Έλεγχος αποτελεσματικότητας εναλλακτικών μεθόδων διαχείρισης όμβριων υδάτων σε αστικές λεκάνες με τη χρήση του λογισμικού SWMM

Μπούκας, Ευάγγελος; Boukas, Efangelos

dc.contributor.author	Μπούκας, Ευάγγελος	el
dc.contributor.author	Boukas, Efangelos	en
dc.date.accessioned	2020-05-28T18:08:27Z
dc.date.available	2020-05-28T18:08:27Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/50725
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.18423
dc.description	Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Επιστήμη και Τεχνολογία Υδατικών Πόρων”	el
dc.rights	Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/gr/	*
dc.subject	Όμβρια ύδατα	el
dc.subject	Αστικές λεκάνες	el
dc.subject	Πράσινες οροφές	el
dc.subject	Περατά οδοστρώματα	el
dc.subject	Αποσύνδεση οροφής	el
dc.subject	Green roofs	en
dc.subject	Permeable pavements	el
dc.subject	Rooftop disconnection	el
dc.subject	LIDs	el
dc.subject	SWMM	el
dc.title	Έλεγχος αποτελεσματικότητας εναλλακτικών μεθόδων διαχείρισης όμβριων υδάτων σε αστικές λεκάνες με τη χρήση του λογισμικού SWMM	el
heal.type	masterThesis
heal.classification	Υδατικοί Πόροι	el
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2019-11-13
heal.abstract	Στην παρούσα εργασία στόχος είναι η μελέτη, η αναπαράσταση και η προσομοίωση της Ζ2΄ ζώνης του παντορροϊκού δικτύου Αθηνών με χρήση του μοντέλου SWMM και η διερεύνηση του πλημμυρικού κινδύνου. Επίσης η εργασία στοχεύει στην ανάδειξη της αποτελεσματικότητας εναλλακτικών μεθόδων διαχείρισης της όμβριας απορροής (LID) όσον αφορά τη μείωση του μέγιστου όγκου απορροής και της αιχμής. Αρχικά, παρουσιάζονται οι τρόποι με τους οποίους γίνεται η εκτίμηση των ακαθάρτων υδάτων και η κατάρτιση των όμβριων καμπυλών. Παράλληλα γίνεται παρουσίαση της εξέλιξης των μεθόδων διαχείρισης της απορροής και της ορολογίας τους, ενώ αναλύονται οι 3 αειφόρες πρακτικές που εφαρμόζονται στην εργασία, (i) Πράσινες στέγες, και (ii) διαπερατά πεζοδρόμια και (iii) αποσύνδεση οροφής. Στη συνέχεια γίνεται παρουσίαση του λογισμικού SWMM περιγράφοντας τις δυνατότητες του και τις υπολογιστικές διαδικασίες, ενώ ακολουθεί η περιγραφή της περιοχής μελέτης στην Αθήνα και η μεθοδολογία που χρησιμοποιήθηκε για την επεξεργασία, απεικόνιση και μοντελοποίηση της περιοχής μελέτης. Επίσης περιγράφονται οι διαδικασίες υπολογισμού των παραμέτρων εισόδου του μοντέλου που χρησιμοποιήθηκαν και ταυτόχρονα κατασκευάζονται τα υετογράμματα σχεδιασμού μέσω της μεθόδου των εναλλασσόμενων μπλοκ. Το μοντέλο βαθμονομήθηκε για την επίτευξη του καλύτερου αποτελέσματος με σύγκριση με μετρηθέντα υδρογραφήματα, ενώ ο καθορισμός των παραμέτρων των αειφόρων πρακτικών βασίστηκε σε βιβλιογραφία που αφορά και μελέτες για τη συγκεκριμένη περιοχή. Με βάση αυτές τις αειφόρες πρακτικές δημιουργήθηκαν 7 σενάρια. Ακολούθησε η προσομοίωση του αποχετευτικού δικτύου με βροχοπτώσεις σχεδιασμού διάρκειας 1, 2, 6, και 12h και περιόδους επαναφοράς 2, 5, 10, 25 και 50 έτη και η παρουσίαση της ικανότητας του δικτύου να ανταποκριθεί. Εφαρμόστηκαν τα 7 σενάρια για περίοδο επαναφοράς 10 ετών και διάρκειες βροχόπτωσης 1 και 12 ωρών, με στόχο την μείωση της απορροής και την αποφυγή πλημμυρισμού των φρεατίων του δικτύου. Τέλος, πραγματοποιήθηκε μελέτη του κόστους κατασκευής και του κόστους κύκλου ζωής αυτών των πρακτικών. Λέξεις κλειδιά: Παντορροϊκό σύστημα, προσομοίωση, SWMM, βιώσιμη διαχείριση των ομβρίων υδάτων, ανάπτυξη χαμηλών επιπτώσεων LIDs, green roof, permeable pavement, rooftop disconnection, life cycle cost.	el
heal.abstract	Sewerage systems are necessary in developed urban areas due to the interaction between human activity and the natural circulation of water, which creates two types of water that require drainage. The first type of water that requires drainage is sewage and the second is stormwater. Thus, the general effects of urbanization on drainage or the effects of replacing natural drainage with urban drainage are the production of higher and more coronal peaks in river flow, the introduction of pollutants and the need for manual wastewater treatment. The purpose of this postgraduate thesis is the study, representation and simulation of the Z2΄ zone of the Athens sewer combined network using the SWMM model and the investigation of flood risk. The work also aims to demonstrate the effectiveness of alternative rainwater drainage (LID) methods in reducing peak runoff and peak. Analysis of water management methods Given the increasing urbanization worldwide and the impact of urban stormwater on both humans and aquatic ecosystems, managing urban drainage is a critical challenge. So urban drainage management has undergone significant changes in recent decades, shifting approaches that were largely limited (usually with the sole purpose flood mitigation) to a more holistic approach. Τhe various terms that have been used to describe stormwater management are: Low impact development (LID) and Low impact urban design and development (LIUDD), Water sensitive urban design (WSUD), Integrated urban water management (IUWM), Sustainable urban drainage systems (SUDS) or Sustainable drainage systems (SuDS), Best management practices (BMPs), Stormwater control measure (SCM), Alternative techniques (ΑΤ) or Compensatory techniques (CT), Source control and Green Infrastructure. The term LID, which is used in this work, is commonly used in North America and New Zealand. This approach seeks to minimize the cost of rainwater management by pursuing a "design approach to nature". This name coincides with these pioneering designs of Environmental Sensitive Area (ESA). In this master thesis three LIDs measures were studied, analyzed, applied and finally evaluated: green Roofs, porous pavement, rooftop disconnection. SWMM Software Storm Water Management Model (SWMM) is a dynamic rain-run simulation model. Developed by the US Environmental Protection Agency between 1969 and 1971, it was the first model to analyze urban runoff. Its application is suitable both for individual rainfall events and continuous simulation of the quantity and quality of water runoff mainly in urban and suburban areas. It is used to simulate runoff and various inputs to the sewer networks and effectively enables the sewer networks to be managed irrespective of their size. It is constantly being upgraded, updated and supplemented with new features to make it one of the most complete and user-friendly models in its class today. SWMM operates by dividing the watershed into a set of hydraulic elements, that is, sub-basins and conduits. Each of these elements is characterized by various hydraulic properties such as size, slope, coefficient of roughness, etc. The SWMM routing section transports the effluent through a system of pipelines, pumps and storage and processing equipment. Overall this program provides a complete environment of the study area for data entry, simulation of hydrological and hydraulic processes and stream quality and finally presentation of results in different formats (graphs, time series tables, frequency analysis etc. Model capabilities The SWMM simulates various hydrological processes involving surface runoff in urban areas. Such processes are:  Rainfall  Water surface evaporation  Snow accumulation and melting  Surface storage  Filtration in unsaturated soil layers  Infiltration of filtered water into layers of groundwater  Surface runoff In all these processes spatial variability can be achieved by dividing the study area into smaller, homogeneous basins, each of which is respectively divided into a permeable and impermeable part. The effluent surface can be channeled between groundwater, basins and inlet points of a drainage system. In addition to hydrological processes, it includes a set of hydraulic forming possibilities. Conceptual model SWMM perceives the drainage system as a series of flows of water and other materials occurring in four main parts of the environment. These sections are (Rossman, 2010):  Atmosphere compartment  Land surface compartment  Groundwater compartment  Transport compartment Study Area and Methodological Framework Study area The oldest part of the sewer network of Athens is the combined section of the network. It is subdivided into sub-basins: Β, Γ, Δ, Ε, ΣΤ, Ζ1, Ζ2, Η1, Η2 and Θ. The stormwater watershed of this area is 1310 he, while the waste water basin is 1250 he. The recipient of this area is KAA., while the recipient of the rain is the stream of P. Daniel and Kifissos river. Methodological Framework The work carried out was as follows:  Inserting the components of combined sewer system into ArcGIS software.  The digitization of building blocks, junctions and conduits.  Bisection of the building blocks with the use of AutoCAD software.  Subsequently, according to the rules of urban hydrology, the urban basins were formed in ArcGIS.  The digitized drainage network (urban drainage basins, junctions, conduits) was inserted into inp.PINS software, with the help of which it was exported in a format suitable for SWMM software.  For the return periods T = 2, 5, 10, 25, 50 and for rain’s duration t = 1, 2, 6, 12 the hyetographs were made with a time step of 10 minutes. Alternating Block Method was used to create the hyetographs. They were then inserted into the SWMM software.  Up next was the evaluation of dry weather runoff and they were inserted into SWMM software.  The model parameters were then calibrated based on recorded rainfall in two conduits.  The system was simulated, for all return periods and for all rain durations, to see how the system responded, and if and where it flooded.  The parameters of the three LIDs were then specified.  