FATE AND TRANSPORT OF MANURE-BORNE PATHOGENIC MICROORGANISMS
Title: STWIR, a microorganism transport with infiltration and runoff add-on module for the KINEROS2 runoff and erosion model: documentation and user manual
Submitted to: United States Department of Agriculture Technical Bulletin
Publication Type: Other
Publication Acceptance Date: December 14, 2010
Publication Date: December 28, 2010
Citation: Guber, A.K., Pachepsky, Y.A., Yakirevich, A., Shelton, D.R., Sadeghi, A.M., Goodrich, D.C., Unkrich, C.L. 2010. STWIR, a microorganism transport with infiltration and runoff add-on module for the KINEROS2 runoff and erosion model: documentation and user manual. United States Department of Agriculture Technical Bulletin.
Interpretive Summary: Modeling water flow and pollutant transport in soils is an essential component of pollution risk assessment and management practice selection. We developed an add-on module for the surface flow model KINEROS2 to simulate surface transport of sediment and manure-born microorganism within a short rainfall-runoff event. The STWIR (Simulator of Transport With Infiltration and Runoff) module permits the integration of different physical and biological processes into one module that improves overall model prediction accuracy. The following processes are included in the simulation: (a) microorganism release from surface applied manure; (b) influx of microorganisms from irrigation water; (c) advective-dispersive transport of microorganisms with runoff water; (d) infiltration of microorganisms into the soil; (e) straining of microorganisms from the infiltrating water by plant litter and vegetation layer; (f) exchange of microorganisms between runoff water and the mixing zone of soil at the surface; (g) attachment and detachment of microorganisms at the solid phase; and (h) microorganism die-off in manure, runoff water, soil mixing zone and soil solid phase. The STWIR module and the KINEROS2 code modifications are described in this manual. These results are important for design, evaluation and implementation of conservation and best management practices nationwide. This work addresses the most important mechanisms and processes of pollutant transport affecting quality of surface water.
Runoff from manured fields is often considered to be the source of microorganisms in the surface water used for irrigation, recreation, and household needs. Concerns about microbial safety of this water resulted in development of predictive models for estimating the concentrations and total numbers of pathogen and indicator organisms leaving manure fertilized fields in overland flow during runoff events. The KINEROS2 surface flow model (Woolhiser et al., 1990; Semmens et al., 2008; www.tucson.ars.ag.gov/kineros) was developed to simulate event based runoff from small agricultural and urban watersheds. The purpose of this technical bulletin is to describe the STWIR (Simulator of Transport With Infiltration and Runoff) microorganism routing add-on module for KINEROS2. Surface runoff transport of soil and manure-born microorganisms are computed based on advection-dispersion equations (module STWIR) coupled with the kinematic wave equation (module KINEROS2). The model and the necessary modifications of the KINEROS2 code are presented.