The expert panel environmental flow assessment builds on the basic approach from Level 1: initial flow recommendations are developed through an integration of hydrologic analysis and information on the linkages between flow regime and river processes. The initial flow recommendations do not require new data collection or modeling but, instead, rely primarily on expert judgment supported by a thorough literature review. The primary distinction between this level and Level 1 is that this synthesis of information and articulation of expert judgment into flow recommendations occurs within the framework of a flow workshop with diverse participants.

The Nature Conservancy developed an example of a Level 2 approach, referred to as the “Savannah Process” because it was first implemented on the Savannah River. This process develops scientifically credible environmental flow prescriptions in a relatively short time through facilitated expert workshops. The Savannah Process has been applied in many rivers in the United States, as part of the Sustainable Rivers Project, and has also been applied to the Patuca River in Honduras.

At the site scale, a Level 2 approach produces a set of initial flow recommendations that can lead to experimental flow releases. Monitoring of such flows can provide a learning opportunity to improve understanding of river processes.

The U.S. Army Corps of Engineers Hydraulic Engineering Center (HEC) and The Nature Conservancy developed the Regime Prescription Tool to help expert panels develop environmental flow prescriptions in a collaborative workshop setting.

At the regional scale, scientists and water managers in the Susquehanna (USA), Magdalena (Colombia) and Potomac (USA) river basins have elevated ELOHA to Level 2 by using expert panels to assess flow needs for river types, rather than for individual rivers, throughout their entire river basins.

Continue to Level 3.