Risk-Informed Decision Making

Once more busy with an interesting project at BC Hydro that might be of interest to you too. Decision making for planning and management of water resources can be an utterly challenging task where several stakeholders with a diverse range of interests and consequently several objectives are part of the process. As an example, operating a hydro-power dam is a task normally done with consideration of several competing objectives such as maximizing power generation and minimizing adverse environmental impacts. They are competing where a long term operational plan demands storing water in the reservoir for later power generation while there is a minimum required flow to be released for a healthy river environment known as environmental flow. Case by case, there might be several other objectives and concerns such as recreational opportunities, water supply for residential and/or irrigational use, navigation etc. This process becomes much more challenging where the reservoir is also being used for controlling floods. The difficult task of reservoir operation planning for minimizing flood damage during flooding periods accompanied by other operational objectives and exacerbated by the lack of time for decision making won't probably be successful unless there is a comprehensive Risk-Informed Decision Making (RIDM) framework. The framework should utilize advanced inflow forecast and scenario generation methods and be able to inform decision makers of the risks involved with each possible decision.

For a better understanding of an RIDM framework, you might be interested in looking at NASA's RIDM handbook which is available for download at NASA's website.

To P3 or not to P3? Abbotsford's Stave Lake Water Project Woes

I'm finding this Stave Lake Water Project and the decision about whether or not to enter into a P3 agreement very interesting. Check out this presentation I found on the official SLWP website if you haven't seen it already. Also, here's an interesting blog on this project (again, note the City-owned twist)

Source: City of Abbotsford SLWP Presentation

Note that this presentation and blog are created by the City of Abbotsford, who, it seems very clear, WANT the P3 desperately (my guess is so that the incumbent can run on a platform about "saving you money"). But there's more to this.

I'm not convinced this particular P3 is a good idea. Makes me think of SNC Lavalin and the Canada Line being at full capacity on opening day because they wanted to drive the profit margin up by making the platforms smaller. Now, we're left with a poorly planned billion dollar capital investment project that we can't expand. duh. If it had been municipally planned and executed, they would have planned giant platforms like the Millenium Line that would last 100 years because they don't want to go back in again - and for them, there's no profit in it. Because it was a P3, going back in is big money. So I'm not convinced that P3's are the way to go with municipal responsibilities such as water - especially over 25 years! It's incredible how many responsibilities municipal governments are shirking.

What's even more interesting is that the annual cost difference between P3 and non-P3 water - although it will be much higher than it is now  - seems to be pretty minimal ($610/year vs. $550/year). I wonder how they account for such a small difference in annual costs when the P3 has almost $140 million more in savings to the City. Where is all that money going? Never mind how crazy it seems that the only way a municipality can get money from the Fed's for capital infrastructure investments is through P3's? That seems a bit wacky, to say the least.

If there's one thing that the banking crash taught us, it's that lax government regulations and P3's are putting government responsibilities in the hands of businessmen who are as wealthy as they are because they drive down the bottom line and plan poorly for long term sustainable development.

... and all anyone is seeing is "vote yes" signs. I wonder where the "vote no" signs are?

Am I way off base here? Wadda y'all think about this bizness?

To get way more information than what I'm supplying here, just google "Abbotsford Stave Lake Water Project". The Tyee has a great story on incumbent Patricia Ross.

