FACULTY OF ENGINEERING SCIENCE MODEL BASED RIVER WATER QUALITY ASSESSMENT UNDER CURRENT AND FUTURE CLIMATE CONDITIONS Thanh Thuy Nguyen Supervisor: Dissertation presented in partial Prof. Patrick Willems fulfilment of the requirements for the degree of PhD in Engineering Science August 2017 Gir đạc it a reson on fre Pls transi MODEL BASED RIVER WATER QUALITY ASSESSMENT UNDER CURRENT AND FUTURE CLIMATE CONDITIONS “Thánh Thay NGUYEN Promotor Dissertation presented in Prof. i, P, Willems pata 6lBimen ofthe Fequitements forthe degre of Members of the Esamination Committee: PRD in Eagineering Secace Prof eit H. Heynen, chat Prof dc iW.
Sansen, chair Prof. iL Sets Prof dei E. van Grensven (Ve Universite Bross) Assoc, Prof dt, Hl Ls Pham (Water Resources Universiy, Hanoi, Viet) August 2017 & Technology (©2017 KU Leuke, Scene, Engnceing Uigsgeven in gen ehecr, Thanh Thuy Ngwen, Kenedbph Arenberg 0 — bus 248, 1.50 Hever Belg) Alle rechten worden. Niet it deze agave mag worden vemenigvai!en/of ‘openbaar gems worden deoe mill van de, fotokepe, cri, minh of op wake endee wie ook seeder voønfgamidjte sche teemeg van de ve Al dghe naensd, No part of the p.liodion maybe eproduced in any Em by pm, hotgpdnk miro, cso or ay oe cans without wren pemmdsion fons the publishes Ai he 6 ie Langage i hy ity Kame iy sss Acknowledgements [No one cạn lve om ether peaple but nơ one ean succeed without support and coop son fom ether people, The day I ch my PHD research ie not 0 fr T ‘would like take s moment to thank all the people vho, consciously or unconsciously, have contributed to this work.
First of all, would Hike to thank my promoter Prof Padddk Willems. You brought me t the river water quality modeling since my Master thesis. Afr my Master, you recommended me to kesp working on the river water quality topic for my PRD, Ar thar moment, I thought there wis aot much work ro do and everything was very cleat. Duriag my PhD, I eaized that aothing is periAet thế gestion was how we ean mitigate the disadvaneages and evaluate thr effes.
(On the way to find the answers, I have received your guidanes, comment and cncouragements. Especially, highly appreciate the rust and ficedom you gave me to fill my reeateh in the USA forthe lst 15 years. I would like to thank “Thay Lai University for retchông mỹ position at the university dường mỹ PRD catch 1 would ike to thank Prof. he Smets and Prof, Enk Toorman for the Follow up ‘of my research and foe providing comments and suggestions from the tart of my PRD research to the faa, Your advice helped me to consider the research prublems in a more comprehensive xay In sđẩtion, T vosld ho ike to thank the other members of my jury for sei feedback on my thesis ext.
Prof, An van Gricasven, thank you for sharing your expertise to improve my farute cseuch, Prof. Thi Huong Lan Pham, thank you for making thế log journey to atend my public defence. Prof, Willy Santen and Prof. Hie Heynen, thank you for chhưởng my jun ao thank Prof.
Yoram Rubin and Dr. Susan Hibbard fy offering the opportunity to be a visting student at UC of Berkeley. 1 would bike Acker to thank Anita, Rita, Yana, Edmundo and Mathias for the adminiexive support, Freddy and Gerd For she echnical support Lâm grateful to dhe Interieuhÿ Counci or Development Cooperation (IRO) for ranting 4 years of my PAD research. [also would like to thanh the Danish Hpdrseic Insite (DHI) and Innoxyze company for providing MIKE.
and InfoWorks software licenses, ad the Flemish Environmental Agency (VMM) for sipphing dats, "Thank you Ingeid Keupers for your excellent work on river water qui modding on which I could build further. Thank you Els Vạn Uytven for your <ouperation, and Vincent Wolfs for dlveing the InfoWerks RS dongle to me uring mỹ maternity leave. Tho would ike so thank all ur group members who sombmtel so the development of WETSPRO and the climate change perturbation ool. More thanks go tall oF my ends who brosgh ny home tò Belgium and the ân very clorfl culture environments A special word of thanks goex to my parents, siblings, niec and ngphew: You aways encouraged and supported me to finish my PHD.
