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An Update on the Hydrodynamics of the Venice Canals Venice Project Center

An Interdisciplinary Qualifying Project Submitted to the faculty of Worcester Polytechnic Institute In partial fulfillment of the requirements for the Degree of Bachelor of Science Student Authors: Junbo Chen

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Anthony DiNino

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Zachary Mintz

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Robert Wolf

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Project Advisors: Professor Fabio Carrera Professor Frederick Bianchi December 17, 2011 https://sites.google.com/site/ve11hydro/ ve11-hydro@wpi.edu


Authorship   Each member of Team Hydro contributed to this proposal with equal amount of researching, drafting, and editing.

Robert Wolf Anthony DiNino

Zachary Mintz

Junbo Chen

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Abstract   This project provides an update on the hydrodynamics of 93 canal segments in the historical center of Venice. During the 1990’s, students from Worcester Polytechnic Institute (WPI) measured the currents in the entire canal system. Since then, there have been many speculations about possible changes in the canal currents. Our team set out to verify whether those rumors were founded. The results of our study show that indeed there have been changes in the patterns of movement of the waters of the inner canals: the speed of some of the northern canals has increased, the area around the Rio Nuovo has slowed down, and some smaller segments have even reversed their direction of flow. In particular, our research has confirmed that the western end of the Grand Canal is displaying a pattern of flow that is the opposite to the direction measured in 1966. Our data was used to update a computer model of the canal hydrodynamics in collaboration with ISMAR. The results of our project indicate that more research is needed to fully understand the behavior of tidal flows, especially in relation to the major lagoon channels.

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Acknowledgements   Team Hydro would like to thank… …The Centro Maree for taking the time to meet with us and give us a tour of their facility, and providing us with the tide schedules. …ISMAR for taking the time to meet with us, answering all of our questions, and working hard on the model. …Paolo Peretti, from IPROS, for generously lending us a lot of his equipment, and taking the time to bring us out on his boat to measure some of the larger canals. …And lastly, our advisors, Professor Fabio Carrera and Professor Frederick Bianchi, for all of their help and guidance. Grazie!

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Executive  Summary   This project revisited 93 previously measured canals in Venice, and analyzed the changes that have occurred in the past ten years. The 1990’s project teams from WPI conducted comprehensive measurements of all the canals’ hydrodynamics. Over the last decade, speculation and discussion have been raised among Venetians and scientists on the possible changes of canal currents. This project was intended to study the behaviors of the overall water movement in order to address the rumors. In the course of eight weeks, we performed over 1650 measurements during a new and full moon period.

Figure 1 - Maps Depicting 1990's Area of Study (Left) and 2011 Area of Study (Right)

The methodology of the past WPI hydrodynamic projects was followed for consistency. The speeds and directions of canal segments were measured and compared to the data compiled in 1999.

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Figure 2 - Speed Change Compared to 1990's during Incoming Tide

Between incoming and outgoing tides, the incoming tides showed more changes in speed. Most of the canal segments did not change their directions from 1999 to 2011; however, with the study focus in Cannaregio, a pattern of canal flow change was discovered. The outer canal speed of Cannaregio had increased when the inner canals experienced speed decrease.

Figure 3 - Map Depicting the Changes on Grand Canal during Incoming Tide

Along with speed decrease of canals connecting between middle and west entrance of the Grand Canal, the change in canal SCOM of west Venice was then investigated. These changes provide evidence towards the idea that the water has been entering from the west entrance of the Grand Canal, which indicated a relative high water level during incoming tide.

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Figure 4 - Map Depicting the Change of Grand Canal

When studying the western opening of the Grand Canal, we observed a clear change of direction in area between the Tronchetto and Canal de Cannaregio. This phenomenon, along with the increasing speed of the Canal de Cannaregio, further supports the theory of water entering from the west of the city.

Figure 5 - Tidal Model Result

Besides conducted fieldwork and analysis, the project managed to collaborate closely with ISMAR in order to re-activate the finite element model developed by Ph.D Georg Umgiesser and Ph.D Elisa Coraci in 1997. Due to the tidal model’s reliance on water level change, we updated

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the canal bathymetry in order to ensure that the model can reflect the change of water movement over time. The tidal model also required actual water levels and velocities of canals to calibrate the forcing factors in the modeling equations. In a compiled data package that we have delivered to ISMAR, the new bathymetry, water levels, velocities, and tide gauges data during days of fieldwork had applied to simulation purposes. The model could shed some lights on the canal flow comparison and analysis. In order to make all collected data and comparison accessible to the world, all the data related to canal hydrodynamics were uploaded to Venepedia, an online wiki dedicated to Venice developed by WPI students. Each canal has an article that entails its location, past and new velocities. This method of data storage may be applied and extended to a programmed database for future projects.

Figure 6 - Suggested Area of Study

Even though our team accomplished a large amount of fieldwork during this term, there is still much more to be done. We recommend this project to be continued and that the remaining 25 segments are measured and analyzed. The future team should look more closely into the flow of the Grand Canal. Also, they should look at the flow of the Guidecca Canal and see what effect it has on the south west of the city. They should re-visit and analyze the three areas of interest: shortcut in the Dorsoduro Area, Sestiere de Cannaregio, and the area in Castello between the northern lagoon and the southern opening of the Grand Canal. Finally, the team should look into creating a mobile application to make data compiling and analyzing easier. 8


Table  of  Contents   Table  of  Contents  ..................................................................................................................................  9   1   Introduction  ..................................................................................................................................  16   2   Background  ...................................................................................................................................  19   2.1   The  Lagoon  .......................................................................................................................................  19   2.1.1   The  Three  Inlets  .........................................................................................................................  19   2.2   Tides  .................................................................................................................................................  20   2.2.1   Astronomical  Effects  ..................................................................................................................  20   2.2.2   Range  Variation:  Springs  and  Neaps  .........................................................................................  20   2.2.3   Effect  of  Tides  on  Canal  Velocities  .............................................................................................  21   2.2.4   Meteorology  ..............................................................................................................................  22   2.2.5   Subsidence  and  Eustatism  .........................................................................................................  24   2.2.6   Topology  ....................................................................................................................................  24   2.3   Tide  Forecasting  in  Venice  ................................................................................................................  25   2.3.1   Centro  Maree  .............................................................................................................................  26   2.3.2   Punta  della  Salute  and  Mareographic  Zero  ...............................................................................  26   2.3.3   City’s  Warning  System  ...............................................................................................................  27   2.4   The  Venice  Canal  Systems  ................................................................................................................  28   2.4.1   Network  .....................................................................................................................................  28   2.4.2   Rii  Terà  .......................................................................................................................................  28   2.5   Canal  Currents  in  Venice  ...................................................................................................................  29   2.5.1   Tide  Delay  ..................................................................................................................................  29   2.5.2   Watershed  .................................................................................................................................  29   2.6   Canal  Maintenance  in  Venice  ...........................................................................................................  30   2.6.1   Insula  S.p.A  ................................................................................................................................  30   2.6.2   Sediment  Accumulation  .............................................................................................................  30   2.6.3   Dredging  ....................................................................................................................................  31   2.7   Past  Hydrodynamics  Studies  .............................................................................................................  31   3   Methodology  .................................................................................................................................  33   3.1   Measuring  Canal  Hydrodynamics  .....................................................................................................  34   3.1.1   Tide  Forecasting  and  Measurement  Times  ................................................................................  35   3.1.2   Measurement  Device  .................................................................................................................  35   3.1.3   Procedure  ...................................................................................................................................  36   3.1.4   Data  Collection  ..........................................................................................................................  37   3.2   Re-­‐activating  the  ISMAR  Tidal  Model  ...............................................................................................  37   3.2.1   Data  Needed  for  Modeling  ........................................................................................................  38   3.2.2   Data  Collection  Procedure  .........................................................................................................  38  

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3.2.3   Model  Calibration  ......................................................................................................................  39   3.3   Investigating  the  accuracy  of  new,  more  modern,  devices.  .............................................................  39   3.3.1   Propeller  Device  .........................................................................................................................  40   3.3.2   TeleDyne  RD  Instruments  ...........................................................................................................  41   3.3.3   Pressure  Probe  ...........................................................................................................................  41   3.4   Publicizing  Hydrodynamic  Data  ........................................................................................................  42   3.4.1   Posting  data  on  Venipedia  .........................................................................................................  42  

4   Results  ............................................................................................................................................  44   4.1   Hydrodynamic  Data  ..........................................................................................................................  44   4.1.1   Canal  Hydrodynamics  ................................................................................................................  44   4.1.2   Directional  Changes  with  Respect  to  Tides  ................................................................................  44   4.1.3   Maximum  Velocities  ..................................................................................................................  45   4.2   ISMAR  Model  ....................................................................................................................................  49   4.3   Propeller  Comparison  .......................................................................................................................  49   4.4   Sustainable  Data  Results  ..................................................................................................................  50   5   Analysis  ..........................................................................................................................................  51   5.1   Incoming  Tide  Analysis  .....................................................................................................................  51   5.1.1   Cannaregio  –  Hydrodynamic  Patterns  .......................................................................................  51   5.1.2   Cannaregio  –  Comparison  Analysis  ............................................................................................  52   5.1.3   Cannaregio  –  Possible  Hydrodynamic  Behavior  .........................................................................  53   5.1.4   Dorsoduro  –  Hydrodynamic  Patterns  .........................................................................................  54   5.1.5   Dorsoduro  –  Comparison  Analysis  .............................................................................................  55   5.1.6   Dorsoduro  –  Possible  Hydrodynamic  Behavior  ..........................................................................  56   5.1.7   Dorsoduro  –  SCOM  Comparison  ................................................................................................  57   5.1.8   Dorsoduro  –  Grand  Canal  Direction  Change  ..............................................................................  58   5.1.9   Dorsoduro  –  MARG  Direction  Change  ........................................................................................  60   5.2   Outgoing Tide Analysis  ....................................................................................................................  61   5.2.1   Cannaregio  -­‐  Hydrodynamic  Patterns  ........................................................................................  61   5.2.2   Cannaregio  –  Speed  Comparison  ...............................................................................................  62   5.2.3   Cannaregio  –  Possible  Hydrodynamic  Behavior  .........................................................................  63   5.2.4   Dorsoduro/San Polo/Santa Croce – Hydrodynamic  Patterns   ...................................................  64   5.2.5   Dorsoduro/San  Polo/Santa  Croce–  Possible  Hydrodynamic  Behavior  .......................................  65   5.2.6   San  Marco  –  Hydrodynamic  Patterns  ........................................................................................  66   5.2.7   San  Marco  –  Possible  Hydrodynamics  Behavior  ........................................................................  67   5.2.8   Castello/Cannaregio  –  Hydrodynamic  Patterns  .........................................................................  68   5.2.9   Castello/Cannaregio  –  Speed  Comparison  .................................................................................  69   5.2.10   Castello/Cannaregio – Possible Hydrodynamic Behavior  ......................................................  70   6   Recommendations  ......................................................................................................................  71   6.1   Lessons  Learned  in  the  Field  .............................................................................................................  71   6.2   Suggested  Hydrodynamic  Studies  ....................................................................................................  72  

