from single, minimal flows to flow regimes;
from a single-species focus to a focus on whole ecosystems;
from the study of the stream channel to the study of riparian and floodplain areas, as well; and
from a hydrology dominated field to an interdisciplinary field that includes hydrologists, biologists, lawyers, geomorphologists and water quality experts.
State-of-the-art instream flow programs will strive to preserve whole ecosystems, mimic natural flow regimes, include riparian and floodplain systems in addition to the stream channel, take an interdisciplinary approach, use a variety of tools and approaches in technical evaluations, practice adaptive management, and involve stakeholders. Instream flow programs will encompass technical evaluations in biology, hydrology and hydraulics, physical processes, water quality, connectivity, and non-technical aspects of stakeholder involvement and goal setting. Integrating technical evaluations into a flow recommendation is an important, challenging task with few well documented methods. Three examples of current or recent instream flow work are highlighted that use a number of these components and show how instream flow studies and programs work in Texas and across the country. Still, there are some major research needs and uncertainties in the science of instream flows, especially with respect to integration, ecological indicators, and spatial scale.