Sampling of Variable, Waste‐Migration Patterns in Ground Water^a

Abstract

A survey of waste‐migration patterns from septic‐tank/ tile‐field systems surrounding Houghton Lake, Michigan indicates that sampling plans designed to detect and quantify waste migration in ground water should be predicated on the concept that the waste plume may be complex and that the plume may not follow regional, ground‐water flow. The waste‐migration plumes at Houghton Lake range from simple, multichemical plumes that move with regional flow to complex plumes that bifurcate, that show different migration patterns for different chemicals, and that move up the regional gradient for short distances. The complexity of these patterns is attributed to a combination of the following system properties: loading rate and recharge at the waste source, local hydrology, chemical‐adsorption capacity of the soil, soil microbiology, regolith texture and fabric, and proximity to other waste sources. Based on the observed patterns, it is suggested that observation wells be placed so that an in‐depth, 3‐dimensional array of samples can be obtained. The wells should be of sufficient depth to insure that deep‐moving plumes can be detected and, if the actual, vertical‐migration pattern is of importance, the wells should allow collection of water samples at a number of depths. The waste‐migration pattern should be monitored throughout the year in anticipation of vertical movement of the plume axis during periods of surface recharge. If more than one chemical is of interest, then it is unsafe to assume that an index chemical, such as chlorides, demonstrates the migration of the other chemicals and analyses must be run for the other chemicals.

Effects of septic tank effluent on chemical quality of alluvial gravel aquifers

“…Bifurcation of flow leading to multiple contaminant plumes from a single septic tank, observed in this study, has also been described by Childs et al (1974). The authors attributed their findings to geological heterogeneity.…”

Model Parameters for Simulating Fate and Transport of On‐Site Wastewater Nutrients

“… 1 Hill and Sawhney (1981); Harman et al (1996); Nagpal (1986); Childs et al (1974); Tofflemire and Chen (1977); Fischer (1999). …”

“…Thus, we recommend the use of a linear sorption isotherm for OWS applications. Hill and Sawhney (1981); Harman et al (1996);Nagpal (1986); Childs et al (1974); Tofflemire and Chen (1977); Fischer (1999). All P sorption data were collected from studies related to wastewater sources as well as studies concerned with P sorption to soils in nonwastewater-related systems.…”

mass transport: 2. Analysis of uncertainty in prediction

“…For the case shown here, heterogeneities in the immediate vicinity of the input zone lead to bifurcation. Bifurcation of contaminant plumes has been reported in several detailed field studies [Childs et al, 1974;$udicky, 1979;Rea and Upchurch, 1980]. Although observed less frequently, single plumes did form in some realizations.…”