DeRuyter Reservoir Outfall Abandonment

DeRuyter, NY

DeRuyter Reservoir Outfall Abandonment

The Job

The DeRuyter Reservoir, in DeRuyter, New York, is a 557 reservoir originally developed as part of the Erie Canal system.

As part of a dam upgrade project, the three parallel 22″ diameter, 300LF outfall pipes needed to be abandoned, along with a stone box culvert downstream of the valve chamber the pipes terminated into.

The Challenge

Each of the three pipes had been previously blindly flanged by divers. Therefore, the only access was from the downstream end within the valve chamber. In order to vent the air displaced by the abandonment grout, vent or placement points needed to be installed just behind the upstream blind flanges, which were approximately 40′ below the water surface.

The Solution

CJGeo worked with the general contractor to design an internal venting system utilizing sacrificial placement pipes installed from the valve chamber. After each of the sacrificial grout pipes was installed, the downstream terminations were bulkheaded, with vent stubs.

CJGeo mobilized a cellular grouting crew, who placed 30lb/cuft cellular concrete through each of the sacrificial grout pipes, until grout returned to the bulkhead vents, confirming fill. The work was completed over two days an onsite-the first day for the abandonment pipes and first lift in the box culvert, and the second day for a top-off pour on the box culvert.

8″ Toe Drain Abandonment

The Job

Lake Whetstone is an approximately 30-acre manmade impoundment located in Montgomery Village, Maryland. It is utilized for stormwater runoff control, and also recreation, with an approximately 1000LF earthen dam.

As part of a retrofit program of the embankment, two 8″, perforated CMP toe drain pipes need to be grouted for a minimum of 100LF, underactive flow.

The Challenge

Each of the two, 100′ long pipes needed to be grouted full, but could only be accessed from the downstream end of the pipes. One pipe had nominal flow, and the second pipe had approximately 10GPM and discharged through an end wall structure at the stilling basin.

The Solution

The project designer, Gannett Fleming, specified NSF Section 61 certified grout (potable water contact) for the abandonment grout. Due to the “one-shot” nature of the project, above-ground mockups, including sacrificial pipe installation, chemical grout cup testing, yield analysis, and visual inspection, were all required prior to the start of grouting.

CJGeo performed the onsite mockup testing and analysis, and then grouted the two pipes in place successfully over a period of two days onsite.

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