VIEWS™ (Visualizing Impacts of Earthquake With Satellites) is a notebook-based system developed by ImageCat Inc. through funding from MCEER. The VIEWS™ system integrates satellite imagery with real-time GPS (Global Positioning System) readings and map layers, and operates in conjunction with a digital camera and digital video recorder, to record damage following a disaster.
As a part of the second field mission in the aftermath of Hurricane Katrina, the MCEER field team is using remote sensing technologies and the VIEWS™ system to rapidly collect “High Resolution Photo” and “High Definition Video” surveys of damage over large geographical areas in New Orleans.
Shubharoop Ghosh of ImageCat Inc. and Carol Hill of the LSU Hurricane Center are part of the remote sensing team representing MCEER in this investigation. The route they took through Orleans Parish and their daily findings are provided below.
General area of deployment
On Day 1 (10/6/05), the remote sensing team focused its investigation on the area between the 17th Street Canal and the Industrial Canal, north of I-610 in Orleans parish (See Figure 1). The areas surveyed consisted mainly of residential buildings (approximately 95% of buildings in the region surveyed), with some major educational institutions, government facilities and parks.
Figure 1. VIEWS™ data collection route from 10/6/05 in New Orleans
(Satellite image courtesy: Digital globe)
The residential areas surveyed were broadly categorized into three groups – 1. Velocity Zones near Levee Breaches, 2. Inundation Zones and 3. Non-Flooded Areas. A brief description of each of these zones is given below, along with an assessment of the magnitude of damage encountered (none, minor, moderate, severe, destruction). Brief notes of observations of the institutional buildings are given following the residential categories.
1. Flood Velocity Zones near Levee Breaches
The areas adjacent to the levee breaches at 17th Street Canal and London Street Canal exhibited unique damage characteristics typical of high velocity areas. The damage to structures was similar at both breach sites, with the exception of significant fine sand deposits in the areas adjacent to the London Street Canal. The extent of these zones generally included about three block by three block area from the location of the levee breach.
Typical damage to residential structures in these areas is generally classified as destruction for 100% of the structures. The primary damage mechanisms were due to flood, with minor damage observed from wind. Damage most frequently observed included movement of the entire structure from its foundation, failure of wall systems, failure of wall sheeting and cladding, window and door failure and significant sand deposits at the London Street Canal. Wind damage appeared to include minimal loss of roof covering, although it is possible that wind damage occurred prior to the levee breach.
2. Flood Inundation Zones
The remainder of area investigated on day 1 (10/06/05) was mainly residential, exhibiting varying flood depths. Flood depths ranged from inches above the finish floor elevation to approximately 10 feet above local ground elevation, determined by visual observation. The damage to structures in these areas varied according to the depth of water in the building.
Typical damage to residential structures in these areas is generally classified as moderate (<10%), severe (80%) and destruction (<10%). These percentages were determined on an aggregate level based upon field observation, and may be subject to revision following more rigorous review of data collected. The primary damage mechanisms were due to flood, with minor to moderate damage observed from wind. Destruction due to wind primarily was attributed to treefall on the structures and in some cases roof failure was observed to occur as a direct result of wind pressure. Buildings that exhibited this type of failure were generally of poor construction.
Damage in these areas was attributed primarily to inundation flooding, with many buildings exhibiting no exterior sign of damage other than a high water mark. There were some instances of window breakage, generally occurring in larger window openings. Contents and interior damage/losses were significant for these areas, with the structure being salvageable only by thoroughly drying and remediating mold in the framing materials. Buildings in these areas may be declared total losses because of the inability to remedy these circumstances.
3. Non-Flooded Zones
Non-flooded residential zones were observed in the lakeshore areas and along Gentilly Boulevard (less than 10% of the study area). Both of these areas are natural high ground from Lake Pontchartrain and the Gentilly Ridge, respectively. Typical damage to residential structures in these areas is generally classified as no damage (50%) to minor damage (50%). Damage was due to direct wind pressures and windborne debris. Damage most frequently observed included broken windows and roof cover failure.
Observations on Institutional and Government locations surveyed on Day 1 (10/6/05):
Southern University New Orleans Branch – Maximum flood depths ranged from 3 feet to 5 feet in buildings on the campus. No window or cladding damage was observed.
University of New Orleans Lakefront Arena – Corrugated metal cladding was missing from approximately 10% of the building, with failure attributed to wind pressure on the southwest side.
University of New Orleans – Maximum flood depth approximately 3 feet on south side of campus, no flooding observed on north end of campus along lakeshore. The Engineering building and Student Recreation Center exhibited minor cladding damage. Less than 10% of windows damaged at Student Recreation Center, no other window/door damage observed.
