Search results for: Keith Schilling

Items from 1 to 14 out of 14 results

article

Sediment and phosphorus contributions from eroding banks in a large intensively managed watershed in western Iowa, United States

Forrest F. Williams, Peter L. Moore, Jade V. Allen, Thomas Isenhart, more

JAWRA Journal of the American Water Resources Association > 60 > 1 > 148 - 162

In this study, a new remote sensing tool was used in conjunction with sampling of river bank sediments to map channel migration patterns and estimate the net contribution of bank erosion to the sediment and phosphorus (P) budget of the Nishnabotna River in southwestern Iowa. Between the years 2009 and 2018, we found that at least 1.81 ± 0.57 × 10⁷ Mg of sediment and 8.26 ± 2.5 × 10³ Mg of P entered...

article

Projected changes in monthly baseflow across the U.S. Midwest

Jessica R. Ayers, Gabriele Villarini, Keith Schilling, Christopher Jones

International Journal of Climatology > 41 > 12 > 5536 - 5549

Baseflow is an essential water resource because it is the groundwater discharged to streams and represents long‐term storage. Understanding its future changes is a major concern for water supply and ecosystem health. This study examines the impacts of climate and agriculture on monthly baseflow in the U.S. Midwest through the end of the 21st century. We use a statistical approach to evaluate three...

article

Changes in monthly baseflow across the U.S. Midwest

Jessica R. Ayers, Gabriele Villarini, Christopher Jones, Keith Schilling

Hydrological Processes > 33 > 5 > 748 - 758

Characterizing streamflow changes in the agricultural U.S. Midwest is critical for effective planning and management of water resources throughout the region. The objective of this study is to determine if and how baseflow has responded to land alteration and climate changes across the study area during the 50‐year study period by exploring hydrologic variations based on long‐term stream gage data...

article

Use of continuous monitoring to assess stream nitrate flux and transformation patterns

Christopher Jones, Sea-Won Kim, Keith Schilling

Environmental Monitoring and Assessment > 2017 > 189 > 1 > 1-12

Delivery of nitrogen from farmed fields to the stream network is an ongoing water quality issue in central North America and other parts of the world. Although fertilization and other farming practices have been refined to produce environmental improvements, stemming loss of nitrogen, especially in the soluble nitrate form, is a problem that has seemingly defied solution. The Iowa Nutrient Reduction...

article

Investigating Hydrologic Connectivity of a Drained Prairie Pothole Region Wetland Complex using a Fully Integrated, Physically-Based Model

Antonio Arenas Amado, Marcela Politano, Keith Schilling, Larry Weber

Wetlands > 2018 > 38 > 2 > 233-245

A fully integrated, physically-based model of a drained and farmed wetland complex in the Prairie Pothole Region of Iowa (termed Ellsworth #2) was developed to investigate hydrologic connectivity of surface and groundwater sources. The model is based on the code HydroGeoSphere, which solves surface and subsurface flow and the interaction between these domains. Physical processes governing the hydrologic...

article

Assessing the Relative Importance of Nitrogen-Retention Processes in a Large Reservoir Using Time-Series Modeling

Elizabeth Hansen, Kung-Sik Chan, Christopher S. Jones, Keith Schilling

Journal of Agricultural, Biological and Environmental Statistics > 2016 > 21 > 1 > 152-169

Nitrogen (N) removal within reservoirs can be substantial, but few studies have reported the relative importance of various N-retention pathways. Assessing N-removal processes in reservoirs is important for quantifying the impacts of reservoirs on downstream water quality. In this study, we used a time-series approach to quantify the relative importance of various N-removal processes in the Saylorville...

article

Effect of heterogeneity on spatiotemporal variations of groundwater level in a bounded unconfined aquifer

Xiuyu Liang, You-Kuan Zhang, Keith Schilling

Stochastic Environmental Research and Risk Assessment > 2016 > 30 > 1 > 1-8

Spatiotemporal variations of groundwater level due to a white noise recharge time series and a random transmissivity field in a bounded unconfined aquifer was studied. The analytical solutions for the variance and covariance of groundwater level were derived with non-stationary spectral analyses and superposition principle. It was found that the fluctuations of groundwater level are spatially non-stationary...

article

Co-Kriging Estimation of Nitrate-Nitrogen Loads in an Agricultural River

Xiuyu Liang, Keith Schilling, You-Kuan Zhang, Christopher Jones

Water Resources Management > 2016 > 30 > 5 > 1771-1784

Daily nitrate-nitrogen (NO₃-N) loads in the Raccoon River, Iowa, were estimated using Ordinary kriging (OK), Cokriging (CK), and a standard rating curve method (LOADEST) based on a dataset of 3451 measurements of NO₃-N concentration collected over 19 years. The CK estimation utilizes the temporal correlation of NO₃-N load with daily discharge and honors the measured points to improve estimation relative...

article

Reducing Fertilizer‐Nitrogen Losses from Rowcrop Landscapes: Insights and Implications from a Spatially Explicit Watershed Model

Eileen McLellan, Keith Schilling, Dale Robertson

JAWRA Journal of the American Water Resources Association > 51 > 4 > 1003 - 1019

We present conceptual and quantitative models that predict changes in fertilizer‐derived nitrogen delivery from rowcrop landscapes caused by agricultural conservation efforts implemented to reduce nutrient inputs and transport and increase nutrient retention in the landscape. To evaluate the relative importance of changes in the sources, transport, and sinks of fertilizer‐derived nitrogen across a...

article

Reducing Nitrogen Export from the Corn Belt to the Gulf of Mexico: Agricultural Strategies for Remediating Hypoxia

