WA:TER


ASSESSMENTS, REPORTS & STUDIES

aerial view to north

FISH HABITAT AS DEFINED BY ACTIVE FLOODING


The BC Ministry of Environment considers a floodplain to be active if it floods at least once every five years. This is an important distinction because only active floodplain is considered fish habitat, and when it comes to most land development, only fish habitat is covered by regulation. In 2008, the Salmon River delta was a single municipal council vote away from from large scale commercial development because it was reported by the developer that the delta did not flood *, and the Ministry of Environment and Salmon Arm City Council accepted this report. Since then the delta has been shown to flood more frequently than once every two years, unequivocally establishing it as critical fish habitat.
* August 2009 - Developer's report finds no evidence of active floodplain - "Within the project area, the Salmon River is contained within well defined banks and does not have alluvial deposits beyond the top-of-bank. Based on an active channel (geomorphological) assessment of the Salmon River, the river is migrating and therefore additional protection measures along the eastern and northeast sections of the property, where the river bends intersect the property, will be required to ensure the 30m SPEA remains intact." (SmartCentres' qualified environmental professional report, August 31, 2009, page 16)
flood patternRiver high water mark represented by orange line & lake high water mark by green line. Development overlay in this and following graphics represents the 2009 proposal.

flood pattern 1920'sThe above photo from the late 1920s shows somewhat different main river channel positions. It also shows Active Floodplain areas presently buried beneath landfill on the SW side of the property.  top  home


SCIENTIFIC EVIDENCE & OPINION IN SUPPORT OF AN ACTIVE FLOODPLAIN

1) SOIL CLASSIFICATION

"The soil within the "I 6 W" cottonwood forest area is a Gleyed Regosol (young mineral soil, permanently or periodically water saturated and oxygen-starved) derived from river flood (alluvial) deposits; it is moderately well to poorly drained, has mottles within 30 cm of the soil surface, and is subject to frequent flooding." (Salmon Arm soil mapping project, April 1979, BC Min. Env., Resource Analysis Branch, Kelowna, B.C.)

2) AGROLOGIST'S LOCAL EXPERIENCE

"Since the subject property is close to the mouth of Salmon River, the elevation of the land is somewhat lower and is subject to flooding during high water levels in late May to early June." (Bob Holtby, P.Ag. from "Holtby" report on removal of subject property from Agricultural Land Reserve, dated July 19, 2004)

3) SALMON RIVER DELTA LOCAL EXPERIENCE

"The river floods pretty much annually to the start of the Interpretive Trail at the Pit Houses on the west side, just downstream from the subject property." This observation correlates well with the high water mark of the active floodplain as observed at the nearby northwest corner of the subject property. (Louie Thomas, pers. comm. Dec. 2009, from a lifetime of experience at the Salmon River mouth area)

4) GEOLOGIC EVIDENCE

"... the delta is still very active, and very unpredictable". (Geologic Development of the Salmon River Delta by Dr. Murray Roed, GEOTERRAIN CONSULTANTS 4890 Westridge Drive, Kelowna, BC V1W 3A1)

5) ANECDOTAL HISTORICAL RECORDS
Ten years later in 1894 (after the CPR line was constructed in 1884/85), following an early and hot spring, "the lake level rose very high" according to the Centennial History of Salmon Arm, written by Ernest Doe in his 1971. Doe estimated about half of the Salmon Valley was under water, "The railway tracks from the Indian Reserve to Sinclair's farm were under water. The track then was a little lower and the fires in the small wood burning (train) engines were extinguished at every attempt to get through.", wrote Doe. Because the valley roads and rail line were flooded, Dairy Farmer A.J. Palmer had to row his full milk containers in a boat across the bay to "Slough Bridge" on the CPR line to ship it to Kamloops.
A note in the 1894 "Inland Sentinel" newspaper reported: "Salmon Arm crops are in a very precarious condition owing to the spring freshets; nearly the whole valley is flooded. Several of the settlers had to leave their homes last week." The newspaper also reported that valley bridges and culverts were washed away and wagon roads were flooded.
1894 ... Around May 29 after two weeks of warm weather, flooding was reported in Salmon Arm. Nearly the whole valley was flooded and several of the settlers had to leave their homes the previous week. James D. Gordon's bridge washed away and the government bridge on the road to Thos. Shaw's Ranch was expected to go shortly. The roads were flooded and the bridges and culverts were afloat. During the last week of May, following the rains of the previous week, warm weather prevailed in the Okanagan Valley and Upper Nicola. Up to that time, the weather had been very cool. Tappen Siding had reported "rain almost every day." Temperatures were between 80-90F (26.7-32.2C) in the shade. Early June the warm weather continued in the Interior. ... Around June 1 at Salmon Arm, nearly the whole valley was flooded. The previous week several of the settlers had to leave their homes because of the flooding.
6) WATER SURVEY CANADA ARCHIVED HYDROMETRIC DATA

