NEWBURYPORT – Faced with the growing impacts of climate change, rising seas and powerful storm surges, city officials are mapping out what needs to be done to protect Newburyport’s drinking water reservoirs.
In a program sponsored by Storm Surge on July 27, city engineer Jon-Eric White sketched out the layout of the Indian Hill, Upper Artichoke and Lower Artichoke reservoirs, and the risk of rising sea levels and storms pushing Merrimack River water over the dam of the Lower Artichoke.
The program was part of the Towards a Resilient Newburyport speaker series and included Tracy Adamski, a vice president of Tighe & Bond, a consulting company hired by the city to update the Artichoke Reservoir watershed protection plan, and Thomas Cusick Jr., Newburyport’s water treatment superintendent.
The watershed around the city’s reservoirs is comprised of almost 4,000 acres with parts in Newburyport (453 acres), West Newbury (3,017 acres) and Newbury (508 acres). Within that expanse of land there are more than 500 homes – the majority on septic systems – and 25 farms.
Because the reservoirs are connected, White said, “our number one priority is to protect our water supply from getting breached from the Merrimack.”
He pointed out that “if any of these reservoirs gets impacted they all go down. … If one gets contaminated we will have to shut them all down.”
Climate change is likely to have broad impacts, from the amount of rainfall in the watershed recharging the reservoirs, to the massive algal blooms that can occur – and did occur in August 2020 in the Lower Artichoke – during periods of low water and high air and water temperatures. Notably, he said, with rising seas, the Merrimack River will eventually overtake the city’s reservoirs, if no preventative actions are taken.
Among the short- and long-term ideas being considered by city officials and the consulting firm are raising the Lower Artichoke Dam to prevent river floodwaters from backing up into the reservoirs; installing a water line from Indian Hill Reservoir, which is the highest in terms of altitude and the deepest; buying more land to prevent nutrients and pollutants from getting into the water supply; seeking new sources of drinking water to meet future needs; providing a connecting, possibly to another community’s water system, for a permanent source of clean water in emergencies; and looking at water treatment plant upgrades to improve treatment methods to remove nutrients, toxins, algae and odors.
Officials are looking at temporary measures, including placing the large “super sack” sandbags upstream of the spillway to raise the level to keep out floodwaters, and installing adjustable flood gates that could be raised to block rising floodwater and be lowered once the river level went down.
On the issue of an algal bloom…