Finally, 7 LIDs scenarios were generated for events with a return period T=10 and duration t=1 and 12 hours, which were simulated to see how the model responds and if it continues to flood. Results Calibration Starting with analyzing the importance and operation of the Nash-Sutcliffe performance factor, we proceeded to calibrate the model using the NSE coefficient on the 1313 and 1640 lines. The efficiency coefficient values were 0.945939 for 1313 and 0.724465 for 1640. The values for both conduits were judged to be satisfactory, based on previous calibrations in these conduits (Kourtis et al. 2017) and despite further trials no better results were obtained. System simulation Then, using the alternating blocks, 20 synthetic rainfalls were created for which the system under study was simulated. The results showed that the system for each simulation failed, that is, there were flooded junctions and conduits that did not meet the limits set by PD (presidential decree)-696/74 (speed <6 m/s and fill ratio y/D> 0.8). LID application When the model was found to be failing, the LIDs for rainwater runoff with a return period of up to 10 years were dimensioned. The aim was to reduce runoff. Peak reduction was achieved in each scenario, and scenario 7 of the combined use of the 3 LID practices achieved the largest reduction, reaching 77% for one-hour duration and 70% for 12 hours duration. Correspondingly, the smallest reduction was for use of Green Roofs and Rooftop Disconnection with 30% and 18.7% for both durations. Cost estimation Finally, the capital cost, life cycle cost and co-benefit of each scenario were calculated. The highest capital cost is in scenario 4 with € 20 million (GR-PP) followed by scenario 7 (GR-PP-RD) with € 17 million. The paradox here is that scenario 4 consisting of only 2 meters of LID is more costly than scenario 7 consisting of 3 is explained, because the number of green roofs which is the most expensive measure is reduced. Then the life cycle cost of each scenario was calculated. This considers the initial investment cost (capital cost) and the so-called Operation & Maintenance Costs (O&M). The largest LCC presents scenario 4 at around € 28 million, followed by scenario 7 at around € 25 million. On the other hand, the smallest LCC shows scenario 3. Finally, there is the co-benefit of the money saving, which is based on benefits such as water saving, energy saving due to less use of cooling, improved air quality and carbon capture and other benefits (Alves et al. 2019). For this reason, this particular benefit can also be referred to as an environmental benefit. Values were cited (Alves et al. 2019) and for green roofs 2.91 € /m2/y and for permeable pavements 2.87 €/m2/y. Summary and Conclusions To summarize, in this master thesis part of the Z2΄ zone of the Athens combined sewer network was modelled. Then using the SWMM software simulations of the operation of the sewer system were performed, and sustainable methods of runoff reduction (LIDs) and their economic analysis were applied. The main conclusions from this work are:  All the scenarios were able to reduce the peak runoff and the volume of runoff. They are therefore considered satisfactory and certainly preferable to the choice of a zero-sum scenario in which no action is taken.  All combinatorial scenarios, that is, those that used 2 or 3 LIDs achieved a higher rate of runoff reduction than those applied individually, with scenario 7 leading.  Implementation of LIDs does not always lead to such desirable results, as based on the literature (Tao et al. 2017, Kourtis et al. 2018), studies have shown to perform better for low intensity and short duration events in reducing both runoff volume as well as peak reduction, while performing worse for high intensity and long duration events.  Combined scenarios have the highest construction costs, and scenario 4, which consists of only two meters, was higher than the next scenario 7 due to the high presence of green roofs.  For the same reason that the higher life cycle costs, including operating and maintenance costs, were again the same scenario.  Still, despite the high cost of this scenario, it does not achieve the highest reduction rate.  These alternative rainwater management methods incur high construction, maintenance and operating costs. As a result, they appear prohibitive, if cut out, from all the additional benefits they offer (financial, quality, etc.). The economic aspect of these in the present work has been computed bibliographically (Alves et al. 2019) as an environmental benefit, constituting a particularly high amount. The highest environmental benefit comes from scenario 4 and then scenario 7.  Finally, scenario 7 is preferred as a worthwhile practice, as it achieves the highest peak reduction rate, without having the highest capital cost or life cycle cost, and with the second highest environmental benefit in monetary terms.	en
heal.advisorName	Τσιχριντζής, Βασίλειος	el
heal.committeeMemberName	Νάνου, Αικατερίνη	el
heal.committeeMemberName	Μπαλτάς, Ευάγγελος	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Πολιτικών Μηχανικών	el
heal.academicPublisherID	ntua
heal.numberOfPages	172 σ.	el
heal.fullTextAvailability	false