Posted on: November 27, 2017 | Water Levels
November 13, 2017
Precipitation rates this summer were near normal until the end of June, with fairly severe drought in July through to late September. The made the draw down rather short and effective overall. Heavy rains in the first half of October extended the drawdown of West Hawk later than it should have, but dry weather since has allowed surplus water to be drained out slowly through the winter without causing the ice on Caddy to rise.
1) Falcon Lake water level control- Preliminary Design Study
The Falcon River has been proven inadequate to handle the discharge flow rate produced by even “normal” heavy rainfall, however, the scope of the options examined does not extend to increasing it’s capacity. Similarly, the options examined do not include re-direction of the Falcon Creek away from Falcon Lake to discharge directly into the Falcon River.
The options DO include 2 gravity drain (stop log) alternatives – one to replace the existing control structure, and the second to replace the existing rock weir, gravity drainage structure with additional stop-log control channels. The 3rd option examined uses the south shore access road as a dam, and provides a pumped discharge, which may work better than the gravity drains – if the Falcon Creek were diverted.
The originally forecast completion date in October 2016, has now been extended to December 2017 or January 2018. The Department (Manitoba Infrastructure) has decided to review the study with the First Nations affected before completing the study. Hopefully, the study will be distributed to the stakeholders affected prior their holding a Study review meeting in order to give them a chance to study the recommendations made before being asked to make comment on it. Regardless of the actual completion date, we can no longer anticipate a new control structure being completed in 2018. Time for selection from the options studied, preparation of the detailed design documents, and tendering of the work, now puts construction into 2019
2) Falcon Lake boat access channels dredging;
No action to relieve this situation has been taken by Sustainable Development as yet, even though this work would have a dramatic impact on the cost of the Level Control Structure discussed above. We’ve been told that there are insufficient funds available to carry out remedial works. Given that these channels were constructed as an inducement by the Province to encourage the development of back-tier cottages in this area; the lack of maintenance of the channels is seen as a dereliction of the Provincial responsibility to maintain access to leased property.
The availability of funds to carry out maintenance of infrastructure is currently under review. A decision on how best the WCA should proceed is pending the outcome of these discussions.
3) Caddy Lake Flood Abatement and Low Water Management
Both of these issues were addressed in a 1976 study carried out by Sustainable Development’s predecessor. Responsibility for the flooding was determined to be the inadequacy of the tunnels under the CN and CP railways crossing the Whiteshell River. Estimates of the costs for the tunnel expansion needed were quite high, so no action was taken. The study did not examine the impact of these tunnels individually, and upgrading the second tunnel (CN Rail) alone may provide substantial flood relief. The CN Rail tunnel is about the same size as the CP Rail tunnel that serves Caddy Lake, and yet the CN tunnel must handle approximately twice as much water – thus creating back-pressure on the CP Rail tunnel. Segregating the impact of these tunnels on flood conditions, has been requested of MI in a study currently underway by MI’s Flood Protection group.
Low water management (relief from excessively low water levels caused by the flat weir discharge control structure at North Cross Lake) could be resolved by raising this weir. However, a fixed weir would exacerbate the flooding issues during high volume spring runoff. This means that the weir modification would have to be at least partially constructed by adding an adjustable stop log weir on top of the existing fixed weir. Both the cost of construction (estimates from the 1976 study – escalated to today’s cost put this work over $1 million) and the difficulty of accessing this location, makes this measure less attractive . This issue will be discussed further with MI following completion of the study that is currently underway.
4) Central Whiteshell Lake Level management:
The lakes in the central park (Big Whiteshell, Lone Island, Jessica, White, and Betula Lake) would stand to benefit from an increase in water supply in relatively dry years such as the one just past. There is potential for directing discharge water from Crowduck Lake into Big Whiteshell instead of Eaglenest Lake. This would allow retention of water from another drainage basin inside the Whiteshell Park . A relatively low level portion of the isthmus dividing Crowduck from Big Whiteshell, may permit the development of a flow channel connecting the two lakes, and adding level control facilities on both the new and existing drainage channels would leave the water level of Crowduck unchanged from what it is now.
Though this is a fairly low priority issue for the committee (compared to previously identified infrastructure improvements), its potential to improve the water level and water quality on these lakes should not be ignored. A topographic survey to assess the potential to establish this connection was discussed with MI during our meeting on November 9th.
5) Betula Lake – Low Water Level Management
Betula has suffered severely low water levels this summer due to low rainfall. A Preliminary Design Study of raising the discharge weir to retain more water was requested again during recent meetings with MI. There is potential for launching this study following completion of the similar study underway on the Caddy Lake discharge.
6) Winnipeg River Water Levels
Concerns have been raised by Directors from the area regarding current low water levels. Their concerns stem from the risk of damage to shoreline infrastructure if the water level is allowed to rise after freeze-up has occurred. The LWCB which regulates the flow in the Winnipeg River has heightened sensitivity to this issue due to similar concerns expressed by WCA’s Water Levels Committee over the last 2 years. They are currently raising the flow in the river in an effort to reduce the probability of having to raise it after freeze-up.
Shelley Pastrick from Dorothy Lake has agreed to join WCA’s Water Levels Committee. We’re looking forward to better representation of the area than we’ve enjoyed in the past.
7) Vice Chair: Neil McMillan (Jessica Lake) has agreed to serve as Vice Chairman of WCA’s Water Levels Cmte.
Summary Prepared by: Alan Roberts – Chair of WCA’s Water Levels Committee