DOI: 10.5066/p9j8lkhh
title: Water Velocity Magnitude and Direction Collected on May 8-9, 2019 at Select Breakwaters in Lake Erie at Presque Isle State Park, Erie, PA

description: Background: Presque Isle State Park (PISP), located in northwestern Pennsylvania, is located on a 3,127 acre peninsula that extends into Lake Erie. Approximately 7 miles long, PISP is a recurving sand spit where the width of the neck is less than 1,000 feet and the center, eastern end exceeds 1 mile. The park boundary extends 500 feet offshore around the perimeter of the peninsula. The spit forms an embayment, Presque Isle Bay, between its southern shore and the northern shore of the city of Erie. A channel at the east end of the bay is maintained by dredging to permit ship access to the harbor. PISP is considered a unique heritage park as it contains the only &quot;seashore&quot; area in Pennsylvania. Sand erosion, as on any natural shoreline, has always been an issue on the Lake Erie side of PISP. Wave action, littoral currents, and extreme weather events move sand from the neck of the peninsula toward the distal end. In 1986, a plan was developed for shoreline erosion control at PISP and the installation of a series of 55 segmented rubble mound breakwaters parallel to the peninsula shoreline from Beach 1 to Beach 10 began on September 11, 1989. The project was completed on November 20, 1992. From 1993 until the present, annual beach nourishment of lake-dredged sand is required to maintain the beaches behind the breakwaters. Even after the establishment of the breakwater system, coastal storms still have a significant impact to the shoreline and there are safety concerns as result of the existence of the breakwaters and the continual input of new sand into the system. The biggest effect from the breakwater system is sediment deposition behind the breakwaters and cutting off longshore transport to the far eastern end of Presque Isle, resulting in an erosion hot spot at the end of the breakwater system. As the sand erodes and moves eastward down the peninsula, it supports the formation of tombolos, connecting the shoreline to the midpoint of the breakwater with a sand bridge. Tombolos inhibit the flow of water down the shoreline and function as a groin allowing the accumulation of sand on one side and scouring out the sand on the other side. Objective: The objective of this study is to collect baseline data on water-currents within the breakwater system to understand the connection between the angle of approach and the water-currents that would be transporting sediment alongshore. Along with the water current data, data is collected to document a snapshot of the bathymetry within the breakwater system. Methods: Velocity magnitude and direction data were collected with a Sontek M9 Acoustic Doppler Current Profiler (ADCP) in the middle of and between breakwaters from breakwater #19 - 31. The depth of water is collected as well. This data was then processed with the Velocity Mapping Toolbox (VMT) (Parsons et al., 2013) in order to output bathymetry data and velocity vectors. Data Form Summary: The data in each zip file consists of an Excel file that contains data processed within the VMT. Output generally includes a point location, depth, water current velocity, and water current direction at that location. See each individual metadata file included in the zip file for specific details. This data can be input into data software such as ArcMap to create visualizations of the data.