Moment Matching for Inflow Scenario Generation

If you have read the previous posts, you know that as opposed to my fellow contributors, my approach to water problems is from an engineering perspective. So one more time I intend to share with you an engineer's perspective through the application of statistics to solve water related problems.
The main topic that I intend to introduce to you today is called moment matching, but first I will explain why we use moment matching for planning and management of water resources. In order to plan the long-term operation of a hydropower reservoir - through utilizing approaches such as stochastic dynamic programming - operation engineers need to have access to the forecasts of future inflows into the reservoir. Clearly, a great deal of uncertainty is inevitable in forecasting future inflows and operations engineers have to consider the pertaining risks. One of the useful methods to managing uncertainties is generating multiple inflow scenarios. Usually inflow scenario trees, which consider the dependency of the inflow at a time step to the inflow at the previous time step, are the desirable structure. Generating multiple potential scenarios of future events through analyzing the available data from similar events in the past is a common approach in many areas of research with numerous practical applications. Similarly, there are several statistical methods to generate scenarios of the inflows into a reservoir through the use of recorded inflows in the past. One of these methods I have been working with recently is called moment matching. It is not always possible to detect the statistical distribution of an event, which is the basis of several inflow forecasting methods, with the available historical data. In these instances, moment matching could be a useful surrogate. As its name implies, moment matching is a method that generates scenarios that match the statistical moments of the historically recorded data. Which moments to include is up to the researchers and depends on the specific problem they are trying to solve. For the case of inflow scenarios, for instance, there some studies have used moment matching for generating scenarios that match the first four statistical moments (expected value, standard deviation, skewness, kurtosis) and also the correlation coefficients (could be serial, seasonal, or spatial correlation) between historical inflows. In 2003, Michael Kaut and his colleagues wrote a paper on developing an efficient algorithm for scenario generation with the use of moment matching. If you are interested in learning more, or if you think the algorithm could be of use to you, do not hesitate to visit Michael Kaut’s website for free access to a full source code of the algorithm.

Annacis Island Wastewater Treatment plant

Secondary Treatment for metro Vancouver

Tucked away neatly on Annacis Island, metro Vancouver’s largest wastewater treatment plant is overwhelmingly large. The plant build in the 1970s originally only provided primary wastewater treatment. Almost 30 years later, before the turn of the millennium, it was upgraded to secondary treatment. Currently the plant cleans the water of over 1 million people. It received around 350 million liters per day in the summer and around 700 million liters per day in the winter. The plant is primarily cleaning influent from residents.

After the mechanical process of the primary treatment (primarily a physical separation) the water entering Annacis island goes through two secondary wastewater treatment processes. The first one is the trickling filter. This is done in towers filled with rocks. The water is expelled through a stream at the top of the tower, and then the water is allowed to flow through the rocks. From there the water is brought over to activated sludge tanks. Here natural soil bacteria are added to the water and they consume and dissolve organic material and consume whatever is consumable. What is left is called floc and this settles to the bottom of the tank. After this process is completed there are only approximately 4 parts per million (PPM) of total suspended solids making the water exceed the minimum standards of the of the Canadian Council of Ministers of Environment. At the end the water is disinfected by chlorine, removed of the chlorine and then pumped into the Fraser river.

The various sludge and floc remaining from the various processes is thickened and digested over a 20 day period, where it is then made into biosolids. The Annacis Island wastewater treatment plant trucks out 4 trucks full of biosolids every single day. The majority of it is trucked (with costs carried by the plant) in order to reclaimed strip-mines throughout the BC province.

Mixing water and oil

I’d seen it before, but that didn’t matter.  The huge gaping holes, the mounds of oily earth, the cutlines breaking up the boreal forest for as far as the eye could see.   Flying over oil sands mining and in situ operations north of Alberta’s Fort McMurray makes one think about the how impacts of our thirst for oil are felt. 

I traveled to Fort McMurray as an Associate with Waterlution, a national non-profit aimed at encouraging dialogue around water issues, at pattern-making and pattern-breaking and at exploring how to have a healthy and sustainable relationship with water.  Waterlution brings together members of industry, First Nations, non-governmental organizations, government and academia to discuss hot water topics in the areas where they’re happening. 

This workshop, “Drilling in the Oil Sands:  Water Usage, Development and Innovation”, took a group of 20 passionate and engaged individuals on a fly-over of open-pit and SAGD operations.  The reactions were varied, but everyone’s eyes were opened.  Throughout the weekend, the group was presented with perspectives from Cenovus Energy, The Pembina Institute, Alberta Environment, the Clearwater Heritage River Society and the Canadian Association of Petroleum Producers. 

The objective of the workshop was to encourage dialogue around some of the major issues associated with water use in the oil sands.  Some of the most prevalent topics of conversation and questions that arose over the three days were:

·      What are the cumulative impacts of in situ operations in northern Alberta?

