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Ispiranje vodovodne mreže se sprovodi nakon što se za određeni deo mreže, ili zone za ispiranje, ustanovi da je voda izložena visokom riziku od zamućenja (promene boje). Uobičajeno se planiranje ispiranja sprovodi ručno i u većini slučajeva predstavlja dugotrajan postupak. Za definisanje plana ispiranja određene zone mreže, neophodno je napraviti skup uzastopnih poteznih ispiranja kojim se ceo deo mreže ispira. U svakom poteznom ispiranju se ispira deo sekundarne (i tercijarne) mreže. Za svako potezno ispiranje potrebno je uz pomoć niza manipulacija zatvaračima na mreži, usmeriti tok vode od fronta čiste vode ka ispustnom hidrantu. Frontovi čiste vode predstavljaju granice dela mreže koji je okarakterisan kao „čist“. Mogu se definisati kroz merenje mutnoće na licu mesta, ili nakon ispiranja konkretnog čvora (odnosno dela mreže u kom se nalazi čvor). Tokom ispiranja cevi, tok vode koji se koristi za ispiranje, mora da ispuni određen skup hidrauličkih kriterijuma, kako bi se promena mutnoće vode, ili zagađenje, adekvatno otklonilo. Sa stanovišta nadležnog komunalnog preduzeća, plan ispiranja mreže treba da bude ekonomičan u pogledu minimalnog utroška vremena i resursa (npr pijaće vode) za njegovu implementaciju. U ovom radu, mogućnost automatizacije i optimizacije planiranja ispiranja, uz pomoć novo razvijenog FPA (eng. Flashing Planning Algorithm) algoritma je testirana i analizirana. FPA algoritam je napravljen kako bi na adekvatan način odgovorio na gore navedene zahteve. Flushing of the drinking water distribution systems is conducted after a certain part of the water distribution network, or the flushing zone, is identified to be a subject to a high risk of discoloration. Typically, flushing planning is performed manually and is usually time-consuming. To derive a flushing plan for a flushing zone, a set of sequential flushing operations needs to be defined. In each flushing operation the parts of the secondary and tertiary network, meeting multiple criterion, will be flushed. For each flushing operation a set of valves manipulations is needed to converge the water flow, from a clearwater front, through the pipes that are set to be flushed, and out of the system via output hydrant. Clearwater fronts are network nodes on the boundary of the network which is deemed as “clean”. They can be defined through in-situ turbidity measurements, or after the actual flushing of the node (part of the network containing the node). To perform the pipe flushing, the water flow used to flush a pipe, needs to meet a set of hydraulic criteria, in order to allow for the discoloration to be appropriately addressed and removed. From the water utility perspective, the flushing plan should be economical in terms of the minimal expenditure of the time and resources (e.g. drinking water) for the implementation. Here, a possibility for the automatization of the flushing planning with the newly developed FPA (Flushing Planning Algorithm) algorithm, was tested and analyzed. The FPA algorithm was designed to address the flushing planning by taking into the account all the above-mentioned criteria.

