Riverside Avenue Topography

Timeline of Events

Figure 1 shows the summarized results of landslide locations and dates.

The 1906 USGS quadrangle (Fig 2) shows the slope was fully forested, with the uphill side cut by a tributary stream gully, and two smaller stream basins, all flowing north to the river.

In 1928 a photo from Winooski, VT. shows a large landslide across from the factory, west of the falls (Fig 3). No other information is given about this event. Though a Vermont Geologic Survey Landslide Hazard Report (Baskerville, 1993) indicates a very large storm covered the state in up to seven inches of rain from Nov 3-7, 1927, which may have impacted the event.

In 1931 the city of Burlington began a project to widen and pave Riverside Ave, add sidewalks, and electric lights. However, the slope from Riverside Ave to the Winooski River is quite steep. By ca.1935 cribbing was built downslope from the road, and filled with gravel and sand (Fig 4). By 1937, aerial photos show only modest housing development on the south side of the avenue, a trend that continues through 1948 images (Aerial Photos).

Little is reported until Sept 1955 when the historic landslide wiped out Riverside Ave. Reports indicated the road was diverted around the scarp at the landfill - Vermont Open Geo Data portal shows this landfill's location at the current junction of Hillside, Hildred and Riverside Ave (Fig 6). Which matches background topography of insurance photos of the event (Fig 5). A secondary failure occurred just west of the main slide in Nov 1955 due to excavation crews toploading the slope edge just to the west.

Images show that by 1962 (the landfill closed in 1960) developments have been built on both the north and south sides of the avenue spanning the whole study area from Prospect street to Colchester ave (Fig 7).

Another slide occurred slightly further west in 1968, the failure event was downslope from Riverside Ave but reached the road. Newspaper photos show three houses in rows and columns that match only one section of development at the time. (Fig 8)

1976 saw a reported landslide divert the Winooski River channel off of Riverside ave (Newspaper Articles). A best approximation was added to the Figure 1, due to the reported 4000 yards of displaced debris. Federal Aid was granted for cleanup, but the Army Corps of Engineers did not take into account Burlington's Full clean up plan.

1981-1983 was a time of private owners dumping trash and fill down slope of their lots on Riverside Ave. Much of this fill came from the development over the old tributary stream gully/landfill. Multiple failures were recorded on the same properties across from a bakery that still stands today (Newspaper Articles).

After these landslides, the city of Burlington undertook a new plan to remove clay and add stone fill and shallow the slope from Riverside Ave to the river (Newspaper Articles). No known failures occurred in this area until the 2019 "Halloween" landslide failed from storm rain inundation behind 465 Riverside Ave (Fig 9).