Adaptive Management of R.L. Harris Dam and the Tallapoosa River

 

Justification

   The Tallapoosa River is fragmented by four large dams that impound or regulate

R.L. Harris Dam on the Tallapoosa River near Wedowee, AL.

over 54% of the Piedmont mainstem (113 km). The middle and upper mainstem Tallapoosa River and the tributaries of the middle Tallapoosa River have been identified as priority areas for conservation.  Although the river retains high levels of diversity and endemism, evidence of depressed fish populations exists in the regulated reach below R.L. Harris Dam. B ased on current knowledge, flow management may be effective for improving biological integrity in the system.  In the Piedmont region, eight GCN species, as identified by Alabama Department of Conservation and Natural Resources are either present or may be reintroduced if habitats are suitable and stable.  In addition, U.S. Fish and Wildlife Service considers four fishes and one mussel to be “at-risk” in the basin.  However, life history, habitat affinities and functional relations of how habitat affects population structure and dynamics data are lacking for each of these species. Recently, adaptive management of the Tallapoosa River below R. L. Harris Dam has been implemented to learn about both faunal (i.e., population) and ecosystem response to flow management.  Adaptive management is highly applicable to development of creative approaches for restoring and conserving native fish, mussel and invertebrate faunas and fisheries of fragmented, regulated river systems. 

Objectives

Sampling on the Tallapoosa River .

1) Compare fish and invertebrate assemblage and population structure between flow-managed and naturally flowing river reaches (including all GNC species)
2) Assess habitat stability and persistence for GCN species and other species of concern; and
3) Determine applicability of adaptive management and habitat restoration for other river systems.

Research

Gage at Heflin, AL, looking upstream on theTallapoosa River. This is a critical spot in the adaptive management process, as this is the site which the flow targets at Wadley, AL are based.

   This project tries to enhance community wide aquatic conservation in the Tallapoosa River by implementing adaptive management of flows from R. L. Harris Dam.  Implementation of flows is coupled with a long-term monitoring plan that evaluates effects of management on fauna and habitat.  Researchers will develop, implement and evaluate strategies for monitoring fauna in large river systems and incorporating that knowledge into future management and conservation programs of river systems.  There are currently two main proposed changes to flows from R. L. Harris Dam; increase in base flow and provision of spawning windows.  Species of concern will be targeted. However, community wide assessment will be conducted.  Two unregulated rivers (Hillabee Creek and the upper Tallapoosa River) will be monitored to assess how state measured variables fluctuate independent of regulated flows (i.e., under ”natural” conditions).

Impacts

Hillabee Creek near Alexander City, AL

   The Tallapoosa River below R.L. Harris Dam provides some of the last free flowing riverine habitat in the Piedmont region.  Restoration of this section of river is needed to maximize available habitat for one of the most diverse aquatic faunas in North America.  In addition, little is known about the response of invertebrates to changes in flows.  We hypothesize that invertebrates may recolonize shoal habitats more rapidly than fishes.  The potential to reestablish a threatened mussel species (e.g., H. altilis) and the potential elimination of the longear sunfish in the river exists.  Quantification of functional relations between aspects of these species life histories and flow conditions are needed for successful reintroduction.

Principal Investigators