1 aio would like to thank Phuong and Simba, who accompanied me since the ‘very frst day of my PHD, We have shared the happy and sometimes though time together, even online or offline any sa proud of being with you, being your wife and your mama, Last bạt not leas, I would like to say thanks eo a very special peeson that L have ‘admired since Iwas small. Your love, your Ife and sour work have been following me and lighting my life and my carer up. Thuy Leuven, Ags 2017 Abstract River water pollution is known sone of the major cmironmengl isues in the world, In order to achieve the sustainable development goals i is crucial to prvvide quantitative information on iver water qualiy. Such information plays a key role in integrated river basin roanagement in genenl ane water qoary management in pariedlar.
Especially climate change with the increase in temperature, extreme flow conditions and changes of ecological systems is predicted to cause watee quality degradation, Ie requtes poley makers o take right remediation actions. Questions have the answered such as how the water quality is, where surface waters are polled, which sources cause stress tớ the rivets, how effective specific actions or measures would be, Many existing methodk have been proposed to answer these questions. They make use of river swatergualty (WQ) observations in combination with models, WQ measurements are limited to some re point long the river and at specifi sme moments “They are also affected by measurement and sampling errs. Therefore, it would be incomplet, inaceurate and uneconomie ifthe WQ seated decision-making would only rely on the available measurements.
By sohing mahematica cations detoibing mansport of pollstants snd their biochemical processes in the aquatic environment, WQ modd can providea more complete picture ofthe WQ state, Theretons, the first main part of the thesit is applying models eo simulate the trảnqpof of pollutants inthe river system and analyse factors that influence this transport Tn the first phase of the research, the three sofware packages MIK 11, Infoorlks RS and InfoWorks ICM were used. In these sofeware packages, only MIKE II and InfolWorks RS allow to model the tine vuiadon in aver bed roughness coocint, The, therefore, were sdeeted for analysing thế seasonal aration oF river bed roughness impacts om water level, The time series of roughness coefficient was calibrated tothe observed water level in MIKE 11, The hộ Aheme time serics of roughness oclfcient in InfoWorks RS was calibrated agains the ‘one calibrated in MIKE, 11 dục to the lack of measured dats, The results show thất InfoWorks RS can simulate the infunce beter than MIKE. 11, but dhe sliferences are relatively small. The ignorance of vegetation growth on the roughness coefident leads to enderesimation in water levels ín summer However, the influence i insignificant during peviods of peak flows.
Because the highese determinant conccntradons often occur during low water level petiods, the influence is impertant for WO modelling studies, The second application ofthe WO move the duy of the influence of model structure uncertaingy on river water quay assessment, First, the physic biochemical processes were sereenel to obtain preliminary assessment on the cite processes and to determine the processes that require a more detdled ‘comparison, Then, local sensivtyanalbs was erred oụt o specify the sensitive pptamercrs and processes. Results show that the hyeeodmamic results, heat transfer rate and ceseration simulations cause lange differences in moddi Simulagon oupots for water temperate and disolved oxygen (DO) concentrations. The ignorance of processes related to sediment trưa, phytoplankton and bacteria has a significant infuence on the higher concentrations of organic matter and lower values of dissoled oxygen ‘concentrations, The thice models show consensus on the main pollutant sources ‘explaining ongunie matter and nitrate concentrations, but diagree on the main factors explaining the DO conecntrdions “The wse of software packages as MIKE. 11 and InfoWorks, which are based on fall hydrodynamic model, show dlificulies in quantifying model structure certainty dục wo the gid Stucrres.
