Water-supply managers need adequate warning to protect water supplies if a contaminant is spilled in an upgradient tributary. The city of Lincoln draws water from alluvium associated with the Platte River near Ashland, eastern Nebraska. Using constant-rate injection methods and a conservative tracer, travel time and degree of mixing of contaminants in the Elkhorn and Platte Rivers were evaluated in 1995 and 1996. The results indicate that, for flows of 584 to 162 m 3

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (µS/cm at 25°C). Turbidity units are given in Formazin Nephelometric Units (FNU).

No abstract

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

BACKGROUND The Management Systems Evaluation Area (MSEA) program is part of a multi-scale, interagency initiative to evaluate the effects of agricultural management (farming) systems-including such practices as irrigation, crop rotation, tillage, intercropping, and application of fertilizers and pesticides-on water quality.