The April–May 2008 flood event in the Saint John River Basin: Causes, assessment and damages

Figures & data

Figure 1. Physiographic features of the Saint John River Basin.

Table 1. April climate normals 1981–2010 for selected stations within the Saint John River Basin.

Item	Edmundston	St. Leonard A	Aroostook	Nictau	Woodstock	Fredericton A	Sussex	Saint John A
Station number	810AL00	8104928	8100300	8103700	8105600	8101500	8105200	8104900
Latitude	45.346°N	47.158°N	46.712°N	47.233°N	46.170°N	45.872°N	45.717°N	45.318°N
Longitude	68.188°W	67.832°W	67.716°W	67.150°W	67.554°W	66.528°W	65.533°W	66.886°W
Elevation (m)	163.0	242.2	80.0	169.7	153.0	20.7	21.3	108.8
Temperature
Daily average (°C)	3	2.9	3.7	2.6	3.7	4.5	4.8	3.7
Standard deviation (°C)	1.5	1.6	1.6	1.5	1.2	1	1.1	1.1
Daily maximum (°C)	8.6	8.1	9.3	9	9.4	10	10	8.5
Daily minimum (°C)	–2.6	–2.5	–2	–3.7	–2	–1	–0.5	–1.2
Precipitation
Rainfall (mm)	46.7	50.2	53.2	57.6	61.6	68.3	69.4	85.7
Snowfall (cm)	11.5	26	18.8	21.4	18.8	18.6	20.3	20
Precipitation (mm)	58.2	77.1	72	79.1	80.4	85.9	89.7	105.3
Average Snow Depth (cm)	51	17	0	1	5	2	1	2

Table 2. Major tributaries of the Saint John River.

Tributary	Drainage basin area (km^2)
Upper Saint John River Basin (upstream of Grand Falls)
Big Black River	1620
Allagash River	3264
St. Francis River	1426
Fish River	2312
Madawaska River	3050
Middle Saint John River Basin (Grand Falls to Mactaquac)
Aroostook River	6276
Tobique River	4326
Meduxnekeag River	1334
Lower Saint John River Basin (downstream of Mactaquac)
Nashwaak River	1764
Oromocto River	2016
Salmon River	3885
Canaaan River	1527
Nerepis River	0
Kennebecasis Rver	1377

Table 3. Summary of 2008 snow water equivalents, Saint John River Basin.

Basin segment	Period	Snow water equivalent (mm)
		Long-term average	2008	% Normal
Upper and Middle Saint John River Basin (upstream Mactaquac)	Early February	119.1	179.5	151
	Early March	164.0	244.7	149
	Mid March	187.7	295.2	157
	Early April	181.0	328.9	182
	Mid April	149.9	272.8	180
Lower Saint John River Basin (below Mactaquac)	Early February	76.4	99.3	130
	Early March	107.5	139.8	130
	Mid March	124.1	159.1	157
	Early April	102.0	168.3	165
Entire basin	Early March	154.9	230.0	148
	Mid March	177.4	266.1	150
	Early April	168.3	302.9	180
	Mid April	133.0	229.0	172
	Early February	112.2	162.7	145

Source: New Brunswick Department of the Environment (2008).

Note: The Saint John River Basin Cooperative Snow Survey is a tabulation of snow survey data collected by a number of agencies including Ministère du Développement Durable, de l’Environnement et de la Lutte contre les changements climatiques du Québec, Maine Public Service, USGS, NB Power, NBDENV and others.

Table 4. Summary of April 2008 climate data for selected stations, New Brunswick portion of Saint John River Basin.

Station name	Station name	Lat.	Long.	Mean temp.	Max. temp.	Min. temp.	Total precip.	Days with precip. ≥1.0	Snowfall	Snow on ground 30 April	Degree days
				(°C)	(°C)	(°C)	(mm)	(mm)	(cm)	(cm)	(°C)
Edmundston	8101303	47.417	–68.324	3.8	22.3	–8.4	89.9	7		4	426.4
St Leonard A	8104928	47.158	–67.832	4.2	19.2	–8.6	75.8	9	19.2	4	413.7
St Leonard Cs	810I001	47.158	–67.832	4.2	19.4	–8.5					415.5
Aroostook	8100300	46.712	–67.716	5.2	21.5	–7.5	75	7	7.2	0	384.1
Bon Accord	8100566	46.651	–67.584	3.8	19	–10	52.5	5	12	0	368.4
Woodstock	8105600	46.17	–67.554	5.4	21	–6.5	65.2	6	5	0	378.2
Fredericton CDA CS	8101605	45.92	–66.609	5.5	22.2	–4.8	45.1	6			374.9
Fredericton A	8101500	45.872	–66.528	5.7	22.4	–4.2	31.7	6	0		368.6
Parkindale	8103828	45.867	–65.067	5.3	20	–6	56	11	0	0	380.4
Gagetown AWOS A	8101794	45.839	–66.450	5.8	22.9	–5.6	35	9			365.8
Gagetown 2	8101800	45.783	–66.15	6.1	22	–4	28.4	5	0		358
Sussex	8105200	45.717	–65.533	6.5	21	–5	33.4	6	0	0	346.4
Mechanic Settlement	8102848	45.694	–65.165	3.9	16.2	–7.6	71.5	10	4		423.3
Saint John A	8104900	45.318	–65.886	5.1	21.5	–5.7	51.4	7	3.2		385.8

Source: Government of Canada (2010).

