Minnequa Reservoir

Customer Need

Minnequa Reservoir, located in Florence, Colorado, USA, had a storage shortage on its hands. The original clay lining system that was installed during the 1970’s failed, and Minnequa Reservoir was not able to take full advantage of its storage capacity. The City of Florence worked with a local engineer and Lange Containment Systems, Inc. to design a liner system that would stand the test of time.

Containment Solution

LCSI began fabricating a 142,500 square feet double-lined liner system. Hypalon/CSPE (60 mil) was selected as the primary membrane liner because of its quality performance record. Gecomposite clay liner (GCL) was also selected as a secondary liner material.

To minimize material waste, LCSI custom-fabricated 20 panels of varying dimensions. The GCL was installed first, quickly followed by panel after panel of 60 mil Hypalon/CSPE. LCSI’s installation crew was careful to efficiently install precise amounts of the GCL and then cover with panels of Hypalon/CSPE to insure the bentonite within the GCL was not activated by possible moisture.

The project was complicated by a unique design feature at the Minnequa Reservoir--a bench dug half way up the slope and around the entire perimeter of the reservoir to hold rip-rap on the upper half of the slopes. To overcome this challenge and protect against possible damage from rip-rap placement, LCSI installed geocomposite material over the rip-rap bench area of the pond to act as a sacrificial layer for the liner.

LCSI completed the liner system and all seam testing on schedule despite inclement weather conditions. Minnequa Reservoir is back in service and is performing as expected. The City of Florence is very pleased with the final product and the timely manner in which it was completed.

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