The Mid-Atlantic Power Pathway (MAPP) is a proposed 152-mile high voltage direct current (HVDC) transmission line project. The transmission line would be buried beneath 16 miles of the Chesapeake Bay and 23 miles of the Choptank River.
MAPP would be the first transmission line to cross the Chesapeake Bay. The precedent set by this first project could lead to other utilities crossing the Bay. It is possible that the 39 mile MAPP route would become the corridor of choice for future utilities. Before this precedent is set a panel of leading Bay scientists should be convened to determine if a transmission line can be cross the Bay without causing excessive harm and, if it can, then what is the best route.
The best example of the type of review required is Greening Blue Energy: Identifying and managing the biodiversity risks and opportunities of off shore renewable energy.1 More than a thousand scientific studies, 400 of which were peer reviewed, formed the basis of the Greening Blue Energy report.
This document is a far cry from Greening Blue Energy. It was compiled by Dorchester Citizens for Safe Energy (DCSE) as an initial attempt to determine if there was valid reason to be concerned about running MAPP beneath the Chesapeake Bay and Choptank River. Following is a summary of potential impacts based upon the very limited number of studies reviewed for this document.
It could take up to 30 months or even longer for the 85 acres of Bay and River bottom to recover from the initial installation. Periodic maintenance may cause additional disturbance. Bottom-dwelling (benthic) organism diversity and numbers would be reduced by the installation with recovery requiring up to 30 months or even longer. The electromagnetic field emitted by the cables could alter the behavior of some fish species out to a distance of about 1,000 feet affecting an area of about 9,500 acres.
The cables may heat to a temperature of 158°F. It is possible heating may induce interstitial currents in adjoining sediments that increase the release of phosphorus and other pollutants from bottom sediments.
Boating could be affected by altering compass readings or through the possibility of anchors snagging a cable, particularly when anchors drag during storms through the soft sediments in deeper waters. While the cables will initially be buried to a depth of six feet the cables could be exposed during storm periods, which happened two-years after the Cross Sound Cable was buried beneath Long Island Sound.
These findings should be considered tentative until verified by the more comprehensive analysis suggested above. A reference to the relevant studies is provided at the end of each finding.