Saturday, May 01, 2010

Chestnut Hill Reservoir at Half Capacity Before the Emergency?

Earlier this year I repeatedly noticed that the water level of the Chestnut Hill Reservoir has been much lower than it usually is at this time of year.

I estimated by around six (or so) feet lower than normal. William Marchione, in his book Allston-Brighton in Transition, gives the size of the Bradlee Basin as 125 acre (5.4 million square feet or 1.56 mile circumference) and a storage capacity of 550 million gallons. Using the conversion of one gallon to 7.5 cubic feet, I estimate the reservoir's "standard depth" as 13.3 feet. That means current water level of 7.3 feet, instead of the usual 13.3 feet.

So the Chestnut Hill Reservoir this spring might only have been just over 50% capacity? Ouch. That extra water would have come in handy right about now.

I wonder if the people at the Massachusetts Water Resources Authority and Department of Conservation and Recreation might now be kicking themselves for letting the reservoir's level get so low earlier this year.


wilbur said...

Great question. As a local resident and reservoir jogger, I too was curious about the lower water level in the reservoir during the winter... which has been rising again lately.

According to the MWRA, an invasive weed called "Eurasian Watermilfoil" had grown up around much of the waters edge causing harm to the reservoir's ecosystem. So in 2009, the weeds (bushes actually) were cut to their roots. Then during the winter, the water level was reduced to activate a "draw-down/freeze-off" strategy to deal with the weeds. Apparently, by reducing the water level the weed's roots have less access to hydration and are more exposed to the frozen ground, which is supposed to eliminate or at least diminish the weeds over time.

The MWRA website notes that it will reduce the water for three consecutive winters and then every other winter to control the problem.

smh said...

Another interesting thing: Because of the low levels, new rocks have been exposed in the reservoir upon which geese have started to make nests and lay eggs. Yesterday, when the MWRA started redirecting water to the reservoir to fill it back up, many of these nests/eggs drowned and got destroyed. Sad, but I suppose access to water for 2 million customers is more important than a few dozen birds.

Michael Pahre said...

I too was worried about that nest destruction: not just the Canada Geese, but the swans -- aren't there at least two pairs (plus a single)?