Long-term freshwater inflow and sediment discharge into Lake Pontchartrain in Louisiana, USA

Abstract

Freshwater and sediment are crucial to the development and health of aquatic and wetland ecosystems in deltaic coastal regions. This study examines the long-term freshwater inflow (1940-2002) and total suspended solid loading (1978-2001), and their relationships with climate variables in three major river watersheds to Lake Pontchartrain, the largest inland estuary in the USA. The results show an average total annual freshwater inflow of 5.04 km3 and an average total annual sediment loading of 210 360 t, with the highest contributions from the Amite River watershed. Over 69% of annual inflow occurred within the six months from December to May. About 66-71% of the annual total suspended solid loading occurred within the four months from January to April. An increasing trend of annual water inflow and sediment discharge was found in the Amite River watershed over the past 60 years, coinciding with the fastest population growth in this upper Lake Pontchartrain basin. Copyright © 2007 IAHS Press.