Projects by Discipline / Water Resources Engineering

Viele Lake Dam Evaluation

Hydrosphere inspected Viele Lake Dam and made recommendations for its rehabilitation. Viele Lake is a public reservoir located in an urban, residential setting at the South Boulder Recreation Center in Boulder, Colorado. It is a former irrigation reservoir that has been enlarged and converted to recreational and aesthetic uses.

Viele Lake Dam is an earthfill, jurisdictional Class 3 small dam located on a tributary to South Boulder Creek. The possible need to more routinely release water to downstream senior water rights owners prompted a dam inspection and evaluation to 1) examine the dam's physical ability to deliver water, 2) identify prudent rehabilitation measures, and 3) determine the institutional ramifications of implementing improvements.

An inspection of the dam and communications with the Colorado State Engineer revealed that this dam had minimal safety issues due to its small drainage area and its stable, gentle downstream slope. Minor rehabilitation could be accomplished without concern that dam re-classification and the corresponding need for more extensive improvements would occur. The primary outlet control, which consists of a single downstream gate valve on a pressurized pipe, was identified as potentially problematic for routine operation and as presenting a risk of inadvertent reservoir evacuation. Hydrosphere developed a report presenting the results of the inspection and a description of rehabilitation options. The options, which were evaluated, included outlet system replacement, construction of a supplemental true siphon outlet structure, and outlet rehabilitation. Rehabilitative maintenance, consisting of addition of a guard gate and other ancillary improvements was subsequently implemented.