Video: Community Flood Resilience Through Streamlined Data Analysis
Jefferson Parish, Louisiana, just outside New Orleans, is starting to employ green infrastructure to improve drainage and reduce flooding in vulnerable neighborhoods. One of the areas they wanted to address was the Bucktown section of Metairie, Louisiana. The historic fishing village is located next to Lake Pontchartrain inside the levee system at a low elevation, making it quick to flood and slow to drain.
“Talking to community folks at our outreach meetings, we learned real quickly how much the flooding in this community was affecting them, not just impeding being able to get in and out of the neighborhood, but just causing a lot of trouble for parents and a lot of anxiety: Every time that it starts to rain, which in South Louisiana is quite often, are they even going to be able to pick their kids up at the end of the day?” — Matt Salmon, Water Resource Design Engineer
Using a grant from FEMA’s Building Resilient Infrastructure and Communities Program, the Parish worked with a Freese and Nichols water resource design team to study how nature-based solutions could improve the effectiveness of a new pump station being installed near Bucktown. Nature-based solutions include green infrastructure tools such as bioretention swales, rain gardens and water barrels. They act more like nature than, for instance, concrete culverts, absorbing or holding water during storms so it doesn’t overwhelm drainage systems.
But to meet FEMA’s Benefit-Cost Analysis expectations for a follow-up grant and stay within budget, the team had to devise innovative ways of streamlining data analysis covering two dozen more stormwater model runs than the number originally planned. The team’s solution reduced analyst time per model run from four hours to two minutes and helped the Parish position for more FEMA funding to improve flood resilience.
“I lived in the Bucktown area while we were working on this project, so I know firsthand that when it rained, flooding in the streets was something that I was very concerned about. There were times it would be raining during the day, and I couldn’t get home because the streets were just so flooded, and I had a lower car and I just couldn’t drive through that or chance it. So, while I don’t have the responsibilities of trying to pick up a child from school or anything like that, just trying to make it home was something that I was concerned about. As I was presenting these things to the public, I had that rapport that we’re in the same boat.” — Kiara Horton, Water Resource Design Engineer
Building sustainability, innovating data analysis, reducing flood risk
Bucktown is one of the first places to fill with stormwater when rain hits — and the last area to drain. Though a new pump station will help, Jefferson Parish also wanted to update their Storm Water Management Model to find ways of boosting the pump’s effectiveness.
A grant through FEMA’s BRIC program funded the original study the Freese and Nichols team performed for the Parish. The goal was to look at alternatives that would upgrade the drainage system to further reduce flooding. That involved analyzing the 25-year storm event to help select stormwater solutions that emphasized green (or nature-based) approaches such as rain gardens, bioswales and planter boxes, and traditional gray infrastructure such as gutters, pipes and retention basins.
But the original project scope didn’t yield enough data to reach the benefit-cost ratio that would qualify the Parish for more FEMA funding to continue the work it needs. That would require 24 more model runs, covering from 2 to 500 years. And analyzing that much data would take far more than the 16 hours allocated in the budget for producing 25-year results.
To significantly speed up processing of the additional modeling data, the team developed a Python-based programming script that automated a previously manual process. Traditional data processing requires a single person to continuously manage ArcGIS to develop maximum water surface elevation at each property in the modeling area for each model run and extract that elevation at each structure.
While this process took approximately four hours for each result, the automated approach dramatically compressed the time required for each result. This yielded the data needed while staying within budget and positioning the parish to apply for the next round of grant funding.
Examples of the green infrastructure alternatives considered
This project recently won a Horizon Award, a quarterly award at Freese and Nichols given to projects that encapsulate our culture of innovation.