Formerly known as Murray Hill reservoir, then Grossmont Reservoir,
and (concidentally?) located on Water Street,
this water storage facility was built in 1913
to receive water from a 37-mile redwood flume
coming all the way from Cuyamaca!
It's the only underground reservoir that I have bothered to visit,
but it's a typical example and illustrates why local reservoirs
are moved underground when civic development gets too close.
I have read some analysis of reservoirs in our North County,
where installing a EPA-required vinyl membrane would cost $12 million
or providing additional water purification with ozone costs 11.5 million.
Either way, it's a necessary measure but a bother and expense to consumers.
to receive water from a 37-mile redwood flume
coming all the way from Cuyamaca!
It's the only underground reservoir that I have bothered to visit,
but it's a typical example and illustrates why local reservoirs
are moved underground when civic development gets too close.
I have read some analysis of reservoirs in our North County,
where installing a EPA-required vinyl membrane would cost $12 million
or providing additional water purification with ozone costs 11.5 million.
Either way, it's a necessary measure but a bother and expense to consumers.
Grassmont is completely underground beneath Harry Griffen Park.
It's just a mile to Anthony's Fish Grotto lake, and not far from
where I grew up as a young man and the water was visible!
where I grew up as a young man and the water was visible!
[These two B/W photos from Helix Water District]
In 1957, the reservoir was expanded and lined to improve water quality.
As the area grew, development encroached on the open reservoir,
increasing the potential for contamination (and drownings).
Helix Water District decided to enclose Grossmont reservoir,
beginning the construction project in 1976.
Completed in 1978, it's 600 feet long, 360 feet wide and 22 feet deep.
The reservoir is almost invisible today, buried below a grassy field
within Harry Griffen Park.
within Harry Griffen Park.
Hence the new name of Grassmont Reservoir.
Signs caution against driving on top of the reservoir
Only the access and pump station is visible, at far right in the photo below.
There were lots of people at the park when I visited on a warm sunny afternoon
but NOBODY on the portion on top of the reservoir ... ?
