Stormwater – Page 2 – Environmental Technical Assistance Program Newsletter

State DOTs Bracing for Highly Active Hurricane Season

As forecasters predict a particularly active hurricane season for 2021, state departments of transportation from Texas to New Jersey are preparing for worst-case scenarios to help citizens get out of town if a big storm ends up heading their way.

[Above photo by the Louisiana DOTD]

The Atlantic hurricane season began on June 1 and lasts through November 30. The National Oceanic and Atmospheric Administration’s Climate Prediction Center predicts a “likely range” of six to 10 hurricanes with winds of at least 74 miles-per-hour to form this year, with three to five major hurricanes with wind speeds of at least 111 mph developing as well.

Even relatively “minor” hurricanes can cause significant damage, especially to transportation systems, as the impact of Hurricane Sally – which struck the Alabama and Florida border in September 2020 – demonstrates.

Five hurricanes made landfall in Louisiana in 2020, prompting evacuations ahead of the storms and road closures in their aftermaths. To ensure quick evacuation of citizens from low-lying, flood-prone areas ahead of such storms, the Louisiana Department of Transportation and Development has a longstanding partnership with the Mississippi Department of Transportation to activate contraflow operations for removing people from New Orleans and coastal areas rapidly.

“The pinnacle of our cooperative efforts come out during an emergency evacuation,” Louisiana DOTD Secretary Shawn Wilson explained. “This region has a very cooperative history. We were in Beaumont (Texas) last year after one of the hurricanes, and we brought in personnel from the Tennessee DOT to help us. We all help each other as the circumstances warrant.”

When activated, the Southeast Louisiana Evacuation Plan calls for the Louisiana DOTD and Louisiana State Police to reverse traffic on the southbound lanes on Interstates 55 and 59. Once traffic reaches the Mississippi state line, the Mississippi DOT takes over traffic control and guides the combined eight lanes of traffic well into the heart of Mississippi.

The Mississippi DOT held a contraflow drill on June 3 to practice moving equipment into place and communicating with each other along the 86 combined miles of “contraflowed” interstate lanes.

“We go through all the motions except actually closing the exits on the interstates,” said Jas Smith, Mississippi DOT’s communications director. “The intention is to quickly evacuate the New Orleans and coastal residents. We want to get them out as quickly as possible.”

The Alabama Department of Transportation also has an interstate contraflow plan ready to go during daylight hours, according to Tony Harris, the agency’s media and community relations bureau chief.

“We only contraflow Interstate 65, north of Mobile, to Montgomery,” Harris explained. “We have a deployment rehearsal where we do everything but stop traffic. It’s like a military operation with about 120 defined steps and procedures.”

The South Carolina Department of Transportation recently released an animated video that explains how its intrastate contraflow works on Interstate 26 from Charleston to Columbia.

Meanwhile, the Florida Department of Transportation recently added several new features to its 511 site along with a new mobile application to assist motorists during hurricane evacuations.

States even as far north as New Jersey are holding evacuation drills “to practice and refine response activities in the event of a major hurricane,” according to a news release from the New Jersey Department of Transportation. “This annual drill is to practice a worst-case scenario in which New Jersey shore communities would need to be evacuated in a short period of time due to a hurricane or other natural disaster,” noted Diane Gutierrez-Scaccetti, the New Jersey DOT’s commissioner. “This gives crews from the New Jersey DOT, the New Jersey Turnpike Authority, and the South Jersey Transit Authority, along with the State Police, an opportunity to test our plans and make sure our emergency personnel are able to quickly and efficiently get people out of harm’s way.”

Georgia DOT Deploys ‘Lessons Learned’ for 2021 Hurricane Season

The Georgia Department of Transportation’s state maintenance office is tapping into five years’ worth of “lessons learned” to help fine-tune its storm response capabilities ahead of the 2021 Atlantic Hurricane Season – which lasts from June 1 through November 30.

[Above photo by the Georgia DOT]

“Over the last five years, after each weather or emergency event, Georgia DOT conducted after action reviews to address key takeaways, identify gaps in operations and brainstorm best practices for moving forward,” explained Larry Barnes, Georgia DOT’s assistant state maintenance engineer of emergency operations, in a statement.

