Using tracking devices to follow the movement of rocks may seem odd, but that’s what’s being done to help the state Department of Ecology and local residents track the effectiveness of anti-erosion measures on the shoreline at North Cove — aka Washaway Beach.
North Cove community members teamed on Jan. 16 with the Department of Ecology to drill holes in about 140 rocks and fit them with passive-integrated transponders, also known as PIT tags. These will be placed among the rock cobble that makes up what is known as the dynamic revetment — strategically placed cobble stones designed to disperse wave energy and limit shoreline erosion. The stones will be monitored to follow their movement along the coastline.
“It was great to see the high level of enthusiasm and participation of the local community,” said George Kaminsky, Department of Ecology coastal engineer, who has been monitoring the rapid erosion of the North Cove shoreline for 25 years. “Their support of this research is incredible, and it is wonderful to experience the positive spirit of the North Cove community.”
Local resident Connie Allen, one of the driving forces behind North Cove’s “Wash Away No More” movement to control shoreline erosion, described the day’s activities.
“Richard Harris, who hosted the rock-drilling event, gathered and washed local basalt weighing 3 to 40 pounds. We sorted the stock into three sizes and drilled the appropriate size hole. After cleaning and drying the hole, Diana McCandless secured the tracking device with silicone.”
Harris had property in the North Cove area that was washed away. McCandless is an environmental specialist with the Department of Ecology. Tokeland jewelry maker Judith Altruda, Pacific County Drainage District #1 commissioner David Cottrell, North Cove resident Bob Merrill, Grayland glass artist Jeremy Bartheld, and local resident Brad Kirkland were among several others participating.
Ecology measured, weighed, photographed and recorded the identification number of each of the rocks Thursday. The rocks were placed Friday “along the dynamic revetment at specific profile locations and elevations,” their placement carefully logged, said Kaminsky.
The tracking devices are small tubes that “work like the chip on a credit card,” said Allen.
“Each tag has a unique identification number that is detected with an antenna connected to a reader unit,” said Kaminsky. The antenna is an oval-shaped wire ring attached to handle and is used similar to a metal detector to locate tagged rocks. “Over time we will use the antenna and reader to detect the tagged cobbles and examine the distance and direction they are moved by waves and currents. We will learn how they may get sorted by size, and also how the size and shape of the cobbles change over time due to collision and abrasion with other rocks. This will help us determine the durability of the material, and how to optimize the overall performance at minimum cost.”
Kaminsky said there will be short-term monitoring this month and more surveys in February and March.
“Monitoring the change in size of the cobbles is more labor intensive and will be done less frequently, depending on how quickly they appear to be getting smaller, and the extent to which funding allows,” said Kaminsky.
Also on hand Jan. 16 was Paul Bayle, a coastline researcher from the University of Bath in southern England. He is researching dynamic revetment using lidar technology, which works similarly to radar but instead makes measurements using laser lights.
“Little North Cove is of interest to English coastline research,” said Allen.