Modelling the quality

As the last post of 2015, let’s look into water quality modelling, in this post we are going to look at the importance of quality modelling and introduce a modelling package.

Importance of quality modelling 

Water availability is dependent on quality and quantity. During the last decades, the water courses have been deteriorated due to anthropogenic discharges of nutrients. The European Directive and the Water Framework Directive both refer to affluent loads and the problem of eutrophication. Mathematical modelling is a useful tool to estimate the pollutant loads into an aquatic environment, to establish relation between what pollutants has what kind of effect on water quality, and to predict the response of the aquatic environment under different scenarios. These simulations are useful tools for management as they assist the decision makers to come up with strategies that considers the basin conditions as well as what the effects could be in case of accidental discharges (Oliveira et al, 2012).

The quality of the freshwater is threatened by population growth, development and expansion of agricultural and industrial activities, and changes in hydrological cycle as a result of Climate Change. The water scarcity hand in hand with decreasing water quality has forced the countries to look into remediation options for river water quality, and hence effective water management strategies to ensure sufficient water supplies with high quality is required (Vieira et al,2012).

QUAL2K

QUAL2K is water quality model for rivers and streams. The model includes many elements such as considering a one dimensional model, assuming the channel is well-mixed both laterally and vertically, assuming steady state, non-uniform for flow hydraulics, heat budgets, and water-quality kinetics that are dependent on heat and mass inputs (Chapra, Pelletierand Tao, 2012).

The model divides the river into smaller sections of “reaches” and “elements”. Reaches represent a length of the river with constant hydraulic characteristics such as slope, bottom width etc. Then each reach can be divided into smaller equally-spaced units called “elements”. The model’s computations are carried out for each element. Then flow balance calculations are carried out for each element by considering a steady-state flow balance equation, then considers the hydraulic characteristics and the presence of weirs. Each element is then considered as an idealized trapezoidal channel and uses the Manning Equation to express the relationship between flow and depth (which we will not get into because I enjoyed other subject more than fluids dynamics!). The model also has a temperature model component and calculates the net absorbed radiation as well. Then the mass balance and flow biochemical reactions are calculated (Chapra,Pelletier and Tao,2012).

In order the get the correct result, a series of computations should be done since they are interdependence. Meaning that a variable such as surface mass transfer coefficient (s) depends on another variable (SOD), which itself is dependent on ammonium and methane concentrations, and so on. Hence, an iterative technique is used in QUAL2K to calculate the fluxes of nitrate, ammonium, and methane, etc. (Chapra, Pelletier and Tao,2012).

Pretty complicated modelling package! It has integrated different fields of water chemistry, fluid dynamics and fluid thermodynamics! Join me in 2016, where I will look into some case studies that have used this package and the results they got!

Wishing you all a fantastic year ahead!

So long,

Activist à Paris- COP21 Coverage

“People with great passion can make the impossible happen.” After knowing her for more than three years, I think it is safe to say that she truly is passionate about what she does. Myrto Skouroupathi is an inspiring Environmental Engineer and activist doing her best and playing her role in finding a solution.She is currently studying for her MEng degree in Environmental Engineering at UCL.

 

I texted her saying that we should catch up and that I wanted to interview her about her experience in Paris. Few minutes later, we are sitting down in the café with our drinks, waiting for them to cool down and I took out a pen and some papers and said “well I think I’m gonna start the interview now”. 

She introduced herself as a member of Fossil Free UCL campaign and an environmental activist. The aim of the campaign is to get UCL divest from fossil fuel companies. “If fossil fuels are bad and wreck the planet investing in them is bad as well.” (And I have to say they have quite an interesting campaign that made some news headlines last year as well. I will show some sneak peaks at the end, but if you are interested you can go and check their campaign.)