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6.3   Suggested  Tide  Delay  Studies  ...........................................................................................................  74   6.4   Suggested  Canal  Data  .......................................................................................................................  74   6.5   Expanding  the  Area  of  Study  ............................................................................................................  75  

7   Bibliography  .................................................................................................................................  76  

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List  of  Figures   Figure 1 - Maps Depicting 1990's Area of Study (Left) and 2011 Area of Study (Right) Figure 2 - Speed Change Compared to 1990's during Incoming Tide Figure 3 - Map Depicting the Changes on Grand Canal during Incoming Tide Figure 4 - Map Depicting the Change of Grand Canal Figure 5 - Tidal Model Result Figure 6 - Suggested Area of Study Figure 7 - Venice Lagoon Figure 8 - Tide Schematic Figure 9 - Water Surface Level Changes with Tides Figure 10 - Diagram of Wind Trend Figure 11 - Storm Surge Schematic Figure 12 - Animation of desired Flood gates Figure 13 – Centro Maree Logo Figure 14 - Punta della Salute Figure 15 - Graphical Interpretation of Siren Signal Figure 16 - Sites of spread of the new warning system in the Old Town Figure 17 - Rii Tera Figure 18 - Insula S.p.A Logo Figure 19 - In-Depth View of Canal Figure 20 - Dredging Barge in Venice Figure 21 - Area of Study Selection Figure 22 - Tide Schedule with Measurement Points Figure 23 - Floatation Device Schematic Figure 24 - Measurement Procedure Figure 25 - Field Form Figure 26 - Tide Schedule for ISMAR

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Figure 27 - Ipros Propeller Measuring Device Figure 28 - TeleDyne River Ray Figure 30 - Area of Study Map Figure 32 - Incoming Velocity Results (Flows from South to North)   Figure 33 - Outgoing Velocity Results (Flows from North to South)   Figure 34 - Santa Croce Incoming Tide Comparison   Figure 35 - Dorsoduro Incoming Tide Comparison   Figure 36 - Santa Croce Outgoing Tide Comparison   Figure 37 - Dorsoduro Outgoing Tide Comparison   Figure 38 - Link 2392 from ISMAR Model   Figure 40 - Cannaregio Incoming Velocities   Figure 42 - Cannaregio Incoming Hydrodynamic Analysis   Figure 44 - Dorsoduro Incoming Velocities   Figure 46 - Dorsoduro Incoming Hydrodynamic Analysis   Figure 47 - Dorsoduro Incoming Grand Canal Analysis   Figure 48 - SCOM Comparison, Incoming   Figure 49 - Guidecca Overall Hypothesis, Incoming   Figure 50 - Grand Canal Direction Change, Incoming   Figure 51 - Grand Canal and CANN, Incoming   Figure 52 - MARG Direction Change, Incoming   Figure 53 - Cannaregio Speed Analysis, Outgoing   Figure 54 - Cannaregio Speed Comparison, Outgoing   Figure 55 - Cannaregio Flow Analysis, Outgoing   Figure 56 - Dorsoduro/San Polo/Santa Corce Speed Analysis, Outgoing   Figure 57 - Dorsoduro/San Polo/Santa Croce Flow Analysis, Outgoing   Figure 58 - Temporary Water Build-up, Outgoing   Figure 59 - San Marco Speed Analysis, Outgoing  

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Figure 60 - San Marco Flow Analysis, Outgoing   Figure 61 - Castello/Cannaregio Speed Analysis, Outgoing   Figure 62 - Castello/Cannaregio Speed Comparison, Outgoing   Figure 63 - Castello/Cannaregio Flow Analysis, Outgoing  

 

 

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List  of  Appendices   APPENDIX A – Hydrodynamic Device APPENDIX B – Calendar APPENDIX C – Schedule for Hydrodynamic Testing APPENDIX D – Hydrodynamic Field Forms APPENDIX E – Maps from Past Hydrodynamics Studies APPENDIX F – Past Hydrodynamic Data APPENDIX G – Hydrodynamic Comparison Between 1999 and 2011 APPENDIX H – Hydrodynamic Database APPENDIX I – Data for ISMAR Model APPENDIX J – Updated Bathymetries APPENDIX K – FTP Website APPENDIX L – New Devices APPENDIX M – Comparison between Bottle and Propeller Devices APPENDIX N – Budget

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1 Introduction   For centuries, water has been a precious resource of life, as it has and continues to provide us with extensive means of energy, protection, and travel. However, water has proved to be dangerous during tsunamis, hurricanes, and floods. This has been evident in recent years with the tragic storms of Hurricane Katrina, and the devastating tsunami that landed on the shores of Japan. Official statistics show Hurricane Katrina caused “971 Katrina-related deaths in Louisiana and 15 deaths among Katrina evacuees in other states.”1 These disasters led to ports and waterways being shut down. As climate change exacerbates, water levels across the world are rising. Due to this fact, cities near water are faced with the threat of elevating ocean levels and waterway obstructions. Venice, in particular, is one city that faces a direct and imminent threat from the rising water level. Rising sea levels are endangering the existence of this beautiful and historic city. For example, in the 1800’s, one of the highest recorded water levels was 157 cm above the zero point, a level that flooded the ground floor of many houses in Venice. High levels like this are “known as ‘Acqua alta’ — high water — and it brings city life to a standstill for several hours.”2 Acqua alta causes inaccessibility of canals due to dangerous water conditions. As evidence of the problem worsening, the city has stated that “[f]loods that once invaded lower areas only seven times in 1900 now creep in nearly 100 times a year.”3 Acqua alta causes inconvenience to both locals and travelers, when the water is high-elevated walkway are needed to facilitate safe travel. Another issue is the high sediment build-up on the beds of canals. Sediment accumulates through displacement of broken canal wall material, sewage, and other particles. Although Venice has made several attempts to alleviate the effects of flooding and sediment build-up, it is difficult to effectively solve the problems without an in-depth understanding of the hydrodynamics within the city.

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J.  Brunkard,  G.  Namulanda  and  R.  Ratard,  "Hurricane  Katrina  Deaths,  Louisiana,  2005,"  DISASTER  MEDICINE  AND   PUBLIC  HEALTH  PREPAREDNESS  2,  no.  4  (2008),  215-­‐223. 2 Sylvia  Poggioli,  http://www.npr.org/templates/story/story.php?storyId=112995748 3 By  John  Keahey,  "In  the  Fray:  Venice  Preserved?  Giant  Sea  Gates  may  be  Swamped,"  Wall  Street  Journal2003.

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In response to the threat of the rising tide levels, several companies and agencies have attempted to improve the canal conditions of the city. In the aspect of damage prevention, the Centro Maree has installed warning sirens for when the tide levels are going to be above 110 centimeters. To understand the cause of this threat, past projects from WPI have taken and analyzed tide and velocity data of all the inner canals. By utilizing the hydrodynamic data collected, ISMAR has developed mathematical models in order to predict the trend of velocity and level change on the canals. In 1999, the local middle school students performed a simultaneous measurement across the city. Using the hydrodynamic data, Insula, a local agency, dredged the canals that are subjected to high sediment build up to maintain proper water flow. The MOSE project is another factor that has contributed to the changes of the canals. The project, which began in 2003, consists of building enormous floodgates at the three openings of the outer ring of the lagoon in order to control the tide level within the barrier. While all these attempts have been valiant, the problems are still intensifying greatly and affecting Venetians’ daily lives. For more than a decade, no measurements were taken to reflect the changes on Venetian canal hydrodynamic. These changes include the dredging of the canals, the naturally rising tides due to climate change, and the effects of the MOSE Project. New measurements need to be taken, so the Centro Maree and other organizations can expand their knowledge of the conditions of the canals to better predict flood patterns and to improve modeling of the canals. The lack of equipment and personnel for a city wide, simultaneous measurement of the canals causes data to only show a part of the city in the same timeframe. A simultaneous measurement can lead to an improvement in data accuracy. The absence of a standard method for consistent data collection also obstructed smooth transitions between researches. This problem includes not knowing which devices are best for hydrodynamic measurements and not having a plan for regularly scheduled measurements. In order to solve these systematic disadvantages, this project collected new measurements, collaborated with organizations in Venice, and formulated a plan for future consistent measurements. The project was designed to help the city of Venice better understand the speed and water levels of the canals by publicizing hydrodynamic data on Venipedia and producing a plan for similar

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measurements to be conducted at regular intervals in the future. Firstly, our group measured canal hydrodynamics and compared our data to that of previous project teams had conducted. With the collected data, we collaborated with ISMAR to re-activate the tidal model. At the mean time when we took measurements, we created Wiki pages for each of the canals that we studied. In the end, we tested new devices and formulated a long-term plan for regularly schedule measurements.

