Dynamics of Nitrate, Phosphorus, and Suspended Sediment Transport in Two Agricultural Streams in Central Illinois

Lampo, Luke

doi:10.30707/etd2017.lampo.l

Cited by 2 publications

(1 citation statement)

References 11 publications

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“…Two 24 bottle ISCO auto samplers were used to sample storm events. One ISCO was permanently in place at WS1 and was triggered when stream turbidity measured by a DTS-12 digital turbidity sensor rose above or fell below certain threshold values (Lampo, 2017). Select storm events at WS1.5 or WS1.25 were sampled with the second transportable ISCO auto sampler that was set to collect a sample every 2, 2.5, 3, or 3.5 hours depending on forecasted weather.…”

Section: Storm Event Samplingmentioning

confidence: 99%

Chloride Signature And Transport In An Urban-Agricultural Watershed

Oberhelman¹

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Manual and high-frequency observations (n = 525) of chloride (Cl-), bromide (Br-), nitrate (NO3-N), sodium (Na +), calcium (Ca 2+), and potassium (K +) in stream and tile-drain waters were conducted in an urban-agricultural watershed (10% urban/impervious, 87% agriculture) to investigate the importance of stormflow to Cltransport and to explore potential differences in the signature of Cloriginating from an urban source as compared to an agricultural source. The study was undertaken in Evergreen Lake Watershed (ELW) located in central Illinois. Samples were collected on a weekly interval from February 2018 to February 2019 at three station along Six Mile Creek (SMC), the main drainage of ELW. All storm events were sampled at high-frequency at the most downstream station while select storm events were sampled at an upstream station to compare how export changes along the stream. Mann-Whitney U test show ratios of Clto Br-(p = 0.045), NO3-N (p < 0.0001), Ca 2+ (p < 0.0001), and Na + (p < 0.0001) to be statistically significantly different between urban and agricultural waters. Clratios indicate that road salt is the dominant source of Clin ELW while KCl fertilizer is a secondary source. Total Clexport during the study period was 7.77x10 5 kg. Storm events are vital to Clexport in ELW, accounting for 57.5% of total Clload during only 19% of the study period. The importance of storm events varies seasonally with winter and spring storms accounting for nearly half of total Clexport, while summer and fall storm event account for only 10% of total export. Results imply two periods of Clflushing in ELW. The first is associated with flushing of road salt from impervious surfaces following the cold season and second is associated with flushing salt build up after the dry season. When road salt is present on watershed surfaces increased discharge always corresponds with increased Clexport. During storm events when road salt is not present on watershed surfaces increased in discharge corresponds with increased Clexport for lower discharges (Q < 4 m 3 /s). At higher discharges the relationship between discharge and Clexport reaches an asymptote (~ 0.2 Kg/s) where further increases in discharge do not correspond with increased Clexport. Overall, urban, tile, and stream waters exhibit some degree of salinization in ELW with respect to Clas almost all sample concentrations were elevated above calculated background threshold concentration of 18 mg/l. These results highlight the dramatic influence that deicing operations on only a small portion of a watershed can have on the Cldynamics of the entire system. Road salt appears to be able to salinize the dominantly agricultural ELW raising Clconcentrations to levels hazardous to ecosystems and water supplies (>100 mg/l), although the exact extent of salinization in ELW remains unknown and is likely confined to surface and ground water in areas where deicing operations occur and that receive road salt runoff. Fertilizer inputs should also not be ignored as this work and others show th...

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Section: Storm Event Samplingmentioning

confidence: 99%

Chloride Signature And Transport In An Urban-Agricultural Watershed

Oberhelman¹

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Chloride source delineation in an urban‐agricultural watershed: Deicing agents versus agricultural contributions

Oberhelman

Peterson

2020

Hydrological Processes

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Analyses (n = 525) of chloride (Cl−), bromide (Br−), nitrate as nitrogen (NO3‐N), sodium (Na+), calcium (Ca2+) and potassium (K+) in stream water, tile‐drain water and groundwater were conducted in an urban‐agricultural watershed (10% urban/impervious, 87% agriculture) to explore potential differences in the signature of Cl− originating from an urban source as compared with an agricultural source. Only during winter recharge events did measured Cl− concentrations exceed the 230 mg/L chronic threshold. At base flow, nearly all surface water and tile water samples had Cl− concentrations above the calculated background threshold of 18 mg/L. Mann–Whitney U tests revealed ratios of Cl− to Br− (p = .045), to NO3‐N (p < .0001), to Ca2+ (p < .0001), and to Na+ (p < .0001) to be significantly different between urban and agricultural waters. While Cl− ratios indicate that road salt was the dominant source of Cl− in the watershed, potassium chloride fertilizer contributed as an important secondary source. Deicing in watersheds where urban land use is minimal had a profound impact on Cl− dynamics; however, agricultural practices contributed Cl− year‐round, elevating stream base flow Cl− concentrations above the background level.

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Dynamics of Nitrate, Phosphorus, and Suspended Sediment Transport in Two Agricultural Streams in Central Illinois

Cited by 2 publications

References 11 publications

Chloride Signature And Transport In An Urban-Agricultural Watershed

Chloride Signature And Transport In An Urban-Agricultural Watershed

Chloride source delineation in an urban‐agricultural watershed: Deicing agents versus agricultural contributions

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