Relationships Between Manure Particle and E. coli Transport from Direct Fecal Deposits Under Steady-State Flows

Pathogens are the leading cause of water quality impairments as defined by the US Environmental Protection Agency and their transport within water bodies is poorly understood. Because of this, watershed-scale, water quality models often have poor bacterial prediction capabilities. To improve the understanding of in-stream bacterial transport, a cow pie was deposited in a recirculating flume with flows ranging from 0.0102 to 0.0176 m(3)s(-1). Water samples were collected and analyzed for Escherichia coli concentration, E. coli attached fraction, and turbidity. E. coli concentrations ranged from 4.72x10(3) to 1.70x 10(5)CFU100 mL(-1) and turbidity ranged from 1.93 to 369 NTU over both locations and all times. The percentage of E. coli attached to particles ranged from an average of 2.9 to 31 % downstream of the fecal deposition point. Spearman correlation analysis demonstrated that bacteria concentrations were significantly related with water depth (rho=0.128, p=0.018), and the concentration of attached bacteria was significantly correlated with both the total concentration of E. coli (rho=0.4081, p=0.009) and turbidity (rho=0.3627, p=0.0214). This analysis is useful to indicate parameters that should be considered when monitoring or predicting bacteria transport in streams.