Za potrebe modeliranja mreža pod pritiskom u praksi se najĉešće koristi EPANET softver, globalno priznat kao pouzdan i robustan. EPANET koristi formulaciju osnovnih jednaĉina koje opisuju teĉenje u mrežama pod pritiskom poznatu kao metoda ĉvorova, za ĉije rešavanje se primenjuje metoda globalnog gradijenta (Global Gradient Algorithm – GGA). Alternativna formulacija metodi ĉvorova jeste formulacija metode prstenova (ΔQ metoda). Osnovna prednost formulacije metode prstenova je znaĉajno manji broj nepoznatih veliĉina, što proizilazi iz ĉinjenice da realne mreže imaju znatno manje prstenova nego ĉvorova. Osnovni nedostatak je neophodna identifikacija prstenova u mreži koja nije jednoznaĉna. U ovom radu je predstavljena nova metoda za hidrauliĉki proraĉun mreža pod pritiskom (TRIBAL–ΔQ), zasnovana na novom algoritmu za brzu identifikaciju prstenova u mreži (TRIBAL) i efikasnoj implementaciji ΔQ metode za rešavanje osnovnih jednaĉina sistema. Cilj predstavljene metode je da iskoristi oĉigledne prednosti formulacije metode prstenova i prevaziĊe poteškoće procesa identifikacije prstenova postojećih metoda baziranih na istoj formulaciji. TRIBAL–ΔQ metoda je testirana na ĉetiri primera realnih mreža razliĉite topologije i složenosti. Poseban akcenat je dat poreĊenju brzine proraĉuna TRIBAL–ΔQ metode sa GGA metodom implementiranom u EPANET. Rezultati ilustruju da, iako zahteva veći broj iteracija za konvergenciju, nova TRIBAL–ΔQ metoda ostvaruje istu preciznost proraĉuna uz bolju numeriĉku stabilnost sa znaĉajnom uštedom raĉunarskog vremena. The most popular software for hydraulic analysis of pressurized water distribution networks nowadays is EPANET, globally recognized as reliable and robust. EPANET uses node-based formulation of governing equations and employs Global Gradiet Algorithm (GGA) to solve hydraulics of the network. Alternative formulation to the node-based one is the loop-flow formulation of governing equations, also known as the ΔQ method. Main advantage of the loop-flow formulation is significantly lower number of unknowns to solve for, coming from the fact that real-sized networks typically have far less loops than nodes. Main drawback is the need to identify loops in the network, a task with multiple alternative solutions and proven to be cumbersome. This paper presents new TRIBAL-ΔQ method for hydraulic simulation in pressurized water distribution networks, based on the new algorithm for identification of loops in the network (TRIBAL) and more efficient implementation of loop-flow method for hydraulic simulation (ΔQ). Main goal of presented method is to exploit obvious advantages of the loopflow method and overcome main drawbacks identified in similar researches. TRIBAL-ΔQ method is tested on four networks varying in topology and complexity. Focus of research is on a comparison of computational efficiency of TRIBAL-ΔQ based solver with GGA based solver implemented in EPANET. Results indicate that TRIBAL-ΔQ based solver is significantly computationally faster than GGA based one, equally accurate and has slightly better numerical stability

This report describes the development of the Flushing Planning Algorithm (FPA) for deriving flushing plans to address discolouration in drinking water distribution systems. The application of the FPA to the water system serving Amsterdam, Netherlands (Waternet), is presented.

The subject of this report is presentation of abilities of sectorization algorithm to identify and create District Meter Areas (DMAs) within the water distribution network of the city of Amsterdam. District Meter Area (DMA) is a distinct hydraulic area of the WDN, separated from the rest of the supply system by isolation valves and one or more metered inlets and outlets (Burrows et al., 2000). Sectorization of Water Distribution Network (WDN) into District Meter Areas (DMAs) is a proven measure for proactive leakage and pressure control. It is considered as the most cost-effective strategy for the control of real water losses. Setting up DMAs can be potentially useful even for water utilities that operate WDNs that do not suffer from high volumes of non-revenue water, such as Amsterdam city WDN operated by Waternet. For example, improved control of the contamination spreading can be considered as an additional significant benefit. Sectorization of WDN must be designed carefully, as required network interventions can endanger network’s reliability in terms of water supply and pressure distribution. Complexity of the real life WDN results in many different alternatives in which network sectorization can be done. Sectorization of WDN into an optimal system of DMAs is a hard task to achieve, especially for the existing and continuously operating WDNs. Every WDN is unique in its topology, characteristics and key sectorization objectives, so there is no common procedure for sectorization of WDN into DMAs, but rather a series of guidelines provided by the different water and other authorities (Butler, 2000; Farley, 2001; Morrison et al., 2007; WAA & WRC, 1985). Sectorization solutions are usually obtained by the “trial and error” technique conducted by a local expert, familiar with all the WDN specifics. Practical application of such approach is illustrated in Grayman et al. (2009) where two large case study networks are redesigned to implement typical DMA design and to allow additional control and isolation of the system in order to improve water security. Beside general criteria given by the aforementioned guidelines (e.g. DMA size, network length), sectorization process should be driven by the case-specific criteria such as required number of feeds, fire flow regulations etc. A more formal approach to sectorization problem, that will enable investigation of alternative sectorization solutions for large WDNs, adopting local design criteria is presented within this research program. Sectorization method employed in this analysis is named DeNSE (Distribution Network Sectorization). It is developed at the University of Belgrade, Faculty of Civil Engineering (Vasilic, 2018). DeNSE sectorization method is based on newly developed uniformity index metrics (Vasilic et al., 2020) which drives the sectorization process and identifies clusters in the network. Originally, DeNSE method relies on common engineering heuristics for placement of flow meters and valves to create DMAs. Although being able to produce a good set of feasible sectorization solutions, using only engineering heuristics limits the search space of potential solutions. In this research DeNSE methodology has been further improved to include an optimization procedure to ensure finding (sub)optimal sectorization solution within the broader specter of feasible sectorization solutions. Least investment for field implementation and maintaining the same level of WDN’s operational efficiency are adopted as sectorization’s main design criteria. Additional local design criteria, specific for the Amsterdam water distribution network, have been included also. These upgrades made to the original DeNSE method proved to be significant, which is confirmed by testing it on two real-life case studies which are part of Amsterdam WDN. Reported results prove that developed method can be used as a decision support methodology valuable to practicing engineers commencing implementation of sectorization strategy in WDN.

