The following is an pdf open letter addressed to the citizens of Alberta, from Bill Wahl of Medicine Hat. The letter expresses how Mr. Wahl has been affected by floods, but also points out how water in Alberta is being managed and areas for improvement. Have a read and please continue to share your thoughts with us through Facebook, Twitter or Email. Thanks for sharing, Mr. Wahl!
An open letter to the Citizens of Alberta
Flood Recovery and/or Flood Prevention
My name is Bill Wahl and I am frustrated!!
Like others in Medicine Hat and Southern Alberta we live in proximity of the South Saskatchewan River [have for 40 years] and have been affected by flooding, all-be-it not this year due to the installation of a high tech backflow preventer after the 1995 flood. We are thankful to family and friends who helped us move out of our home and for better preparedness of disaster services.
The main reason for my frustration is that I always thought that the dams on the tributaries of the South Saskatchewan River were there in part to help us out during times of impending floods. The Alberta Government meetings after the ’95 flood reported that flooding was caused by a severe precipitation event that occurred in very close proximity to the Oldman River Dam. That and a combination of technical issues caused by washed out flow sensors, telephone communications and the short time from onset of precipitation to significant increases in inflow did not give dam operators sufficient time to spill water ahead of high water entering the dam. Although dam safety was never an issue, water was released from the dam at a rate no greater then inflow. So what happened this year? According to records obtained from Alberta Environment and Sustainable Resource Development, the 2013 peak was ~5590 cm3/s and the 1995 peak was ~4200 cm3/s. The gauging station reports of the 2013 peak was more than 1m higher than 1995. The cross section of the river valley at other locations will affect this value to some extent. Levels in Medicine Hat never reached those predicted with an increase of 50 cm3/s increase in flow rate over 1995 reported. Persons who experienced the 1995 levels commented on water levels about 20 cm higher; all this being enough to cause significantly damage in Medicine Hat. How is it that the dam[s] that impact our flow rate could not have done more to mitigate flood issues this year given the knowledge gained from the ’95 flood, and new technologies for weather forecasting? We have experienced more floods in the past 20 years than the first 20 years of living by the river.
Using the internet, phone, and communicating with acquaintances I have learned a few things. My first conversation was with an engineer who works with a team of others who oversee Dam Maintenance and Integrity. During our conversation he kept referring to the ‘owners and operators’ when discussing dams and reservoirs. After farther prompting I learned that the majority of large Alberta dams and reservoirs are privately owned and operated. Most of water contained in these facilities is used for irrigation which has an economic benefit to both owner and user; or, for the production of hydroelectricity which is sold back to the grid for consumer use. It is to the owners and operators benefit to keep water levels in their facilities as high as is safe to do so. Most of the dams and reservoirs upstream from the South Saskatchewan River were at or around 98% of capacity prior the June flood. It appears that only the Ghost Lake and Reservoir near Cochrane was overly high, and it looks like they had already moderated two significant inflow events. The purpose of a reservoir or dam is specified in its licence; owner/operators function within guidelines provided by the Alberta Government. They have considerable autonomy and the Alberta Government cannot mandate that they lower their water reserves in an attempt to mitigate flooding. Their main priorities are to maintain a quantity of water to best meet their intended purpose without adversely effecting dam integrity.
My next contact was an acquaintance now retired after being involved with the Alberta Water Commission. He confirmed what I had learned from the Dam Safety Engineer and added some additional information. Two of the major dams in the Saskatchewan River System, the Oldman and the Dickson on the Red Deer, are operated for different priority purposes.
The Oldman is a strategic impoundment created to meet the needs of the downstream irrigation districts, which have their own infrastructure to manage day to day water call needs. The Oldman is typically lowered over the course of the summer as licenced demand exceeds natural river flow. The Oldman reservoir is filled the following year with the spring freshet and early summer precipitation. Each irrigation district will have their internal reservoirs at preferred levels by the end of the irrigation season (end of Oct). This also allows the Oldman some flexibility going into summer depending upon moisture reserves, precipitation, and degree of expected snow melt in the cordillera. As we have seen, if the Oldman reservoir gets too full, they will release water according to established guidelines and also to ensure the structural integrity of the dam itself. Operators are very cognizant of the impact of flood flows downstream; regularly managing small peak flows to keep the river below bank full, and operating during large events to attenuate the peak to the extent possible.