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2 Background   Venice, the queen of the Adriatic, has nurtured her residents for hundreds of years. Worldly renowned for its inner canals, Venice connects people with these artistically created water arteries. The Venetian canals not only work as main transportation media, but also as the city’s cleaning system. The beauty of Venice builds upon its canals.

2.1 The  Lagoon   Venice is a city located in the middle of the largest lagoon that attaches to the Adriatic Sea. The lagoon is estimated to be around 6,000 years old, and was created by the buildup of eroded soil from three rivers, the Piasve, the Sile, and the Brenta. The city is comprised of 117 small islands that formed in the sediment of the lagoon. Connecting these islands is a network of more than 150 canals that flow all around the city. These canals are the arteries that keep Venice alive and provide a vital source of transportation and the means of waste removal from the city. With the canals of Venice being so crucial to the survival of the city, it is critical to try and find a way to prepare and preserve the city from the rising levels of the sea.4 2.1.1 The  Three  Inlets   Due to its connection to the Adriatic Sea, the lagoon forms three natural openings to allow water flow into and away from the lagoon. Distributed along the coast, Lido, Malamocco and Chioggia are located in an upper, middle, and lower section as depicted in figure on the right5. Geologically, Lido and Malamocco affect Venice as they direct tide from the Adriatic Sea. The effect Figure 7 - Venice Lagoon 4

Brian  J.  Scully  et  al.,  Return  to  the  City  of  Water  -­‐-­‐  Quantifying  Change  in  the  Venetian  Canals  (Worcester,  MA:   Worcester  Polytechnic  Institute,  2011). 5 1.          http://3.bp.blogspot.com/_t9o_X64s0CU/TNswo8iOTgI/AAAAAAAADjc/yh1_KBE6PGk/s1600/Venice-­‐ lagoon.png  (accessed  10/11,  2011).

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of the openings will be introduced later in the Section 2.2.6 and 2.5.2.

2.2 Tides   Generally speaking, the effect of tide can be observed as one plays with waves on a beach. However, the Earth alone does not form tides. The gravitational forces exerted by the Moon and Sun are the leading factors that cause the rise and fall of sea level. Due to Venice’s vicinity to the Adriatic Sea, tides directly determine the water levels of its canals

2.2.1 Astronomical   Effects   The changing distance separating the Moon and Earth also affects tide heights. When the Moon is at perigee, the range increases, and when it is at apogee, the range shrinks. Every 7½ lunation (the full cycles

Figure 8 - Tide Schematic

from full moon to new to full), perigee coincides with either a new or full moon causing perigean spring tides with the largest tidal range. If a storm happens to be moving onshore at this time, the consequences (property damage, etc.) can be severe.6 7 2.2.2

Range  Variation:  Springs  and  Neaps

The semidiurnal range (the difference in height between high and low waters over about a half day) varies in a two-week cycle. Approximately twice a month, around new moon and full moon when the Sun, Moon, and Earth form a line (a condition known as syzygy) the tidal 66 7

D.  A.  Ross,  Introduction  to  Oceanography  (New  York,  NY:  HarperCollins,  1995). Richard  Vooren,  http://commons.wikimedia.org/wiki/File:Tide_schematic.svg  (accessed  10/11,  2011).

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force due to the Sun reinforces that due to the Moon. The tide's range is then at its maximum: this is called the spring tide, or just springs. It is not named after the season, but derives from an earlier meaning of "jump, burst forth, rise" as in a natural spring. When the Moon is at first quarter or third quarter, the Sun and Moon are separated by 90° when viewed from the Earth, and the solar tidal force partially cancels the Moon's. At these points in the lunar cycle, the tide's range is at its minimum: this is called the neap tide, or neaps (a word of uncertain origin). Spring tides result in high waters that are higher than average, low waters that are lower than average, 'slack water' time that is shorter than average, and stronger tidal currents than average. Neap tides result in less extreme tidal conditions. There is about a seven-day interval between springs and neaps.8 9

Figure 9 - Water Surface Level Changes with Tides

2.2.3 Effect  of  Tides  on  Canal  Velocities   The tides' influence on current flow is much more difficult to analyze, and data is much more difficult to collect. A tidal height is a simple number, which applies to a wide region simultaneously. A flow has both a magnitude and a direction, both of which can vary substantially with depth and over short distances due to local bathymetry, which is the study of underwater depth of lake or ocean floors. A flow proceeding up a curved channel is the same flow, even though its direction varies continuously along the channel. Surprisingly, flood and ebb flows are often not in opposite directions. Flow direction is determined by the upstream 8

US  National  Oceanic  and  Atmospheric  Administration  (NOAA)  National  Ocean  Service  (Education  section),   http://oceanservice.noaa.gov/education/kits/tides/tides07_cycles.html  (accessed  10/3,  2011). 9 http://en.wikipedia.org/wiki/File:Water_surface_level_changes_with_tides.svg#filelinks  (accessed  10/11,  2011).

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channel's shape, not the downstream channel's shape. Likewise, eddies may form in only one flow direction. 2.2.4 Meteorology   Meteorology is defined as the scientific study of the atmosphere. Due to its geographical position and its surroundings, Venice is subject to many different meteorological effects that directly affect the city. A few of these factors will be introduced in the following paragraphs. 2.2.4.1 Wind   Wind plays a critical role in Venice’s meteorological change. There are a numerous number of winds that affect the Mediterranean Sea, but the main one that affects Venice is called the “Bora” wind because it blows right through the Adriatic Sea. The figure below shows various wind trends in the Mediterranean Sea. The two trade winds are boxed. The top one is the Bora, previously mentioned, and the next is the Sirocco. The Sirocco comes in from the south and acts against the Bora wind.

Figure 10 - Diagram of Wind Trend

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As shown in figure above, only a very small opening is accessible between Italy and Greece for water movement. This opening is the only path water can flow in or out of the Adriatic Sea. During times of strong, forceful wind, the Sirocco winds can be very detrimental to the tides approaching to Venice. While high tide exits the Adriatic Sea, the Sirocco Wind blows directly at the single opening and pushes the high tide back towards Venice. This causes the city to experience two high tides at the same time. To explain, the one high tide comes and goes, and time passes until another high tide arrives. As the second high tide arrives, the previous high tide returns due to the gusts of the Sirocco winds. Occurrence has been recorded in the Venetian history books on multiple occasions. The record high tide and flooding, which happened in 1966, occurred because of this phenomenon. The tide level was recorded at 194 cm above sea level. The strange fact is that neither this record tide level occurs at full nor new moon, at which the highest of tides are expected to occur. In worst scenario, this wind coupled with high tide during new and full moon could produce a tide of over two hundred centimeters. 2.2.4.2 Pressure   Another meteorological factor affecting the hydrodynamics of Venice is pressure. Under lowpressure system caused by high winds, a phenomenon called “storm surge� occurs to lead to an offshore rise of water. In areas where there is a significant difference between low tide and high tide, storm surges are particularly damaging when they occur at the time of a high tide.

Figure 11 - Storm Surge Schematic

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In these cases, this increases the difficulty of predicting the magnitude of a storm surge since it requires weather forecasts to be accurate to within a few hours. A schematic of storm surge is depicted in figure above.10 11 2.2.5 Subsidence  and  Eustatism   Two major factors affecting the hydrodynamics of the Venetian canals are subsidence and eustatism. Subsidence, by definition, is “The gradual caving in or sinking of an area of land.” For Venice, the land is in the process of sinking into the earth. Since this land is intertwined with water, it greatly affects the hydrodynamics of the canals. This sinking is said to be from projects that pump water out of the subsurface of Venetian land.12 There have been laws passed to end these projects which will slow down the subsidence of the land.13 The second factor is eustatism. This term refers to the overall rising of the world’s water level due to climate change. It is also due to the plate tectonics of the ocean floor. As one slides underneath another, the plates become thicker and cause the water level to go up.14 The climate changes in the world are drastically affecting tides in all countries. Studies say the highest water level could increase 4.2 centimeters and more per year if climate changes continue the pattern they are on.15

2.2.6 Topology     Topology is the study of land structures and their formation. Venice has various topological factors that affect its canal hydrodynamics. As previously mentioned in the wind section, the opening between Italy and Figure 12 - Animation of desired Flood gates 10

National  Weather  Service,  "Extratropical  Storm  Surge,"  Meteorological  Development  Laboratory,   http://www.nws.noaa.gov/mdl/etsurge/  (accessed  10/10,  2011). 11 SuperManu,  http://en.wikipedia.org/wiki/File:Surge-­‐en.svg  (accessed  10/11,  2011). 12 Giorgio  Cassiani,  and  Claudio  Zoccatelli,  "Subsidence  Risk  in  Venice  and  Nearby  Areas,  Italy,  Owing  to  Offshore   Gas  Fields;  a  Stochastic  Analysis  ,"  http://eeg.geoscienceworld.org/cgi/content/abstract/6/2/115 13 Scully  et  al.,  Return  to  the  City  of  Water  -­‐-­‐  Quantifying  Change  in  the  Venetian  Canals 14 Ibid. 15 Joseph  Adam  Zsofka  et  al.,  Hydrodynamics  of  the  Inner  Canals  of  Venice,  1999).

