Flood Details - 1986-04-01 - 1986-04-04

General: A late-January thaw created antecedent conditions that were important contributing factors to floods on the Saint John and Nashwaak rivers in April 1986. On January 29, recently formed ice jams began to freeze into place at Lower Becaguimec Island on the Saint John River, and between McLaggan Bridge and Nashwaak Bridge on the Nashwaak River. These ice jams remained in place until April and exacerbated flooding conditions when the spring freshet began. Throughout much of New Brunswick, river flows increased gradually in late March as mild weather returned. Above normal daytime temperatures occurred at the end of March, causing a surge in snowmelt and runoff. In the Fredericton area the maximum daytime temperature fluctuated between 10 and 19 degrees Celsius from March 26 to April 3, while the minimum night time temperatures for the same period ranged between -3 and +2 degrees Celsius. On March 27, 43 mm of rain fell at Fredericton. Saint John River Basin: Mild temperatures during the last two weeks of January, with rain on January 27, caused the breakup of the ice cover between Hartland and Florenceville. The broken ice formed an ice jam, which eventually came to rest two kilometres downstream of Hartland on Lower Becaguimec Island, on January 28. The ice jam caused a temporary increase in water levels, but no flooding. Temperatures dropped below freezing on January 29, and remained seasonably cool until late March. During this time the jam consolidated and solidified as the ice fragments froze together to a depth of approximately three to 3.6 metres. The backwater caused by the ice jam became less and less apparent after January as river flows decreased. River flows increased gradually in late March as mild weather returned. Especially mild weather prevailed from March 26 to April 3, with rain on March 27. Discharges from the Beechwood Dam rose from 793 cubic metres per second on April 1 to 3172 cubic metres per second on April 4, in response to rapidly increasing inflows to the headpond. Early on April 2, broken ice above Stickney moved downstream, forming an ice jam that lodged temporarily at Lower Presque Isle. At noon, the jam (five kilometres in length) moved five kilometres further downstream, and came to rest with the toe [downstream end of the ice jam] at the upstream end of Upper Becaguimec Island. When the ice jam moved to Upper Becaguimec Island, located about two kilometres downstream of Simonds, the water level at Simonds increased suddenly from 47.09 metres to 48.52 metres at approximately 13:00 hrs. The water level gradually increased thereafter until 21:00 hours, then stabilized at approximately 49.7 metres until 13:00 hours, April 3. This was sufficient to cause overnight flooding of Route #103 near Simonds. On April 3, the discharge from Beechwood Dam increased gradually during the day, from 2747 cubic metres per second at 14:00 hours to 3 172 cubic metres per second at 20:00 hours. A surge of flow, which originated 38 kilometres upstream at Tinkers Dam on the Aroostook River. Although partially contained within the headpond of Beechwood Dam this surge caused further increases in the water level at Simonds where the ice jam was continuing to restrict the river¿s flow. At 18:22 hours, April 3, the water level peaked at 51.14 metres, causing heavy flooding in the Simonds area. It forced the evacuation of at least six families from their homes, and further flooded the highway, isolating a three to five kilometre stretch of Route #103 for a number of hours. Some of the evacuations were carried out using boats and a helicopter. On the opposite side of the river, Route #105 near Upper Brighton was flooded, and a few area residents reported water damage to their basements. Ice also damaged a number of utility poles; however interruptions to electrical and telephone services were minor. Between 21:00 hours and 22:00 hours on April 3, the ice jam at Upper Becaguimec Island released, causing the water level at Simonds to drop by 2.3 metres in less than an hour. The water level continued to decline, and by 01:00 hours, April 4, it was near normal, at 46.58 metres. The ice jam at Lower Becaguimec Island, which had formed in late January, was still present at the end of March. As river flows increased, water levels in Hartland rose higher than normal due to the channel restrictions caused by this ice jam. On April 1, the water level at Hartland was 45.50 metres for most of the day, then began to rise at a steadily increasing rate to 47.35 metres by 24:00 hours, April 2. The water level generally continued to increase, but at a reduced rate, and peaked at 48.01 metres at 21:50 hrs, on April 3. The water reached the underside of the road and railway bridges crossing the mouth of the Becaguimec Stream, and came to within approximately one metre of the underside of the Hartland covered bridge. The ice jam at Lower Becaguimec Island broke at 23:00 hours on April 3, causing the water level at Hartland to quickly fall 1.25 metres. The Hartland water level continued to decline, reaching 45.90 metres by the morning of April 4. Subsequent analysis of this flood revealed that, although ice jams frequently lodge at Upper Becaguimec Island, they do not usually remain in place as long as in this case. It is likely that the backwater created by the ice jam at Lower Becaguimec Island extended upstream, beyond Upper Becaguimec Island. This backwater probably allowed the ice jam at Upper Becaguimec Island to stay in place longer than normal, thus requiring a greater-than-normal river flow to dislodge it, and greatly aggravating flooding in the area. Ice jams also occurred in the Rivière Verte, Perth-Andover, Hartland and Woodstock areas of the Saint John River valley, but significant flooding only occurred at Simonds and Woodstock. The Woodstock area began to flood on April 4, shortly after the ice jam at Lower Becaguimec Island let go, causing ice to pile and jam from Newburg downstream to Lower Woodstock. The water level peaked during the early morning of April 4, closing Water Street in Woodstock. Ice caused slight damage to the fence behind the sewage treatment plant, and Centennial Park flooded. Route #105 near Newburg was flooded temporarily with about 0.3 metres of water, and the Canadian Pacific railway line was blocked by ice at Newburg Junction. Nashwaak River Basin: The Nashwaak River overflowed its banks and flooded Route 107 between Nashwaak Bridge and McLaggan Bridge on April 1, closing the road until April 2. At its peak, the water was over 0.5 metres deep on the highway, but did not flood any buildings. The flood was caused by an ice jam that had formed in January during a flood. Petitcodiac River Basin: In Salisbury, flooding damaged one of the village¿s three sewage lagoons, releasing sewage into the Petitcodiac River. About six metres of an earthen wall, enclosing the lagoon, collapsed between March 30 and April 1. The lagoon was located on intervale land on the north bank of the Petitcodiac River. Ice jams in the river had caused flooding of the intervale and erosion of the lagoon wall.

n Simonds, some residents stated "the flood was the worst in 80 years".

Saint John River: The floods in the Simonds area were by far the most damaging of the flood period. Flood damage compensation was paid to about 40 families or organizations by the provincial government (EMO) and amounted to $258 819. In particular, a mobile home was pushed off its foundation by the ice and was flooded to the ceiling. Other houses were flooded, some as much as half the height above the ground floor. Some basement flooding resulted in spilled furnace oil from tanks, causing potential contamination problems, in addition to damaging the structure and materials within. A private airstrip next to the river was completely flooded. Three light aircraft were submerged, 350 metres of runway was severely damaged, and the parking lot was completely washed away. Route 103, on the west bank of the river, was flooded with water and ice, closing it to traffic from April 3 to April 5. Route 105, on the east bank, was closed during the night of April 3 because of flooding. The flooding caused damages to the road shoulders and guardrails, as well as a number of utility poles. Petitcodiac River Basin: The damage to the sewage lagoon in Salisbury was estimated at $20 000. Poor ground conditions at the time prevented immediate repair, and these repairs may have been delayed a month or more.