Výsledky vyhledávání - "Robert D Libra"

Contrasting NO3-N concentration patterns at two karst springs in Iowa (USA): insights on aquifer nitrogen storage and delivery

Autor: Ryan J. Clark, Xiuyu Liang, Robert D. Libra, Keith E. Schilling, You-Kuan Zhang, Christopher S. Jones

Publikováno v: Hydrogeology Journal. 27:1389-1400

Evaluating the patterns of NO3-N concentrations at karst springs can be used to infer hydrologic processes and nutrient dynamics in karst aquifers. In this study, NO3-N concentrations observed at two karst springs in northeast Iowa (USA) were evaluat

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::ceed76f08b12dbaa1d9ecbf2d2bcbdca
https://doi.org/10.1007/s10040-019-01935-y

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Estimating groundwater age in the Cambrian–Ordovician aquifer in Iowa: implications for biofuel production and other water uses

Autor: Keith E. Schilling, Robert D. Libra, Peter J. Jacobson, David W. Peate, J. Michael Gannon, Richard J. Langel

Publikováno v: Environmental Earth Sciences. 76

Deep confined water from the Cambrian–Ordovician (C–O) aquifer is being increasingly used for ethanol production in Iowa. In this study, we used isotopic age dating to estimate the age of groundwater in the aquifer and assess how groundwater use

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::0e2f34562fe28c086f5482d3cfed1443
https://doi.org/10.1007/s12665-016-6321-y

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INCREASED BASEFLOW IN IOWA OVER THE SECOND HALF OF THE 20TH CENTURY

Autor: Robert D. Libra, Keith E. Schilling

Publikováno v: Journal of the American Water Resources Association. 39:851-860

Historical trends in annual discharge characteristics were evaluated for 11 gauging stations located throughout Iowa. Discharge records from nine eight-digit hydrologic unit code (HUC-8) watersheds were examined for the period 1940 to 2000, whereas d

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::f4bc3dcf72d4345cedaad0bdffac48a9
https://doi.org/10.1111/j.1752-1688.2003.tb04410.x

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Results from the Big Spring basin water quality monitoring and demonstration projects, Iowa, USA

Autor: Huaibao Liu, Robert D. Libra, R. D. Rowden

Publikováno v: Hydrogeology Journal. 9:487-497

Agricultural practices, hydrology, and water quality of the 267-km2 Big Spring groundwater drainage basin in Clayton County, Iowa, have been monitored since 1981. Land use is agricultural; nitrate-nitrogen (-N) and herbicides are the resulting contam

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::f7a66ef328cd9cff4f40ca02d7827cdc
https://doi.org/10.1007/s100400100150

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The Relationship of Nitrate Concentrations in Streams to Row Crop Land Use in Iowa

Autor: Keith E. Schilling, Robert D. Libra

Publikováno v: Journal of Environmental Quality. 29:1846-1851

The relationship between row crop land use and nitrate N concentrations in surface water was evaluated for 15 Iowa watersheds ranging from 1002 to 2774 km 2 and 10 smaller watersheds ranging from 47 to 775 km 2 for the period 1996 to 1998. The percen

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::f3dbc0331b0c0c1614887e750a8cd961
https://doi.org/10.2134/jeq2000.00472425002900060016x

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DETECTING CILANGES IN THE SPATIAL DISTRIBUTION OF NITRATE CONTAMINATION IN GROUND WATER

Autor: Robert D. Libra, Zhi-Jun Liu, Dale L. Zimmerman, George R. Hallberg

Publikováno v: Journal of the American Water Resources Association. 33:1209-1218

Many studies of ground water pollution in general and nitrate contamination in particular have often relied on a one-time investigation, tracking of individual wells, or aggregate summaries. Studies of changes in spatial distribution of contaminants

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::2be66f57da676d1dd9a8ce088e627c6a
https://doi.org/10.1111/j.1752-1688.1997.tb03547.x

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Simulation Of Spring Discharge From A Limestone Aquifer In Iowa, USA

Autor: Huaibai Liu, R. D. Rowden, You-Kuan Zhang, Robert D. Libra, Er-Wei Bai

Publikováno v: Hydrogeology Journal. 4:41-54

A lumped-parameter model and least-squares method were used to simulate temporal variations of discharge from Big Spring, Iowa, USA, from 1983 to 1994. The simulated discharge rates poorly match the observed one when precipitation is taken as the sol

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::9da462fe4eaf359fc7d11c9453654ec6
https://doi.org/10.1007/s100400050087

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