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Greece has created astonishing tide situations in history. Venice’s unique positioning in the Adriatic Sea changes the hydrodynamics properties of its canals. Only three openings exist between the Venetian lagoon and the Adriatic. The barriers that surround the lagoon create higher currents through the three openings. To alleviate these high currents and also attempt to lower the elevating water level, a city improvement project called MOSE project has begun. 16 2.2.6.1 MOSE  Project   One of the many projects to combat the effects of flooding in Venice is the MOSE Project. The MOSE Project, named after the biblical prophet Moses, is a series of massive floodgates that will rest on the bottom of the sea most of the time and rise up during high tide events to seal off the lagoon form the tide.17 The gates will be constructed in the three entrances to the lagoon from the Adriatic Sea, effectively sealing of the lagoon form the sea when the gates are in an up position. The gates have been designed to last for the next 100 years of rising sea levels but some don’t think they will be effective for that long.18 Work on the MOSE project began in 2003, after approval from the Italian government, and should be completed in 2012 with a total cost of $7 billion.19 The goal of this project is to attempt to relieve Venice of the issue of high tidal flooding.

2.3 Tide  Forecasting  in  Venice   Tide forecasting plays a vital part in predicting velocities of canals. During a month, the semidiurnal range varies in a two-week cycle. Around new moon and full moon, the tide range during a day has its maximum. Thus, canal velocity and depth varies accordingly due to tidal movement. Accurate tidal prediction will not only lead to better canal hydrodynamic measurement, but also can provide useful scientific data for ecological analysis. Figure 13 – Centro Maree Logo

16

Telegraph  UK,  6.  http://www.telegraph.co.uk/news/worldnews/europe/italy/3629387/Moses-­‐project-­‐to-­‐secure-­‐ future-­‐of-­‐Venice.html  (accessed  10/11,  2011). 17 By  John  Keahey,  In  the  Fray:  Venice  Preserved?  Giant  Sea  Gates  may  be  Swamped,  D.10 18 Ibid. 19 "MOSE  Project  Aims  to  Part  Venice  Floods:  1,"  Morning  Edition  (2008),  1.

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2.3.1 Centro  Maree     Centro Maree, “the tide center” in English, was established in the 1970s’ to service the City of Venice to observe tides. When Centro Maree needs to warn the city of an impending flood they sound a siren on the San Marco bell tower. The center can monitor good quality of tide data and give accurate information for scientific research. In October of 2003, Centro Maree was awarded a title of “Istituzione Centro Previsioni e Segnalazioni Maree” for its scientific achievement through the collaboration with various national research organizations. For this project, Centro Maree provided accurate tide data for optimal measurement time via its observatories. 20 2.3.2 Punta  della  Salute  and  Mareographic  Zero  

Figure 14 - Punta della Salute

The Punta della Salute is one of the main tide forecasting points of the Centro Maree and is located at the southern end of the Grand Canal. The location is used as the zero reference point or mareographic zero point of the city of Venice. Mareographic zero is the universal zero water level of the city that was established in 1897.21 The actual zero point is located 23 centimeters below the surface of the water in order to keep all level measurements standard. Most of Venice is over 100 centimeters above the zero point but around 5% of the city is still flooded when the

20

Citta  di  Venezia,  http://www.comune.venezia.it/flex/cm/pages/ServeBLOB.php/L/EN/IDPagina/1644  (accessed   September  16,  2011). 21 http://www.salve.it/uk/soluzioni/problemi/p_acque_alte.htm  (accessed  October  9,  2011).

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tide level is 100 centimeters.22 With the mareographic zero, the Centro Maree can predict how much of the city will flood and warn the citizens accordingly. 23 2.3.3 City’s  Warning  System   A new acoustic warning system had been implemented in 2007 to give aleats of high tides to citizens and travellers. In four different uprising degrees of tidal levels, the system will transmit in gradual sonic scale, respectively. When a long siren is heard, it means the tide will reach 110 centimeters. Two sounds in increasing scale mean 120 cm. Three-tone scale growing means 130 cm. And lastly, for 140 cm and higher, the system will alert with four sounds in increasing scale.24 25

Figure 15 - Graphical Interpretation of Siren Signal

2.3.3.1 Understanding  the  Importance  of  the  Warning  System   It is crucial to understand the warning sound during measurement taking. The signal will be repeated several times to allow easier recognition of expected tide level. Due to the possible repercussion that might be caused by high tides, the warning can be heard even throughout Venice. Various key locations have been chosen to spread warning across the old town of Venice.26 27

22

Citta  di  Venezia, http://www.palazzograssi.it/en/punta-­‐della-­‐dogana/museo/punta-­‐della-­‐dogana-­‐venice.html2011/10/11). 24 Citta  di  Venezia,  "Sirene  Allertamento  Acqua  Alta,"   http://www.comune.venezia.it/flex/cm/pages/ServeBLOB.php/L/IT/IDPagina/13623  (accessed  10/9,  2011). 25 Ibid. 26 Ibid. 27 Ibid. 23

27


Figure 16 - Sites of spread of the new warning system in the Old Town

2.4 The  Venice  Canal  Systems     Canals are the core transportation method in Venice. A thorough study of the Venetian canal system will be beneficial to solve the complexity among canals segments and their correlations to each other. Because most of the canals are connected, when one canal shuts down, the closure can directly impact on the entire canal network. Besides the canal network, underground waterways are studied in order to understand the “ripple effect”. 2.4.1 Network   Firstly, canals have intrinsic effects on the water movement. Frictions from the canal walls and bottom alter the movement of the water and create a different flow, even turbulence. Since the canals from a whole network in the city, each canal affects another canal. So the hydrodynamics of one canal are mutual with the hydrodynamics of all the canals it is adjoined to. 2.4.2 Rii  Terà   A few canals are currently getting either worked on or shut down. Two ways in which canals are shut down are called “Rii Terà Tombatti” and “Rii Terà con Volti.” 28 “Rii Terà Tombatti” is the filling in of a canal. This filling greatly disrupts the flow of the canals, but after the initial filling, there is no continuing effect on their hydrodynamic properties. “Rii Terà con Volti” is the capping of a canal. Water still flows underneath these caps and they greatly affect the 28

Zsofka  et  al.,  Hydrodynamics  of  the  Inner  Canals  of  Venice

28


Figure 17 - Rii Tera

hydrodynamics of the canals because there is no room for tide elevation. A map of the canals that have been subjected to these procedures is shown above.29 30

2.5 Canal  Currents  in  Venice   The effect of currents caused by tide delay can show the location of watershed. By matching the time delay during high tides in Venice, currents of canals will meet and collapse to form a temporal water accumulation in certain areas of Venice. Both tide delay and watershed will be introduced below. 2.5.1 Tide  Delay   The Centro Maree takes tide forecast at the Punta della Salute, located at the southern tip of Venice. However, the tide schedule is only accurate for the Punta della Salute. It takes an interval of delay for the peak of the tide to travel past this point. Different canals will reach the peak tide at different times depending on the path and distance from Punta della Salute to the measurement point. Tide delay is measured numerically, with all canals north of the point being positive, and all water south being negative. This phenomenon can be used to determine currents. If canals in northern Venice reach tide peaks simultaneously as the Punta della Salute, another current might be affecting the expected tide delay. 2.5.2 Watershed   Watershed is a phenomenon that occurs somewhere near central Venice. There are two main currents that meet in Venice: the first one is from the north and comes from the Adriatic Sea, the second travels along the coast of Italy and travels south into Venice. The watershed is the place where these two currents meet. Tide delay can be used to determine possible the watershed locations. 29 30

Scully  et  al.,  Return  to  the  City  of  Water  -­‐-­‐  Quantifying  Change  in  the  Venetian  Canals Venepedia,  http://venipedia.org/index.php?title=File:Rii_Tera.png  (accessed ��10/11,  2011).

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2.6 Canal  Maintenance  in  Venice   The city of Venice is constantly under restoration, with the canals being part of that process. The city’s sewer system empties into the canals and sometimes settles on the floor of canals; this dirties the water. Since the city is built on water, it brings in sediment from the ocean, which also settles and can pile up. This can impede water flow. The ocean water itself is harmful too. The salt from the water can erode the buildings and architecture over time.31 2.6.1 Insula  S.p.A   A government-sponsored company on Venice’s urban construction and maintenance, Insula has performed various types of improvement on the city’s hydraulic system of internal channels since 1997. Insula contributes to the preservation of Venetian canals. Due to historical damage of tides and sewage on the canals, Insula restores the walls of the bank to ensure stability of banks and buildings and maintain pedestrian feasibility on bridges for high tides. 3233

Figure 18 - Insula S.p.A Logo

2.6.2 Sediment  Accumulation   Several years ago a hydrodynamic study was conducted in the canals of Venice to try and understand sediment build-up. This study took data in various canal segments of Venice in order to understand where sediment would accumulate. The data was taken, using self-recording electromagnetic current meters, in 15-day periods for each of the three canals selected in the four zones of Venice.34 Using this data and hydrodynamic equations, Figure 19 - In-Depth View of Canal 31

32

Venipedia, Insula

Ibid.

33

Insula  S.p.A,  http://www.insula.it/index.php/azienda/manutenzione-­‐e-­‐salvaguardia  (accessed  September,  16,   2011). 34 Elisa  Coraci,  Georg  Umgiesser  and  Roberto  Zonta,  "Hydrodynamic  and  Sediment  Transport  Modelling  in  the   Canals  of  Venice  (Italy),"  ESTUARINE  COASTAL  AND  SHELF  SCIENCE  75,  no.  1-­‐2  (2007),  250-­‐260.

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hydrodynamic models were developed to trace the buildup of sediment within the canals. The study concluded that while some of the sediment came from the residential and commercial sewage systems, most of the sediment contributions came from lagoon input.35 This study provides a sound support for locating where most of the sediment accumulation occurs in canal segments and for examining what effects the sediment build-up might have on canals’ hydrodynamics properties. 2.6.3 Dredging   Insula, a public-works company in Venice, dedicates its best effort to maintain the Venetian canals. In the early 1990’s, they had dredged most of the canals. They emptied the water, cleared the sediment and sewage, and restored as much of the architecture as they could. They removed about 338,000 cubic meters of sediment in 1993.36 Unfortunately, canal maintenance has proven to be a long-term effort. The sediment build-up is inevitable due to the unstoppable flow from the sea.

