Application of SWAT and APEX models for Upper Maquoketa River Watershed in Northeast Iowa

Saleh, A.A.M.; Gassman, P.W.; Abraham, J. D.; Rodecap, John

doi:10.13031/2013.13766

Cited by 6 publications

(6 citation statements)

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“…Additional limited indirect testing of APEX was performed by comparing SWAT output (with nested APEX simulations) with measured data, as reported by . More in-depth testing of the combined APEX-SWAT modeling system by Saleh et al (2003) for January 1999 to December 2001 resulted in R 2 values of 0.79 and 0.74 for streamflow and nitrate, respectively, at the UMRW outlet, but weaker streamflow and nitrate R 2 statistics ranging from 0.39 to 0.51 and from 0.24 to 0.42, respectively, for the other three sampling sites ( fig. 10).…”

Section: Umrw Apex Calibration Resultsmentioning

confidence: 98%

Invited Review Article: The Agricultural Policy/Environmental eXtender (APEX) Model: An Emerging Tool for Landscape and Watershed Environmental Analyses

Gassman¹,

Williams²,

Wang³

et al. 2010

Transactions of the ASABE

147

110

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The Agricultural Policy/Environmental eXtender (APEX) model was developed by the Blackland Research and Extension Center in Temple, Texas. APEX is a flexible and dynamic tool that is capable of simulating a wide array of management practices, cropping systems, and other land uses across a broad range of agricultural landscapes, including whole farms and small watersheds. The model can be configured for novel land management strategies, such as filter strip impacts on pollutant losses from upslope crop fields, intensive rotational grazing scenarios depicting movement of cows between paddocks, vegetated grassed waterways in combination with filter strip impacts, and land application of manure removed from livestock feedlots or waste storage ponds. A description of the APEX model is provided, including an overview of all the major components in the model. Applications of the model are then reviewed, starting with livestock manure and other management scenarios performed for the National Pilot Project for Livestock and the Environment (NPP), and then continuing with feedlot, pesticide, forestry, buffer strip, conservation practice, and other management or land use scenarios performed at the plot, field, watershed, or regional scale. The application descriptions include a summary of calibration and/or validation results obtained for the different NPP assessments as well as for other APEX simulation studies. Available APEX GIS-based or Windows-based interfaces are also described, as are forthcoming improvements and additional research needs for the model.

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Section: Umrw Apex Calibration Resultsmentioning

confidence: 98%

Invited Review Article: The Agricultural Policy/Environmental eXtender (APEX) Model: An Emerging Tool for Landscape and Watershed Environmental Analyses

Gassman¹,

Williams²,

Wang³

et al. 2010

Transactions of the ASABE

147

110

View full text Add to dashboard Cite

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“…The hydrological component of the SWAT model has been previously validated for several watersheds throughout the USA (Arnold et al, 1998(Arnold et al, , 1999Saleh et al, 2000Saleh et al, , 2003 where representative data are available. To the best of author's knowledge, only few studies have been made regarding the application of physically based hydrological models to Ethiopian catchments among which are Conway (1997), Kebede et al (2006), Lijalem et al (2007), Tadele and Foerch (2007) and Gragne et al (2008).…”

Section: Introductionmentioning

confidence: 99%

Hydrological modelling of Ethiopian catchments using limited data

Mekonnen

Wörman

Dargahi

et al. 2009

Hydrological Processes

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Abstract:The hydrological component of the soil and water assessment tool (SWAT) model is adapted for two Ethiopian catchments based on primary knowledge of the coherence spectrum between rainfall and stream flow data. Spectrum analysis using the available nearby climatic data is made to limit the temporal and spatial scales (inverse rate coefficients) subject to the calibration of compartmentalized runoff models. The exclusion of unwarranted time scales in the calibration implies that the model efficiency (r 2 values) decrease only moderately between calibration and validation, and the optimization is focused on warranted problems. On the basis of the available data for the two Ethiopian catchments, the implication is that only periods longer than about 50 days can be reliably evaluated in the model. The model structure of SWAT for the surface runoff and groundwater flow response is modified to make the time scales consistent with the results of the spectrum analysis. An optimization algorithm is developed to constrain and combine the model parameters with the spectrum analysis results.

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“…The manure was applied in mid-February while the ground was still frozen prior to planting the corn, and the type of manure used was chicken litter. Even though the nutrient composition of poultry manure varies depending on several factors (such as species, feed ratio, type of litter), P content is generally high compared to cattle manure (at about 30 -50% that of nitrogen) [36] (Nicholson et al). The application of chicken litter in fields that may be considered to have nutrient rich soils can result in the overapplication of P and nutrient transport to surface water [37] (Sharpley et al).…”

Section: Soluble P In Surface Runoffmentioning

confidence: 99%

Phosphorus Modeling in Tile Drained Agricultural Systems Using APEX

Francesconi¹,

Co.²

2016

J Fertil Pestic

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Phosphorus (P) losses through tile drained systems in agricultural landscapes may be causing persistent eutrophication problems observed in surface water. The purpose of this paper is to evaluate the state of the science in the Agricultural Policy/Environmental extender (APEX) model related to surface and tile P transport. This was accomplished using data from a monitored corn-soybean rotation field in the St. Joseph River watershed, IN. The estimation of soluble phosphorus (SP) in surface runoff and tile flow in APEX includes a user defined linear (based on GLEAMS) and nonlinear (Langmuir) sorption option. The results suggest that the inclusion of the Langmuir isotherm improved (18%) SP sorption estimates in surface runoff during the corn year only when P inputs were added, whereas the linear method was more appropriate during the soybean year when no fertilizers were applied. Similarly, SP estimates in tile flow were improved (30%) when using the Langmuir option during the corn year, though the overall model performance predicting this variable were very poor. Modeling improvements of P partitioning processes in APEX can help predict more realistic outputs. Yet to achieve this in tile flow, water percolation processes need to be improved to reflect preferential flow conditions often found in long-term no-till fields and in soils with high clay content. Greater accuracy in the estimation of the effect of artificial drainage systems, common in the US Midwest, should result in the improved evaluation of agricultural conservation practices in order to examine strategies that could reduce P losses for water quality purposes.

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Application of SWAT and APEX models for Upper Maquoketa River Watershed in Northeast Iowa

Cited by 6 publications

References 0 publications

Invited Review Article: The Agricultural Policy/Environmental eXtender (APEX) Model: An Emerging Tool for Landscape and Watershed Environmental Analyses

Invited Review Article: The Agricultural Policy/Environmental eXtender (APEX) Model: An Emerging Tool for Landscape and Watershed Environmental Analyses

Hydrological modelling of Ethiopian catchments using limited data

Phosphorus Modeling in Tile Drained Agricultural Systems Using APEX

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