Efficient real-time dredging monitoring

Shallow water dredging projects are often periodic and highly dynamic operations. The dredger must move quickly from one place to another and swiftly change operation from dredging to rock dumping. Contemporary advanced dredging projects are driven by tight specifications and multilayered structure where the dredging is followed by deposition of several layers of different size rocks, each of which has its own elevation and thickness requirements. In dynamic projects as this the hydrographic surveys conducted for dredge and rock dumping monitoring become a logistics issue and impacts the dredging time and efficiency. The dredger must often move out to let the survey vessel pass through. The survey data must be swiftly processed and passed back to the dredger operator to show the compliance with the design. This iterative process results in inefficient use of time and materials and often requires expensive reworks. In such situations there is a need for a different approach for bathymetric data acquisition and processing. The process shall provide instantaneous feedback to the dredge operator with simple displays allowing them to take a corrective action on spot without waiting for the survey and data processing to complete. At the same time the solution must provide full transparency for the survey manager and hydrographers. The survey manager requires instant access to the data remotely, perform GIS operations, prepare progress reports, approve and manage the data. That must be satisfied without any degradation of the bathymetry data quality and adhere to the required standards for hydrographic surveys. The paper presents a real-time dredging monitoring turnkey solution facilitating the above outlined needs used during the Parallel Thimble Shoal Tunnel Project for Chesapeake Bay Bridge-Tunnel. The technology is being used by Chesapeake Tunnel JV during the construction of a second two-lane parallel tunnel under the Thimble Shoal navigation channel next to the existing tunnel. The project is required to fulfil very tight specification in the multilayer design. It requires fast-paced real-time dredging monitoring that provides instantaneous information to the operators in the cabin about the mission progress and allows for corrective actions on the spot without additional INS surveys. Concurrently, the survey manager can seamlessly access fully refraction corrected and RTK aided bathymetry data with the GIS software of their choice and prepare reports, templates and perform other data manipulation.