Sektorizacija odnosno podela vodovodne mreže na osnovne zone bilansiranja (eng. District Meter Areas – DMAs) predstavlja najisplativiju i opšte prihvaćenu strategiju za kontrolu vodnog bilansa, pritisaka i smanjenje gubitaka u mreži. Izbor zona bilansiranja nije jednoznačan zbog čega je identifikacija optimalnog rasporeda izuzetno zahtevan zadatak, naročito u slučaju postojećih distributivnih sistema. Pored osnovnih kriterijuma (npr. veličina zona i dužina mreže) postupak sektorizacije treba da obuhvati i dodatne „lokalne“ kriterijume specifične za mrežu koja se razmatra kao što su minimalni broj dovoda, zadovoljenje protivpožarnog opterećenja itd. U ovom radu je prikazana metodologija za sektorizaciju zasnovana na primeni novog indeksa uniformnosti mreže (eng. Uniformity Index) koja omogućava identifikaciju klastera u mreži ujednačenih po potrošnji. Optimizacioni algoritam, podržan inženjerskom logikom, je korišćen za određivanje položaja kontrolnih uređaja (zatvarača i merača protoka) na granicama prethodno identifikovanih klustera, čime se uspostavljaju zone bilansiranja. Osnovni kriterijumi za vrednovanje i izbor optimalnog rešenja su minimalna ulaganja u neophodne intervencije u mreži i očuvanje pouzdanosti sistema. Rezultati testiranja metodologije na realnom primeru vodovodne mreže, sa primenom lokalnih kriterijuma, potvrđuju da može biti od značajne koristi u inženjerskoj praksi u procesu sektorizacije. Sectorization of Water Distribution Network (WDN) into District Meter Areas (DMAs) is a proven measure for proactive leakage and pressure control. Sectorization of WDN into an optimal system of DMAs is a hard task to achieve, especially for the existing and continuously operating WDN. Beside general criteria (e.g. DMA size, network length), sectorisation process should be driven by the case-specific criteria such as required number of feeds, fire flow regulations etc. This paper presents sectorization algorithm that utilizes newly developed uniformity index which drives the sectorization process and identifies clusters in the network with uniform demand. Engineering heuristic is coupled with optimization algorithm in order to search the broader range of feasible solutions and identify (near)optimal positions of flow-meters an isolation valves on clusters’ boundary edges, converting them to DMAs. Least investment for field implementation and maintaining the same level of WDN’s operational efficiency are adopted as main criteria for solution evaluation and selection of preferable solution. Testing algorithm on a part of real-life WDN, subjected to the specific local design criteria, proved it can be a valuable decision support tool for sectorization process.

