The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1876-04-07
HEMPSTEAD RESERVOIR.

NO IMMEDIATE DANGEE--A PREMATURE TEST
on AN EXPENSIVE PLAN.
The violent storm Of rain on April and 4, accom-
panied by a heavy gale from the northeast, swept
through tho Hampstead Valley, tearing down and
fences flooding the roads swelling the streams on the
southern watershed of that beautiful section OF Long
Island, and filling with alarm tho minds OF tho resi-
dents OF Rockville Centre and East Rockaway. The
greatest danger anticipated possible rupture OF
the new Hampstead reservoir dam. With its scvcn
hundred and fifty million gallons Of wafer stored on
elevated ground from one TO two miles distant, having
its natural outlet to the running through tho two
settlements, there seemed sufficient cause for
dread Tho storm passed, and the work
OF the engineers at the reservoir wthstood the
test The Hampstead storage reservoir is located
about two miles southwest OF Hampstead. The basin
has an average width OF 1000 feet aud is mile and
uc.tcnlhs OF mile In length II was constructed by
excavang tie earth both SIDES oil Old and
water course. passing through slight valley IN
southwcsteriy direction from Hampstead toward Hemp
stead Bay on the southern shore OF the island. The
earth removed from the proposed basin was banked
upon the sides, forming leyces on the casterly and
westerly SIDES about hundred feet wide and eight
feet above the level OF the adjacent land. Al the
southern end OF the BASIN or Reservoir Gam was con-
structed, with gate AMI weir. The water
gate opens into u conduit connecting the basin wilh
Hampstead Pond, ono OF the naiural reservoirs used
tor supply ing Brooklyn with fresh water
On tuesday last when the storm was at It's height,
there feet o water IN the great
The VIVA was blowing strong the northeast, and,
sweeping The surface OF neary two miles Of water,
heaped up the and drove them against the dam
with terrific force. 4 trestlc bridge which spanned
The reservoir midway OF lis length carried away
torn to pieces. The timbcrs ot the bridge swept
upon the dam and Dy ncessant beating broke down the
temporary shield OF planks placed above the finished
stone facing the dam and intended 10 prevent the
washing OF the enbahkmcnt above not yet faced with
granite Eye witnesses say that the waves broke SIX
feet high against the unfinished dam und washed the
sand facing vi the clay empankmcnt away, d,ssolving
II Ike sugar IN cup VI iea." The foreman Of the
works eyes Watched the progress OF tho
Storm and soon us possible commenced 10 repair
the damage. wall OF granite powders was
run the face OF the dam, 100 feet IN length,
and coarse pebbles, Of sand, poured be-
hind the walls to keep, 10y their weight, the sand OF
tho embankment from further washing Alter the
water became still line OF panklug was con-
s,ructca outside Of the temporary stone WALL 10 pro-
tcct II still further.
feet eleven inches in depth, and when sounded yes
tcrday morning gave a depth OF fourteen iect one
and halt inches. The DAM IN It's present unfinished
condition, is intended 10 Withstand pressure Of
twelve feet oil water ana when completed Is calculated
with compact cmbahkment laced with granite rising
feet higher, giving total height of twenty eight
feet along the entire taco OF the dam.
A careful inspection made yesterday afternoon
showed that the castcrly aud westerly em6ankments
good order and perfectly safe. From the
nor hcrn cmbankment, the one nearest Hempktead,
all in the grade OF the bottom of the
Of ieet toward the dam. Therefore, the
greatest pressure southern end OF the basin,
and there the danger. II any, exists. Above the
finished stone fac the action the waves daring the
late storm VISIBLE to the height OF SIX or eight
feet, but the material that had been washed
away had not at any point uncovered the
main object OF resistance, the ed
clay bank behind the sand The outer slope Of
tho dam about thirty leet height aud nearly lS0o
feet length, did exhibit any detect Indication
OF Interior damage Twelve men all that have been
at work since the storm-wcrc employed IN covering
The inner slope with gravel and pebbles and car
ryIng the temporary stone wall higher IN order TO
meet II necessary, the increase Of the depth OF water
10 nineteen feet, that being the depth which tho
Common Council Of Brooklyn propose to have IN the
reservoir before they Will allow the contractors TO
open tho gates and reduce the pressure OF water on
The cost Of carrying up tho temporary stone wall
and its backing OF gravel aud pebbles TO resist nue
teen pressure before the intended facing Is
properly LAID, viii be about $1,000 Then, after that
experiment has been finished and tho wat =
lowered ID Twelve feet, the temporary work will have
be removed and the granite facing buit up 10 tho
required hcight-twcnty-e feet At present there
seems be Immediate OF alarm Tor tue safety
The work. and the numerous residents between the
dam and East Rockaway feel from an nunda-
ton from that source.
In constructing the dam the earth was excavatcd TO
the proposed depth OF ,hs reservoir, and a trench
made 100 feet Ia width Two parallel rows OF pIles,
twelve feet apart were then driven to depth
OF sixteen icct INTO the sand the piles Of eac. row
beng tongucd and groovcd and made water tight Tho
space between the piles was then excavaed depth
OF i've icct and in laid bed OF concrete three
feet In thickness Upon this was placed pndde wall
twelve feet vide ut the bottom. soping on both SIDES
until IL reached height OF twcnty-eght feet. with
width Of six feet Mt the top This puddle was made
and rolled down with Il roller weighing 1900
pounds. Then three Inches OF clay
was laid and rolled with the same pressure,
and SO until the wall was completed As each layer
OF clay rolled down. layer OF hard sand SIX inches
deep, was rolled with 5000 pounds pressure on the
inner aud The iront OF the sand aud clay
bank dam toward the was then faced with
granite, eighteen inches thick laid N foot of gravel
The slope oil the granite lace three icct and one loot IN
height, the object OF the granite face beiug simply TO
the sand from washing away. The stone lace IS
II feet high the perpendicular and 10 feet on
the slope and Tie water Is, therefore, TWO cet one and
q hall inches above it,
Mayor Schroeder President Slocum, OF tho depart.
mcnt OF Brooklyn city Works; Colonel Adams. chief
engineer. and Colonel kcency OF Kingsley kccney,
the contractors visited the reservoir yesterday aud
made examination oil the works. but Vt late hour
last evening had not made their report