“This effort has allowed us to continue to build up resources and develop more effective weather and emergency response plans to ensure that we are able to clear roads and restore mobility to Georgians as efficiently and safely as possible,” he said.

Some of the storm response tactics developed from those takeaways include:

Each of Georgia DOT’s seven districts now features a “Chainsaw and Emergency Response” trailer stocked and ready to go for debris removal operations.
A hurricane gate contract for continued maintenance on all gates statewide to ensure they are ready for contraflow operations, if needed.
Upgrading the agency’s WebEOC system – originally deployed in 2015 and used by its emergency operation center – to improve incident management, resource tracking, and mapping capabilities.
Securing debris clean-up contractors to clear both state routes and interstates post disaster, allowing Georgia DOT forces to work more efficiently and to provide off-system assistance to counties and local municipalities who request it.
Improved communications through Sonims: rugged mobile devices that more robust communication capability for in-field teams during disaster recovery operations. Sonims can also track where crews have been working resulting in more efficient clean up, the Georgia DOT said.
Increasing the number of mobile message boards, barrels, and cones available for hurricane-response needs.

The Georgia DOT added that, according to the National Oceanic and Atmospheric Administration, the 2021 hurricane season is expected to be “above average” with an anticipated 13 to 20 named storms, six to 10 hurricanes, and three to five “major” hurricanes –defined as Category 3 or greater – predicted to develop over the next six months.

Nevada DOT Offering “Water-Smart” Advice to State Residents

The Environmental Division of the Nevada Department of Transportation is offering state residents landscaping advice on pesticide and herbicide use as well as “water-smart practices” when conducting residential landscaping activities.

[Above photo by the Southern Nevada Water Authority]

“Most people are surprised to learn that homes can be a source of pollution,” explained James Murphy, the Environmental Division’s program manager within Nevada DOT, in a statement – noting that his division oversees disciplines such as stormwater, air quality, noise, wildlife biology, environmental engineering, and cultural resources.

“We encourage Nevada residents to take steps to avoid polluting our waterways, such as avoiding overwatering and applying pesticides, herbicides and fertilizers sparingly, with caution, and per product labeling,” he said.

Murphy explained that, in Nevada, sewer systems and stormwater drains are separate systems. Water that goes down the drain inside a home via toilet or sink goes to a wastewater treatment plant where it is treated and filtered. Conversely, water that flows down driveways and streets into gutters goes directly into a storm drain that flows untreated into lakes, rivers and streams.

Thus runoff from landscaped areas may contain fertilizers, pesticides or other materials that are harmful to lakes and streams, stressed Charles Schembre, an environmental scientist with the Nevada Division of Environmental Protection.

He explained that the most important thing residents could do to prevent stormwater contamination from landscaping activities is to avoid watering the sidewalk. Installing a buffer between the lawn and sidewalk – such as rocks, woody mulch or plants – will prevent runoff onto the sidewalk. This is a critical component in reducing runoff of pollutants into storm drains, he said.

Other tips include:

Use “healthy soil” practices and use organic fertilizers and pesticides sparingly; make sure to follow product label instructions.
Consider planting trees, seeds and plants that are native to Nevada, which require less water.
Use “selective” herbicide applications to target just weeds and avoid affecting desirable plant species. Avoid spraying during conditions where herbicides may drift to non-target plant species – specifically when wind speeds are greater than 15 mph.
Use organic mulch or other pest control methods whenever possible.
Install a buffer between the lawn and sidewalk to prevent irrigation runoff onto the sidewalk.
Pick up pet waste and dispose of it properly.
Use a commercial car wash or wash your car on the grass so the water infiltrates into the ground instead of spilling into storm drains.

Pew Trust: How Flooding Impacts Maryland’s Transportation System

A recent study indicates that major flooding occurring outside designated flood zones is significantly affecting Maryland’s highways, bridges, tunnels, and other roadways. As a result, such flooding “interrupts daily life; delaying or blocking passage of emergency response vehicles and people trying to get to work or school.”

[Above photo by Jay Bock, Flickr.]

