Six communities which had a history of SSOs agreed to become Case Study partners with DWSD in an attempt to better understand the causes of and impact from SSOs occurring within the DWSD service area. The key elements of the study included: Quantification of inflow from footing drains connected to sanitary systems; assessment of the relative impact of SSO on water quality; and, evaluation of the cost effectiveness of footing drain disconnection relative to storage or transportation to the WWTP. An exhaustive review of the results of similar studies was completed in addition to extensive field measurement of footing drain flows and modeling of the collection system. TYJT participated in a footing drain flow monitoring program which involved measurement of footing drain flows from more than 15 residences in five communities. The results of the field measurements were evaluated to quantify the impact of rainfall intensity and volume, soil types and house age on the volume and rate of flow generated in footing drains. The field results and an evaluation of other similar studies were documented in a report. The results of the study were used in a SWMM model to assess the cost effectiveness of corrective measures needed to prevent future SSOs. An SSO sampling program was conducted to quantify the loading and temporal distribution of pollutants in actual SSOs occurring within the DWSD service area. Data from the sampling plan was presented in a report, along with data from other similar studies detailing the impact that SSOs have on surface water quality in Southeast Michigan.
The results of the footing drain impact assessment were presented at WEFTEC 2003 in a paper titled A Summary of Footing Drain Flow Studies: Residential Footing Drain Flows and Their Role as a Significant Cause of SSOs and Wet Weather 1/1.
Status of Project:
Project Completed 2004 |
