Thursday, June 16, 2016

Ecohydraulics Lab at University of Central Florida

I just want to let our readers know that I am currently doing my PhD at University of Central Florida where I work with Ecohydraulics group. We have recently launched our lab website which I thought might be of interest to you, so here's the link to our lab website: You may also want to check my personal webpage at: We expect to post about and discuss many aspects of our research in water resources.

Tuesday, August 14, 2012

Reservoir Operation during a High Inflow or Flooding Period

Making a decision on the best way to operate a reservoir during a flooding or high inflow event is a multi-objective and challenging task; and depending on the size of the reservoir, the level of success is usually highly affected by water level in the reservoir before the event occurs. Therefore, decision making before and during these events is too complicated to be handled only by reservoir operation planners’ judgement. A Risk-Informed Decision Making (RIDM) framework to acquire all the necessary information from multiple sources and providing planners with the collected information and a pre-designed and solid guideline to follow in order to make recommendations to decision makers seems to be the best approach to deal with this task.

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. 

Finally, the performance matrices, decision makers desirable risk-taking level on each objective, and relative importance of the objectives are inputted into a Multi-Criteria Decision Making (MCDM) software package. The outcome is a ranking of the operational alternatives for the task of reservoir operation during the flooding or high inflow period. If the recommended alternative is acceptable to decision makers, the corresponding operational plan might be implemented. Otherwise, the decision makers might order developing new operational alternatives and reiterating the process.

Sunday, May 20, 2012

Multi-Criteria Decision Making

Decision Making could be defined as a process in which a decision maker makes a specific choice among several existing choices. Multi-Criteria Decision Making (MCDM) as its name suggests pertains to a decision making situation where the decision maker considers multiple criteria in order to make a choice. Benjamin Franklin is allegedly the earliest known person to create a simple method to solve this type of problems. As a result of the rapid growth of operations research during and after World War II, numerous methods have been invented to help decision makers face the challenge of MCDM problems. As an invaluable book on MCDM, Smart Choices by Hammond, Keeney, and Raiffa is strongly recommended to interested readers. Moreover, for a thorough description of MCDM history and other information and resources related to MCDM, you may have a look at MCDM Society website. I also spent some time working on developing a new method for solving MCDM problems with the use of fuzzy numbers, which enable more flexibility in taking account of uncertainties, and the results are published in a paper that might be of interest to you. With a simple search into literature, the variety of approaches and techniques to solve MCDM problems will be revealed.

MCDM techniques can be very helpful in solving water related problems due to the fact that most of the large-scale water related decisions impact multiple active components in a watershed system. (This concept was the base for the definition of Integrated Water Resources Management by Global WaterPartnership in 2000). If you have read the previous post, one of the applications of MCDM in water resources planning and management is in planning for reservoir operation. In fact, MCDM is somehow an impartible component of a Risk-informed Decision Making framework for reservoir operation during floods. I hope to be able to explain each of the components of such a framework through a number of posts in the future and explain how they connect and create a coherent framework in the end.

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

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.

Wednesday, October 26, 2011

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.

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.