacts module may be filled out either individually or as a group; however, it was designed with the expectation that individuals familiar with the hydropower project will answer the questions (i.e., licensees, environmental consultants, state and federal resource agencies, NGOs, and others). It will likely take you over an hour to fill out the entire Questionnaire. The Questionnaire will identify key functions of the riverine ecosystem that may be affected by a hydropower project's construction and/or operations.
2: Prioritization Module
Results from the RFI Questionnaire can be slimmed down to 3-5 “Key Topics” (i.e., RFIs flagged through ≥50% “Yes” responses) and “Uncertain Topics” (i.e., RFIs flagged through ≥50% “Uncertain” responses) through use of the Prioritization module.
3. Report Module
View detailed report for River Function Indicator Questionnaire (RFIQ).
4. What's Next? Module
Examples of previously implemented environmental studies and mitigations, as well as information about relevant permitting and regulatory information, will be provided for each identified topic in the What's Next? module. The information from the Questionnaire may be used as a resource during the study plan development phase of a FERC licensing proceeding, the EDS Toolkit does not recommend specific study methodologies or suggest any specific protection, mitigation, or enhancement measures.
The Six River Function Indicator (RFI) Categories
The EDS Toolkit was developed to provide interested parties with a systematic and transparent process for identifying riverine ecosystem functions that may be affected by a hydropower project's construction and/or operations and to identify relevant datasets and data gaps. Each RFI represents a group of environmental metrics used to measure a common characteristic of an ecosystem. The tool's questions address a checklist of 42 RFIs organized into six categories described below in Table 1: Biology & Biota, Connectivity & Fragmentation, Geomorphology, Land Cover, Water Quality, and Water Quantity. The RFIs are based on the results of an extensive literature review of environmental metrics which integrated the viewpoints of multiple interested parties and the scientific research community.
Table 1. The six River Function Indicator (RFI) categories and their importance for understanding hydropower impacts
DefinitionImportance for Understanding Hydropower ImpactsMetrics assessing the degree to which a particular land cover type or ecosystem maintains continuity (connectivity) or the degree to which an ecosystem or land cover type is disconnected (fragmentation).
Dams and their associated infrastructure can disrupt aquatic, riparian, and terrestrial connectivity, as well as groundwater connectivity, all of which can directly affect the habitat quantity and quality for organisms in an ecosystem. Quantifying connectivity changes is therefore important for a full accounting of the environmental effects of hydropower.
RFI Category Code Details
DefinitionImportance for Understanding Hydropower ImpactsMetrics related to the dynamic evolution of topographic and bathymetric features created within an ecosystem.
Hydropower development can disrupt a river system’s geomorphologic equilibrium through altered sediment and flow regimes. These changes have the potential to impact the availability and quality of habitat for plants and animals within the system.
RFI Category Code Details
DefinitionImportance for Understanding Hydropower ImpactsMetrics used to characterize the amount of water found within streams, reservoirs and/or groundwater aquifers as well as the flows between them.
Hydropower development can alter the hydrologic cycle through the impoundment of previously free-flowing water, increased evaporation rates, and altered groundwater recharge patterns. Because hydropower systems may be operated to fill a variety of purposes, changes to water quantity may occur at a variety of temporal scales. Changes to hydrologic regimes can ultimately affect human and wildlife populations through altered water availability and habitats.
RFI Category Code Details
DefinitionImportance for Understanding Hydropower ImpactsMetrics associated with characterizing the physical material at earth’s surface pre- and post-hydropower development.
Land cover type is an important measure of ecosystem health because it influences many other environmental properties ranging from river and floodplain sedimentation rates to fragmentation of habitats and wildlife populations at scales ranging from site to landscape. Land cover changes can be used to more-fully describe ecosystem changes associated with hydropower development, such as increases in wetted surface from reservoir formation, and fragmentation of the surrounding landscape through installation of supporting infrastructure (e.g., transmission lines, roads).
RFI Category Code Details
DefinitionImportance for Understanding Hydropower ImpactsMetrics related to water quality characteristics, including water temperature, dissolved oxygen levels, and nutrient and pollutant Water quality characteristics can be directly or indirectly affected by hydropower development and operation. Changes in water quality can adversely affect the health of humans and wildlife.
RFI Category Code Details
Version 6 of the EDS Toolkit provides a new What’s Next? module with connections to DOE's Regulatory and Permitting Information Desktop (RAPID) Toolkit for Hydropower developed by the National Renewable Energy Laboratory (NREL). Once users have identified key RFIs to explore further, they may explore information about relevant regulations and permit requirements pertaining to those key environmental indicators in the RAPID Toolkit. The connections between the EDS Toolkit and the RAPID Toolkit are illustrated below.