The study – entitled “Flooding Impacts on Maryland’s Transportation System and Users” by strategic consulting firm ICF with support from The Pew Charitable Trusts — examines how flooding affects nearly 15,000 lane miles of state-maintained roadways or roughly about 20 percent of Maryland’s overall lane mileage. The findings draw from data collected between 2006 and 2020 by the Maryland Department of Transportation.

The report’s researchers reviewed 2,771 flood-related incidents for which geospatial data was available and found that 78 percent occurred outside the 100- or 500-year flood zones mapped by the Federal Emergency Management Agency. Those incidents took place, on average, only about 0.3 miles from the mapped flood areas, but even so, the findings underscore that flooding is not limited to mapped zones.

The report also identified locations along state highways that are especially flood-prone, making them prime targets for infrastructure resilience or relocation investment. Data from the past 15 years shows clusters of flood incidents on state highways, including more than 100 locations with at least five flood events within about 1,000 feet of one another. Seven locations appear to be especially at risk, with at least 30 such incidents among them, the study found.

The report also shows how flooding disrupts travel, causes safety risks, and generates economic productivity losses, among other adverse consequences. Flooding of state-maintained roadways in Maryland accounts for weeks of traffic disruptions annually, averaging 1,582 hours or 66 days per a year. Although most flood-caused lane closures lasted less than four hours, 16 percent of all disruptions lasted longer than 12 hours.

The study found that those incidents affected, on average, more than 480,000 people annually. On top of that, economic impact of lost work time and delayed deliveries cost about $15 million per year in Maryland and totaled more than $230 million during the study period.

Each flood incident resulted in an average of about $80,000 in user delay costs, Pew’s researchers noted – considered “just a fraction” of the fiscal impact because it does not factor in other expenses, such as emergency response and infrastructure repairs.

Maryland DOT P3 Project Building Stormwater ‘Smart Ponds’

The Maryland Department of Transportation recently unveiled three “smart ponds” built via a public-private partnership or P3 stormwater control project that seeks to reduce pollutants and curb local flooding.

[Above photo by Maryland DOT]

The agency said this “smart pond” project is the first of its kind involving a state transportation department and it involved the Maryland Department of Environment, Environmental Protection Agency, Walmart, and The Nature Conservancy.

The Maryland DOT said this “smart pond” technology – developed by Opti – uses sensors and software to monitor real-time conditions such as water level and storage volume. Then, using Internet-based weather forecasts, the system remotely operate valves that control timing and volume of water discharge from the ponds as longer retention time increases water quality by capturing more sediment and nutrients.

Thus, when rain is in the forecast, the system can automatically open valves to drain the pond prior to precipitation, the agency said – helping maximize stormwater storage efficiency and reducing downstream flooding.

“These smart ponds are another innovative way we’re working to improve the communities we serve,” explained Greg Slater, Maryland DOT secretary, in a statement. “We’re being responsible stewards of the environment while at the same time helping protect the infrastructure that supports our hard-working residents and businesses.”

The Maryland Environmental Service, The Nature Conservancy, and Opti originally signed a contract in July 2020 to retrofit three stormwater runoff ponds located at Walmart stores as “smart ponds.” Concurrently, the Maryland DOT plans to spend $3.25 million to purchase 80 acres worth of Chesapeake Bay impervious area treatment credits generated by the smart ponds at Walmart. After certification of the credits, the Maryland DOT will begin purchasing the credits this spring.

The agency said this smart pond partnership represents the first time a state department of transportation is purchasing credits from a Water Quality Trading Program. Maryland’s program created a water quality marketplace for credits generated by pollutant reductions elsewhere in Maryland’s portion of the Chesapeake Bay watershed – offering “market-based” economic incentives for pollutant reductions.

The cost to Maryland DOT for these new credits is about $37,500 per acre, including installation of smart pond technology and 20 years of monitoring, inspecting, operating and maintaining the ponds by The Nature Conservancy and Opti. That is significantly less than the average construction cost of $150,000 per impervious acre treated through stormwater control devices such as swales, bio-retention cells and stormwater ponds, the agency noted – and that $150,000 cost does not include operation and maintenance. Overall, the Maryland DOT said it owns about 800 ponds that could benefit from this smart pond technology.

Nevada DOT Roadway Work Includes Floodplain Improvements

Department of Transportation launches the “next phase” of major reconstruction of Great Basin Boulevard and East Aultman Street in Ely, NV, the agency is placing a particular focus on floodplain improvements.

