The Underwater Acoustic Services (UAS) and High Definition Survey (HDS) teams of Fenstermaker recently performed an inspection of D’Arbonne Dam in Union Parish, Louisiana.  The dam, built in 1961, and owned and operated by the Bayou D’Arbonne Lake Watershed District, was due for a conditional and safety inspection to determine the dam’s structural integrity and provide valuable information for establishing a long term maintenance and safe operation program for the structure. This Louisiana Department of Transportation (LA DOTD) project was led by The Riley Company of Louisiana, Inc. with Fenstermaker providing specialized services as a sub consultant. Another sub consultant, ARCADIS U.S. Inc., added structural engineering expertise for the dam superstructure. 

The Fenstermaker team was tasked with creating a comprehensive surface model and high resolution topographic model of the as-found condition of the dam superstructure and substructure and the water bottom approach and egress. To accomplish the requirements of the project, the field inspection was organized into three components; the HDS superstructure and environment survey, the UAI under water acoustic imaging and profiling survey, and the visual safety inspection. The field data acquisition and inspection was performed from November 6 to November 9, of 2007, a total of four days of field work. Fenstermaker combined the results of the underwater acoustic imaging and profiling survey with the HDS survey in order to provide the client with a complete 3D model of the dam structure. The observations made from the visual safety inspection were used to develop recommendations for maintaining the structure’s integrity and safe operation.  Observations from the underwater acoustic survey warranted further investigations requiring divers. Fenstermaker’s Underwater Acoustic team worked in conjunction with divers from Glenn Underwater Services, to provide underwater environment visualization and direction thus enhancing dive task efficiency and providing an increased level of safety in dive operations.

The integration of high definition survey and underwater acoustic survey methods represents a specialized combination of services offered by very few firms in the world.  Underwater acoustic and high definition survey technologies can greatly reduce maintenance and remediation cost by identifying the specific areas where repairs are warranted and eliminating the need for repairs on structurally adequate sections. In addition to saving time and money, clients are equipped with unparalleled precision on project deliverables, assuring them of accurate, comprehensive information to enable the most knowledgeable and effective maintenance decisions.

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