Posted on February 14, 2024
Researchers at the U.S. Army Engineer Research and Development Center’s (ERDC) Environmental Laboratory (EL) are conducting field studies along the lower James River in Virginia to assess the environmental impacts of dredging and if they continue to justify the existing time-of-year restrictions (TOYR) for dredging in the area.
One primary mission of the U.S. Army Corps of Engineers (USACE) is maintaining federal waterways to ensure safe, reliable and efficient navigation. In order to fulfill this mission, USACE conducts routine maintenance dredging to keep channel depths at required levels. However, there are dredging TOYRs in place, which prohibit dredging operations during specific timeframes due to concerns of negative environmental effects.
In some situations, these TOYRs could potentially cause more challenges than advantages.
“If shoaling occurs within a federal channel and cannot be removed due to a TOYR in place, the cascading negative impacts can range from increased dredging operation costs to additional transit times for shipping vessels which then leads to inflation in the costs of products and goods and also intensifies carbon emissions,” said Matt Balazik, research ecologist with ERDC-EL’s Wetlands and Coastal Ecology Branch.
“A majority of TOYRs have been in place for decades due to precautionary principals, meaning there was an assumption that massive negative actions were occurring, but they lack validation,” Balazik said.
For the James River specifically, the TOYR for dredging is in the spring to allow anadromous fish the opportunity to spawn without the dredge affecting them.
Balazik and his team provided objective science to suggest that the TOYR within the lower James River may not be warranted, and removal may provide a better environmental outcome.
“Dredge activities are not likely a significant issue for the spawning process, but we needed to get data to prove this, Balazik said.
In collaboration with the USACE Norfolk District and Virginia Commonwealth University Rice Rivers Center, Balazik conducted preliminary studies of tagging anadromous fish in an effort to track their reproductive habits in relation to dredge operations.
“There is no science to show dredging is having a negative impact,” Balazik said. “Some fish even swam right by the dredge and remained unphased.”
This evidence was shared at a recent James River partnership meeting consisting of members from USACE and natural resource agencies such as the Virginia Marine Resources commission. Balazik presented his findings and explained why the TOYR for the lower James River should be reexamined.
A joint memo of agreement was signed by all parties to remove the TOYR in 2025 and 2026 enabling USACE to dredge during the anadromous fish run in the spring and explain whether the dredge has any notable impacts. If data suggests that dredging does not hinder anadromous fish reproduction, decision makers may then consider permanent removal of the TOYR.
“We are letting science do the decision making,” said Balazik. “If we can prove dredge plumes are not negatively impacting the spawning, then that will set a precedent for other districts and could potentially open up more dredging time throughout the entire nation.”