Eileen McLellan, Dale Robertson, Keith Schilling, Mark Tomer, more

JAWRA Journal of the American Water Resources Association > 51 > 1 > 263 - 289

SPAtially Referenced Regression on Watershed models developed for the Upper Midwest were used to help evaluate the nitrogen‐load reductions likely to be achieved by a variety of agricultural conservation practices in the Upper Mississippi‐Ohio River Basin (UMORB) and to compare these reductions to the 45% nitrogen‐load reduction proposed to remediate hypoxia in the Gulf of Mexico (GoM). Our results...

article

Relative importance of climate and land surface changes on hydrologic changes in the US Midwest since the 1930s: Implications for biofuel production

Xianli Xu, Bridget R. Scanlon, Keith Schilling, Alex Sun

Journal of Hydrology > 2013 > 497 > Complete > 110-120

The US Midwest is an important area of first generation biofuels, accounting for 80–90% of US corn and soybean production (2009–2011). However, there are potential adverse impacts of biofuel production on water resources in this area. The objective of this study was to assess potential impacts of biofuel production on water resources by exploring relationships between hydrologic changes and climate...

article

Cokriging estimation of daily suspended sediment loads

Zhongwei Li, You-Kuan Zhang, Keith Schilling, Mary Skopec

Journal of Hydrology > 2006 > 327 > 3-4 > 389-398

Daily suspended sediment loads (S) were estimated using cokriging (CK) of S with daily river discharge based on weekly, biweekly, or monthly sampled sediment data. They were also estimated with ordinary kriging (OK) and a rating curve method. The estimated daily loads were compared with the daily measured values over a nine-year-period. The results show that the estimated daily sediment loads with...

article

Temporal variations and scaling of streamflow and baseflow and their nitrate-nitrogen concentrations and loads

You-Kuan Zhang, Keith Schilling

Advances in Water Resources > 2005 > 28 > 7 > 701-710

The patterns of temporal variations of precipitation (P), streamflow (SF) and baseflow (BF) as well as their nitrate-nitrogen (nitrate) concentrations (C) and loads (L) from a long-term record (28 years) in the Raccoon River, Iowa, were analyzed using variogram and spectral analyses. The daily P is random but scaling may exist in the daily SF and BF with a possible break point in the scaling at about...

article

Baseflow contribution to nitrate-nitrogen export from a large, agricultural watershed, USA

Keith Schilling, You-Kuan Zhang

Journal of Hydrology > 2004 > 295 > 1-4 > 305-316

Nitrate-nitrogen export from the Raccoon River watershed in west-central Iowa is among the highest in the United State and contributes to impairment of downstream water quality. We examined a rare long-term record of streamflow and nitrate concentration data (1972-2000) to evaluate annual and seasonal patterns of nitrate losses in streamflow and baseflow from the Raccoon River. Combining hydrograph...

Filter options

Publication date

Last year (1)
Last 3 years (1)

Close

Date range setting

Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.

From:

To:
Set your own date range

Keywords

ASSIMILATION (2)
BASEFLOW (2)
CLIMATE (2)
COKRIGING (2)
DENITRIFICATION (2)
SAMPLING FREQUENCY (2)
WATERSHED MANAGEMENT (2)
AGRICULTURAL HYDROLOGY (1)
APPLICATION/CONTEXT (1)
BEST MANAGEMENT PRACTICES (1)
BEST MANAGEMENT PRACTICES (BMPS) (1)
BIOFUELS (1)
CENTENNIAL (1)
CHEMICAL LOADS (1)
DAILY NITRATE-NITROGEN (NO3-N) LOAD (1)
DAILY SUSPENDED SEDIMENT LOAD (1)
EFFECT OF HETEROGENEITY (1)
EROSION (1)
EUTROPHICATION (1)
GEOSPATIAL ANALYSIS (1)
HYDROGRAPH (1)
HYDROLOGIC MODEL (1)
HYDROLOGY (1)
LAND USE (1)
LAND USE/LAND COVER CHANGE (1)
MIDWEST (1)
MISSISSIPPI (1)
NITRATE NITROGEN (1)
NITRATE-NITROGEN (1)
NITRATE-NITROGEN CONCENTRATIONS AND LOADS (1)
NITRATE–NITROGEN (1)
NON-STATIONARY SPECTRAL ANALYSIS (1)
NONPOINT SOURCE POLLUTION (1)
NON‐POINT SOURCE POLLUTION (1)
NUTRIENTS (1)
PHOSPHORUS (1)
PHYSICALLY-BASED MODEL (1)
PRAIRIE POTHOLE (1)
RATING CURVE (1)
RESERVOIRS (1)
RIVERS/STREAMS (1)
SCALE (1)
SEDIMENT TRANSPORT (1)
SPATIOTEMPORAL VARIATIONS OF GROUNDWATER LEVEL (1)
STATISTICAL METHODS (1)
STREAM DISCHARGE (1)
STREAMFLOW (1)
SUBSURFACE DRAINAGE (1)
TIME-SERIES MODELING (1)
TOOLS AND METHODS (1)
VARIATION AND SCALING (1)
WATER (1)
WATER QUALITY (1)
WETLANDS (1)
more

Data set

Springer (5)
Wiley (5)
Elsevier (4)

INFONA - science communication portal

Search results for: Keith Schilling

Add recipient

Sending message cancelled

Are you sure you want to cancel sending this message?

Send message

Filter options

Publication date

Date range setting

Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.

Keywords

Data set

Journal

Reporting an error / abuse

Sending the report failed

Accessibility options