The Papillion Creek Watershed in Nebraska and the Arkansas River system in Kansas share many similar qualities. Both systems include cities that are roughly equivalent in size-Omaha, Nebraska and Wichita, Kansas. Both have a similar mix of urban and agricultural land use, and both share a similar topography. Both fecal coliform bacteria (FCB) studies used statistical modeling, trend line analyses, mass loading analyses and fate-transport dynamic modeling. Specific examples and findings are compared and discussed.While both studies shared similarities, the Wichita water quality study is unique in that, in addition to water column grab sample data, it includes sediment sampling data, Antibiotic Resistance Analyses (ARA), and dry weather and wet weather hydrographic sampling at fourhour intervals; the latter of which provided actual fate-transport patterns.Technical findings from the Wichita data add valuable insights about the potential longevity of fecal coliform bacteria. It has been widely believed that outside of the host organism, FCB will typically survive for 24 to 48 hours. Testing results from the Wichita study showed that FCB persist for extended periods of time in sediment, including relatively cold-water conditions. Hydrographic sampling during dry weather, non-runoff conditions uncovered a distinct diurnal pattern that was highly suggestive of sediment as being a significant source of FCB.Technical findings to date from water quality modeling for FCB for both studies suggest:• FCB levels are highly dependent on runoff events and sediment transport mechanisms.• FCB levels are well above surface water quality standards for "summer season" primary contact recreation. • Urbanized areas contribute approximately another order of magnitude above already high non-urban contributions of FCB under median weather conditions. • It is possible that background FCB levels from wildlife alone may be higher than standards currently allow.• Comprehensive best management practices will be required to control sediment, bacteria, and nutrients. • Regulatory compliance for FCB will be difficult. KEYWORDSFecal coliform bacteria, water quality modeling, WASP, MIKE11, watershed impairment.

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The Papillion Creek Watershed (Watershed) consists of 402 square miles of drainage area with urban and rural land uses that spans three counties in eastern Nebraska. Numerous stream and reservoir impairments exist within the Watershed that impact primary contact recreation, aesthetics, fisheries, and overall water quality. Water quality modeling of fecal coliform (FC) bacteria was conducted to determine the extent of FC pollution and to determine recommended Best Management Practices (BMPs) that would control concentrations of FC bacteria. Statistical and dynamic water quality modeling were used in this effort.The City of Omaha maintains a large network of water quality sampling sites within the Watershed. For each site, a standard set of statistical correlations were made for FC dependencies on flow, precipitation, and turbidity, which provided clues as to the pollution sources. FC mass loading probability curves were also developed that compared the maximum permissible levels of FC to values actually measured.Fate-transport dynamic modeling for FC bacteria concentrations within the mainstem stream segments was accomplished using non-proprietary WASP software. FC loadings were indexed to the various land uses within the Watershed. Basic hydraulic parameters for both 2002 baseline and future growth conditions were used to develop the bacterial fate and transport mechanisms.Technical findings from water quality modeling for FC bacteria to date suggest:• FC bacteria levels are highly dependent on runoff events and sediment transport mechanisms.• FC levels are well above surface water quality standards for "summer season" primary contact recreation. • Urbanized areas contribute another order of magnitude above non-urban contributions of FC bacteria under median conditions. • It is possible that background FC levels from wildlife alone may be higher than standards currently allow. • Comprehensive BMPs will be required to control sediment, bacteria, and nutrients. • Regulatory compliance for FC will be difficult. KEYWORDSFecal coliform bacteria, water quality modeling, WASP, watershed impairment.