|
Lake Townsend Dam and Spillway Replacement Project
Read more! Project featured in The Journal of Dam Safety, Volume 8
History
Lake Townsend Dam, Spillway and Water Treatment Plant were constructed in the 1960s. Lake Townsend is the largest of the City's municipal reservoirs, at 1,542 acres. Popular for such recreational uses as boating and fishing, this reservoir has the capacity to supply 30 million gallons of water per day (mgd).
Project Scope
Lake Townsend Dam consists of a gated concrete spillway, raw water intake structure, and pump station. In 1980, the dam’s concrete structure began to exhibit signs of distress due to the effects of Alkali-Silica Reactivity (ASR). View samples of Alkali-Silica Reactivity on the dam.
This process takes place when chemical reactions occur between certain minerals in the concrete. As the property of the concrete changes, an expandable gel is formed. Combined with moisture, this gel severely damages the concrete and over time threatens the stability of the structure. ASR is only associated with early concrete manufacturing. Today’s concrete mixes use protective measures to prevent this problem from occurring.
In January 2007, temporary repairs to provide structural support began on Lake Townsend Dam and Spillway due to the severe concrete deterioration. After careful consideration, it was determined that replacement and expansion of the spillway was necessary to ensure dam stability and compliance with new regulations.
To avoid any interruption in the City’s potable water supply, replacement of the raw water intake and pump station took place first and was completed in June 2009. Crowder Construction has begun construction on the new spillway and is expected to be completed by fall 2011. View project map. The entire project is estimated to cost about $34 million. View new construction photos of the dam and spillway. Past Construction Photos |