The Changing Water’s Edge - 06/23/2011 – 8:30AM-12:30PM
|Simulated LiDAR Survey|
On June 23, 2011, experts, researchers, and governments officials came together to discuss the potential effects and implications of sea level rise. Every aspect of sea level rise and its results were examined during the four hour meeting held at Save the Bay in Providence. The meeting was composed of three major sections: maps and resources for local managers, case study presentations and discussions, and a view from the private sector.
Rhode Island does not have a plan to deal with sea level rise; however, it is crucial that one be developed, as the Newport Tide Gauge shows that the rate at which the sea level is rising is increasing. Planning is currently in Phase 1, consisting of data consolidation as well as the identification and quantification of vulnerable assets. Storm surge and spring high tide in Wickford can be viewed as precursors of impacts from sea level rise.
The LiDAR data was collected on May 2, 2011 and the product delivery is expected by the fall of2011. The deliverables should include raw point cloud data as well as classified points that specify ground, non-ground (trees, buildings, etc.,) water, and noise (ie. birds.) The existing data from 1997-2009 consists of maps of different scales, formats, and quality. Those maps have been compiled to make one accurate map available for viewing on ArcGIS. The information derived from LiDAR data can help standardize the accuracy of our understanding of the terrain of Rhode Island. It has such precise resolution, its margin of error is only +/- 6inches. The previous map had a margin of error of greater than +/- 3 feet.Recently a LiDAR(Light Detection and Ranging) survey of RI took place. The data from these surveys can provide a foundation for elevation data of the state, which can allow for predictions of areas that will be most impacted by sea level rise. LiDAR has a number of benefits. First of all, it is very precise, recording over 100,000 points per second. It has the ability to get multiple returns from a single pulse: in other words one pulse could detect a bird, the trees over which it is flying, and the ground beneath that tree canopy. The two major LiDAR products are digital surface models and digital elevation models, the latter of which can create bare earth digital elevation models(DEMs) which are used to calculate the areas impacted by sea level rise. The bare earth DEMshave 10 foot cell sizes and are hydroflattened, showing neither contour lines nor bathymetry.
|A one foot sea level |
rise in Wickford Harbor
Following the presentation and discussion of the compelling SLAMM maps, there was a discussion with North Kingstown town officials. After a short break, panelists from Bristol,Newport, and Warwick discussed the potential impacts of sea level rise in their respective areas. Diane Williamson, the Community Development Director in Bristol, discussed concerns regarding storm surge and the infrastructure in the Poppasquash/Hope Street infrastructure where culverts are being blocked by the receding seawall. There is a question of whether or not to repair the road, as it is at such a risk for flooding, it may be a waste of money.
In terms of flooding, she succinctly said it “hits you at home because it is your home.” Her talk was followed by a presentation by Newport Planning Director, Paige Bronk. He discussed how storm surge is also a concern in the area, as Newport lies well within a 100-year floodplain. Storm surge threatens retail business on Thames Street; however, due to the historic nature of those buildings, raising them remains controversial. Bronk called for a stronger state building code that will consider flooding. He also encouraged zoning relief for properties at risk of coastal flooding. Finishing this portion of the meeting, Janine Burke from the Warwick Sewer Authority discussed how the floods of 2010 presented a true challenge to the wastewater infrastructure in the city. She provided forceful pictures and statistics about how the Sewer Authority faced an unprecedented challenge from the floods; her office was evacuated on March30th and water levels there rose to six feet. The floods tested pumping stations that were “built like submarines,” completely wiping out six of them. The biggest impact of the floods could be seen in sanitary sewer overflows and electrical system problems. As a result of the floods, the wastewater treatment employees are now actively involved in emergency planning. Burke suggested that in planning for climate change, the following are major points to be addressed:energy efficient initiatives, renewable energy, consideration of future hydrology, and avoidance of construction in floodplains.
|A three foot sea level |
rise in Wickford Harbor
|A five foot sea level |
rise in Wickford Harbor
Overall, the day was hugely informative for all of those involved. The speakers highlighted the extent to which sea level rise will have far-reaching implications, many of which are often not immediately obvious.