Addisonaly, ro get convergence i results, a small time step is required. The simulation for long periods and big systems requires very long simulation time, Therefor, these models age inapplicable For studies in which many simulations or long simulation periods are needed. One solution isthe use of fast conceptual models. The main contibution of this thesis is extending the COnceptaal River Water Quality madel based on the InfoWorks RS (CORIWAQ-RS) processes and results, The research started from, the code that Keupets (216) developed for MIKE.
11, The model conceptuaizes rivers using cascades of reservoirs and lumps the advection diffusion physica biochemieal processes. The hydeodynamie inputs are derived from the ours of the fall hydrodymamie models. We performed) comparative analysis on the CORIWAQRS and CORIWAQ-MIKEI models. Resuks indicate chat the Aloe » ‘concept medels perform equally wel asthe original MIKE 11 and IniAWorke IRS models, but with much shorter simulation time (10 times).
The successful ‘esting ofthe conceptual mods opens a development avenue towards problem sling in che context of WQ contrl and management. Next, CORIWAQ-RS was considered on the bass of neo «spss of applictions: uncertainty analysis ofriver WQ input and assessment ofeimate change impacts fon iver water quali. In addition to the incomplee knowledge on the WQ pracestes, lack of pollution input data is known as one of the major uicerrinhy sources in WQ modeling Model mmprovement, hence, should focus on obaining more information on the inp/boundhuy conditions, Given that there ate so ‘many pollusant sourees along 2 ver, model improvement actions should focus fon the most important souces to optimize the cost-benelit ratio of the ations Tnpat uncertsindes were modeled by the stochastic regression approach, i adding randomly time series of errors to estimated tine series by regression ‘sations, Based on sensitivity indies related to the model output error variance, important poliudon sources were identified, The contibution of input uncertainties tớ toal model output residuals was guandEod bythe total variance ‘oF made! outpat errors đúc to lips, The application of CORIW.RŠ for climate change impact analysis involved © quancfying climate change impacts on river lows and concentrations; (i) Setermining and evaluating inpur factors that primarily contol the changes and Gi) evalsating the wncerajngy of climate change scenatios on the water quality assessment, recpiation, potential evapotranspiaton and air empeature in 30 climate change scenatios were sradedelly downscaled from 30 Generalized Climate Model runs, The influences ate evaluated for the observed pedod 2000- 2010 and the target period 2050. The hydrologieal made, regression and stochastic approaches were applied t transform the climate change signals for meteorclojedl variables to changes in runoff, nitrogen loads from catchments, DO concentitions and physico-biochemical rates.
It is shown that climate change ma lead co highly negative impacts for DO concentrations, The climate change impacts ats, however, highly uncertain, especially for the high recor periods “The ease study sdected to implement al cbjecites of the doctoral research i the Moise Net sivereatchmeat ia Belgium, Beknopte samenvatting ollie van riverwater stat bekend als đến van cúc voomaamae nilieuproblemen wereld, Om de dourzame onevikkeingsloslen te kunnen benfken is het crucial om kwintitatieve informatie te anayeeren mbt. de riversaternaitt Ze spect cen crle tl in het itera strocmgebiedbeheer in hor algomecn en in het watefbealieiebchecr inet bữzondir. Op velelocuier wereld worden de waterhwaliteitsnormen no niet gehaald. Bovendien kan de Kimuanernndeing de waelaaaltet van waterlopen negiúef belavloeden KHmaarertndring mượt immers voor een toemame in de Iueht en wsteremperstour, voor meer extreme wserloopdcbiren, zowel tocncmende pickavoeren als dalende hagwaterafvoeren, en gereltcerde wiigingen aan het cologich ayvtcom.
Tr is daatoor nocd aan sancti en Limautadapeaiestategicén. Om de ontuikkeling oF het omtwerp vận aulke straps te ondersetnen wordt in modern waterbeheer gcbruik gomsskt van simahdiemodelen.