Figure 11. Hydroseeder being used to put leaves on the White River in Hartford, Vermont (March 1994).
was about 50 cm, and was covered by 5 to 15 cm
White River Junction, Vermont
of snow. The leaves were applied on top of the snow.
The White River, from the confluence with the
The estimated solar radiation and air temperature
Connecticut to the Hartford Village Bridge (Fig.
for Montpelier* and snow depth at the site A dur-
13), has a history of ice jams with no fewer than
ing the test period is plotted in Figure 12.
nine major jams forming in this reach since the turn
The day after the leaves were put on the ice 6.5
of the century. The most recent jam occurred in
cm of snow fell, burying the leaves. By 18 March
the spring of 1990 and resulted in the collapse of
the leaves at site A were covered by about 15 to 20
two piers and loss of a span on the Bridge Street
cm of snow. Nevertheless, on the 23rd the overly-
crossing. The two sites we chose to dust (sites C
ing snow had completely melted in the dusted area
and D in Fig. 13) are historical ice jam locations.
at both sites, while the undusted area was cov-
The dusting was accomplished on 17 March 1994.
ered by an estimated 1015 cm of snow. When the
We placed six stakes in the ice at each test section
so we could measure the amount of thinning in
ice washed out of both test sections on the 27th,
this region. The configuration of the stakes is
there was still snow on the undusted ice, but the
shown in Figure 14.
dusted ice was free of snow.
Although no snow measurements were taken
at site B, observations indicated that the melting
Bridge Street Bridge (Site C)
in this area was probably similar to that at site A.
Due to a dwindling supply of mulched leaves,
only eleven bags of mulched leaves were added
This section of the river was less shaded than site
to the 9,500 L of water and used at the Bridge Street
A so we expect the melting may have been accel-
Bridge. Stakes were placed on the ice at regular
erated in this reach compared to site A.
intervals perpendicular to the north bank of the
river, so we could measure the distance the
hydroseeder could spray the leaves using the can-
non. We found using the 1-in. (2.5-mm) nozzle the
*The met data were obtained from the BarreMontpe-
hydroseeder had a range of 40 m. The flared nozzle
lier Airport, which is located about 4 miles from the test
cut down the range to 30 m. From the bridge,