Dillard University – Access was not granted to Dillard University. Damage observed from the street included minor roof damage. Evidence of flooding was present, although no water marks were observed from the street adjacent the university.
USDA Research Southern Regional Research Laboratory – Maximum flood depth approximately 2 feet, no structural, cladding or window damage observed.
New Orleans Theological Seminary – Flood depths ranged from no flooding on the south end of the campus along the Gentilly Ridge to approximately 3 feet on the north end of the campus. Residential houses and dormitories on the campus exhibited minor wind damage and moderate to severe flood damage. Flood damage in residential buildings is described in more detail under the Inundation Zones section above.
On Day 2 of the field investigation, the MCEER Remote Sensing team visited the mid-city area of New Orleans. The specific area of investigation was the triangular area bounded by I-610 to the north, I-10 to the east and US Highway 90 to the west. The existing land use categories in this area were more varied than the area investigated on Day 1. In addition to residential neighborhood, it comprised of substantial small to medium sized businesses, schools and hospitals in the area.
Figure 4. VIEWS™ data collection route from 10/7/05 in Mid City area of New Orleans
(Satellite image courtesy: Digital Globe)
Damage to Residential Structures
Residential damage observed in the study area was limited to flood inundation areas and areas where no flood waters impacted buildings. These areas are described in more detail in the field report from Day 1. Buildings surveyed in Day 2 were generally old construction, in varying states of repair. Typical housing styles encountered were generally elevated at least two feet above grade by blocks or built up over parking areas.
Several houses in the inundation areas did not experience damage from floodwaters because they were sufficiently elevated. The majority of the houses in the inundation areas, however, did experience flooding, although the impacts of the flood depth were mitigated by the traditional elevated construction.
Wind damage ranged from none to severe, generally depending upon the condition of the building. Many homes experienced significant roof cover and sheathing loss and some window and door penetration was also observed. In general, the homes that exhibited regular maintenance and repair faired significantly better than their neglected counterparts. The general composition of the building stock toured today consisted of approximately 80% of the buildings in poor to fair condition.
Damage to Commercial Structures
The composition of commercial facilities varied from small neighborhood shops and restaurants to engineered multi-story office buildings. The smaller businesses were of similar construction of many residential buildings in the area, and exhibited very similar damage characteristics. The second level of commercial structures, including national chain retail and service stores, generally performed well under the experienced wind conditions. Minor to moderate damage wind damage was noted at some locations, although the majority of structures in this classification experienced no to very minor wind damage.
Engineered office buildings exhibited no to minor wind damage. Flood damage was dependent generally upon the floodwater elevation for commercial structures, as the majority of these buildings are slab on grade structures. The maximum observed floodwater depth for commercial structures was approximately four feet.
Damage to Government and Institutional Structures
Damage to institutional buildings was observed to be minor. Surveyed buildings included the Orleans Parish courthouse, schools and the LSU Medical Center. These buildings exhibited minor window breakage but generally performed very well. Flooding in the observed areas ranged from no flooding in occupied space (Orleans Parish courthouse) to approximately 3 feet (LSU Medical Center). Damage to contents and interior of the first floor was extensive, but when reported as a percentage of the building replacement value, the flood damage is considered minor.
The areas surveyed in Day 3 of the remote sensing team field investigation included the Central Business District (CBD), Warehouse District, French Quarter, Industrial Canal levee breach, the Ninth Ward area, the western side of St. Bernard parish, and surrounding residential areas (See Figure 5).
The flood inundation areas observed were located primarily northwest of Rampart Street and north of St. Claude Avenue on the Eastbank. The absence of flooding along the Mississippi River is due to the higher elevation of the natural river bank. The main areas along the Mississippi River included the CBD, Warehouse District and French Quarter. Buildings in these areas were generally not subject to the inundation flooding, and performed well under the wind hazard conditions.
Figure 5. VIEWS™ data collection route from 10/8/05 in and around downtown New Orleans
(Satellite image courtesy: Digital Globe)
Damage to Central Business and Warehouse Districts
The CBD and Warehouse Districts generally consists of multistory engineered structures, including hotels, banks, office buildings and governmental buildings. The majority of these areas were outside of the flood inundation zones, although some flooding extended on the northern edges to depths of approximately 3 feet. Although this depth of flood caused significant damage on the first floor of the affected buildings, the replacement value of the buildings in these areas allows the classification of flood damage for the overall buildings as minor. These structures also performed well under the wind conditions, exhibiting only minor window breakage to some buildings.
