Blog

Category: Issues

June 19, 2017

Flood Risks Remain for SC Communities

Running from June 1 through November 30, the Atlantic hurricane season has begun. The National Oceanic and Atmospheric Administration (NOAA) forecasters predict an above-normal 2017 hurricane season with the predictions showing a 70 percent likelihood of 11 to 17 named storms of which 5 to 9 could become hurricanes and 2 to 4 are predicted to be Category 3 or above.

As we contend with the 2017 season and reflect on the devastating flooding events many in our state experienced in 2015 and again in 2016 because of Hurricane Matthew, it’s hard not to stress over the possibility of encountering such an event this year. Davis & Floyd has witnessed the challenges faced by those experiencing flood damages and those providing public services spanning from emergency responses through recovery and into mitigation, where possible, in advance of our next event.

As an engineering firm that provides stormwater management and flood hazard mitigation, Davis & Floyd recognizes the need to bring awareness to the risks associated with flooding. While we would like to find a simple solution to removing such risks, there are practical limitations in what truly can be accomplished in protecting our property against the forces of nature. Whether it’s increasing rainfall rates and depths or sea level rise along our coast and tidal systems, there’s little doubt that our challenge in becoming a better prepared and more resilient community will be ever increasing.

We recommend that everyone seek a basic understanding of flood risks to life and property. Be “Flood Smart” and review your insurance policies since flood coverage is not part of most and there is a 30-day waiting period for coverage to take effect. Visit the National Flood Insurance Program at www.FloodSmart.gov for more information on flood insurance coverage.

Finally, heed the guidelines and directives provided by the South Carolina Emergency Management Division (SCEMD) http://scemd.org/ and local agencies when a storm threatens your area.

Additional resources to assist in your hurricane season preparations and understanding of flood hazards may be found by visiting:

2017 South Carolina Hurricane Guide
SCDOT Evacuation Routes
National Hurricane Center
FEMA Flood Map Service Center
South Carolina Flood Mitigation Program

Tide overtopping Broad Street at Lockwood Drive in Charleston, SC (Photo - Jared Bramblett)

Tide overtopping Broad St. at Lockwood Dr. in Charleston (Photo – Jared Bramblett)

November 11, 2016

Honoring Our Veterans

South Carolina Army National Guard clearing sand from Edisto Island's Palmetto Boulevard following Hurricane Matthew

South Carolina Army National Guard clearing sand from Edisto Island’s Palmetto Boulevard following Hurricane Matthew

At Davis & Floyd, we see our work as a civic service and honor those who give the utmost in service to our country – our veterans. As we spend today thanking our veterans for their service, 28 of which are Davis & Floyd employees, we wanted to share the story of one of them who exemplifies community and professional service.

When Hurricane Matthew rolled through South Carolina, we were on alert for infrastructure damage and flooding that would warrant a Davis & Floyd response. At the same time, certain South Carolinians were watching in a more official capacity once Governor Nikki Haley gave her State of Emergency declaration. One such respondent was US Army National Guard Capt. Chris Huber, PE and 1221st engineer clearance company commander.

Chris is based in our Columbia office and trains yearly for situations like this as part of the South Carolina Army National Guard.

“We have pre-set areas with a set mission tasking that we are to support in the event that they need help, however if another area is in need we can move to support other missions. As soon as a State of Emergency is declared we begin officially alerting the unit to possible activation, however during Hurricane season we pretty much just stay on alert,” Chris explains.

His unit was sent to Edisto Beach and assigned lead command, allowing him to request equipment to assist his team’s mission to clear roadways. The company’s wartime mission is to conduct route reconnaissance, minesweeping, minefield-clearing operations, and more. After the storm, the team used similar skills to clear the way using dump trucks, skid steers, and chain saws to make room for larger equipment to come in and continue recovery efforts.

Before Hurricane Matthew, Chris’s company was integral in October 2015’s flood response. They helped restore the City of Columbia’s drinking water supply.