Figure 20 - Dredging Barge in Venice

Insula will need to plan dredging due to newly formed sediment build-up over time. 37

2.7 Past  Hydrodynamics  Studies   People have been studying the hydrodynamics of the canals for many years. Many scientists, as well as residents, in Venice are interested in the water movements in city and the surrounding lagoon. This data is useful because recent hydrodynamic data can be compared to the past, and the changes can be analyzed. Paluello performed the first study in 1900. This is significant because it was the first time the canals were studied in depth. He only measured one direction (instead of both the incoming and outgoing directions), but the data was still valuable to have. Fabris performed another study in 35

Ibid. Insula S.p.A, 37 Ibid. 36

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1937. This study was more qualitative. Fabris described the movement and direction of the water in the canals. Dorigo did the first high tech study in 1966. Dorigo measured the canals using new instruments (such as a propeller device), and measured both the incoming and outgoing directions. Alberotanza and Dazzi used a dye in 1970 to analyze the water movements in the canals. They put the dye in the water and watched it move through the city. In 1991, the organization known as CNR performed another study on the Grand Canal. They used instruments that collected data continuously. This study was the first to show a change in direction in the northwest opening of the Grand Canal. This caused people to wonder what had caused the change between Dorigo’s measurements in 1966 and the CNR Grand Canal study. In 1991, over 100 middle school students performed a citywide simultaneous measurement on the canals. This simultaneous measurement is the most accurate since canals can change from day to day. Maps from these studies can be viewed in Appendix L. WPI students began studying the hydrodynamics of the canals in the 1990’s. The projects of 1990’s introduced reliable measurement techniques and devices. Throughout the 1990’s, the students collected a lot of hydrodynamic data. In 1999, the project group compiled all of the data from past WPI projects, other organizations such as UNESCO and Insula, and their own data. This was the last project for ten years. In 2010, WPI students revisited the canals. In order to validate the hydrodynamics of the canals and compare their data to the past projects, the 2010 project team started to re-measure canals that had been measured in the 1990’s. Since they did not have time to re-measure every canal, the project is being continued.

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3 Methodology   The project was designed to help the city of Venice better understand the speed and tide levels of the canals by collecting current hydrodynamic data, comparing to past projects, and publicizing this data. The following were the completed objectives: 1)

To quantify canal velocity and compare to past measurements.

2)

To re-activate the tidal model.

3)

To publicize data of various canals on Venipedia and team website.

4)

To investigate the accuracy of new, more modern, measurement devices.

This project focused on measuring canal velocities. We measured the velocities in order to compare to past measurements, re-run the old ISMAR model, and validate the accuracy of more modern measurement devices. We conducted this study from October 23, 2011 to December 17, 2011, and in that time span measured a total of 93 canals segments. Since the maximum canal velocities occurred during the full moon and new moon periods, there were only two main fiveday periods designated for measuring. The team selected canals in all six districts in order to give a comprehensive overview of the canal network. During the days in between the full and new

Figure 21 - Area of Study Selection

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moon, we compiled the necessary data for the ISMAR model, worked on our report, Venipedia articles, and planned for the next measurement period. We finished the term with an updated model of the canal network, and recommendations for future projects. On the days leading up to the designated measurement times, our team went out to survey canals, and plan a detailed route for efficient data collection. The team chose the canals depicted in figure 13 based on five principles: •

Availability of past data so comparisons could be made

Location

Hydrodynamics

Accessibility

Amount of boat traffic

The first and most important thing that we had to look at was the available data. We had to measure canals that were measured in the 1990’s so there would be data to compare to. However, we also had to make sure that we were not repeating any canals that were measured last year. Due to the fact that canals in Venice are distributed in its six districts, we made sure to perform measurements in all of the regions in order to fully understand the water movements throughout the entire city. Our team could eliminate possible canals based on our hydrodynamic knowledge. For example, we didn’t spend time measuring many horseshoe canals because their velocities were close to zero. Another important factor was accessibility. The team had to select canals segments with nearby sidewalks and bridges. Lastly, we selected canals based on their importance to the city. We measured major canals with a lot of boat traffic because this data is most valuable to the resident of Venice.

3.1 Measuring  Canal  Hydrodynamics   Our project consisted of taking new hydrodynamic data and comparing to the past measurements. The methods we used had to match the methods that were used by the 1990’s teams, so accurate comparisons could be made. We recovered data from the 1999 project in order to compare our data to the past, and analyzed what could have caused these changes.

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3.1.1 Tide  Forecasting  and  Measurement  Times   The team took measurements according to specific times forecasted by the lunar tide schedule. The projects done in the 1990’s and 2010 measured at a specific time in the tide cycle, and we wanted to measure at the same time to be able to accurately compare to their data. We took data at two main points during the tide cycle. We measured the incoming tide flow at the point halfway between the low and high tide as the canal was filling up. Then, we measured the outgoing tide flow at the point halfway between the high and low tide as the water was emptying out of the canal. Past projects picked these times because they are the points when the canals are flowing at their maximum velocity, and we used the same points in order to accurately compare to them.

Figure 22 - Tide Schedule with Measurement Points

We went out 30 minutes before the scheduled midpoint on the tide cycle, and then stayed out until 30 minutes after. This gave us a one-hour window to measure the canal velocities. Before the scheduled measurement day, the team went out and surveyed the canals that were planned Going out early and selecting segments that are nearby of each other was important because it maximized the number of accessible canals in the one-hour window. Each team averaged about five canal segments during the measurement window. 3.1.2 Measurement  Device   We used the same tool that the past projects had used. The flotation device is composed of an empty water bottle that is used for flotation, two aluminum plates that are used as resistance in order to be pushed by the water, and a lead weight that is used to sink the aluminum plates into the water. The aluminum plates are placed in the part of the canal that has the maximum

35


velocity (middle of the canal, 1/3 of the canal deep). We also tied a string to the bottle so we could reel the device back in after the measurement was complete. The flotation bottle and weight device might not seem like the most accurate device, but it is to keep comparison consistent. By using this device, we could accurately compare our data to the past projects’.

Figure 23 - Floatation Device Schematic

3.1.3 Procedure   For this part of the project, we split into two teams of two. Each team had a person that would throw the device into the canal and hold onto the leash, and a person that would time the device and record the data. We chose two points alongside of the canal as the beginning and end points of the measurement. Stationary landmarks, such as poles or sidewalk cracks, were selected so that accurate distances could be measured. Then, the person with the device would throw the device as close to the center of the canal as possible. The teammate with the stopwatch would time how long it takes for the device to go between the landmarks. After that, the distance between the starting and ending points was measured. This measured distance divided by the

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recorded time gives the velocity of the canal. We repeated this procedure three times for each canal segment and took the average velocity of three trials.

Figure 24 - Measurement Procedure

3.1.4 Data  Collection   The following table was used to record the data in the field:

Figure 25 - Field Form

3.2 Re-­‐activating  the  ISMAR  Tidal  Model   In 2000, ISMAR published a journal article in regards to the modeling of the inner channels of Venice. ISMAR managed to produce a handful of simulations with an existing 2-dimensional model. They would start by running their Venice lagoon model to get the velocities at all of the openings to Venice channels. Then, they ran the new Venice model to get the velocities of all of

37


the canals within Venice. To further calibrate and validate their model, ISMAR utilized a series of field measurements from WPI’s project teams in the 1990’s. The accuracy of this model depends largely upon the measurements from actual fieldwork. We met with ISMAR many times during the term to discuss what data would be needed in order to reactivate this model. In our revisit of the canals, we provided our measurements of canal hydrodynamic data, in the hope that our data could help produce an updated model. Ultimately, with the results from ISMAR, we were able to present a more complete picture of the hydrodynamics of the Venetian canal network.

Figure 26 - Tide Schedule for ISMAR

3.2.1 Data  Needed  for  Modeling   Using a series of mathematical equations, the model of the Venice canal network can be produced. ISMAR would begin by running their lagoon model in order to get the velocities at all of the openings to the city. To run this model, they obtained the water levels and wind velocity from a tide gauge in the lagoon. We also were able to provide them with the water levels at the Punta della Salute and Punta della Misericordia. There were certain parameters that we would need to give them with our measurements in order to make the model work. For each velocity measurement from the fieldwork, we recorded velocity, date, time of day, water level, and update bathymetries. 3.2.2 Data  Collection  Procedure   In order to get a complete picture for the model, we measured at many different points during the tide cycle. During the full and new moon periods, we measured three times between low and high tide (once an hour after low tide had occurred, once at the midpoint of the curve, and once

38


an hour before high tide). This procedure was repeated three times between high and low tide. As the velocity measurements were being taken (using the same procedure as 3.2), the team measured the water levels. We attached a tape measurer to a long stick, and used this to measure the water levels. Since the water levels were often higher than the stick, the distance from the sidewalk to the surface of the water was taken. Then, we used Insula’s Ramses website to obtain the heights of all of the sidewalks in the city, which we used to obtain the absolute water levels for each canal that we measured. The last important parameter for the model is the bathymetries, or depth, of all of the canals. The old model ran on bathymetry data obtained by Insula back in the 1990’s. To run an updated model, we needed to obtain the updated bathymetries. Thanks to Insula, who sent us a GIS map layer with all of their data, we were able to find the average depth of every canal segment in Venice. 3.2.3 Model  Calibration   After compiling our data into an accessible spreadsheet with the required hydrodynamic parameters, we collaborated with ISMAR for the calibration of the model. The calibration was based on trial-and-error principle, which required time and effort. They would run the model using estimation for the friction of the canals (this was called the fudge factor). The model would result in velocities for the canals, which could be compared to our measured velocities to determine the validity of the model. The friction would be altered until the model was accurate.

