PARTICLE-TRACKING ANALYSIS OF FLOW PATHS AND TRAVELTIMES FROM HYPOTHETICAL SPILL SITES WITHIN THE CAPTURE AREA OF A WELLFIELD

Velocity fields computed from simulated flows from a steady–state, three–dimensional numerical model of a glacialdrift/carbonate–bedrock aquifer system were used in conjunction with a particle–tracking program to delineate traveltimerelated capture areas of a municipal wellfield and to compute flow paths and advective traveltimes from hypothetical spill sites located along interstate highways and heavily traveled State routes. Results indicate the municipal wells operated by the City of Columbus, Ohio, capture flow from certain highway segments but other discharge points, including quarrydewatering systems, the Scioto River, and Big Walnut Creek, capture flow from other highway segments. Advective traveltimes from three hypothetical spill sites to the municipal wells range from 900 to 5,100 days under normal pumping rates and from 450 to 3,100 days under estimated maximum pumping rates. The 2,000–day capture area of the wellfield is approximately 30 percent larger (16 square miles) and contains approximately 4.5 more miles of highway under estimated maximum pumping rates compared to normal pumping rates. Copyright © 1990, Wiley Blackwell. All rights reserved