·      What steps are industry members taking to protect water resources?

·      How is groundwater regulated?  What are the impacts of extracting groundwater and injecting disposal water?

Oil is typically extracted from oil sand in one of two ways: 

1.     Open-pit mining, which mines the oil sand deposits close to the surface by physically removing the processing the sand.  This type of operation results in large pits and often uses freshwater resources from surface waters.

2.     In situ extraction, which removes the oil from below the surface using steam, solvents or some combination of the two.  This type of operation has measurably less impact on the surface and often uses brackish (saline and not suitable for drinking or other industrial uses) water from aquifers.

Both of these types of operations must dispose of wastewater left over from the processing.  Open-pit mines store their waste in tailings ponds.  In situ operations inject their disposal waters back into aquifers. 

The workshop included a tour of Cenovus’ Christina Lake in situ operation to develop an understanding of oil extraction by steam-assisted gravity-drainage (SAGD).  These operations inject steam, generated from heated groundwater, underground to separate oil from the sand and pump the oil to the surface.  The water is extracted from aquifers, which in most cases are brackish.  Cenovus is taking great strides toward efficiency of water use in these operations, which helps to reduce the steam-to-oil ratio (SOR) – an important measure of water efficiency in in situ operations.  High efficiency SAGD operations have an SOR of about 2.5 (barrels of water per barrel of oil).  In comparison, open pit mines may have water to oil ratio of over 4.  In both cases, a proportion of the total water used to produce each barrel of oil is recycled and used multiple times in the process. 

All water use, surface water or groundwater, requires a license in the province of Alberta.  Surface waters are heavily monitored and regulated for quality and quantity, primarily because they are relied upon for industrial, agricultural and municipal uses across the province.  Groundwater is relatively poorly understood and poorly regulated.  Monitoring, modeling and regulation are becoming a priority, but with only a fraction of the 89 new proposed or approved in situ projects operating, there is some question what the long-term impacts might be considering the current lack of understanding of the groundwater system. 

This post is intended to provide a glimpse into oil extraction in northern Alberta.  Some resources that can provide additional information and perspective are:

• The Pembina Institute reports on in situ operations
•  Water Matters with a backgrounder on in situ operations
• Canadian Association of Petroleum Producers on Water Conservation, Efficiency and Productivity
• Cenovus Energy on their Christina Lake operation 
• Alberta Environment on groundwater regulation 

One of the best ways to understand and to affect change around an issue is to engage in dialogue with the stakeholders.  Get out there, talk to people and use your knowledge, expertise and energy to get the word out! 

For your interest, check out Waterlution for information on upcoming workshops in your area, including an upcoming workshop on hydraulic fracturing for natural gas extraction in Fort Nelson, BC.  

An Introduction to Wastewater Treatment

Wastewater treatment technologies and their developments are significant in the lives of all people. This is true whether they are conscious of the intricate system under the earth or not. Vancouver, with its population of 2 million, produces around 1 billion liters of wastewater every single day. In cities throughout the world, wastewater must be transported and treated with care in order to contribute to creating a high standard of living for its people.

When wastewater from a city reaches a wastewater treatment plant, it goes through a pretreatment process. Here a 6mm mesh is run through the water to catch plastics or stones or any inorganic matter, which could disrupt the wastewater treatment system. After pre-treatment there are three levels of cleaning technologies available for the water; primary, secondary and tertiary.

Afterwards, the wastewater is transferred into a sedimentation tank. This step of primary treatment is primarily a physical process, where the water is allowed to settle into its different components. The oils and greases rise to float on the water, and the biological waste drops to the bottom to form sludge. This treatment stage can remove approximately 60% of TSS (Total Suspended Solids) from the wastewater. The layers are separated and the solid waste is brought to landfills treated and dried in lagoons to later be used as biosolids. In Vanoucer 2 of its 5 major treatment plants, Iona and Lions Gate plants, still only treat the water with primary treatment.