[Above graphic by Nevada DOT.]

First, to enhance drainage in preparation for the roadway improvements, Nevada DOT crews constructed nearly 2,300 feet of concrete drainage pipe and open drainage channel in 2020 in order to convey stormwater from near the Orson Avenue and North Street intersection to Murry Creek. The agency added in a statement that those drainage improvements will continue as part of the project in 2021 and, when coupled with Great Basin Boulevard drainage improvements slated for 2021 as well, the work is the first step toward reducing floodplain limits and associated flooding concerns.

The overall project – overseen by the Nevada DOT in partnership with the City of Ely – is to reconstruct deteriorated local roadways while also upgrading the city’s water and sewer facilities. Planned upgrades alongside the floodplain improvements include a “complete streets” concept to reconstruct sections of Aultman Street and Great Basin Boulevard and reconfigure lanes to provide a safer route for drivers, pedestrians, and bicyclists.

Real-Time Storm Force Prediction Model for Coastal Bridges

Dr. Teng Wu, Mr. Shaopeng Li, and Dr. Kallol Sett from the Institute of Bridge Engineering at University at Buffalo recently unveiled a new model to improve extreme damage “risk evaluation” for coastal bridges due to hurricane wave force and storm surge.

That research focuses first on using a synthetic 10,000-year hurricane record, together with a deep neural network-based framework to predict surge and wave forces on the bridges located in specific areas. It then taps into the North Atlantic Coast Comprehensive Study or NACCS database – built to identify flood risk and mitigation strategies – which uses damage outcomes from 1,050 “synthetic hurricanes” to provide storm surge elevation and significant wave height predictions for pre-determined locations.

All of that information is then used to determine the probability of bridge failure dependent on how susceptible a bridge deck is to being lifted off its foundation structure, those researchers said; an event known as “bridge deck unseating” that is highlighted in the video below:

Dr. Wu — associate professor at the University of Buffalo’s department of civil, structural, and environmental engineering – said during a recent presentation that the reason a new coastal bridge failure model is needed centers on the rising number of Americans living in coastal regions and their corresponding exposure to severe weather.

According to a 22-page report by the National Oceanic and Atmospheric Association, almost 40 percent of the United States population – some 127 million people — now live in coastal areas that are increasingly vulnerable to severe hurricanes.

For example, Hurricane Sandy, which made landfall in New Jersey in 2012, caused $70 billion worth of damage to densely developed areas in New Jersey and New York – with the damage to roads and bridges representing a large portion of that monetary loss.

Dr. Wu noted that the training of deep neural network focuses on damage to bridges due to bridge deck unseating as that is the most common occurrence during hurricane storm surge.

Graphic image provided by the University of Buffalo

For example, during Hurricane Ike in 2008, some 53 bridges in the Houston/Galveston region suffered damage – and many of those damaged structures either were constructed of timber or were low-clearance water-crossing bridges. That’s why analyzing the type of bridge, bridge clearance, and the predicted storm surge and wave height for hurricane storm season in a particular coastal area can give valuable sustainability information and aid in risk planning and emergency response, Dr. Wu noted.

The University of Buffalo research included a case study on “simply supported” coastal bridges in New York State – a study that included a risk assessment for bridge deck unseating caused by storm surges and waves. Three different “clearances” of coastal bridges – which is the distance between the bottom of the bridge deck to the mean water level – were considered in that risk analysis, with the resulting case study looking at bridges in two different areas of the region: one close to the coastline and one in the Hudson River.

That case study found that the annual damage rate to bridges decreases as the clearance increases, and bridges at the coastline are more vulnerable to storm surges and waves due to the larger surge/wave level, as expected. What the risk analysis framework does, explained Dr. Wu, is pinpoint where risk reduction strategies will be most effective – highlight those coastal bridges with the highest risk of damage from storms, allowing for more targeted mitigation planning. Dr. Wu added that this research can also help in emergency management disaster response by highlighting the infrastructure most at risk for damage and allowing for more focused traffic management and operations planning.

Hawaii DOT Launches Storm Water Online Learning Series for Kids

Protecting the ocean, rivers, and streams from pollution is the focus of a new online learning series for kids launched by the Hawaii Department of Transportation’s Storm Water Management Program.

