Balancing lake ecological condition and agriculture irrigation needs in the Mississippi Alluvial Valley

Agriculture, Ecosystems and Environment
By: , and 

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Abstract

The Mississippi Alluvial Valley includes hundreds of floodplain lakes that support unique fish assemblages and high biodiversity. Irrigation practices in the valley have lowered the water table, increasing the cost of pumping water, and necessitating the use of floodplain lakes as a source of water for irrigation. This development has prompted the need to regulate water withdrawals to protect aquatic resources, but it is unknown how much water can be withdrawn from lakes before ecological integrity is compromised. To estimate withdrawal limits, we examined descriptors of lake water quality (i.e., total nitrogen, total phosphorus, turbidity, Secchi visibility, chlorophyll-a) and fish assemblages (species richness, diversity, composition) relative to maximum depth in 59 floodplain lakes. Change-point regression analysis was applied to identify critical depths at which the relationships between depth and lake descriptors exhibited a rapid shift in slope, suggesting possible thresholds. All our water quality and fish assemblage descriptors showed rapid changes relative to depth near 1.2–2.0 m maximum depth. This threshold span may help inform regulatory decisions about water withdrawal limits. Alternatives to explain the triggers of the observed threshold span are considered.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Balancing lake ecological condition and agriculture irrigation needs in the Mississippi Alluvial Valley
Series title Agriculture, Ecosystems and Environment
DOI 10.1016/j.agee.2017.06.022
Volume 246
Year Published 2017
Language English
Publisher Elsevier
Contributing office(s) Coop Res Unit Atlanta
Description 7 p.
First page 354
Last page 360
Country United States
State Arkansas, Mississippi