3.3 Investigating  the  accuracy  of  new,  more  modern,  devices.   The final objective of this project is to validate new measurement devices. In the past, WPI students have used a floatation device made out of a bottle and cans to measure the velocities of the Venetian canals. In order to obtain more accurate results, we looked into better technology. Ours sponsors let us borrow some of their equipment to test out their accuracy. We were able to measure canal velocities and tide levels using these new devices. We plan to consider these instruments when making our recommendations for the future.

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3.3.1 Propeller  Device   The first device we received was a propeller device. The water current would spin the propeller, and the number of rotations (that occurred in the 30 second interval) would appear on a box. The team positioned the device 50 cm below the water level of the canal, and in the middle of its width. We tied the device to a rope and lowered it into the water from the middle of a bridge going over the chosen canal.

Figure 27 - Ipros Propeller Measuring Device

We recorded the number of rotations, and referred to a study, which created three equations to calculate velocity (which equation was chosen was based on which interval “n” was situated in, and n= # of rotations / # of seconds). Paolo Peretti, a hydraulic engineer from IPROS, generously lent us this device. The team compared the hydrodynamic results obtained with the propeller device to those obtained using the bottle device

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3.3.2 TeleDyne  RD  Instruments  

Figure 28 - TeleDyne River Ray

A second device that we used to measure the velocities was the TeleDyne River Ray. Paolo Peretti took us out on his boat to measure the Canal de Cannaregio (we were not able to measure this canal using the bottle device because it is too wide and has too much boat traffic during the day). We tied this instrument to the side of his boat, and using sonar, were able to measure the velocity of the canal. 3.3.3 Pressure  Probe   Paolo Peretti, from IPROS, also let us borrow a pressure probe that we used to measure water levels. One of our objectives that we were not able to complete was analyzing the tide delay phenomenon. When performing tide delay measurements, students need to estimate when the

41


peak tide (high or low tide) occurs. This is very difficult because the change in water level is gradual, which is why the instrument proved to be helpful.

Figure 29 - Pressure Probe

The team went out a half hour before the predicted high tide would occur and stayed out until a half hour after. This way, we made sure that we did not miss the peak tide, and that we could accurately record the delay in peak tide occurrence. We tied the pressure probe to a stick and put the stick into the canal. The pressure probe would record data and store it every ten seconds. After the hour, we would connect the probe to a computer, and it would show us all of the data and produce a graph.

3.4 Publicizing  Hydrodynamic  Data   In the mission statement for our project, it states that this project is designed to help the residents of Venice better understand their city. We could not just stop after measuring the velocities of each canal, or re-activating the old ISMAR model. In order to let people know our data and analysis, we published our data in a place that can be viewed by anyone, so that anyone interested in the hydrodynamics of the Venetian canals would be able to locate and download the data. 3.4.1  Posting  data  on  Venipedia   We created a Venipedia page for each canal and each canal segment. The canal pages give an overview of the canal and its location. On the canal segment page, we provide all of the data,

42


both physical properties (such as width and length), and our hydrodynamic data. We are waiting for a program to be created that will automatically input all of our data onto these pages.

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4 Results   This section contains the hydrodynamics results that were taken during the duration of this project.

4.1 Hydrodynamic  Data   The team took two sets of measurements during the seven-week term, each lasting five days. 4.1.1 Canal  Hydrodynamics   During the project, the team measured a total of 95 canal segments. In total of over 1650 measurements taken, three measuring windows were conducted during the incoming and three intervals during the outgoing tide. The canals were chosen from each of the six sestiere. The team encountered a few problems along the way. These problems included broken devices, boat traffic, boat obstruction, and inaccessible canals. Despite these problems, the project always prevailed. The team’s Area of study can be found in figure below.

Figure 30 - Area of Study Map

4.1.2 Directional  Changes  with  Respect  to  Tides   While the team took the measurements, the data was recorded on one of our designated field forms. Since we were recording velocity, the team needed to find not only magnitude but also direction of the given canal. When documenting the direction, we followed the results method of

44


the 2010 WPI Hydro team. They documented the behavior of the direction of flow during incoming tide versus outgoing tide. The canals could behave in four different categories: flow in different directions during incoming versus outgoing tides, flow in the same directions, be stagnant for both tides, or be stagnant for one tide and flow during the other. This year’s project found, out of the 95 segments measured, 70 flowed in different directions during incoming versus outgoing tides (73.7%), 2 flowed in the same directions (2.1%), 5 were stagnant for one tide and flow during the other (5.3%), and 4 were stagnant for both tides (4.2%). Staying consistent with last year’s results, most canals tend to flow in different directions during incoming versus outgoing tides.

Figure 31 - Tide Behavior of Canal Segments

4.1.3 Maximum  Velocities   Once the measurements were taken at the six points, the team picked out the maximum velocity (half way between the peak tides). Past WPI studies categorized the canals into four distinct groups. If the canal had a speed ranging from 0-1 cm/s, then it was said to be Stagnant. If the canal had a speed of 1-10 cm/s, it was known as “lazy”. Canals were categorized as mid-ranged if it had speeds anywhere between 10 and 20 cm/s. Finally, canals were Fast it they had a speed greater than 20cm/s. Our results for the speeds for incoming and outgoing tides are shown in the two figures below, respectively. 45


Figure 32 - Incoming Velocity Results (Flows from South to North)

Figure 33 - Outgoing Velocity Results (Flows from North to South)

4.1.3.1 Incoming  Tide   Of the 95 canal segments measured during the incoming tide, 9 were considered stagnant (9.9%), 24 of the segments were lazy (25.7%), 39 were mid-ranged (42.9%), and 20 of the segments were calculated as fast (22.0%). The figures below show two examples of incoming tide 46


comparison (vs. 1990’s data) charts created by the team. The team created a chart for each sestiere. The average velocity of these canals in the 1990’s was calculated to be 17.34 cm/s. Our team calculated the average velocity for our measurements to be 15.05 cm/s. The team also found a trend of most canals flowing from south to north during incoming tide. There were six exceptions to this statement, because we found the segments of GRIS1, GRIS2, MAGA, PANT, VERO1, and VERO2 to being flowing from north to south.

Figure 34 - Santa Croce Incoming Tide Comparison

Figure 35 - Dorsoduro Incoming Tide Comparison

4.1.3.2 Outgoing  Tides   Of the 95 canal segments measured during the outgoing tide, 7 were considered stagnant (7.7%), 10 of the segments were lazy (11.0%), 44 were mid-ranged (48.3%), and 30 of the segments 47


were calculated as fast (33.0%). The average velocity of these canals in the 1990’s was calculated to be 16.84 cm/s. Our team calculated the average velocity for our measurements to be 19.12 cm/s. Figure 27 and Figure 28 show an example of an outgoing tide comparison (vs. 1990’s data) chart created by the team. All the comparison charts can be found in Appendix E.

Figure 36 - Santa Croce Outgoing Tide Comparison

Figure 37 - Dorsoduro Outgoing Tide Comparison

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4.2 ISMAR  Model   The team was able to send the data we recorded to our sponsors at ISMAR. With this data, they were able to run their Finite Element Model. The data we provided them with consisted of the velocities we recorded and water level measured at thirty given Canals, up-to-date bathymetry file, and the water levels at the Punta della Salute and Misericordia tide gauges for the three days that measurements took place. Using the bathymetry and tide gauge recordings, the model was able to calculate velocities of all canals during the given three days. Ph.D Elisa Coraci, from ISMAR, then used our recording velocities to calibrate the resulting velocities from the model. An example of this resulting velocity can be found in figure below. The dotted blue line represents the model velocity while the red line represents the velocities our team recorded.

Figure 38 - Link 2392 from ISMAR Model

4.3 Propeller  Comparison   The team was also able to record results of velocities measured with the bottle device versus velocities measure with the propeller device. The team found, on average, that the propeller recorded a velocity that was 5 to 6 cm/s faster than the resulting velocity of using the bottle device. An example of these results can be found in figure below. The full list of propeller comparison data can be found in Appendix K.

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Figure 39 - Propeller Comparison Data

4.4 Sustainable  Data  Results   With all the data taken, the team hoped to be able to publicize this information on an online resource, like Venipedia. Due to the desire of an automatic filing program, the team instead documented the results into a format that will fit this database. This file will be saved and is ready to be used once the program is finished. Once this happens, all data taken by the 2011 Hydro Team will be available for all on Venipedia.

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5 Analysis   This chapter contains the analysis of the results obtained from our hydrodynamic data. For the 95 canal segments we measured in this year’s project, we categorized the results and comparisons by incoming and outgoing tides, as well as by the 6 historical districts of Venice. With the main focus in Cannaregio and Dorsoduro, we created a comprehensive analysis on factors that can possibly affect the speed and directions of canals. The comparisons in this section are derived from this year’s field data to the 1990’s. To eliminate possible sources of error, we filtered our comparisons so that only the speed change of 5 cm/s and above can present on figures.

5.1 Incoming  Tide  Analysis   This section is devoted to the analysis for the incoming tide results. 5.1.1 Cannaregio  –  Hydrodynamic  Patterns  

Figure 40 - Cannaregio Incoming Velocities

One of the more controversial districts that we studied is Cannaregio. Located near the northern lagoon, the speed of canals close to the lagoon flowed rapidly (around and above 20 cm/s). In figure above, the deep colored canals show that canals in the perimeter work effectively during incoming tides to transfer tide from the Grand Canal to the northern lagoon. CANN, NOAL and

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FELI were among the fastest in our fieldwork due to their adjacent connections between Grand Canal and northern lagoon. This can lead to a water bypass from the district center. As showed in the lighter-colored area, horizontal canals such as MISE and SENS work in resistance as water flowing from Grand Canal to northern lagoon during incoming tide. 5.1.2 Cannaregio  –  Comparison  Analysis  

Figure 41 - Cannaregio Incoming Changes from 1999

In the comparison of our fieldwork to the 1990’s, two areas in Cannaregio showed large changes in scale to the rest. The lower canals connecting to the Grand Canal, MARC and NOAL have slowed down by 15 cm/s, while the horizontal canal ORTO and ALVI sped up by 10 cm/s. We believe that the cause could be that in over 10 years, the water inflow has shifted north during incoming tide. As the Grand Canal is being filled in, the northern lagoon might have experienced water inflow earlier than the Grand Canal. Ten years ago, it appeared that the Grand Canal interacted more rapidly to the adjacent ones like MARC and NOAL. But ten years later, major canals in Cannaregio such as MISE and SENS all have slowed down due to a visual “bypass” around Cannaregio.

