Water Quality Characteristics of Tailwater Recovery Systems Associated with Agriculture Production in the Mid-Southern US

Authors: ISEYEMI, OLUWAYINKA - Arkansas State University; Reba, Michele; HAAS, LEEVI - Arkansas State University; LEONARD, ETHAN - Arkansas State University; FARRIS, JERRY - Arkansas State University

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/29/2021
Publication Date: 2/15/2021
Citation: Iseyemi, O., Reba, M.L., Haas, L., Leonard, E., Farris, J.L. 2021. Water Quality Characteristics of Tailwater Recovery Systems Associated with Agriculture Production in the Mid-Southern US. Agricultural Water Management. 249. https://doi.org/10.1016/j.agwat.2021.106775.
DOI: https://doi.org/10.1016/j.agwat.2021.106775

Interpretive Summary: Tailwater recovery (TWR) systems are on-farm storage reservoirs that are constructed to supplement depleting groundwater sources. Water is stored in the reservoirs and used later in the season to irrigate crops. These systems have the potential to influence agricultural water quality in the region. Three TWR systems were selected to improve our understanding of how excess nutrients and sediment are influenced by location and design. Reservoir levee protection reduced sediment and some nutrient values in the systems. Water quality parameters measured in storage reservoirs were consistently lower than those measured from influent and effluent of the TWR systems. The findings from this study will influence water resources water quality modeling and planning in the Lower Mississippi River Basin.

Technical Abstract: In the Mississippi Delta, tailwater recovery (TWR) systems are water conservation practices implemented to mitigate downstream nutrient losses and alleviate groundwater depletion as supplemental irrigation sources. This study was conducted to characterize water quality within TWR systems and assess the influence of precipitation and fertilizer application events, as well as reservoir levee protection, on water quality. Three TWR systems were selected, and water samples were collected during the growing seasons of 2014-2016. Nitrate (NO3) and dissolved inorganic orthophosphate (DIP) were observed to be significantly lower (P< 0.001) in reservoirs when compared with TWR influent and effluent; hence, reservoirs demonstrate a vital role in reducing downstream nutrient contribution. Mean NO3 in the reservoirs, TWR influent, and TWR effluent was 0.05 ± 0.01 mg L- 1, 0.10 ± 0.01 mg L- 1, and 0.14± 0.02 mg L- 1, respectively. Mean DIP concentrations in the reservoirs, TWR influent, and TWR effluent was 0.39 ± 0.03 mg L- 1, 0.96 ± 0.04 mg L- 1, and 1.03 ± 0.08 mg L- 1, respectively. Mean NO3 concentration was also significantly lower (p= 0.001) in the reservoir with levees protected with vegetation (0.02 ± 0.01 mg L- 1) compared to (0.06 ± 0.01 mg L- 1) reservoirs with levees protected with concrete rubble. Total suspended solids (TSS) of the influent and reservoir were significantly different, with the reservoir TSS reduced on average by 43% compared to the influent. Water quality was influenced by reservoir levee protection materials, especially NO3 and dissolved oxygen concentrations which were lower with vegetated protection.