“Being a company commander is like being a project manager on a bigger scale, you are responsible for everything that happens and fails to happen in your unit,” said Chris. “I also believe that being an engineer requires a great deal of attention to detail and that’s one thing the military is very big on.”

For Chris, Veterans Day is a day for reflection on experiences (good and bad) and friends made along the way.

“It is also a day to remember those who are no longer with us to celebrate how far our country has come and reminder that we are still at war and the fight continues every day. “

To Chris and our other veterans, we thank you for your service. We’re so grateful to have you working on behalf of not only Davis & Floyd, but South Carolina and the United States of America.

October 28, 2016

(Re)Building for Hurricanes and Other Natural Disasters: Part 2

Market Street drainage

Market Street drainage

Last week, we wrote about how proper preparation and rehabilitation of structures go a long way to preventing loss of life and property in a natural disaster. In our half-century of work, we’ve engineered safe solutions for historic structures, large industrial-purpose buildings, towns and neighborhoods, and transportation needs. Yet each of these projects comes with different requirements and sets of best practices.

In particular, transportation planning and project execution are highly affected by weather events.

For example, when we work on bridges, we design for resiliency, accounting for the extreme conditions that are brought about by natural disasters such as flooding, impacts from debris, high winds, and earthquakes.

Transportation infrastructure and its ability to perform at its best is as much a need before and after as during natural disasters. As we saw during Hurricane Matthew’s evacuation of the South Carolina coast, the sudden increase in travel needs and potential for dangerous weather can be an instant game-changer after the call is made by the governor.

On our construction projects, we are in close contact with local and SCDOT representatives and in the event of incoming bad weather, all barrels, cones, and temporary signs that can be removed from the project are removed to avoid the risk of becoming projectiles in high winds. For projects on evacuation routes, we always are prepared to meet protocols, which include stabilizing sites and staging the project to allow for no lane reductions as well as seeing that all possible lanes of traffic are opened.

We also maintain 24-hour monitoring of all projects for the duration of the storm. After the storm, we assess the damage and make any emergency repairs that are needed to keep the roadway open. Once the evacuation is complete, permanent repairs are undertaken to the roadway.

In Charleston, low-lying areas frequently are prone to flooding, but our work on the city’s drainage system improved much of the recovery. The City Market area notoriously has been waterlogged in previous storms, but thanks to our work in progress, installation of drop shafts and a new tunnel 120 feet underground, many businesses avoided incoming water and were able to open the day after Hurricane Matthew passed – an improvement over years past. The next phase of the project being designed includes completing the drainage project and improvements to the streetscape.

Steve Kirk, the city’s senior engineering project manager, said the pump station ran for hours and pumped over 50 million gallons of stormwater in total. The project is still yet to be completed, but we’re so pleased at the early successes of the project and grateful that the City of Charleston had a quick and safe recovery.

October 21, 2016

(Re)Building for Hurricanes and Other Natural Disasters: Part 1

Photo of micropiles at Rivers Education Center

627 micropiles (over 10 miles in total length) were installed to strengthen Rivers Education Center’s existing building foundation.

As our state continues work to clean up and rebuild after Hurricane Matthew, we’ve breathed a collective sigh of relief that the damage wasn’t worse. Much of the forecasting focused on high winds paired with the Lowcountry’s notorious flooding.

What Davis & Floyd has found in over a half-century of working across South Carolina is that proper preparation and rehabilitation of structures go a long way to preventing loss of life and property in a natural disaster. Two projects that illustrate this are our work on the Rivers Education Center and barracks at The Citadel.

We’ve written before about the Rivers Education Center’s stability for earthquakes. Those same precautions and more protect the building and our students from hurricane-related dangers.

