An Overview Of Our Solution
Low income and minority communities are at significantly higher risks to natural disasters. New Orleans’ Lower 9th Ward was the hardest hit part of the city during Hurricane Katrina and is still struggling to rebuild itself ten years later. Founded by Brad Pitt in 2007, Make It Right began with a goal of rebuilding safe, sustainable and affordable homes for families who lost everything in the storm. Since then we have expanded to build safe, sustainable, LEED Platinum certified and Cradle to Cradle-inspired homes, buildings and communities for people in need across the United States. Our work in New Orleans has led to innovations in affordable homebuilding – proof that high-quality, healthy homes can and should be available for everyone. By implementing advanced construction techniques and using sustainable products, we are setting the green standard in construction and improving community resilience to disasters. Additionally, training local contractors in new building methods and demonstrating the economic feasibility of non-traditional building materials directly impacts New Orleans and indirectly results in safer, stronger, and greener building practices nationally.
- Population Impacted: 378,715
- Continent: North America
912 Magazine Street
New Orleans, LA 70130
Identify the likelihood and frequency of this hazard
Explain how vulnerable the community is to this hazard
List the potential affects of this hazard
Identify how sensitive the community is to these affects
Base Flood Elevation (BFE) is a standard set by the Environmental Protection Agency that represents a flood with a 1% chance to equal or exceed in any given year. For the Lower 9th Ward, the standard is typically 3’ above the crown of a street or the top of a curb, picking the highest of these two as the baseline. Make It Right builds homes that are 2’ above this 3’ standard giving homeowners an added level of security from flood waters. The Lower 9th Ward is below sea level and every drop of water that gets to the storm drain must be pumped out. Pervious concrete is a highly porous form of concrete which allows rainwater and storm runoff to be retained in a holding bed under the concrete, keeping water out of the city’s pumping infrastructure, and allowing for groundwater recharge. Make It Right uses pervious concrete for parking pads, sidewalks, and walkways in all of our residential construction. This in turn allows the majority of rainfall and runoff to avoid the drainage system by being retained on site to either recharge the natural aquifers or evaporate. Make It Right has worked closely with the City of New Orleans to create the city’s first pervious concrete test street, and has multiple streets in the Lower 9th Ward that have utilized pervious concrete for its parking lanes. These parking lanes help reduce runoff into the city drainage by 50%. This reduction of runoff helps keep water out of the city system allowing the pumps to catch up quicker with the high amount of water that falls during rain events.
Describe Your Solution
In New Orleans, we have built over 100 houses at elevations ranging from 2’ to 5’ above BFE. We have used both concrete columns and treated wood pilings to elevate these homes. While the 5’ elevation provides the most flood protection, the cost increase is greater, and access for elderly homeowners becomes more difficult. Because of this, we now build at a standard 2’ above BFE using treated piles that are driven into the ground up to 40’. We are also significantly reducing the risks from flood waters to near zero by raising structures well above the common height that floods occur. Read more here and here. New Orleans receives an average of 62” of rain annually. During the rainy season, it can receive several inches in an hour. When this occurs, the pumping system is overloaded by this large quantity of water. Because of this, roads often flood and remain flooded for several hours damaging cars, and transportation throughout the city stops. Water overloads the system due to impermeable surfaces: driveways, sidewalks, roads, parking lots, etc. To minimize this, we use pervious concrete for all our driveways and sidewalks, which ensures the majority of water stays in place or is retained in a gravel basin under the pervious. By allowing the soil to absorb and retain water, it abates soil subsidence which ultimately causes the ground to sink and increases the risk of flooding. Read more here. Due to New Orleans’ infrastructure design, main drainage access points are typically located along city streets, using the roads as the main point of conveyance of ground water runoff. We have worked with the city to create pervious parking lanes and a road that will allow testing on how pervious concrete can mitigate overloaded drainage systems due to impervious conditions.
Raising houses above the Base Flood Elevation of 3’ to 5’ saves each of our homeowners over $1,000 annually. Homeowners can remain at home, when appropriate, instead of unnecessary evacuation or displacement, and return to work quicker, ensuring minimal economic disruption. Utilizing pervious concrete reduces city costs associated with pumping water out of the city during heavy rain events. New Orleans spends over $40 million a year pumping water out of the city. If the city replaced roads needing repair with pervious concrete, the premium associated with this material would be recouped in 8 months from savings.
Increasing building elevation can save a house from being destroyed, and the subsequent debris from being sent to a landfill. Preventing damage to the structure also eliminates the need for new building materials to repair or rebuild. Make It Right is elevating our buildings with substantially less materials. Pervious concrete increases soil moisture retention which prevents land subsidence that causes damage to roadways and buildings. Energy is saved by reducing the amount of storm water that would otherwise need to be pumped out.
Making a home more resilient to flooding allows homeowners to shelter in place during non-mandatory evacuations, which eliminates the strain on emergency services and transportation systems. By using non-traditional designs and building materials in a historically low income neighborhood, we are building awareness to the availability of these features, which have historically been thought of as being expensive and unattainable.
What were the negative or unintended impacts (if any) associated with implementing this solution?
We have encountered one negative impact from raising the elevation of our homes. Our elderly residents or those with decreased mobility have a harder time accessing their front doors. We mitigate this by making our homes handicap accessible which does increase the building cost. One unintended impact of using pervious concrete is having to educate local contractors and government agencies who did not have much experience with it previously. In order to install this risk mitigation we had to prove the efficacy of pervious concrete. Educating them on the product specs and installation techniques has been time intensive and costly.
Return on Investment: How much did it cost to implement these activities? How do your results above compare to this investment?
We have found that using piles to elevate our houses is very cost effective. There is no cost premium associated with building 2’ feet above BFE versus building at BFE. However, by building 2’ above BFE, our homeowners save over $1,000 annually in insurance premiums. We targeted traditional roads that needed replacements or repairs to use pervious concrete. We found there is a 20% premium associated with using pervious concrete versus standard asphalt. We worked with the city, to quantify the cost of pumping storm water out of the area, and found that the additional cost is offset in 8 months due to the reduced amount of pumping that would be needed.
What are the main factors needed to successfully replicate this solution
Geographic location is one factor for the successful replication of elevated building and pervious concrete. To successfully replicate this solution, we would target areas that have historically been prone to flooding; and local governments that are open to new solutions to historic issues, such as changing building codes as needed, to implement these solutions. They must be willing to see the additional costs associated with these solutions as an investment in the community. Contractors must also be open to learning new techniques associated with pervious concrete to provide accurate labor costs and to help push the product into mainstream use. We have spent a great deal of time educating the local workforce on installation techniques and on the associated benefits of using a higher BFE and pervious concrete. We would also need a populace who has previously faced flooding problems and are open to change. Once the public is educated on the benefits, they can push their local governments, contractors, and neighbors to adopt these solutions. The greatest benefit comes when these solutions become common practice - as property values are decreased by having a blighted, flooded building next to an elevated, pervious concreted home.