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5.1.3 Cannaregio  –  Possible  Hydrodynamic  Behavior  

Figure 42 - Cannaregio Incoming Hydrodynamic Analysis

The triangular area shaped by FELI, CANN and ORTO/ALVI worked as the main route of water transfer when tide first reached FELI (lower right arrow). A temporary water level difference was built up, with relative high level (plus on the figure) in Grand Canal, and relative low water level (minus on the figure) in the northern lagoon. There were three possible routes for water to shed off from the Grand Canal in order to balance the water level difference: FELI, MARC and CANN (depicted as the three upward arrows). Among these, CANN played the major role in water transfer due to its width and linearity. Water tended to move into center of Cannaregio due to the water level difference. But in our comparison to the 1990’s data, the speed has decreased in over 10 years. We therefore consider the center canals to be a resistant of the overall water transport in this region. However, in order to explain the increasing speed of the upper most parallel canal, ORTO and ALVI, there has to be another water flow that redirected the water from FELI to ORTO.

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Figure 43 - Cannaregio Incoming Hydrodynamic Analysis Zoomed In

As depicted in the figure above, the only pathway that could greatly affect the flow direction from the FELI was some influence from the northern lagoon. When the two flows met, the poach-shaped entrance served as a pump, which caused the increase of water speed of water flowing through ORTO and ALVI. 5.1.4 Dorsoduro  –  Hydrodynamic  Patterns  

Figure 44 - Dorsoduro Incoming Velocities

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The canals we studied in Dorsoduro area has an intriguing mechanism of transport phenomena; during incoming tide, some water flowed directly from the Grand Canal into the west opening of the grand canal. Despite water flowing through in Dorsoduro, the speeds of the canals were not rapid compared to those of Cannaregio. In average, the canals that we measured were 12 to 13 cm/s. 5.1.5 Dorsoduro  –  Comparison  Analysis  

Figure 45 - Dorsoduro Incoming Changes from 1999

The most debatable change that we found was the consistent speed decrease among the five canal segments. After over ten years, the speed of NOVO, the major pathway cutting through Dorsoduro, has slowed more than 10 cm/s. With the actual speed of 12 to 13 cm/s, the NOVO canal has only reached half of the speed of that in the 1990’s. This dramatic decrease of speed led us to investigate the surrounding canals in order to find some connections that caused this change.

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5.1.6 Dorsoduro  –  Possible  Hydrodynamic  Behavior  

Figure 46 - Dorsoduro Incoming Hydrodynamic Analysis

In order to understand the speed decrease in Dorsoduro, we started with the entrance of incoming flow. The Grand Canal carried large amount of water to the first turning point as depicted in figure. Due to the shape of this turning, the southern entrance of NOVO received a fairly large amount of water flux. The remainder of water flow would then continue going through the Grand Canal towards Cannaregio.

Figure 47 - Dorsoduro Incoming Grand Canal Analysis

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After the water reached Cannaregio, the flow started to shed off into the northern lagoon, across into Cannaregio as mentioned in the previous discussion. However, because the change of water speed is mainly caused by water level difference, it is reasonable to suspect that there had been water entering from west Venice. One of the major pathways of water is SCOM (long glowing arrow). If it can be proved that the incoming tide reaches the meeting point in figure, the relative water level difference between the east entrance and west exit of NOVO would be less than that of ten years ago. The less the water level difference between the two points, the slower the speed canal moves. 5.1.7 Dorsoduro  –  SCOM  Comparison  

Figure 48 - SCOM Comparison, Incoming

To obtain the key evidence of water incoming from the western entrance of the Grand Canal, we compared our data to the measurement conducted in the 1990’s. When measured in 1990’s the flow of SCOM was stagnant. But when we measured SCOM this year, we observed steady water movement flowing into the Grand Canal entrance during incoming tide. This observation also solidified our assumption of water passing through the Guidecca channel.

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Figure 49 - Guidecca Overall Hypothesis, Incoming

When water entering from the eastern Venice, a large portion of water would flow through the Guidecca channel. The channel is wide and has the capacity of carrying water to western Venice. When this strong water flow met water coming from the southwest, this caused the flow movement happened in SCOM. We suspected that there had been some influence from the south in over ten years. But more evidences are needed to support this hypothesis. 5.1.8 Dorsoduro  –  Grand  Canal  Direction  Change  

Figure 50 - Grand Canal Direction Change, Incoming

Another assumption that we made was the change happening in the western part of the Grand Canal. Because the Grand Canal has the greatest water-transport capacity among the inner canals of Venice, it could be a bold assumption on any changes, especially directional, that occurred over time. In 1966, the direction of the Grand Canal was westward, as shown in figure. But in

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our fieldwork, we realized the direction has changed in over 50 years. Instead of splitting the water into CANN and the western entrance of the Grand Canal, the two segments of the Grand Canal were joining and flowing out of the city from CANN.

Figure 51 - Grand Canal and CANN, Incoming

Another proof of the hypothesis is the increase of speed in CANN from comparison. After the water meet at the southern opening of CANN, water speed has increased 10 cm/s in ten years. The only cause of water entering from the western entrance of the Grand Canal the water rising from the western part of Venice, which could be coming from the SCOM.

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5.1.9 Dorsoduro  –  MARG  Direction  Change  

Figure 52 - MARG Direction Change, Incoming

As an outcome of the speed decrease in Dorsoduro, we noticed some inner canals have changed directions in our comparison. The MARG canal, connecting to NOVO, has changed its direction from southward to northward during incoming tide. We suspected that this was caused by the decrease of water level difference at two ends of NOVO. In 1990’s, the relative water level between NOVO was fairly high, which indicated that the incoming tide had not yet reached the western part of Venice. However, in our hypothesis, water was able to reach the western part of Venice due to the change happened in SCOM. As a result, the water level difference between the two ends decreased. This caused the water from the southern Dorsoduro be able to push its incoming water towards NOVO, which led to this direction change on MARG.

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5.2 Outgoing Tide Analysis This section is devoted to the analysis for the outgoing tide results. 5.2.1 Cannaregio  -­‐  Hydrodynamic  Patterns  

Figure 53 - Cannaregio Speed Analysis, Outgoing

The speeds of canals in Cannaregio during the outgoing tide were very rapid. Located at the northern tip of the Venice Island, Cannaregio contacted the direct impact of outgoing flow faster than any other district. As a result, almost all canals were above 15 cm/s, with CANN carrying over more than 30 cm/s.

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5.2.2 Cannaregio  –  Speed  Comparison  

Figure 54 - Cannaregio Speed Comparison, Outgoing

The comparison of outgoing speed during outgoing tide showed that the speed of CANN had decreased in over ten years. And for the canals adjacent to the Grand Canal, the speed had decreased. The less utilized canals could indicate that water at the northern lagoon shifted from toward to the northeastern part, which may cause the water speed in other districts to increase.

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5.2.3 Cannaregio  –  Possible  Hydrodynamic  Behavior  

Figure 55 - Cannaregio Flow Analysis, Outgoing

During outgoing tide, all three main routes (CANN, MARC, FELI) were reacting rapidly to the need of the Grand Canal transfer. This created a temporary water level difference between the upper-west parts of Cannaregio to the Grand Canal. Because the Grand Canal carried the most amount of water, water flowed very rapidly from north to south as if they were being sucked into the Grand Canal. The large opening from the north of FELI and east of ORTO could also allow more water flowing into the Grand Canal.

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5.2.4

Dorsoduro/San Polo/Santa Croce – Hydrodynamic  Patterns

Figure 56 - Dorsoduro/San Polo/Santa Corce Speed Analysis, Outgoing

Overlooking the three districts, we observed that NOVO and canals nearby were reacting rapidly to the outgoing tide. The temporary water level difference was thus created between the two ends of Dorsoduro. The speed of NOVO and nearby canals had an average of 20 cm/s, which was significantly higher than the data of incoming tide. Another interesting observation was that the canals adjacent to the Grand Canal in Santa Croce and San Polo had speed of 10 to 15 cm/s, which were faster than the incoming tide. This indicated that these canals were utilized more often during outgoing tide to shed off from the Grand Canal.

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5.2.5 Dorsoduro/San  Polo/Santa  Croce–  Possible  Hydrodynamic  Behavior  

Figure 57 - Dorsoduro/San Polo/Santa Croce Flow Analysis, Outgoing

The overall flow directions were within our prediction. Water tended to shed south in order to redirect into the Grand Canal, and escape to the southeast exit of the Grand Canal. NOVO connected directly between the Grand Canal entrance and the turning point.

Figure 58 - Temporary Water Build-up, Outgoing

Right before the NOVO entered the turning point, we suspected a subtle water build-up zone in the southern canals of San Polo. The water that entered into the Santa Croce and San Polo canals

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would exit at the circled area. Joining with the main water flow from the Grand Canal, water started to build up and create a relative high water level compared to its southern part. 5.2.6 San  Marco  –  Hydrodynamic  Patterns  

Figure 59 - San Marco Speed Analysis, Outgoing

Due to the temporary water build-up in the north of San Marco, the water speed of this area were moving very rapidly, in an average of 25 cm/s during outgoing tide. The fastest area that we have studied so far, San Marco played a key role in transport water from the middle of Grand Canal, directly into the exit. Among the canals we measured, some of the fastest ones were located in San Marco.