Many water utilities, especially ones in developing countries, continue to operate low efficient water distribution networks (WDNs) and are consequently faced with significant amount of water (e.g. leakage) and revenue losses (i.e. non-revenue water – NRW). First step in reducing the NRW is assessment of water balance in WDN aimed to establish the baseline level of water losses. Then, water utilities can plan NRW reduction activities according to this baseline. Sectorization of WDN into District Metered Areas (DMAs) is the most cost-effective strategy used for active leakage (i.e. water loss) control, achieved by monitoring the flow data on DMAs’ boundaries. Sectorization of WDN has to be designed carefully, as required network interventions can endanger network’s water supply and pressure distribution. In this thesis new methods and algorithms, aimed to support making more effective and objective decisions regarding the WDN sectorization procedure, are presented, tested and validated. Presented methods and algorithms are part of proposed decision support methodology compensating for disadvantages in available methods, valuable to practicing engineers commencing implementation of sectorization strategy in WDN. Main sectorization objective adopted in methodology presented in this thesis is to design layout of DMAs that will allow efficient tracking of water balance in the network. Least investment for field implementation and maintaining the same level of WDN’s operational efficiency are adopted as main design criteria. New sectorization algorithm, named DeNSE (Distribution Network SEctorization), is developed and presented, adopting above-named objective and design criteria. DeNSE algorithm utilizes newly developed uniformity index which drives the sectorization process and identifies clusters. New engineering heuristic is developed and used for placing the flow-meters and isolation valves on clusters’ boundary edges, making them DMAs. Post sectorization operational efficiency of WDN is evaluated using adopted performance indicators (PIs). Top-down approach to hierarchical sectorization of WDN, particulary convenient for water utilities constrained with limited funding and insufficient reliable input data, is also implemented in DeNSE algorithm. New method for hydraulic simulation, named TRIBAL-DQ is developed to address the issue of low computational efficiency, recognized in available sectorization methodologies employing optimization. TRIBAL-DQ is a loop-flow based method which combines the novel TRIangulation Based ALgorithm (TRIBAL) for loop identification with efficient implementation of the loop-flow hydraulic solver (DQ). TRIBAL-DQ method is tested on various networks of different complexities and topologies. This thesis reports only results of testing on literature benchmark networks, used to validate methods’ performance. TRIBAL-DQ method based hydraulic solver is compared to the node based solver implemented in EPANET, most prominent software for hydraulic calculation of WDN. New TRIBAL-DQ solver showed significant dominance in computational efficiency, with stable numerical performance and same level of prediction accuracy. DeNSE algorithm is benchmarked against other available sectorization methodologies on real-sized WDN. Obtained results demonstrate the ability of DeNSE algorithm to identify good set of feasible solutions, without worsening operational status of the WDN compared to its baseline condition. Reported computational efficiency of the algorithm is one of its strong points, as it allows generation of feasible solutions for large WDN in reasonable time. In this field, algorithm particularly outperforms methods employing multi-objective optimization (e.g. minutes compared to hours). Комунална предузећа која управљају водоводним системима, нарочита она у земљама у развоју, суочена су са проблемима дотрајале и лоше одржаване дистрибутивне мрже који за последицу имају значајне количине воде која се губи у дистрибуцији. Први корак ка смањењу губитака у водоводном систему је процена водног биланса у дистрибутивној мрежи како би се утврдило почетно стање система, а затим и приступило планирању и предузимању мера за смањење губитака како би се то стање поправило. Најисплативија, и опште прихваћена, стратегија за остваривање овог циља је подела дистрибутивне мреже, односно њена секторизација, на тзв. основне зоне билансирања (ОЗБ). ОЗБ се у мрежи успостављају јасним дефинисањем њихових граница, на којима се инсталирају изолациони затварачи и мерачи протока. Избор ОЗБ није једнозначан, и приликом њиховог дефинисања мора се водити рачуна о планираним интервенцијама у мрежи које могу имати негативан утицај на водоснабдевање потрошача и распоред притисака у мрежи. У овој дисератацији су приказане и тестиране нове методе и алгоритми намењени за подршку одлучивању приликом секторизације водоводне дистрибутивне мреже на ОЗБ. Презентоване методе и алгоритми надомешћују недостатке постојећих метода и могу бити од користи инжењерима који се у пракси баве задатком секторизације дистрибутивних мрежа. Основни циљ методологије за секторизацију приказане у овој дисертацији је дефинисање распореда ОЗБ који ће омогућити ефикасно праћење водног биланса у дистрибутивној мрежи. Основни критеријуми за вредновање и избор оптималног решења су минимална улагања у неопходне интервенције у мрежи и очување поузданости система. У дисертацији је приказан нови алгоритам за секторизацију водоводне мреже, назван DeNSE (Distribution Network SEctorization), заснован на претходно наведеном основном циљу и критеријумима. Секторизација применом DeNSE алгоритма је базирана на употреби новог индекса униформности мреже, који омогућава идентификацију зона у мрежи уједначених према потрошњи. За дефинисање ОЗБ, на границе претходно идентификованих зона потребно је поставити мераче протока и изолационе затвараче. За ове потребе развијена је и приказана методлогија засновна на практичним инжењерским принципима. За процену поузданости система након секторизације коришћени су усвојени индикатори перформанси (PIs – Performance Indicators). Предвиђена је и могућност за хијерархијску секторизацију дистрибутивне мреже, нарочито привлачна за комунална предузећа која располажу ограниченим финансијским средствима и имају потребу да процес секторизације изведу у неколико фаза. Услед проблема са значајним рачунарским временом који имају постојеће методе за секторизацију које користе оптимизацију, у оквиру истраживања је развијен и нови метод за хидраулички прорачун мрежа под притиском, назван TRIBAL-DQ. TRIBAL-DQ метод је заснован на примени новог алгоритма за идентификацију прстенова у мрежи базираног на триангулацији (TRIBAL – TRIangulation Based ALgorithm) и ефикасној имплементацији нумеричког модела хидрауличког прорачуна базираног на методи прстенова (DQ). TRIBAL-DQ метод је тестиран на бројним дистрибутивним мрежама различите сложености. У овој дисертацији су приказани само резултати добијени применом на тест-мрежама познатим из литературе, како би се потврдила њихова ваљаност. TRIBAL-DQ метод је упоређен са методом коју користи најпознатији софтвер за хидраулички прорачун мрежа под притиском – EPANET. Резултати приказују значајну предност новог метода у погледу рачунарске ефикаснонсти, уз очување нумеричке стабилности и тачности решења хидрауличког прорачуна. DeNSE алгоритам је упоређен са постојећим методама за секторизацију дистрибутивних мрежа. Резултати потврђују да је нови алгоритам у стању да идентификује скуп могућих решења, која не угрожавају поузданост система и снабдевање потрошача. Рачунарска ефикаснонст DeNSE алгоритма је једна од његових најзначајнијих предности јер омогућава идентификацију не једног, већ скупа могућих решења за реалне дистрибутивне мреже у релативно кратком рачунарском времену. Ова чињеница посебно долази до изражаја када се рачунарско време DeNSE алгоритма упореди са рачунарским временом метода које користе оптимизационе алгоритме (минути у поређењу са сатима). Belgrade: University of Belgrade-Faculty of Civil Engineering