Table 5. Rainfall amounts (mm), 27–30 April 2008, at selected climate stations, Saint John River Basin.

Station name	Station number	Monday	Tuesday	Wednesday
		28 April	29 April	30 April
Edmundston (precip)	8101303	0	61.2	0.6
St Leonard A	8104928	1.0	35.6	0.6
Aroostook	8100300	6.8	32.6	0.6
Bon Accord	8100566	5.0	32.5	0
Woodstock	8105600	4	33.8	0
Fredericton A	8101500	0	11.7	T
Parkindale	8103828	0	4.8	0
Gagetown 2 (precip)	8101800	0	6.2	0
Sussex	8105200	0	3.2	0.6
Saint John A	8104900	0	16.4	0.2

Precip: precipitation; T: trace amounts.

Source: Government of Canada (2010).

Figure 2. Daily discharges recorded at four hydrometric stations along the main stem of the upper Saint John River, April–May 2008.

Figure 3. Unit daily discharges recorded at four hydrometric stations on tributaries to upper Saint John River, 22 April–12 May 2008.

Figure 4. Flood profile for 2008 along the Saint John River upstream of Grand Falls (RVA 2009).

Figure 5. Stages along the lower Saint John River, April–May 2008.

Figure 6. Flooded Brunswick Street, downtown Fredericton (courtesy Stefan Kruse, citizen).

Table 6. Flood stage frequency (2008) – Lower Saint John River.

Water level station	Maximum daily flood stage						Maximum instantaneous flood stage
	Period of record	No. of years	Missing years	Flood stage, April–May 2008 (m)	Return period (years)		Period of record	No. of years	Missing years	Flood stage, April–May 2008 (m)	Return period(years)
					EV	LP					EV	LP
Saint John River at Fredericton	1930–2012	79	1962,1963, 1987,1989	8.28	22	39	1968–2012	45	---	8.67	30	61
Saint John River at Maugerville	1971–2012	41	---	6.89	17	29	1971–2012	41	1980	6.92	17	27
Saint John River at Upper Gagetown	1994–2012	19	---	6.41	29	45	1994–2012	19	---	6.43	28	45
Jemseg River at Jemseg	1970–2012	41	1982, 1995	6.10	29	45	1970–2012	40	1976, 1980, 1995	6.11	28	47
Saint John River at Gagetown	1994–2012	19	---	6.03	33	43	1994–2012	19	---	6.06	33	43
Saint John River at Oak Point	1923–2012	73	1926, 1949–1959 inclusive, 1966–1969 inclusive	5.29	31	53	1970–2012	43	---	5.35	33	39
Saint John River at Saint John	1970–2012	40	1982, 1995	5.08	39	55	1970–2012	39	1972,1984,1995,2005	5.20	47	62

EV – extreme value distribution I; LP– Log–Pearson distribution.

Table 7. Flood stage and 2008 peak stage for several communities along the Saint John River.

Location	Flood stage	Spring 2008 peak stage
	(m)	(m)
Saint-François-de-Madawaska	160.2	162.8 E
Clair (Fort Kent)	157.1	158.4 E
Edmundston	139.0	143.10
Perth–Andover	77.2	78.29
Simonds	48.5	49.64
Hartland	45.7	47.91
Woodstock	41.4	41.83
Fredericton	6.5	8.36
Maugerville	6.0	6.92
Jemseg	4.3	6.11
Grand Lake	5.0	6.24
Sheffield–Lakeview Corner	5.1	6.45
Oak Point	4.7	5.36
Saint John	4.2	5.20

E – estimated.

Table 8. Saint John spring 2008 flood disaster assistance payments.

County	Flood disaster assistance paid (CAD$)	No. of claims
Madawaska	$6,649,327.28	464
Victoria	$748,685.00	71
Carleton	$533,877.81	21
York	$5,681,027.21	420
Sudbury	$3,853,861.80	282
Queens	$1,455,081.07	189
Kings	$946,067.09	128
Saint John	$331,600.79	45
Total	$20,199,528.05	1620

Data courtesy of the New Brunswick Emergency Measures Organization.

New Brunswick Department of the Environment. 2008. Saint John River Basin cooperative snow surveys. New Brunswick Department of the Environment, Fredericton, NB.

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Government of Canada. 2010. Archived hydrometric data. Government of Canada, Ottawa, ON. http://climate.weather.gc.ca/ (accessed July, 2014).

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R.V. Anderson Associates Limited (RVA). 2009. Flood forecast model refinement. Final report. Prepared for the New Brunswick Department of Environment, R.V. Anderson Associates Limited, Fredericton, NB, 18 pp. + appendices.

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