A moderate percentage of the building stock consisted of older masonry structures. Some of these structures exhibited more severe damage from wind, including cladding failures and structural wall and roof failures. These failures were generally limited to older structures.
Damage to French Quarter and Surrounding Residential Areas
No flooding was observed in the French Quarter. Of all of the locations visited in this investigation, the French Quarter exhibited the lowest amount of overall damage and had functioning electricity, natural gas and water services. The architectural style of many buildings in the French Quarter includes operable shutters, which appear to have protected many windows in this area. Minor to moderate roof damage was observed, although the majority of the buildings in the French Quarter appeared to be well maintained and newer roof covering performed well in the wind conditions.
Residential areas to the northwest and northeast of the French Quarter were subject to flooding northwest of Rampart Street and north of St. Claude Avenue. Buildings in this area were traditional in style and very similar to the buildings surveyed on Day 2 (10/7/05) in the mid-city area of New Orleans. The elevated style of some of these houses mitigated flood damage, although the majority of buildings in the inundation areas experienced moderate to severe flood damage. Similar to the performance of residential buildings from Day 2, the existing condition of the building greatly influenced the severity of wind damage.
Velocity Zone adjacent to the Industrial Canal Levee Breach
Complete destruction was observed approximately five blocks outward of the breach in the Industrial Canal levee. Velocity damage was observed for approximately ten blocks from the levee breach. The damage observed was similar in nature to the damage observed at the breaches investigated on Day 1 of this investigation (17th St. Canal and London St. Canal) but much more severe and widespread.
Ninth Ward and Western St. Bernard Parish
The majority of the buildings surveyed in this area were residential buildings or small to medium retail stores. Flooding in these areas was extensive, surpassing the eave height of many single story houses in the northern part of the area. Because of the depth of the floodwaters, many homes were displaced from their foundations in areas that did not appear to have experienced high velocities. The flood damage to all of the buildings surveyed is classified as severe to destruction. Wind may have been a significant damage mechanism for some of the buildings in these areas, although buildings classified as experiencing significant wind damage in this investigation have generally been in some state of disrepair.
The areas surveyed in Day 4 of the remote sensing team field investigation included neighborhoods of Uptown, Garden District, Carrollton and Broadmoor in the area west of I-10 and north of St. Charles Avenue (See Figure 6).
Figure 6. VIEWS™ data collection route from 10/9/05 in and around Uptown and Garden District, New Orleans
(Satellite image courtesy: Digital Globe)
These areas are primarily residential, and varying levels of flood depths were noted throughout the area. Non-flooded residential zones were observed in the area just north of St. Charles Avenue. This area exhibits higher ground elevations due to the adjacent Mississippi River bank. Flood depths ranged from no flooding to approximately 7 feet above local ground elevation further away from the Mississippi River. The flood damage to structures in these areas varied according to the depth of water in the building.
Damage to Garden District Residential Areas
The buildings in the Garden District are discussed in this report separately from the other buildings surveyed because of their size. The buildings discussed here are typified by the older, well maintained mansions lining St. Charles Avenue. Damage in the surveyed areas of the Garden District was primarily window breakage, roof covering failure and damage due to tree fall. Loss of roof covering was the most common form of damage noted in this area. Many areas of the Garden District did not flood, and although much debris still remains, the damage experienced throughout other surveyed areas of New Orleans was not present. Treefall debris was significant in the area surveyed, with many older oak and magnolia trees uprooted.
Damage to other Residential Areas
Other residential areas surveyed were both inside and outside the extent of flood inundation zone, with water depths up to approximately seven feet. The depth of flood waters dictated the severity of damage in the impacted areas, with most homes experiencing severe damage from flooding. The majority of buildings also exhibited minor to moderate roof covering damage and window breakage. Roof covering damage was generally limited to buildings with older roofing material, although some buildings with new roof covering were also damaged. Clay tile ridge covers attached to asphalt shingle roofs typically performed poorly, becoming a debris source to the same building or an adjacent building. Debris from trees was significant in these areas.
Damage to Commercial Buildings
Commercial structures in the area were limited to small businesses, which performed similarly to the residential structures and were affected by both flood and to a lesser degree by wind.
Damage to Institutional Buildings
Major institutional buildings surveyed included Tulane and Loyola Universities and Memorial Medical Center. Flooding was observed at the Tulane University toward the northern end of campus, with no flooding along St. Charles Avenue. Moderate wind damage was observed at the Loyola campus, with significant roof cover failure to one of the buildings. Memorial Medical Center experienced minor wind and flood damage, with flood depths of approximately three feet.
Submitted by Shubharoop Ghosh and Carol Hill
October 6-9, 2005