Andy Martin, PE

James Kerrigan, PE

Need for the project Wet weather CSOs into White River

Federal Consent Decree

LTCP to reduce the CSO volume by 83% and CSO frequency to 8/yr based on typical year rainfall

Alternative Analysis CSO Storage Basin

In line Storage using Inflatable dam

In Line Storage using Weir Wall with Orifice

CSO Storage Basin Larger footprint

Does not enable the use of existing infrastructure

Cost - $ 5.2/gal based on the EPA cost curves for open storage basins

Inflatable Dam Enables the use of existing infrastructure

Requires external power source

Requires security alarm – Inflatable Dam Installation in remote location

Requires control system and telemetry

Requires maintenance

Failure results in overflow event

Cost - $ 1.2/gal

Inflatable Dam

Weir Wall With Orifice

Weir Wall With Orifice

Weir Wall With Orifice Enables the use of existing infrastructure

It is a passive device

Doesn’t require external power source

Needs no maintenance

Cost - $ 0.8/gal

Sewer Location Map

ISD2

ISD1

Existing Condition of the Sewer

108” Relief Sewer Max Flow Depth for Storm Events

Profile of the Relief Sewer

Site Plan for Construction – ISD 1

Site Plan for Construction – ISD2

Working Model of In-Line Storage

CSO Reduction CSO volume reduced from 84 MG to 24 MG (70%)

CSO frequency reduced from 43 to 8 times per year (81%)

Questions?