Water Inflows in Gravity Dam Construction Joint

Case description

The Nipawin Hydroelectric Station was constructed in the early 1980’s on the Saskatchewan River. Since that time, SaskPower has experienced problems with significant water inflows entering the headworks drainage gallery through various construction joints.


Peter White’s specialized engineering services were retained to assess the existing site conditions and prepare technical recommendations for resolving these water inflow problems by chemical grouting.

Small diameter core holes were strategically drilled to a depth of several meters to intercept leaking construction joints for investigation, consisting of locating water inflows, measuring flow rates and observing connections between adjacent core holes. Additional holes were drilled as necessary to provide a suitable spacing between adjacent holes prior to the start of chemical grouting operations.

Working during winter when the construction joints were open, the grouting contractor’s personnel, under Peter White’s direction, used water-activated polyurethane grout to systematically reduce and cut-off the major inflows of cold water.

Grouting contractor’s crews successfully completed water control work at various construction joints and reduced the volume of water entering the Nipawin Hydroelectric Station headworks drainage gallery.

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