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Forecasting changes in water quality in rivers associated with growing biofuels in the Arkansas-White-Red river drainage, USA

Excess nutrients from agriculture in the Mississippi River drainage, USA have degraded water quality in
freshwaters and contributed to anoxic conditions in downstream estuaries. Consequently, water quality is a
significant concern associated with conversion of lands to bioenergy production. This study focused on the
Arkansas-White-Red river basin (AWR), one of five major river basins draining to the Mississippi River. The
AWR has a strong precipitation gradient from east to west, and advanced cellulosic feedstocks are projected to
become economically feasible within normal-to-wet areas of the region. In this study, we used large-scale
watershed modeling to identify areas along this precipitation gradient with potential for improving water
quality. We compared simulated water quality in rivers draining projected future landscapes with and without
cellulosic bioenergy for two future years, 2022 and 2030 with an assumed farmgate price of $50 per dry ton.
Changes in simulated water quantity and quality under future bioenergy scenarios varied among subbasins and
years. Median water yield, nutrient loadings, and sediment yield decreased by 2030. Median concentrations of
nutrients also decreased, but suspended sediment, which is influenced by decreased flow and in-stream processes,
increased. Spatially, decreased loadings prevailed in the transitional ecotone between 97° and 100° longitude,
where switchgrass, Panicum virgatum L., is projected to compete against alternative crops and land uses at
$50 per dry ton. We conclude that this region contains areas that hold promise for sustainable bioenergy production
in terms of both economic feasibility and water quality protection.

Author
Henriette I. Jager , Latha M. Baskaran   , Peter E. Schweizer   , Anthony F. Turhollow   , Craig C. Brandt  , Raghavan Srinivasan
DOI
10.1111/gcbb.12169 
Publication Year
Bioenergy Category
Project Title
Forecasting Water Quality and Biodiversity
WBS Project Number
4.2.1.40
Contact Person
Henriette I. Jager
Contact Organization
ORNL
Phone
Email
jagerhi@ornl.gov
Funded from the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Bioenergy Technologies Office.