Secondary treatment can be found in the Northwest Langely, Lulu Island and Annacis island plants. The secondary treatment processes can remove up to 90 percent of the organic matter in wastewater by using biological treatment processes. Generally, anaerobic bacteria is added to the wastewater to break down sugars, fats, and short chain carbon molecules. There are many different types of secondary wastewater treatment technologies available.

The third level or stage of treatment is tertiary treatment. Few cities in the world have achieved the successful implementation of this technology. The controversy in tertiary treatment is its very high costs as well as the end product. The water is clean enough to be returned into the taps of the city. Generally populations are uncomfortable with the use of this type of water. Tertiary treatment generally includes various types of disinfection and microfiltration. It is often called ‘water polishing’ or ‘effluent polishing’.

Recently the Canadian Council of Ministers of Environment announced that all wastewater treatment facilities in the country must be at least secondary treatment plants. In the next 20 years Metro Vancouver plans to upgrade Iona and Lions Gate to fulfill these regulations, as well as fulfill the city’s own sustainability goals.

Click here for a nice explanation of wastewater treatment with visuals: http://www.youtube.com/watch?v=byWWbjcxHxY&feature=related

Forest harvesting impacts on peak flows

As a Hydrotechnical Engineering (one of the areas of specialization in Civil Engineering) student, my area of focus is reservoir operation during high flow events. Although I just use the inflow data other specialists provide me with, hydrology and inflow forecast is the starting point of reservoir operation planning process. Forest harvesting as an influential element which can change the inflow amount until forest regrowth is complete, has been a controversial area of study in forest hydrology.

In the eyes of the public and usually policy-makers, logging trees and removing forests increases the magnitude of floods and consequently exacerbates its destructive impacts. On the other hand, historically, forest hydrologists have tended to rely on the chronological pairing analysis of peak flow events to study the impact of forest harvesting on peak flows which has led them to have opposite views ("Forest impact on floods due to extreme rainfall and snowmelt in four Latin American environments 1: Field data analysis" as one of the most recent examples). Throughout the years, many scientists have demanded that the public and policymakers improve their understanding of natural phenomena such as floods. But is it the public who need to improve their understanding of the behavior of nature?

In order to study the impacts of forest harvesting on peak flows, there are usually two small neighboring watersheds (which are quite similar) that are chosen, one as control watershed which remains unchanged and the other one as treatment watershed which is clear-cut, or treated in another way depending on the objectives of the study. Using statistical methods, the relationship between paired peak flows, which stem from the same meteorological events in the neighboring watersheds, is captured and used to figure out how this relationship changes as the result of clear-cutting in the treatment watershed. This type of pairing of the events is known as chronological pairing. To avoid getting too technical or going through statistical complexities involved in making inferences from the graph results of this type of pairing, let us suffice to say that the related studies tend to conclude that the impact of forest harvesting on the magnitude of peak flows diminishes as the size of the meteorological event increases so that the highest peak flows are almost unchanged. Moreover, in some cases there are suggestions that peak flows with the return period of higher than a particular number of years, like 10, are not affected by logging.

Recently, Younes Alila, a professor at the Department of Forestry in University of British Columbia, and his colleagues have published a paper on the topic utilizing frequency-based pairing of events. In the paper, the authors reveal how chronological pairing of events leads to an irrelevant hypothesis and how the blind use of some statistical methods to support the hypothesis without giving sufficient thought to the process has misled forest hydrologists for several decades. The authors, through appropriate and insightful use of statistical methods accompanied with physical reasoning of natural phenomena, finally prove that the public view on the impact of forest harvesting on floods turns out to be closer to reality than traditional view in the forest hydrology studies.

The publication of the paper as a new paradigm to dismiss years of controversy over the impact of forest harvesting on flood magnitude, at least for small watersheds, has been objected by some scientists who have spent several years of their career on similar studies with opposite conclusions. For further reading, below you can find the links to the original paper, a critique to the paper, and the reply of the authors to the critique.

Forests and floods: A new paradigm sheds light on age-old controversies.

Comment on “Forest and floods: A new paradigm sheds light on age-old controversies” by Younes Alila et al.

Reply to comment by Jack Lewis et al. on “Forests and floods: A new paradigm sheds light on age-old controversies”