Indiana Water Monitoring Council 
Maximizing resources through improved communication,
                  coordination, data sharing, and collaboration

Incorporating "instream flows" in regional supply plans to better protect critical ecosystems

Historically, Indiana water management programs have been concerned primarily with protecting water quality (keeping water clean) and preventing flood damage (keeping water in its place). As demand for water increases in our state, we are now finding that withdrawing too much water from a stream or river at the wrong time can have negative effects on the ecological health of that waterbody. Flows that are too low in summer may limit rearing habitat, concentrate fish in shrinking pools with declining water quality and dry up portions of the channel inhabited not only by fish but by mussels, crayfish, and other invertebrates that are important in fish and wildlife food chains. Low flows in winter may limit suitable overwintering habitat and ice-free refuges. Sustaining a minimum flow to keep an endangered species from extinction may also interfere with watering crops during dry times and boaters from enjoying a lake full of water. There is a balance that needs to be struck between ecosystem protection and necessary water resource development. 

Managing our water resource in a way that sustains both human and aquatic life needs is an increasingly important topic, both in Indiana and throughout the United States. Nine states now have regulations that protect their water resource from removing too much water at the wrong time of year. This type of planning requires input and interactions from biologists, engineers, hydrologists, farmers, utilities, politicians, lawyers, boaters, environmental groups, and ordinary citizens. Much discussion remains to be done on this important topic, and relevant information is needed for decision-making.    

Optimal management of instream flows requires data related to streamflow and fish populations. This information enables scientists to link flow conditions with increases or decreases for various fish species. It's also important to track the populations of other aquatic animals during winter months and times of drought to gauge the overall health of streams when our aquatic ecosystems are stressed.  

Water-resource professionals in Indiana with experience addressing "instream flow" issues:

  • Greg Bright (Commonwealth Biomonitoring)
  • Jeff Frey (USGS)
  • Mark Pyron (Ball State University)
  • Jack Wittman (Intera)

Related resources:

Indiana Administrative Code, 2015, Water Resource Management IC 14-25-7-14, Indiana Department of Natural Resources, Division of Water, accessed October 22, 2015 at:

Arthington, A.H., et al., 2006, The challenge of providing environmental flow rules to sustain river ecosystems, In: Ecological Applications 16(4), Ecological Society of America, pp. 1311-1318, accessed March 22, 2016 at:

Pritchett, T., and Pyron, M., 2011, Fish assemblages respond to habitat and hydrology in the Wabash River, Indiana, River Research and Applications 28, pp. 1501-1509. 

Katapodis, C., 2005, Developing a tool kit for fish passage, ecological flow management and fish habitat works, Journal of Hydraulic Research 43(5), pp. 451-467.

This page written and maintained by Mark Pyron of Ball State University. 
© Indiana Water Monitoring Council
Powered by Wild Apricot Membership Software