Monday, November 30, 2015

Latest SAC Questions Answered by GVW

1.    Question: The following submission with questions was received regarding the Kalamalka Lake Water Source:

In preparation for the October 22 Agenda I posed two questions asking how many days over the past four years were the entire Greater Vernon domestic water users on the Duteau Creek Source and how many days on the Kal Lake Source.

The reply was:

i.) Duteau Creek Treatment Plant was shut down for a period of four (4) days in 2013 Due to increased turbidity.

ii.)   Kal Lake Treatment Plant was shut down for a period of one hundred (100) days, one (1)    day to repair a burst pipe and two (2) days for maintenance. The plant was closed for ninety seven (97) days due to increased turbidity.

Of the ninety seven (97) days of closure due to increased turbidity, thirty three days in 2013 were due to milfoil rototilling as well as a number of days in early 2015 for the same reason. The balance of the closure days was due to spring run-off.

It is well known that for most of the year Kal Lake raw water is virtually drinking water quality requiring very little treatment. On the other hand Duteau Creek water source requires a very high degree of costly treatment (with more being proposed).

Staff notes to the statements above: As a water utility, GVW and the authors of the MWP are bound by the BC Drinking Water Protection Act to meet Provincial standards at all times. TM7 completes the analysis necessary to assess if Kalamalka Lake raw water meets Provincial standards, which is the subject at the SAC meeting on December 3, 2015. As an additional note, each turbidity event listed in the Question Paper 1 would normally require a public notification (Water Quality Advisory or Boil Water Notice); however, since we shut dowm MHWTP and relied fully on DCWTP a water quality notice was not required. Public notification causes hardship to a community (stress to customers, increased treatment costs at a customer level, negative view of the community by visitors impacting tourism, etc.) and are expensive to manage for a water utility (increased notification and laboratory costs, dramatic increase in overtime wages, resource allocation to respond to operational issues and public taking staff away from regular duties, etc.).

My questions are:

2.    Question: With the milfoil-rototilling program being confined to the north end of Kal Lake would it not be possible to move the domestic water intake pipe further out into Kal Lake to avoid the fallout from rototilling?

Answer: Milfoil-rototilling is an extremely beneficial service that the Okanagan Basin Water Board (OBWB) provides to our community. Without it, Kal Lake and the local beaches would become overgrown with milfoil resulting in a loss to community recreation and tourist attraction. The extra plant life in the area would also increase the turbidity and organics in the Kalamalka Lake intake, therefore there are additional benefits to GVW as a water purveyor. OBWB staff indicate that all the milfoil must be rototilled to control its growth, hence, rototilling should not be isolated to certain areas.

Notwithstanding the benefits, milfoil-rototilling operations has been acknowledged to impact the Kalamalka Lake intake water quality. In response, GVW staff have been working closely with OBWB and FLNRO (who operate the Kalamalka Lake weir to Vernon Creek) to reduce the impact and are developing operations plans to address this and issues being examined are:

·         Impact to water quality and area being rototilled (OBWB rototillers have installed a gps on their rototillers and location is being correlated to water quality impacts)
·         Assessing impacts on water quality when the weir discharging to Vernon Creek is open verses when its closed. When it’s open, flow from Coldstream Creek flows directly into Vernon Creek and does not reach the intake.
·         Rototilling timing - there is some conflict between what is the best time for GVW and the time that is best time for OBWB which we are currently working through. OBWB’s work window is October 15 to April 1 and the rototiller is shared between Wood Lake and Kalamalka Lake. Wood Lake is more likely to freeze over in early winter; therefore OBWB prefers to start their rototilling on Wood Lake or they may not get a chance if the lake freezes. However, during this window the weir is open and turbidity flows to Vernon Creek. The outflow is controlled by the Province and is shut down near the end of December for fishery purposes. An alternative time is when the water quality in Kalamalka Lake is naturally poor (freshet) and there is a high risk that this source must be turned off anyways; however, this is getting late in OBWB’s season and they prefer completing in colder temperatures for better die off of the milfoil.
·         GVW has been participating in a study in partnership with the District of Lake Country and MFLNRO since 1997. This study includes water sampling at various depths and is being conducted Larratt Aquatics. The sampling period of the study is completed during the growing season (May - November) due to safety issues thus there is water quality monitoring from December to April. It can only be speculated that the turbidity would be less if the intake was extended further and deeper in the lake, however, there is evidence that when the lake is fully mixed (no thermal stratification) and the weir is closed, the flow from Coldstream Creek can impact the water quality at all depths examined and at times, impact the deeper depth of 30 m more during large freshet events.
·         Currently, from an operations point of view, it is a relatively easy task to shut off the Kalamalka Lake intake and service everyone with Duteau water during the times that OBWB rototills, especially when it is a planned shutdown. When OBWB is rototilling, the operations staff are fully aware of the potential water quality impacts and communicate frequently with our municipal operations partners and OBWB. The turbidity and UVT trends are watched closely and as the trend for increased turbidity and/or reduced UVT occurs relatively slowly, the intake is usually shut off before operational parameters are exceeded. This avoids middle of the night or weekend alarms with overtime as all operations groups (GVW, Vernon and Coldstream) and management have a role to play in decision making and turning valves. The switch in water sources is relatively easy from an operations perspective but must be completed in a coordinated fashion and customers must be notified.