Myrto with some of her fellow members of Fossil Free UCL headed to Paris on December 10^th.Along with a lot of other activists from People & Planet, Friends of the Earth etc., they stayed in a temporary structure at the Paris Event Center, provided by the government. The next day they got medical and legal briefing at the ZAC (The Climate Action Zone),during which they were advised on what to do if they got arrested or if tear-gas or pepper spray were used! -quite scary. On the 12^th, Day of Action, they set out to the streets of Paris along with people from Indigenous nations at Norte Dome and Arc de Triomphe, carrying red flowers in honor of past and future climate  victims.

source : The Irish Times

 “It was empowering to see so many people. When I was in the street marching with thousands of people, knowing that we're risking getting arrested, I really felt that we had the power.” She talked about how fascinating it was to witness the bond the indigenous people have with nature and to hear their stories and how they are experiencing the impacts of Climate Change. She told me the story of  a 19 year-old native American boy and how he was saying that his tribe, which relies on what nature provides for their survival, was struggling to provide for their people due to their polluted water, and how he clearly remembers his grandfather being able to feed the whole family by fishing few years back. “It is disheartening how the most vulnerable people are not portrayed.” 

Source : Indigenous Environmental Network

 

 Being confused about the agreement myself, I asked what she thought of the COP21 results. “Activists considered it a failure. The fact that the agreement is not legally binding is a big flaw. To me, it even shows that many leaders still don't consider climate change a big issue, otherwise they wouldn't have their people's futures depending on the good will of other leaders and industries”. She then continued saying that even if the countries “behave” and fulfill their intended INDCs, we will still be dealing with 2.7 degrees of warming, results of which are going to be catastrophic. Furthermore, that the agreement does not talk about how the target is going to be achieved and there is no mention about facing out fossil fuels. This is perhaps due to a lot of lobbying from fossil fuels companies and the fact that some decision makers actually believe that geoengineering can be the solution. She then said that the main gap in the agreement is the fact that it fails to mention the rights of indigenous people, who will soon become climate refugees if the warming exceeds 1.5 degrees. “The world we are creating is one where thousands, even millions, of human lives are considered collateral damage, worth sacrificing in the name of endless development. The system we live in, survives and thrives on exploitation: of resources, of people, of their birth lands, of nature. As long as the agreement is made on the same terms, for me it is bound to fail.” 

Her response to how each of us could contribute and be part of the solution, was to educate ourselves as much as we can, but we should do it outside of our computers and rooms, as “you’ll never fall in love with nature if you lose touch with it." She then stated that if we want to fully understand the people who have suffered from climate change , we should put ourselves in their shoes, and this is not done by just reading about them. she continued. We should then spread our knowledge and find what we are good at and use it for good.

“How would you summarize your experience?”

“Paris was not the game changer we were expecting. We didn't achieve what we wanted. The indigenous people returned to their sinking and dying homelands with no promising news. The few in power got richer, the millions in poverty got poorer. Yet what I experienced in Paris filled me with awe and hope. In the end it's up to you to decide what's more powerful: Millions of people across the world risking their safety and even their lives for a better, fairer world, or a handful of elites cowardly hiding behind their money. Personally, what I keep from Paris is this: When the police came to break a peaceful ceremony of indigenous people thanking Mother Earth for all that it has provided, we all held hands and one of the indigenous people said : “Don't let go. We will leave, but we are all connected.” WE ARE ALL CONNECTED...” 

Source: Isabel Bennett member of Fossil Free UCL

Well that is a wrap for this post, hope that you enjoyed it and that you gained some new perspective. It sure taught me new things and widened my view and reminded me the importance of sharing your experiences as well as hearing others'. As Myrto concluded, we are all connected and we should see climate change as OUR problem and not let the fact that we are less vulnerable make it less important.

Before I end this post I am going to leave you with some links to check out if you are interested and as promised share some of the Fossil Free UCL campaign pics.

The Fossil Free UCL campaign Facebook

you can also sign their petition here

The Indigenous Environmental Network website

The Indigenous Environmental Network Facebook

Source: Fossil Free UCL

Source: Fossil Free UCL

Source: Fossil Free UCL