The Dickson Dam upstream of the City of Red Deer has a slightly different mandate. The priority for the reservoir is to provide stable downstream flows between 40-50cm3/s. This supplements natural flow and contributes to the Instream Flow Needs and Water Conservation Objectives that have been established to ensure aquatic health and assimilation of contaminants from downstream urban centres such as the Cities of Red Deer and Drumheller. Another purpose of the Dickson is to ensure a minimal flow regime throughout the winter, essentially for the same purpose as mentioned above. One of the secondary functions of the Dickson is to help manage downstream flood attenuation, particularly for Red Deer. It is interesting to note that Red Deer and Drumheller did not sustain the same flood damage that was experienced farther south in part because of less precipitation. Part of the operational complexity for the Dickson involves providing recreational levels of water in the reservoir that has, over time, become known as Glennifer Lake. It is a well beaten path in Alberta where reservoirs built for domestic or agricultural use have become recreational destinations surrounded by expensive developments. Dam and reservoir usage and guidelines vary and the province has little appetite for adjusting the existing operational policies for the dams. However, there could be room to gain some efficiencies of use that would benefit downstream users, especially in times of water shortages or to assist in downstream flood attenuation.
A telephone call to the Department of Municipal Affairs resulted with me being contacted by a representative of the Alberta Environment and Sustainable Resource Development. This was extremely helpful, confirming that operating guidelines for Waterton, St Mary and Oldman require the reservoirs to be drawn down over the course of the summer to a maximum level for the winter, balancing the probability of filling the next year and the probability of needing to manage a large snow pack and run off in the spring. as high as is safe. Issues of not having enough water would be very concerning on many fronts. Even with advanced weather forecasting it is difficult to totally predict what might occur in the various catch basins of the South Saskatchewan River System. The farther away from the mountains the water travels, the more difficult it is to predict flow rate and rise. This was experienced in Medicine Hat as the crest forecast of the 2013 was delayed numerous times. The Oldman Dam did store incoming water in the flood pool and the surcharge zone. Outflow from the reservoir was increased very soon after inflows became significant and continued to increase in sync with inflows until the peak flow occurred. Operations did not lower levels in anticipation of increased water flow into systems to the north. It was also interesting to find out there are no dam/reservoirs upstream from the Glenmore Dam in Calgary but there are more numerous dams upstream from Calgary on the Bow. Dam and reservoir owners and operators do not work collectively to proactively mitigate flooding by lowering levels in anticipation of high stream rates and levels downstream. It was suggested we need a review of the purpose and operation of dams in Alberta. The goal would be to determine whether water management can better meet daily requirements of water use and consumption as well as mitigate potential environmental catastrophes that storms and climate change might cause. This would be to everyone’s advantage.
Do I feel a little bit better? Perhaps a little, I think pressure needs to be put on the Alberta Government to make flood attenuation a huge priority. Consider the disruption that would have resulted to transportation of goods and commodities if bridges in Medicine Hat would have gone out. The destruction of public and private property in southern Alberta was massive as a result of this flooding. We need to ask the question: what did the managers of the Diefenbaker Dam in Saskatchewan do to regulate the increased inflow so that flooding did not happen as it did in 1995? All Albertans are contributing financially to the flood recovery efforts as provincial and municipal administration redirect funding from other initiatives into the recovery process. When multiple insurance claims are paid out, some companies increase all premiums in an attempt to top up reserves. There are municipal administrations like Edmonton who have created a series of dry ponds that are sports playing fields until they are required to become reservoirs to store excess water that storm sewers can’t handle. I am sure that there are coulees and valleys on crown land near some of our large dams that might be put into service in a similar way. Over the years Albertans have contributed more than $4,000,000,000.00 of taxes and revenue into the formation and development of our dams and reservoirs; perhaps it’s time to formulate a new model of how this network is managed.