The original 2-story unreinforced brick masonry school building was built in 1938 and considered unsafe for continued use in 2009. Davis & Floyd designed the restoration to meet all current codes for hurricane and seismic resistance as a school facility, meaning that the wood roof structure was strengthened and properly attached with over 3,000 hurricane/seismic ties and anchors. Floors were braced into the supporting walls and walls were reinforced with shotcrete on the interior faces. Stairwells also were reinforced. The whole building foundation was supported with micropiles for added stability. The building’s restored windows are energy-efficient and hurricane impact resistant. The school is now being utilized by two groups – the Charter School for Math and Science and the Lowcountry Tech Academy.

Across town, we also worked on replacement dormitories for The Citadel campus over a period of several years. The unique shape and style of the barracks buildings with central open quadrangles and covered walkways made the hurricane and seismic/earthquake designs more challenging. Davis & Floyd performed a detailed initial architectural and engineering study of the existing 4-story unreinforced masonry buildings to determine the renovations required to bring them up to code. The study revealed that it was more economical and safer to replace the four barracks with new structures, designed for full code compliance.

The new buildings are constructed entirely of concrete, making them some of the strongest structures in the Lowcountry in the face of hurricane or seismic threats. The new windows are impact resistant, while maintaining the original unique appearance.

With improvements like these and foresight on new projects, proper engineering can help South Carolina citizens stay safe in the face of a storm. We’re glad to be a part of the solution.

Part 2 will deal with best practices and more on flooding and drainage systems.

July 26, 2016

Research in Our Ranks: Porous Pavement Bike Lanes

Photo of bike tire

Transportation has always been one of Davis & Floyd’s strongest sectors and because of that we recognize that the challenges of public transportation are often about integrating options beyond automotive.

That is why we wanted to take a minute to highlight research done by one of our own – Tripp West, PE. An engineer in the Charleston office, Tripp works on project teams for water resources, transportation, and land development projects for both public and private clients. Through design, preparation of plans and specifications, permitting, and cost estimating, he has been essential on multiple plans, analyses, and developments.

Tripp always has been passionate about helping others meet their basic needs, from clean water to safe living spaces, access to work, and a means to move people and goods. While working on his engineering degree, he was a founding member of a group called Clemson Engineers for Developing Countries. His focus on sustainability is one reason he believes that engineers can make great strides as we tackle future problems like climate change and rising sea levels.

With that in mind, we wanted to share some of Tripp’s thesis research on porous pavement bike lanes adjacent to impervious traffic lanes. He was able to analyze the distance required for water running onto a porous pavement to fully infiltrate into the pavement – proving that it is linearly proportional to the width of the adjacent impervious traffic lanes and the rainfall intensity. It is also inversely proportional to the sum of the rainfall intensity and pavement hydraulic conductivity.

Why are his findings on porous pavements so important? We will let Tripp explain:

The inclusion of bicycle lanes or pathways is increasing in urban areas where local governments are looking for ways to increase alternative modes of transportation and provide safe routes for the increasing number of cyclists choosing to ride their bicycles around town rather than drive a vehicle. Even from a site design perspective, we are now required to include in our plans how pedestrian and bicycle access will be accommodated within our developments and how those pathways will connect to existing routes. One of the leading causes of increased flooding is the conversion of pervious areas (forests, farmland, and other open spaces) to impervious areas (buildings and pavement), which increases the volume of downstream runoff leading to potential flooding issues. The addition of paved bicycle lanes and pathways in a road corridor further increases the total amount of impervious area required for that facility.

Pervious pavements, which allow water to drain through the surface, are already being used in other applications where traditional pavement is required to reduce the overall volume of runoff leaving a site. The goal of this project was to investigate the feasibility of using pervious pavements for the bicycle lane application and then identify which components of the system would need to be further investigated in hopes of creating a design guideline for using this application in practice.

The pervious bicycle lane concept could potentially be implemented within new road corridors, alongside existing roadways, or incorporated into maintenance and retrofits of existing streets.

Today, Tripp and his Davis & Floyd colleague Mike Horton are serving in an industry advisor role with his former professor on a new research project. The project, entitled “Performance Based Design of Low Impact Development Technologies in Response to Climate Change Induced Changes In Rainfall Patterns,” is funded through the SC Sea Grant Consortium.