The uncertainty of the input data for infiltration systems (e.g. estimates of stormwater flow, pollution, terrain characteristics) favors the use of simple physically based models, such as the Green-Ampt method. The modification of the method, presented in this paper refers to the introduction of a time-changing ponding depth, which allows for continuous calculation of the position of the wetting front in the system, without changes in the boundary conditions at every time step (an analytical solution). Initial testing shows promising results for the infiltration basin, and future results will include testing of a biofiltration unit. ICUD 2017 - 14th IWA/IAHR International Conference on Urban Drainage - september, 10-15. , Prague, Czech Republic

This work shows a way to size and calibrate parameters of urban stormwater collection and treatment infiltration system. Its design allows collection of stormwater runoff events for a 2 year return period and infiltration time of less than a period between two critical stormwater events. Functioning of this system has been trialed with chaleng tests, loading the system with clean water, and results obtained have been used to calibrate preliminary hydrodynamic model. This model consists of two parts, one that follows water balanse in infiltration system, and second part which models the infiltration by using simplified Green-Ampt equations. Calibration of the model has been performed by using PEST methodology, and acquired parameter values have been subjected to sensitivity analysis. Conslusions obtained from the model have been used to design monitoring sollution for infitration system, which enables continues performance measurements of the system. U radu se prikazuje dimenzionisanje i kalibracija parametara infiltracionog sistema za prikupljanje i tretman kišnice sa urbanog sliva. Sistem je dimenzionisan tako da prihvati kritične kišne epizode povratnog perioda od 2 godine i da ih infiltrira za period manji od razmaka dva uzastopna kritična kišna događaja. Funkcionisanje sistema je provereno probnim opterećenjem sa čistom vodom i ovi rezultati su iskorišćeni za kalibraciju preliminarnog hidrodinamičkog modela. Model sadrži deo koji prati bilans vode u infiltracionom sistemu i deo koji modelira infiltraciju uprošćenim Grin-Emptovim (Green-Ampt) jednačinama. Kalibracija je odrađena PEST metodologijom, a dobijene vrednosti parametara su proverene analizom osetljivosti modela. Zaključci dobijeni sa modela su iskorišćeni za projektovanje sistema za monitoring infiltracionog bazena, koji će omogućiti kontinualno merenje performansi sistema.

