Greater Vernon Water Utility instituted Stage 1 water conservation measures indicating that our water supply is in danger of running short.
Obviously, there are consequences of such measures in terms of budgetary shortfalls, business activities and inconvenience to domestic and business customers.
Using the information presented below I believe that we are reasonably well off with our water supply and our customers were quite responsible users of water if for no other reasons they were frugal with their money. So read the presentation below and decide whether or not my information is credible.
Figure on below the Duteau Creek reservoir levels on July 15, 2015.
Figure 1
Figure 1 above demonstrates the status of the Duteau Creek reservoir on July 15, 2015 provided by GVWU staff at the August 6 GVAC meeting. The August 1 level was penciled in by staff as well.
Note the total capacity of the reservoir at slightly over 18,000 ML (18,000,000 cubic meters). On August 1 it contained between 12,000 to 12,500 ML's of water.
Figure 2
Agriculture irrigation ends on September 15. Based on the above two figures it is unlikely to have water shortages at the end of the irrigation season.
There is more. The 2012 Master Water Plan was designed based on estimated domestic water demands from 2011 to 2052 as demonstrated by Table 1 below. According to those estimates domestic water demand in 2011 should have been 9,670 ML and by 2052 it would increase to 13,360 ML. The MWP was sized based on these estimates. However, the consultants also provided a Technical Memorandum suggesting methods to reduce consumption.
Unfortunately, these recommendations were not considered in sizing the MWP system. We actually paid for a plan that is over sized. The real consumption for the years 2011-2014 is depicted in Table 2. While some over sizing is desirable one must also consider the cost implications of an over sizing of 52%. However, that is not the point. The point is that the customers have consumed well below the projected consumption levels and it is not necessary to punish them further with an additional 10% consumption reduction.
Unfortunately, these recommendations were not considered in sizing the MWP system. We actually paid for a plan that is over sized. The real consumption for the years 2011-2014 is depicted in Table 2. While some over sizing is desirable one must also consider the cost implications of an over sizing of 52%. However, that is not the point. The point is that the customers have consumed well below the projected consumption levels and it is not necessary to punish them further with an additional 10% consumption reduction.
Table 1
As demonstrated by Table 2 below the actual consumption during the four years from 2011 to 2014 was only about 61% of what was predicted.
Table 2
Table 3 below demonstrates that the agricultural consumption levels were even more significantly lower lower than what was allocated by the MWP. Instead of using 17,400 ML the actual consumption for 2011-2014 averaged at 39% of predicted or 6,823 ML.
The forgoing demonstrate that both domestic and agriculture consumption are well below that of expected. The question is then: how can we be short of water when we only use 61% of the predicted domestic consumption and 39% of allocated agricultural consumption? As was shown above the Duteau Creek reservoir holds 18,000ML of water and we use an average of slightly over 6,800 ML per year. Duteau could easily provide the actual annual agricultural demand plus the small volume of domestic supply.
Staff also revealed that they are utilizing the Kalamalka source more in order to save Duteau water. That means that we probably use some Kalamalka water for crop irrigation. I believe it would be worth exploring what really is happening with our water supply.
One additional water source is Goose Lake with an annual storage capacity of 2,360 ML/a. That would be an additional source to supplement the agriculture water supply.
Table 3
Table 4 below is the actual consumption table from the GVWU Annual Report 2014. Note the total water consumption (domestic and agriculture combined) for 2014 was 12,630,961 cubic meters. Compare it to the Duteau reservoir capacity at 18,000,000 cubic meters and the available water licenses on Kalamalka Lake of 8,800,000 cubic meters. Are we short of water?
Table 4
I might be wrong in my assessment even though I used data provided by staff and consultants. If I am wrong please show me where I erred.
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4 comments:
Its big business telling everyone that we live in a desert and are running out of water, think of all the high paying jobs on the line telling us what bad waterhogs we all are, and how we have less water available than anywhere else in Canada...and that the average person uses 675 l per day. If that were the case the GVWU bank account would be overfilling, just like the dams do every year in this dry desert.....
Excellent analysis, Mr. Kiss.
The bureaucrats simply don't want to go against the province's "request" that the entire province reduce water usage by 30 per cent.
Thank you for what you do!
The "% difference" column in Table 2 meaningless.
The way this number has been calculated provides no useful information, other than to show a very high percentage designed to support your argument. In fact, this number could be in excess of 100% if actual water demand had been less than 50% of predicted water demand. What would a number in excess of 100% even mean?
A more valid calculation would be to show the actual water use a percentage of projected water use. In 2011, actual water demand was 65.8% of predicted water demand. In 2014, actual water demand was 60.5% of predicted water demand. I would agree that the predicted demand is overstated, but why is this the case? Engineers don't make predictions, they make projections based on a number of assumptions. It is far better to overestimate demand and to size system based on projected peak demand than to have as system that is undersized and unable to meet peak demand.
If the politicians don't like the assumptions used to calculate the projected future water demand, then work with the professionals doing the work to come up with a set of assumptions more to your liking.
It is good practice to design systems with safety factors, excess capacity etc. I would rather have an oversized water system that one that is at 100% of capacity all the time. The cost of a larger diameter pipe is inconsequential when you already have the trench dug and have to repave the road anyway.
My presentation was entitled: "Water supply review. Are we really short of water in Greater Vernon?"
What I tried to point out was that we are using significantly less water than for what the system was designed. That, I believe, I did. I questioned the need to reduce consumption by 10%. Ten percent of what? 10% of the design capacity, 10% of last year's consumption or what nebulous point we could consider 100%? I do believe we should not waste water but the consequences of unnecessary cut in usage is revenue shortage. To recover the revenue shortages rate increases will have to follow. In the past rate increases had the most adverse effect on low water consumers. My concern is for low water consumers who proportionally bare the largest share of the utility costs.
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