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5.2.7 San  Marco  –  Possible  Hydrodynamics  Behavior  

Figure 60 - San Marco Flow Analysis, Outgoing

The temporary water build-up caused a relative high water level, located near the northern part of San Polo. And this created a very large water level difference between across San Polo. Joining by some minor inflow from the Castello district, the overall flow movement of San Polo was consistently fast, from north to south.

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5.2.8 Castello/Cannaregio  –  Hydrodynamic  Patterns  

Figure 61 - Castello/Cannaregio Speed Analysis, Outgoing

The speeds of canals in Castello have been moving fast during incoming and outgoing tides in the past ten years. Due to the linearity of its canals, canals took water from the northern east of the lagoon directly down to the south exit of the Grand Canal. In an average of over 25 cm/s, the canals near the Arsenal are within our scope to study their changes over time. A couple canals in between Cannaregio and Castello were also flowing fairly fast, 18 cm/s in average. This area intrigued our interest to investigate the relation between these canals during outgoing tides.

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5.2.9 Castello/Cannaregio  –  Speed  Comparison  

Figure 62 - Castello/Cannaregio Speed Comparison, Outgoing

The area in blue color indicates that the speeds of the canals have decreased in our comparison; area in red indicates that the speeds have increased. Even with the decrease among the canals in Castello, their speeds were still rapid enough to carry large amount of water into the south. However, the red area in Cannaregio now functions as a significant pathway for water in the northeast to shed off. And this increase supports our previous assumption on water build-up in the San Marco area; water through the red area will join with the flow from the Grand Canal and Cannaregio north, to form an even greater flow in the Grand Canal.

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5.2.10 Castello/Cannaregio – Possible Hydrodynamic Behavior

Figure 63 - Castello/Cannaregio Flow Analysis, Outgoing

The fast movement in the Castello canals indicated a relative high water level up north in the lagoon, and a relative low water level in the Grand Canal exit. The north lagoon also shed water to the middle of the Grand Canal due to the suction force caused by the rapid flow from the south of Cannaregio.

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6 Recommendations   This section is dedicated to sharing our experiences with future students who may take on this assignment of Canal Hydrodynamics. We hope they heed this advice for we feel it will lead them to complete a successful project.

6.1 Lessons  Learned  in  the  Field   Before arriving in Venice, our team read the 2010 Canal Hydrodynamics recommendations section to prepare ourselves for the seven week project. The first advice they had was to “survey” the canals that were to be measured in the near future. This is the act of going to the canal to view where possible measurements could be taken. We advise future teams to not do this. This method proved to be a waste of time for many reasons. The 2010 team said it would be good to get to know the area where you will be taking measurements and know where it is located. Our team still did not know the exact location after surveying. We advise the team instead map out a route and carry it with them at all times. As for seeing which canals are accessible, we advise the future team to refer to the Insula website. Under their Ramses project, you can find a thematic model, which shows all heights of sidewalks throughout the city. They label this model “altimetry.” Using this, it can be seen if the canal is accessible and even pick a spot along the sidewalk where you wish to do the measurement. We also found surveying to be ineffective because of parked boats. Many times, the team found a great spot to do a measurement, but when the time for measurement came, a boat was parked right in the way. The future team will only know the right spot at the exact time of measurement. There will also be changes between the measurement during incoming and outgoing tide. The team will just need to adapt and figure a way to get around the problem. Another reason for not surveying is to conserve energy. The future team will do a lot of walking and surveying will add to this if done. For the bottle device that is used for measurements, the schematic states to use fishing line. This proved to not be strong enough, because on the first day of measurements, both devices’ fishing

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line broke. The team then decided to switch to thicker white string that can be found at any hardware store in Venice. On multiple occasions, the Venetian locals attempted to talk to us and we assume ask us what we were doing. Our team’s Italian vocabulary is very limited and it was very difficult to understand them and respond. We advise the future to team to memorize a sentence in Italian along the lines of “we are measuring the speed of the canal. We are not fishing.” Also some locals thought our team was throwing trash into the canals and were extremely upset. When this happens, immediately take the device out of the water and show them it. Next we advise you say the sentence that was memorized in Italian and even say the names of your sponsors. The locals will probably then get the big picture of what the team is attempting to do. Finally, our team did many measurements at the early hours of the morning. We underestimated how cold it would be during this time. A couple members of the team caught a cold because we were not prepared for the weather conditions. We advise the future teams to bring a lot of warm clothes. They should wear layers and a rain layer on top. The first day is the worst, but don’t quit because measurements get easier as the team got more used to the early hours and weather.

6.2 Suggested  Hydrodynamic  Studies   The 2011 Canal Hydrodynamics IQP Team was able to take measurements and obtain velocities for 93 canal segments. When added to the 52 canal segments measured by the 2010 team, the result is 145 canal segments measured.38 As previously mention, the purpose of our project was to compare our data to the data taken the 1990’s. Their total number of canal segments measured was 170.39 Doing the math, this still leaves 25 canal segments. This is not a large number but it is still important that they are done. Only having to measure 25, the next team could possibly measure the 25 during each of the new and full moons they encounter while in Venice. This not only takes care of the 1990’s comparison but could also compare the differences in speeds during full and new moon.

38 39

{{8 Scully,Brian J. 2011}} {{5 Ozbas,Halil I. 1999}}

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Our team strongly recommends that the next term work very closely with our sponsors from this term. They were detrimental to the success of our project. Mr. Paulo Peretti, from Ipros, could not have been more generous during a project. He took time to discuss good canals to measure, take us on his boat to measure canals, give us devices to measure speed and level, and discuss the results of our measurements. He would be extremely helpful to any future WPI team. The three sponsors from ISMAR were also a big part of our presentation. They took time out of their busy schedules to meet and talk hydrodynamics. They also took time to work with us on re-running the finite element model. If not other advice is used, we hope this be the one that is the most. These sponsors could not have been any more helpful and we fully recommend future team use these imperative resources.

Figure 64 - Recommended Area of Study Map for 2012 Team

In the figure above, our team has chosen some canals that we recommend the next team measure. One reason why we chose these is because they are canals that have still yet to be measured. So measuring these would finish the comparison of the 1990’s data. Also, they are areas of very high interest. A lot of the canals are adjacent to the Grand Canal. We chose these so the team could get more insight of the flow of the Grand Canal and how it sheds through the ones it is connected to. This is very important for the most northern canal that was selected, since it is connected to the part of the Grand Canal that changed directions since 1966 and is speeding up. We chose a good number of canals in the Dorsoduro and Castello region. This is because they are region where we found interesting changes. Lastly, we chose canals in Guidecca. We picked

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these because there is an interesting movement in the Guidecca Canal, where it is possibly curling up and into the south west of the city. The next team that attempts this project will complete the comparison with 1990’s. Our team advises that this project should be continued by starting another comparison. With the near finish of the MOSE flood gates; there will be many changes within the next ten years. Another 10 years without measurements would hurt the knowledge of water movement through the canals of Venice. There are many phenomenon that we mentioned in our analysis section that need to be carefully looked annually. The team also was able to test a new propeller device as previously mentioned. Even though it is important to use the bottle device for a consistent measurement, we believe it would still be helpful to use this propeller device. The device proved a lot easier to use that the bottle device. We feel it would be most helpful when measuring the larger canals, because throwing the bottle into the middle of the canal proved difficult on these specific ones. We advise to continue the comparison between the bottle and propeller device in hope that they become similar enough to just use the propeller.

6.3 Suggested  Tide  Delay  Studies   Tide delay is a very important topic when it comes to Canal Hydrodynamics. Having tide delay data can possibly show where the watershed is located which adds to the speculation of a tide coming from the west of the city. Even though our team did not get any tide delay data, we were still able to test two different tide delay devices. We strongly recommend that future teams use these devices rather than the plumb bob technique used in 2010. The plumb bob method seemed to be extremely inaccurate and a waste of time. These two devices measure the pressure of the water and with this you can figure the exact time when the water is at it’s highest or it’s lowest.

6.4 Suggested  Canal  Data   As past projects have done, all our team’s data was compiled into excel files for future viewing. We recommend that this data be put on an online resource, like Venipedia for example. A template for all the individual canal segment pages was created this year. In this template, the

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program extracts the data from the excel file and puts it directly into the Venipedia page. We recommend that next year’s team use this program so all our recorded data be open to the public. Also done this year, the Noise WPI project team created a phone application where the user can record a sound, take a picture of the source of the sound, type a description of the sound, record the longitude and latitude of the recording, and upload all the information on to an online source instantly with the press of a button. Once on the web, a map is made that shows spots where there is a high and low density of sound. We suggest next year’s team create something like this for Hydrodynamics. In this application, the user would measure the canal and type the velocity into the description. The user would then take a picture of the measured canal. When it is uploaded, the program will then make a map, with colored arrows for example, that shows velocity. This would make data compiling easier and create useful visuals for explaining water movement.

6.5 Expanding  the  Area  of  Study   As last year’s team mentioned, there is a need for more than one project that works on the subject of canal.40 A big underlying issue of Hydrodynamics is sedimentation. We believe that there needs to be a separate project that works only on the build-up of sediment. They would figure outs its origin, areas of high build-up, and how much of the sediment that came in also went out. We feel this is a very important topic to undertake. Because of the number of measurements we took, our team did not have enough time this term to even look into any of this subject. This team could collaborate with Insula and inform of areas that need to be dredged and also create precautionary ideas maybe to slow down sedimentation rates. Another project to be started is one on study the infrastructure of the canals. During measurements, the team noticed multiple canal walls and bridges that were either broken or eroded. A project should be set aside to explore the city and document these problems. They then should meet with Insula and inform them of these infrastructure deformities. Most of these were found in canals that were hidden, and in result, were not seen by many people. We feel if not action is taken; the problem could get worse and could lead to major collapses. 40

{{8 Scully,Brian J. 2011}}

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