MORE STUFF ON CHASE RIVER DAMS

Lawrence Rieper : jULY, 2013

In 1903, the following city reservoirs were listed, along with their capacities:

  • #1=  8 million gallons (after 1910 = 14 million gallons);
  • #2 = 11 million gallons;
  • #4 = 71 million gallons;
  • #6 = 22 million gallons

(City of Nanaimo, Finance Department, Series 6, Published Financial Statements 1901- 1932, Nanaimo Community Archives)

#1is currently the city reservoir, and #2 is the Upper Colliery Dam on the other side of
Nanaimo Lakes Road. #4 is now known as Morrell Lake or Power Line Dam.. It is believed that #6 was until not so long ago on the Chase River, south of the Rifle Range and north of the Fish & Game Club (It supplied water to the City by a 10-inch pipe).

In 1976, the following reservoirs are listed, along with their surface areas:

  • #1 = 3.83 acres (Sect. 1, Nanaimo Dist. & Sect. 4, Range 8, Mountain Dist.)
  • #2 = 5.89 acres (Sect. 3 & 4, Range 8, Mountain Dist.)
  • #3 =  6.34 acres (Sect. 1 & 2, Range 7, Mountain Dist.)
  • #4 = 18..64 acres (Sect. 7 & 8, Range 9, & Sect. 7, Range 8, Mountain Dist.)
  • #5 =   7.05 acres (Sect. 1, Nanaimo Dist. & Sect. 5, Range 8, Mountain Dist.)

(Taken from a Certificate of Encumbrance dated 26th August 1976, NCA)

Again, #1, 2 and 4 are straightforward. #3 appears to be #6 renumbered. #5 is an oddity, an allocated space between #1 and Middle Colliery dams (Harewood Improvement District, 1970 Water System Map, NCA) .Some present day covered reservoirs are numbered too: #2=Lost Lake; #3A/B=College Park; #4 = Rod Glen; #7 = Tanya Drive.

From the above, there is historical evidence of a number of extra dams feeding into the Chase River. The older ones would originally have been wooden structures.#1, which dates from 1887, was rebuilt with concrete in 1910. #2 was rebuilt after collapsing in 1921. #4 was rebuilt in 1985.The last two are earth berms.
I surmised in my, “Deny. Deny, Deny” that dotted line shown in the 1963 Chase  River Inundation Study, from Morrell to Westwood Lake might indicate water flowing from Westwood into Morrell. Having looked more closely at the topography,   I believe the opposite is true. If the two dams at the north end of Morrell Lake were to break, water would flow towards Westwood Lake, but possibly dissipate en route.

In 2004, Morrell Lake was drained in about two weeks using a 12 inch pipe. The water flowed southeast along the power line, then east at ‘MC’ gate, under the Yew Trail bridge and under Nanaimo Lakes Road into the Chase river. It filled up within the first winter.. It is now necessary that the lake be drained again soon.

There has been consultation with the city of Nanaimo and Dam Safety Branch regarding timing so as not to affect water flow in the Chase River and Colliery dams. Quite soon, the Western Toads (Anaxyrus Boreas) will develop from tadpoles and move from the lake into the woods, an optimum time for draining Morrell Lake. Whether or not the water in Morrell Lake can significantly affect the downstream, CON and DSB seem concerned about the possibility.

There are Red-Legged Frogs (Rana Aurora) at Morrell Sanctuary. The 1980, “An Ecological Survey of the Harewood Colliery Dam Park”(NCA) lists Red-Legged Frogs at Colliery Park.
Like the Western Toad, these amphibians are listed under Canada’s Species At Risk Act, Schedule 1-Special Concern. Since there is a waterway linking Morrell and Colliery lakes, it isn’t much of a stretch to anticipate Western Toads at Colliery Park too. There is also the possibility of the herb Beggarticks, another Species of Special Concern and Townsend Moles, an endangered species, at Colliery Park.

Not very long ago I was asked about a waterway flowing from Westwood Lake, through Nanaimo Military Camp to Chase River. I didn’t think it very likely. However the 1944 map of the camp (NCA) shows an un-named creek running from the old ammunition bunkers nearest to Westwood Lake through the southwestern section of the camp, under Nanaimo Lakes Road and into the Lower Colliery Lake. It is also partly shown on more recent city maps. It is not clear whether or not water could flow from Westwood Lake.

In the Nanaimo Daily Free Press for April 28th, 1960, under the heading “Harewood Buys Park For $24,000 Over 20 Years,” was the following, “………Colliery dams, covering 60 acres, which have been acquired this month for $24,000 from the Canadian Collieries after being leased for three years……….Improvements at the dams include stocking with fish, construction of truck bridge and floodgates to regulate flow, development of a  gravel pit, trails, diving boards, beach and other facilities to improve the area” The park had been leased for three years previously. It has been rumoured that special considerations were placed on the deal when the dams were purchase, or when they were handed over to the City of Nanaimo at amalgamation. The A.F.Buckham Papers at BC Archives contain a number of correspondence files that might have some mention of the sale. The question remains whether or not the safety issue that staff have been pushing, would trump a legal responsibility to maintain the dams in perpetuity, always supposing such a document exists, or could some compromise be found?

It has been shown that some of the speculation in the 2010 Seismic Hazard Assessment Middle & Lower Chase River Dams was flawed, particularly regarding lack of rebar in the concrete and not being attached to bedrock. However it is the 2012 Chase River Dam Breach Flood Inundation Study that is the problem. It assumes that the dams would collapse very quickly by earthquake or flood and a huge surge of water would flow down the Chase River killing over a hundred people. I suggest thoroughly analyzing the 1963 Chase River Inundation Study and the 2002 Chase River Incremental Damage Assessment in comparison to the 2012 study. Only the maps of the 1963 (and BC Archives does not permit me to publicize it) and 2002 studies have ever been seen (City website -Hazards). We must demand the full reports be made public. They both model breaches of more dams on the Chase River system with the release of more water than the 2012 study. We need to know what conclusions were drawn from these earlier studies. If they are radically at odds with the latest study, then serious doubts must be cast on the findings of the 2012 inundation study. I have also shown in my “Is Nanaimo Safe?” that there is reason to question the 2012 Population At Risk and subsequent death toll. What was done at Westwood Dam could be done for the Lower Colliery Dam to slow the release of water to a manageable level, along with other mitigation options.

Lawrence Rieper: July, 2013

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