Rehabilitation of 1.0 MG Clearwell Tank, Lewisville, TX

The City of Lewisville was investigating rehabilitation options for their 1.0 MG clearwell tank at the Lewisville Water Treatment Plant after inspection of the tank revealed various issues concerning the interior and exterior of the tank. This conventionally reinforced cast-in-place concrete tank is 106 feet in diameter with an 18 foot wall height and 15 feet of backfill around the exterior wall. The tank also features a flat slab roof supported by interior concrete columns.

The City contacted DN Tanks (formerly Natgun) Concrete Tank Services (CTS) to evaluate the condition of the tank and failed previous repairs. An underwater inspection confirmed leakage was occurring through cracks and joints in the concrete floor and wall. In addition, there were structural deficiencies at various column bases and pipe penetrations. The through wall inlet pipe had significant spalling and deterioration leading to concerns about the strength of the wall and water tightness as well.

CTS’s expertise in watertight tank penetrations, structural repairs, and leak mitigation was used to develop a plan to rehabilitate this tank. The plan included the application of an elastomeric waterproofing material on the interior floor, floor joints, and column bases as well as structural repair to the inlet pipe to strengthen the wall and prevent further deterioration.

In addition to the interior repairs, the concrete exterior of the tank was weathered and the existing access hatches were inoperable. CTS cleaned and restored the deteriorated concrete then applied a high performance decorative coating to seal the exposed exterior surface of the tank. New hatch curbs were designed and constructed for the installation of two new aluminum roof access hatches equipped with stainless steel hardware to increase operational lifespan and meet TCEQ requirements.

The City now enjoys a newly refurbished tank that will serve them for years to come!

Construction Highlights

  • 05/03 – CTS Mobilization
  • 06/18 – Interior Repairs Complete
  • 06/24 – Exterior Rehabilitation Complete
1.0 MG
106' diameter| 18' wall height
Lewisville, TX
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