Dividing a complex water distribution network (segmentation) on smaller zones, with defined entry and exit points, is a precondition for better water loss management. In order to obtain these zones, often called District Metering Areas, it is necessary to divide a complex looped water distribution network on separate units by closure of minimal number of pipes. It is convenient to use existing isolation valves, placed earlier in the network, for this task. Water distribution network is analyzed as a topologically sorted system made out of pipes (connections), nodes and existing isolation valves. Segments in the distribution network are defined, where they represent a part of the network that can be isolated from the rest by closing certain isolation valves. Algorithm presented, has the task to, based on the hydraulic model of the water distribution system entered through standard software (EPANET, 3Dnet), define network segments, accidental disconnection of the network parts as a result of the isolation of a segment, as well as a water demand shortfall which will occur due to the segment isolation. Algorithm is based on topological incidence matrices, which are used in the hydraulic model of the water distribution network. Methodology shown is applied on the example of water supply network of the Italian city of Ferrara. Podela složene vodovodne mreže (segmentacija) na manje zone, sa jasnim ulazima i izlazima, je preduslov za uspostavljanje bolje kontrole nad gubicima. Da bi se formirale takve zone, koje se često zovu i osnovne zone bilansiranja, potrebno je složenu i prstenastu vodovodnu mrežu podeliti na odvojene celine zatvaranjem minimalnog broja cevi. Pri tome, zgodno je koristiti postojeće izolacione zatvarače, ranije postavljene u mreži. U radu se prikazuje algoritam za automatsku segmentaciju korišćenjem postojećih izolacionih zatvarača. Vodovodna mreža se posmatra kao topološki uređen sistem koji se sastoji od cevi (veza), čvorova i postojećih izolacionih zatvarača. Definišu se segmenti distributivne mreže koji predstavljaju delove mreže koji se mogu izolovati od ostatka sistema zatvaranjem određenih izolacionih zatvarača. Predstavljeni algoritam za segmentaciju ima za zadatak da na osnovu hidrauličkih modela vodovodnih mreža unetih preko standardnih softvera (EPANET, 3Dnet) definiše segmente mreže, nenamerna isključenja u mreži kao posledicu izolovanja određenog segmenta, kao i deficit u vodosnabdevanju koji će se izolovanjem određenog segmenta javiti. Algoritam je baziran na topološkim matricama povezanosti, koje se koriste u hidrauličkim modelima vodovodnih mreža. Prikazana metodologija za segmentaciju je primenjena na primeru vodovodne mreže italijanskog grada Ferara.

An experimental catchment has been established at the Faculty of Civil Engineering in Belgrade to study urban stormwater runoff generation processes as well as measures for water quality improvements and volume decrease. One of such measures is construction of infiltration basins or soakways that receive stormwater runoff and gradually infiltrate it into the ground. Infiltration is modelled in two ways: by a simplified method and by a method based on sharp wetting front. Both models have been calibrated on data from hydraulic challenge tests with clean water. The paper compares the two modelling approaches and sets boundaries in their usage. Zbornik radova Građevinskog fakulteta

Water distribution networks are complex systems whose task is to deliver to the consumer a sufficient amount of water, of satisfactory quality. Reliability analysis of the operation is an important issue in the planning of further development and maintenance of the existing system. Reliability is considered from multiple standpoints, because besides a task to supply consumers, this domain includes the protection of consumers from potential danger. In this context it is necessary to consider isolation valve system installed in the distribution network whose mission is to exclude certain parts of the network. Segments of the distribution network are defined as parts of the network that can be isolated from the rest by closure of certain isolation valves. As water distribution systems have complex structures, it is necessary to apply the algorithm for defining segments. Presented algorithm has the task to, using the hydraulic models of water networks entered via standard software (EPANET, 3Dnet ), define the network segments, accidental disconnection of the network as a result of the isolation of a segment, as well as a shortfall in water supply. Topological incidence matrices are utilized, which are used also in hydraulic models of water supply networks. Methodology used for segmentation is described through a simple example. Zbornik radova Građevinskog fakulteta

