Hydrographic Survey – Houston Ship Channel, Texas
CRA has carried out depth surveys at this dock on the Houston Ship Channel for over 10 years. At the peak of dock operations, we were performing routine check surveys every three months as well as pre-dredge and post-dredge surveys. These are typically conducted using single-beam depth sounders with real time differential GPS based on Trimble receivers using signals from the U.S. Coast Guard on our 18 foot center console survey boat.
Data is logged on a notebook PC running “Hypack” software. The data is edited in our Houston office and imported into a Bentley Microstation v8 CAD file using the Corps’ program, “Alisound,” to produce a plan view bathymetric chart. We also produced cross-sections (also in Microstation) and a volume computation of the amount of material removed using the average end area method. We also use the repeated surveys to try to predict sedimentation rates and dredging schedules for Cemex.