La Crosse Airport Taxiway Expansion
Dredging Engineering Support Services
Wisconsin’s La Crosse Municipal Airport (LSE) is bordered by the Mississippi River, Black River and Lake Onalaska. Abutting the airfield, Lake Onalaska and its wetlands provide high-value habitat to many species of fish and a flyway stopover for vast numbers of waterfowl.
Due to safety concerns associated with the need for aircraft to cross the primary runway during taxing operations, in the 1990’s the Federal Aviation Administration (FAA) issued a recommendation that the airport construct a full parallel taxiway (F) along the west side of the field. To extend Taxiway F, however, an 8-acre section of Lake Onalaska would need to be filled. To allow for the engineered fill of the extension, removal of poor-quality overburden material, generally silts, would be required by dredging. Once mitigation plans were approved by environmental agencies to account for habitat loss, the Airport received the go-ahead for its Taxiway F expansion project.
Under contract to MACTEC Engineering and Consulting, Lally served as principal engineer for the Taxiway F dredging and dredged material management project. Lally’s responsibilities included determining the optimal dredging and disposal approach, providing guidance on geotechnical analysis and treatability studies, development of contract plans and specifications, permitting assistance, procurement support, performance verification and construction oversight.
Project construction began in September 2009, with preparation of a three-acre geotextile tube dewatering area, followed by initiation of hydraulic dredging operations. The work progressed smoothly and was completed by a qualified and dedicated team of contractors and field engineers. The targeted 16,500 cy of the overburden silts, up to 4-ft thick, were removed accurately using a GPS-integrated electronic positioning system, pumped from the lake to the dewatering area, injected with flocculent by means of automated dosing system, then distributed via a manifold system across the geotextile tubes for dewatering and consolidation. Following confirmatory testing, decant water meeting State water quality standards was permitted to be discharged back to Lake Onalaska. The dredged solids remain on site in the containment cell for long term consolidation and beneficial re-use on the airport’s landscaping projects.
Services Provided
Determine Dredge and Disposal Approach
Guidance on Geotechnical Analysis and Treatability Studies
Develop Dredging Plans and Contract Specifications
Knowledge Sharing / Mentoring Staff
Construction Oversight Support
Location
La Crosse, Wisconsin