The peak Shuswap Lake levels, measured at Canoe as metres above sea level (MASL), are shown on the following plot (red points). Also shown (blue points) on the horizontal axis, are the corresponding peak Salmon River cubic metres per second (CMS) flow rates, measured at the Trans Canada bridge over the river, for 1970 to 2008. The red line across the plot denotes the high water mark (HWM) for the lake as determined by the province, currently 348.7 MASL.

In each year a slight lag of the peak lake level behind the peak river flow can be seen. The peak lake level occurs on average 30 days after the peak river flow, although the lag times vary widely from year to year, ranging from 12 to 54 days. The following years had lag times of 15 days or less: 1972, 1981, 1985, 1990, 1996 and 2006. Also worth noting is that the contribution (input) of the Salmon River annually to the lake, at approximately 150 million cubic metres (CM) per year, is far less than those of the Shuswap River (approx. 2.8 billion CM per year), the Eagle River (approx. 1.3 billion CM per year), and the Adams River (approx. 6 billion CM per year). The plot shows that there is a clear link between the Salmon River's peak flows and the lake's peak levels. This, however, really implies that the Salmon River's flow behaviour at spring runoff is essentially the same as that of the Shuswap and Eagle, with the impact of the Adams runoff less clear. There is a suggestion from the blue flow points that flow rates for the Salmon River have been increasing during the 90's and beyond, although over the span of 41 years the upward trend is not statistically significant.

The highest lake level in this time span is seen in 1972. Eight out of the 41 years show peak levels above the 348.7 HWM. In 1972 the lake level peaked at 349.7 MASL, i.e. a metre above the HWM, and caused dramatic flooding. Even more widespread flooding occurred in 1948, with the most extensive flooding seen back in 1894. Extensive flooding may occur, e.g. in 1972, when peak level is very high, but peak flow is less dramatic. It may also occur, e.g. in 1997, when peak flow is very high, but peak level is less dramatic. This indicates that the interaction between the Salmon River's spring runoff and the rising levels of the lake during spring runoff is complex. It is clear that flooding of the river's delta and surrounding wetlands can occur not only from the river overtopping its banks, but also from the influx of the lake's water over a land area which has a trivial gradient or slope towards the lake. Additional complications are the damming effect of the CPR tracks across the delta and wetlands (there are only two exits for the river's runoff to escape to the lake, or for the lake's waters to flow onto the delta), and predicted significant increases in peak river flows caused by pine beetle devastation in the Salmon River watershed over the past 6-7 years. The complex interplay between spring river runoff flows and rising lake levels emphatically makes the point that thorough studies of this interplay - studies which have apparently never been carried out here - are critical in developing appropriate flood risk management strategies and insurance, and in guiding good development planning. lake levels and river peak flows 7) PHOTOGRAPHIC EVIDENCE
flood depositsRiver flood (alluvial) deposits. flood lichen linesLichen lines on trees result from frequent flooding.
active floodplainThis May 14, 1993 air photo shows the flood "foot print" of the Salmon River at its peak discharge volume for 1993 of 43.8 cubic meters per second. On that day the river's discharge volume was very near its five year average flood level. The B.C. Riparian Area Regulation sets the 1 in 5 year flood level "foot print" as the indicator of the extent of fish habitat. Much of the water-filled looping river oxbow area in the middle left side of the area, black line marked "subject property", was buried in land fill between September 1998 and September 2001, wiping out valuable fish habitat and functioning flood water dispersion channels. WA:TER believes that this oxbow area must be restored to its former condition.

