THE ROLE OF THE STREAMBED IN RIVERBANK FILTRATION

摘要

In an effort to understand the removal characteristics of the Great Miami River's (GMR) streambed, the Greater Cincinnati Water Works completed a cooperative Flowpath Study with the United States Geological Survey and Miami University in Oxford, Ohio. Twelve monitoring wells were drilled adjacent to the river along two ground-water flowpaths between the river and production wells. Two of those wells were drilled from the top of the riverbank at a 20 to 30 degree angle from horizontal. These wells were termed inclined wells. These two inclined wells allowed the study team to collect samples approximately 5 to 10 feet directly below the streambed. Associated surrogates (aerobic spores, particle counts, algae, and turbidity) were collected from the inclined wells and used to evaluate the streambed's ability to reduce potential biological contaminants. Giardia and Cryptosporidium were both detected in the river but were never detected in the inclined well. Throughout the study, the streambed demonstrated a range of reductions from 0.5 log to 4 log in the measured parameters. In this riverbank filtration system, the streambed is a significant barrier against infiltration of contaminants.