3.    Question: By increasing the intake distance further out into Kal Lake it would also increase the depth, would this not negate most of the spring run-off?

Answer: Heather Larratt’s study showed an improvement to water quality if the intake was located at 30 or 40 m in depth instead of the current depth of 20 m (see Table 1 below). However, when the spring freshet is large, the 30 m depth is impacted more than the 20 m depth. See plume diagram Attachment “A”.

It was recommended that if GVW considers increasing the intake that they also keep the ability to draw from the 20 m depth as well when the 30 m intake was impacted. The current intake pipe may result in insufficient suction pressure for the pumps to operate at maximum day demand and cannot be simply extended to the 30 m intake depth. Based on this, two configurations could occur, keeping the current 20 m intake operational and installing a separate larger intake pipe to a depth of 30 m. The study also investigated building a tower with the new intake that has the ability to take water from various depths.

Nonetheless, even though there are benefits of deepening the intake depth, it is not guaranteed that GVW would never have water quality events on this source or that filtration could be avoided long term and hence the MWP recommended that the money would be better spent on filtration to meet the IH water quality objectives on a continuous basis.

Table 1 – Kalamalka Lake: Water Quality Parameters for Various Depths

Kalamalka Lake 2000-2014
North 20 m
North 30 m
North 35
North 40 m
Distance to pumphouse* m
Average temperature oC
# of seiches over 2 oC/yr
Max        seiche        temperature fluctuation oC




Hardness mg/L
Total calcium mg/L
Total organic carbon mg/L
Chlorophyll-a ug/L
Turbidity NTU
UV Transmissivity %
Avg algae counts cells/mL
E. coli cfu/100 mL
<1-270 span="">
<1-40 span="">
<1-1 span="">
<1-1 span="">
Total coliforms cfu/100mL
<1-3700 span="">
<1-530 span="">
<1-19 span="">
<1-1000 span="">

4.    Question: Would a deeper intake pipe all but eliminate the possibility of contamination and clogging from a possible Zebra Mussel infestation?

Answer: No, once Kal Lake is impacted by Zebra or Quagga mussels an increased depth of the intake  would  not  eliminate  the  issue of clogging.                 The  following  is  a  statement from the University of California, Center for Invasive Species Research, see link at:

Where quagga and zebra mussels co-exist, quagga mussels appear to outcompete zebra mussels, and quagga mussels can colonize to depths greater than those achieved by zebra mussels and are more tolerant of colder water temperatures. For example, in Lake Michigan, zebra mussels made up 98.3% of mussels in 2000, by 2005 quagga mussels represented 97.7% of collected mussels. Zebra mussels were found at densities of around 899 per square meter, but quagga mussels now dominate at 7,790 mussels per square meter. Quagga mussels have been found at depths of up to 540 feet in Lake Michigan where they filter feed year round.”

