ARS | Publication request: Overland transport of manure-borne pathogen and indicator organisms: modeling and uncertainty assessment with the KINEROS-STWIR model

Submitted to: Federal Interagency Hydrologic Modeling Conference
Publication Type: Abstract Only
Publication Acceptance Date: March 21, 2010
Publication Date: June 19, 2010
Citation: Guber, A.K., Pachepsky, Y.A., Shelton, D.R., Goodrich, D.C., Unkrich, C.L. 2010. Overland transport of manure-borne pathogen and indicator organisms: modeling and uncertainty assessment with the KINEROS-STWIR model. [abstract]. Joint Federal Interagency Hydrologic Modeling Conference. p.360.

Technical Abstract: Runoff from manured fields is often considered as the source of microorganisms in surface water used for irrigation, recreation, and household needs. Concerns of microbial safety of this water resulted in the need in models to estimate the concentrations and total numbers of pathogen and indicator organisms leaving manured fields in overland flow during runoff events, and the ability of vegetated filter strips to reduce the transport of pathogens and indicators from the edge of fields to surface water sources. The runoff and sediment model KINEROS is applicable both at field and at plot (vegetated strip) scales and can serve as a hydrologic driver for the overland contaminant transport modeling. The objective of this work was to develop an add-on to KINEROS to simulate the overland transport of manure-borne fecal coliforms and E. coli. The add-on STWIR has been developed and successfully tested with data from simulated rainfall experiments at vegetated and bare 2x6 m plots and with data from the 3-ha field obtained after manure applications. The STWIR includes the earlier developed and tested model of bacteria release from manure as affected by rainfall intensity and vegetation. The KINEROS-STWIR model was then used in sensitivity and uncertainty analysis at both scales. At the plot scale, relatively long high-intensity rainfalls, low hydraulic conductivities, high soil moisture contents before the rainfall, and high dispersivity were the main reasons for the partial failure of vegetated filter strip. At the field scale, the substantial uncertainty was encountered due to variability up to 6 orders of magnitude in coliform concentrations in manure. Using plot scale modeling in Monte Carlo simulations of rainfall-runoff events with distributions of the environmental parameters of the rainfall runoff events can be useful for risk-informed site-specific decisions on the VFS design and placement. Similar simulations at the field scale can characterize the fine-scale uncertainty in inputs of the watershed-scale microbial water quality models that are used in regulatory practices.