This paper presents a general solutions for disposal of waste and atmospheric waters in the villages Blace and Brus, which were pre­pared under the IPA III component PPF4 - Project Preparation Facility 4, IPA 2010. Legislation relating to the discharge of water - EU Directives, including the Directive on Urban Waste Water, directs towards the selection of separation systems for the collection and disposal of waste and storm waters and treatment of waste waters in treatment plants before discharge to receiving waters. This is particularly important in terms of protecting downstream water flows and prevention of environmental degradation. Simulation models are built, separately for the used and atmospheric water, for the analysis of the existing sewer system and sizing of new. Models were made in the software package 3DNET, hydro information tool which incorporates terrain elevation data, the land use and the geometric data for the network pipes and channels. U ovom radu su prikazana generalna rešenja odvođenja upotrebljene i atmosferske vode naselja Brus i Blace koji su pripremani u okviru IPA III komponente PPF4 - Project Preparation Facility 4, IPA 2010. Zakonska regulativa koja se odnosi na odvođenje upotrebljenih voda - Direktive EU, uključujući i Direktivu o gradskim otpadnim vodama, usmerava ka odabiranju separacionih sistema za prikupljanje i odvođenje upotrebljenih i atmosferskih voda i prečišćavanje upotrebljenih voda u postrojenjima za prečišćavanje pre ispuštanja u prijemnike. Ovo je posebno značajno sa aspekta zaštite nizvodnih vodotoka i sprečavanje degradiranja životne sredine. Za potrebe analize postojećih kanalizacionih mreža i dimenzionisanje novih, napravljeni su simulacioni modeli, odvojeno za upotrebljenu i atmosfersku vodu. Modeli su pravljeni u softverskom paketu 3DNet, hidroinformacionom alatu koji u sebi sjedinjuje visinske podatke o terenu, o nameni površina kao i geometrijske podatke o mreži cevi i kanala.

Efficiency of optimization of water networks in terms of expenditure of computer running time depends on the speed of the hydraulic calculations. In this paper use of the ΔQ method for network calculation, was tested on the example of reconstruction of distribution network in New York City. This method was used in a standard format, as well as in two modified versions. The first modification relates to the use of computed corrections ΔQ for the current situation, in the hydraulic calculation of alternative solutions within the evaluation function. The second modification involves introducing flow corrections ΔQ as additional variables, to be also a subject of optimization. In this paper genetic algorithms (GA) were used as the optimization method, which are efficient in terms of running time and finding suboptimal solutions. Efikasnost optimizacije vodovodnih mreža u pogledu utroška računarskog vremena zavisi od brzine hidrauličkog proračuna. U ovom radu je ispitana mogućnost korišćenja ΔQ metode za proračun mreža na primeru rekonstrukcije distributivne mreže grada Njujork. Ova metoda je korišćena u standardnom obliku, kao i u dve modifikovane varijante. Prva modifikacija se odnosi na korišćenje sračunatih korekcija ΔQ za postojeće stanje, pri hidrauličkom proračunu alternativnih rešenja u evaluacionoj funkciji. Druga modifikacija podrazumeva uvođenje korekcije protoka ΔQ kao dodatne promenljive, odnosno kao veličine koja se optimizuje. U radu su kao optimizacioni metod korišćeni genetski algoritmi (GA) koji su efikasni u pogledu računarskog vremena i u pronalasku suboptimalnih rešenja.

Optimizacijom vodovodnih sistema u postupku projektovanja može se ostvariti značajna ušteda u poređenju sa tradicionalnim pristupom Trial and Error. Najčešće se koriste genetski algoritmi kao optimizacioni metod. Razmatra se ekonomski aspekt kao kriterijum za izbor optimalnog rešenja, i primer kako pravilno formulisati kriterijumsku funkciju. Da bi bila ispunjena hidraulička ograničenja, npr u pogledu minimalnih i maksimalnih pritisaka, koristi se kaznena funkcija koja rešenja koja ne ispunjavaju ove uslove udaljava iz skupa povoljnih.

