Assessing the Effectiveness of Alternative Tile Intakes on Agricultural Hillslopes

Autor: Christopher G. Wilson, Matthew T. Streeter, William D. Ettema, Benjamin K. B. Abban, Adrian Gonzalez, Keith E. Schilling, Athanasios N. Papanicolaou
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Water, Vol 16, Iss 2, p 309 (2024)
Druh dokumentu: article
ISSN: 2073-4441
DOI: 10.3390/w16020309
Popis: Existing surface inlets behind terraces and water and sediment control basins (WASCoBs) were replaced with alternative tile intakes (ATIs) in agricultural fields of southeast Iowa. These ATIs consisted of a buried column of gravel atop woodchips. Computational, experimental, and field methods were used to design and evaluate the ATIs’ capacity to reduce sediment and nutrient export. Single-storm simulations using the Watershed Erosion Prediction Project (WEPP) provided boundary conditions for permeameter experiments that yielded a hydraulic conductivity for the layered gravel–woodchip configuration of 4.59 cm/s ± 0.36 cm/s. Additionally, a proportional amount of sediment was retained in the permeameter (42%) compared to the amount that settled on the permeameter surface (58%). Event monitoring of field-installed ATIs during three growing seasons measured a sediment trapping efficiency of 86 ± 12% that led to deposition rates of 5.44 ± 3.77 cm/yr, quantified with 210Pb profiles. Percent reduction values were 43% for nitrate and 17% for ortho-phosphate. Finally, long-term continuous-storm modeling using the WEPP suggested that these ATIs could withstand at least 75 25-year events before clogging. Modeling using the Agricultural Conservation Planning Framework suggested watershed-scale load reductions of 1.6% for NO3 and 1.4% for total P for ATIs draining 6.8% of the modeled watershed. Using ATIs in conjunction with WASCOBs and terraces, or as standalone practices, can be a cost-effective means for keeping sediment and nutrients in the landscape.
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