PROJECT NARRATIVE
BACKGROUND
Venice, Italy, made up of 118 individual islands, has been a cultural hub for hundreds of years. Ships traveling between Europe and Asia often stopped at the ports of Venice where goods and culture was exchanged. The art and architecture located in this unique area is without equal. However, Venice was built in an area that was generally inhospitable for long-term growth. As the city rapidly drained the groundwater, the city began subsiding. This along with the rising sea levels due to global climate change has led to repeated flooding of many iconic, commercial, and residential buildings, making the city no longer ideal to live in. Many permanent residents left the island for homes in the larger coastal cities and renting their homes to travelers. Over the last 100 years, the population has dropped catastrophically while tourist numbers drastically increase. In order to combat flooding, the government created the MOSE Project, a series of gates and locks that would block incoming water at the three main inlets of the Venetian Lagoon. The process of installation of MOSE has taken longer than expected while sea levels have risen more than expected during the designing of the gates. These factors, along with the cost of operation, make the MOSE not ideal for long term usage. Additionally, MOSE is only deployed during “acqua alta” events, or extreme high tide. This means that any high tide below 80 cm will not cause the barriers to deploy. Many buildings in low-lying areas of the island will be inundated even during these events.
SITE SELECTION
After conducting research, several problems were identified all relating to human health and flooding. Many of the ports located on the coast facing the lagoon can emit harmful aerosol and sediment that can spread several kilometers, especially as runoff collects contaminants and spreads them even greater distances. As more and more people visit Venice and the surrounding Veneto region, more people have the potential to come in contact with harmful pollution and byproducts from industry. Additionally, many areas that are flooded frequently will develop black mold, a toxic mold to humans. Bricks and many other stones used in Venice are very porous, creating an ideal home for black molds. As tourism is a primary economic driver, it would be impractical to limit the growth of tourism. This means a focus needs to be made on targeting areas of high risk than can limit the spread of toxins through cities. These areas were determined by making a suitability model containing proximity to city and industrial areas, water ways, points of interest (tourist attractions, museums, historic sites, etc.), and short term rental properties. The problems associated with the island of Venice are slightly different, as they are on a more intimate scale and considered building footprints for density, short term rental locations, and points of interest. Water ways were not considered on this scale as nearly the entire island is in direct contact to the water via interconnecting channels.
PROPOSAL
The proposal outlines three phases of intervention. “Ascend Phase” includes raising the buildings on the island of Venice and retrofitting them with industrial flotation devices. This method requires the most initial capital and the most stakeholders, making it the most difficult to acquire. However, this method will last the longest even under dramatic sea level rises. The raising of Galveston, TX and Chicago, IL are two examples from over 100 years ago where buildings were lifted with jack screws 11 and 10 feet, respectively. This is similar to Houston, TX (Galveston Bay is where Houston is located). However, the reasons for the need to increase city levels were due to different reasons. Along the Texas coast, sea level rise is due to storm surges and waves while in the Venetian lagoon is increased heavily due to tidal fluxes. “Block Phase” creates a super levee around the lagoon tying into higher elevations inland. This method is most likely the cheapest solution and requires less stringent stakeholders, allowing it to be an ideal solution. However, this solution is a temporary fix. As sea levels rise, the height of the super levee will not increase. The proposed height of 10 feet is not likely to be exceeding from sea level rise over the next two to three hundred years. However, if storm surges inland increase, the super levee will create a bowl effect. In order to combat these negative impacts, windmills will be able to pump and exchange water from lagoon to ocean as need be to maintain salinity and water levels. Precedents such as the Chenier Ronquille Barrier Island in Louisiana offer insight into choosing sediment to create the barrier as well as some of the benefits on a smaller scale. “Collect Phase” is a supplementary phase, as on its own it will not help mitigate flooding on a large scale. By creating green spaces higher up in the water shed, toxins can be removed from water, groundwater can be replenished, and runoff will be decreased. By finding a city with a similar climate, values were placed in the Green Values Stormwater Toolbox, a calculator used to determine the effect of green spaces added into a development. The site was created as a 1-acre site and extrapolated based on the regional makeup of Veneto. With just 1% of the land phytoremediated and 5% of the impervious surfaces removed, groundwater is expected to be replenished, water treatment costs decrease, and runoff is decreased.
EVALUATION CRITERIA
The three proposals will be evaluated on specific criteria. By measuring current runoff and discharge rates in the Venetian Lagoon, the effectiveness of the reduction can be observed over time. Additionally, water tests near the mouths of rivers can determine if water quality is improved over time. As the water levels increase in the lagoon, floating areas can be monitored and recorded when inundated with water. Testing buildings for black mold and determining other signs of damage due to flooding and comparing over time will help determine if the flotation devices combat the negative effects of flooding. Finally, the barrier can be evaluated by measuring water quality near the island, measuring monetary increases by allowing more places for residential and commercial sites, and measuring the water levels of the ocean compared to the lagoon. If water is more effectively sustained on the ocean side, the water on the lagoon shore should be a different height than that of the ocean.
