Thursday, June 16, 2016
Ecohydraulics Lab at University of Central Florida
Tuesday, August 14, 2012
Reservoir Operation during a High Inflow or Flooding Period
The framework, as a guideline, requires gathering information on possible inflow scenarios for the probable high inflow or flooding period. These scenarios are inputted into simulation and/or optimization models developed for the task of reservoir operation. The outputs of these models are probability density functions for the value of the objectives function(s) and variables of the model(s). The outputs are generated separately for each different operational alternative. In order to analyze the performance of operational alternatives on each objective, a number of streamflow impact curves are coupled with the outputs of simulation and/or optimization models to translate the variables values into meaningful data to evaluate the alternatives performance and generate a performance matrix for each alternative.
Sunday, May 20, 2012
Multi-Criteria Decision Making
Tuesday, February 21, 2012
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.
Sunday, November 13, 2011
To P3 or not to P3? Abbotsford's Stave Lake Water Project Woes
![]() |
| 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.
Wednesday, October 26, 2011
Moment Matching for Inflow Scenario Generation
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.
Saturday, July 23, 2011
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.
Wednesday, July 13, 2011
Mixing water and oil
- 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
Sunday, June 12, 2011
An Introduction to Wastewater Treatment
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
Thursday, June 9, 2011
Forest harvesting impacts on peak flows
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”
Wednesday, June 8, 2011
Happy World Oceans Day!
Thursday, June 2, 2011
Amazing song about Tahltan First Nations Sacred Headwaters Campaign
Rachelle van Zanten is a fantastic Canadian singer/songwriter who recently wrote a song for the Tahltan First Nation's campaign to protect the Sacred Headwaters of the Nass, Skeena and Stikine Rivers in BC. Check out this emotional and fantastic music video by Taylor F.
Through some geographic serendipity, these three rivers are all born in the same watershed, a place of wild beauty and untouched terrain. The watershed is also home to Caribou, Wild Salmon, and many other less famous but equally important species.
So it is concerning, to say the least, that Royal Dutch Shell is planning to drill over 1000 Coalbed methane wells into the this watershed, potentially causing damaging effects to this ecosystem stretching from the headwaters to the Pacific ocean. The potential ecosystem-level damage of this project has had little voice. Recently, though, it got one. The female elders of the Tahltan First Nation conducted a peaceful protest to stop initial drilling of Klappan Mountain by Fortune Minerals, and most of the elders were arrested. The second voice, was Rachelle.
Click here for more information on the campaign, and check out this teaser for a great film called Awakening the Skeena.
What better way to celebrate world oceans day than to listen to music about water and protecting our sacred province!
Monday, May 16, 2011
Steven Solomon's thoughts on water scarcity
Friday, May 13, 2011
Running Dry
Tuesday, May 10, 2011
World Oceans Day is June 8th!
This year WOD is focusing on Youth: The next Wave of Change. I encourage you to check out the websites that explain WOD, and think about organizing an event of your own to celebrate. How about inviting the neighbourhood kids and their parents to your house, a local park, or community center to do a workshop on rainwater collection for garden watering! Maybe even a day of kayaking the coast or going to the closest beach to turn over rocks and look for crabs!
It's time to make our coastal areas and the oceans that connect them a priority. I'll post again about WOD closer to the day!