water flows  top  home



PROFESSIONAL COMMENTARY


NATURE CONSERVANCY OF CANADA

"The mouth of the Salmon River where it enters Salmon Arm is part of one Terrestrial Priority Conservation Area (#25 - Salmon Arm) and two Freshwater Priority Conservation Areas (#9 - Shuswap Lake and #37 - Salmon River). These PCAs are all rated as having the highest conservation value and highest vulnerability in the Okanagan Ecoregion. ... Of 137 Terrestrial PCAs in the Okanagan Ecoregion, only 14 have these highest rankings. Of additional interest is the fact that the Terrestrial and Freshwater PCAs overlap in the area of interest. ... Areas of overlap have increased relative importance for biodiversity."
SR Delta from Larch Hills

LAUCHLAN FRASER

(October 19, 2009) - Professor and Canada Research Chair in Community and Ecosystem Ecology
"I am aware of a proposed 400,000 sq ft SmartCentres shopping centre on a floodplain at the mouth of the Samon River ... I am adamantly opposed ... The Salmon River is an important ecosystem, providing critical spawning habitat ... and feeding habitat for fish and birds ... Floodplains provide essential ecological services. The proposed development ... would impact hydrology and nutrient dynamics ... , with the additional impact of light, noise, and air pollution and surface water contamination. Not only would this affect salmon behaviour and spawning but it might increase nutrient loading in Shuswap Lake, causing eutrophication. ..." [Full letter]

MARK ANGELO

(Fall, 2009) - Rivers Chair, Outdoor Recreation Council of BC.
"I'm currently heading overseas but wanted to send you a quick note to express my support for your efforts to protect the Salmon River. Like many others, I share your concerns about the potential impacts of a massive shopping center in the midst of the Salmon River's active floodplain, an area that comprises critical salmon habitat. This same area also floods regularly, providing nutrient-rich habitat for juvenile salmon throughout the network of channels that cross the
SR Delta from Shuswap Lake floodplain. The black cottonwood/snowberry habitat found there also has many important attributes and, aside from becoming increasingly rare, it also sustains a number of red-listed species. For all these reasons, the Salmon River found its way onto BC's endangered rivers list in 2008. I greatly appreciate the efforts of you and your colleagues to speak up for the river - and I am very supportive of your endeavours.

All the best, Mark Angelo, CM, OBC, DSc(hc), MSc."

KING CAMPBELL

(October 23, 2009) - Head of BC Agriculture Programs, Ducks Unlimited Canada
"... Like Mary Thomas, it is our focus to look for solutions. DUC encourages city council to direct the energy of the developer and the community towards a solution to protect the environment. A significantly reduced building footprint or development at an alternate location for this extensive proposal will secure a healthy environment; and in the long term will leave a legacy that supports business investment, the community, the lake, waterfowl, wildlife, and the public." [Full letter]
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REPORTS


1. ENVIRONMENTAL ASSESSMENT AND BIOPHYSICAL REVIEW [ Part 1, Part 2, Part 3, Part 4, Part 5, Part 6 ]:
Proposed Development at 2571 and 2971 10th Ave. SW, Salmon Arm, B.C.

Ecoscape Environmental Consultants, 102 - 450 Neave Court, Kelowna, BC V1V 2M2

2. SPRING INVENTORY RESULTS ALONG THE SALMON RIVER, SALMON ARM

Ecoscape Environmental Consultants, 102 - 450 Neave Court, Kelowna, BC V1V 2M2

3. GEOLOGIC DEVELOPMENT OF THE SALMON RIVER DELTA

Dr. Murray Roed, Geoterrain Consultants, 4890 Westridge Drive, Kelowna, BC V1W 3A1

4. SALMON RIVER CHANNEL STABILITY ANALYSIS

M. Miles, Fraser River Action Plan, Department of Fisheries and Oceans, 555 West Hastings Street,
Vancouver, BC V6B 5G3
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