ELOHA Atchafalaya

The Ecological Limits of Hydrologic Alteration (ELOHA; Poff et al. 2009) is designed to guide the water resource community through analyzing and monitoring the hydrologic response of a river to flow alterations. The Atchafalaya River Basin (ARB) in Louisiana provides a unique environment to test the appropriateness of the ELOHA framework when applied to a long-term floodplain enhancement project.  Since 2005, Louisiana State University has collected water quality, habitat observations for a Corp of Engineers (USACE) restoration project in Buffalo Cove Water Management Unit. As part of this project, several water input elements were constructed within the Unit to alter water circulation and improve water quality.  Using ELOHA, we calculated baseline and developed hydrograph statistics at multiple Areas of Influence (AOI) delineated for each of the flow alteration elements. We then related the differences between the baseline and developed hydrograph for each AOI to the restoration alterations and tested whether ecological parameters such as dissolved oxygen and temperature were impacted.  We argue that the ELOHA framework, while primarily recommended for developing regional instream flow standards, can also be a powerful framework to guide quantitative analysis of the outcomes of floodplain restoration projects when flow alteration is a primary objective.