Teche-Vermilion Pumping Station and Flow Discharge Regime on Bayou Teche, Louisiana

Abstract

The flow regime of Bayou Teche, a relic channel of the Mississippi River in Louisiana, has been directly and indirectly altered extensively over the past several decades in response to major flood events, to maintain irrigation practices, and to mitigate the related effects of modifications implemented on connected systems. One of these mitigation strategies was adding a pump station intended to renew flow from the Atchafalaya River to Bayou Teche, which had previously been severed due to flood protection efforts. This severance caused low flow and saltwater intrusion in Bayou Teche which became problematic for the health of this stream and diminished availability of water for agriculture. Therefore, in this paper, I reviewed hydrographic data to determine if the flow had been reestablished as intended. Data were sourced from USGS using daily mean discharge data collected from USGS gauge Bayou Teche at Keystone Lock & Damnear St. Martinville, Louisiana – (07385700). My methods include analysis of pre-control structure mean annual discharge on years 1974-1978 and post-control structure years 1984-1988. Hydrographs, linear regression modeling, and summary statistics did not reveal an increase in stream discharge at this location along Bayou Teche but did reveal significant correlative effects of the pump station in diminishing flow. I conclude that the infrastructure may not have been functioning as intended or was being offset by other factors. A simultaneous increase in water usage when the pump station was complete in anticipation of increased flow may have occurred, which counteracted the intended benefits. Precipitation rates may have contributed as well during the years of interest. My study highlights the complexity of managing interconnected water systems and how complicated efforts to predict and control hydrologic outcomes can be. Additionally, the reliance on USGS hydrographic data demonstrates the value of consistent and reliable monitoring, but also reveals gaps in understanding the entire scope of potential influences.