The following link provides further information on the risks from zebra and quagga in the Aquatic Invasives! A Menace to the West produced by the Oregon Sea Grant:

5.    Question:  Why GVW is appear not to be attaching any priority on this situation?

Answer: The question goes beyond the terms of reference for the committee; however, we will provide an answer. As shown in the answers above and in the assessment completed in TM7, it is apparent that GVW has been “putting a priority” on this option for many years now with an 18 year on-going study and more recently the Kalamalka Lake Assessment Plan. The following is a link to the Kalamalka Lake Assessment Plan and other work completed in the Duteau and Kalamalka Lake watersheds: source-assessments-and-protection

6.    Question: (Question has been reworded slightly to provide clarity). There appears that there is a discrepancy in TM3 as it states that “it is predicted that GVW will face increased water supply shortages in the future unless storage is increased to support the predicted growth in the domestic sector.”  Then in Table 2 of the TM3 summary, the following is stated:

Okanagan Lake License

And then TM3 also says Other small transfers from within the same watershed are much more feasible such as transferring BX Creek, Coldstream Creek and other small licenses to either Kalamalka Lake or Okanagan Lake.

Staff assumes the question is if GVW is at risk of increased water shortages unless storage is increased and there is a good chance that a license can be obtained for Okanagan Lake by transferring licenses, then why are we not doing this?

Answer: The MWP review of options took the direction that the analysis would not be constrained by water licenses. This option was certainly explored fully as a viable option as will be seen in TM9, Options Analysis. Whatever option was recommended based on lifecycle costs and the non-cost considerations options rating, then any constraints would be worked through, including obtaining or transferring water licenses required by the option selected. This assumption eliminates the extensive work that may be required to transfer water licences or obtain new water licences to only find out that in the end option was not selected.

7.    Question: (Question has been reworded slightly to provide clarity). Within TM5 there are the three numbers presented: $80.9 million, $137.2 million and $619.6 million. Why the huge discrepancy between these three numbers?

Answer:  Each number represents something different as follows:

·         $80.9 million is the amount that must be spent in order for GVW to install the pipes necessary to twin the distribution system and achieve full separation of the potable and non potable (agricultural) systems. It includes the projects in Table 7-1 of TM5 that are not yet constructed ($63.8 M) in addition to transmission main twinning ($17.1 M) that is required to support fully a separated system for a total of $80.9M.
·         $137.2 million represents the replacement costs of a fully separated agricultural distribution system (pipes only). This would include the $80.9 M that must still be spent to construct the pipes necessary and the infrastructure (pipes) that currently exists in the GVW distribution system that can be used for the separated system (valued at $57 M). In other words, if GVW were to construct a fully separated distribution system (pipes only) from scratch to service its agricultural customers, it would cost $137.2 M.
·         $619.6 million represents the replacement costs for the entire GVW distribution system (pipes only) and includes the domestic and agricultural system. In other words, if GVW did not exist and a water system had to be built to service all GVW customers to the current level of service (pipes only), it would cost $619.6 M to do so.

The costs in the three points above only looked at pipes (mains and transmissions) and did not calculate the value of other infrastructure required to operate a water system, such as pump stations, PRV stations, reservoirs, tanks (enclosed reservoirs), service mains, etc. If these items had been included in the valuation of the above estimates, the costs for each would have been much higher.

8.    Question: When comparing 2013 and 2014, what percentage of the total revenue for water was base rate revenue and what percentage was consumption revenue?

Answer: Question 8 and 9 goes beyond the terms of reference for the committee, a discussion of rates and revenue is addressed by the Greater Vernon Advisory Committee (GVAC) and the RDNO Board as part of budget discussions and did not form part of the work scope of the MWP and hence, is not within the terms of the SAC mandate to discuss or make recommendations. However, we will provide an answer. It is assumed the question is around the ratio between the infrastructure base fee and the metered consumption fees. The following provides the percentage of that ratio calculation but does not include agricultural allocation fees, interest income, grants, meter sales, construction/development fees, etc.

·         2013 Actuals – base 53.1%; consumption 46.9%
·         2014 Actuals – base 54.0%; consumption 46.0%
·         2015 Budget – base 54.8%; consumption 45.2%

Based on YTD (third quarter (Q3) 2015), we currently estimate that 2015 will be approximately 54/46 split of base/metered. Below is a graph presented to GVAC in May regarding prior years ratio of base fee to metered rate.

9.    Question: “Are base rate revenues and consumption revenues maintained in separate accounts”?

Answer: Yes, rate revenues and consumption revenues are tracked in separate general ledger (GL) accounts.

"Waiting for someone to ask why ag lines haven't been separated from domestic lines," offers Kia.

No complaints from agriculture obviously!
If lines were twinned, there'd be nobody to subsidize agriculture's water rates...or lines.