Evapotranspiration is an important component of hydrological balance and it is calculated based on reference evapotranspiration (ET0). In the last fifty years there have been many empirical models developed for determining ET0. In May 1990 United Nations Food and Agricultural Organization (FAO) recommended the use of Penman-Monteith method as a standard for this purpose. Method defines ET0 as a potential evaporation from horizontal reference surface. Orientation and slope of the surface, however, have an impact on the amount of available solar energy and therefore on the value of ET0. Available energy that is involved in the process of evapotranspiration is called net radiation and it depends, among others, of the amount of extraterrestrial solar radiation and atmosphere transmissivity. In this paper, we present method for calculation of extraterrestrial solar radiation which takes into account both slope and surface orientation as well as method for calculation of net radiation on the surface considering all three radiation components (direct, diffuse and reflected). Model was tested using data from Smederevska Palanka meteorological station. Results show that increasing slope decreases value of ET0 for north oriented surfaces and increases for south oriented. Evapotranspiracija je značajna komponenta hidrološkog bilansa koja se računa na osnovu referentne evapotranspiracije (ET0). Poslednjih pedeset godina razvijen je veliki broj empirijskih modela za proračun ET0. Organizacija Ujedinjenih nacija za hranu i poljoprivredu (eng. United Nations Food And Agriculture Organisation - FAO) u maju 1990 preporačila je upotrebu Penman-Monteith metode za proračun ET0. Ova metoda je postala široko prihvaćena u svetu i koristi se kao standard. Metoda definiše ET0 kao potencijalno isparavanje sa horizontalne referentne površine. Orijentacija i nagib površine međutim imaju uticaj na količinu raspoložive sunčeve energije a samim tim i na vrednost ET0. Količna raspoložive sunčeve energije koja učestvuje u procesu evapotranspiracije naziva se neto radijacija i zavisi, između ostalog, od radijacije koja stiže na granicu atmosfere i transmisivnosti atmosfere. U radu je razvijen metod za proračun radijacije na granici atmosfere u zavisnosti od pada i orijentacije površine kao i postupak za proračun neto radijacije na površinu pod nagibom uzimajući u obzir sve tri komponente radijacije (direktnu, difuzionu i komponentu refleksije). Testiranje modela sprovedeno je koristeći podatke sa meteorološke stanice Smederevska Palanka. Rezultati modela pokazuju da se sa povećanjem nagiba smanjuje referentna ET0 za severno orijentisane površine, a povećava za južno orijentisane.

Sufficient water well yield is a result of both hydrogeological characteristics of the media and well construction - its design and installation. The choice of water well design and construction materials is influenced by material strength, jointing system, durability, chemical inertness, price, local availability and familiarity. Key elements of the water well design project are: well screen diameter and length, well screen slot openings, and filter pack characteristics (if needed). This paper includes analysis of actual and possible water well yield. One industrial well site is used to determine hydrogeological parameters using a step-drawdown pumping test. The magnitude of parasitic loses on the water well, determined using field measurements, shows that the chosen water well design is inadequate. Izdašnost bunara je posledica karakteristika hidrogeološke sredine i same bunarske konstrukcije - njenog projekta i izgradnje. Na odabir tipa konstrukcije i materijala utiče jačina konstrukcije, način izrade, trajnost, hemijska otpornost na karakteristike vode, cena, kao i dostupnost i familijarnost sa posebnim tipom konstrukcije. Ključni elementi projekta bunarske konstrukcije su: prečnik i dužina filterskog dela, veličina otvora filterske konstrukcije, kao i karakteristike filterske ispune (ako je potrebna). U ovom radu sprovedena je analiza ostvarene i moguće izdašnosti bunara. Na primeru industrijskog izvorišta određene su hidrogeološke karakteristike sredine analizom rezultata opita probnog crpljenja sa stepenastom promenom protoka. Veličina parazitskih gubitaka na bunaru, utvrđena terenskim merenjima, je pokazala da je postojeća bunarska konstrukcija neadekvatna.