[Photo courtesy of Hawaii Department of Transportation.]

The Hawaii Storm Patrol Online Learning Series teaches children – known as “keiki” in Hawaiian – about storm drain systems, how they carry rainwater off roadways to prevent flooding, and why preventing litter, debris, chemicals, and other pollutants from entering storm drains helps preserve the environment.

The free series is available at stormwaterhawaii.com and can be viewed on a desktop, laptop, or mobile device.

The agency noted that this video series is comprised of four animated videos that explain the water cycle, how Hawaii’s storm drains work, different types of pollution, and the impact of storm water on our ocean and near shore waters. Characters from the popular Hawaii Storm Patrol: New Recruits booklet star in the series and offer tips to protect the environment.

Each video is followed by a short quiz to help young viewers retain information and students who complete the online learning series become an official recruit of the Hawaii Storm Patrol and can download a specially designed Zoom background to use for their virtual classes.

An instructor’s guide is included to help parents and teachers utilize the online learning series in a remote learning or classroom setting. “Our in-person, in-classroom storm water presentations were well received by students and teachers. Keiki now understand the importance of protecting the environment and are eager to learn how they can help,” explained Jade Butay, Hawaii DOT’s director, in a statement. “We wanted to build on the success of our in-classroom program and creating a remote learning version enables us to reach more students and expand the awareness of storm water pollution prevention.”

Iowa DOT Studies Erosion, Sediment Control Techniques

To determine the effectiveness of its erosion- and sediment-control techniques, the Iowa Department of Transportation recently teamed up with Iowa State University over two construction seasons to establish which ones worked the best and which ones needed improvement.

[Photo courtesy of Iowa Department of Transportation.]

According to an Iowa DOT blog post, Melissa Serio with the agency’s construction and materials group teamed up with Mike Perez, an Iowa State researcher, to examine alternative erosion and sediment control techniques and adaptations used successfully by other transportation agencies to see how well the Iowa DOT’s standard practices.

Some of Iowa DOT’s frequently used erosion and sediment control techniques include: fabric silt fences to slow water flow and collect sediment; porous mesh tubes (called wattles) filled with straw or other material to control storm water flow; sediment basins or small retention ponds to hold water until solid materials can settle; and rock check dams.

“While we were convinced these elements help control erosion and sediment, it wasn’t clear whether these were the most effective or whether there were other approaches that could be undertaken to achieve better or less expensive results,” Serio explained. “It was important to understand the feasibility of possible changes to practice and identify the right improvements that could be put in place at the right price.”

While some of Iowa’s existing techniques already performed well, several potential improvements became apparent over the course of the two-year study. For example, simple adjustments to silt fences included reducing the space between posts, adding wire support to the fence’s fabric backing, and cutting a notch, or weir, at the top of the fence so that overtopping of water could be directed to the most desired location.

The Iowa DOT detailed that and other improvements in its final report and technology transfer summary.

Even as the research pointed to potential new best practices, the Iowa DOT said this study “also challenged our expectations.” For example, sediment basins appeared not to be as effective a sediment control measure as had been previously thought. In fact, some data collected suggested that water leaving the basins might have more sediment than it had when entering.

“Further research in a controlled environment will provide more insight, but these initial findings are extremely valuable as we seek to maximize the effectiveness of our erosion and sediment control measures,” the agency noted. “We plan to include the most effective and cost-efficient erosion and sediment control treatments identified in this research project as part of standard road plans in the near future – mostly likely beginning the spring of 2021,” the Iowa DOT said.

State DOTs on the Front Lines of Storm Preparations

State department of transportation crews along the Gulf Coast prepared for the arrival of two potentially dangerous storms this week – highlighting the key ways state DOTs protect critical infrastructure and the residents it serves during severe weather events.

[Above photo courtesy of Louisiana DOTD.]

Crews in Texas, Louisiana, and Mississippi cleared storm drains and ditches, lowered light masts, paused highway construction projects and pre-positioned barricades, signs, and portable dams to prepare for the impact of hurricanes Marco and Laura – even as forecasts for the intensity and paths those storms changed almost hourly.

“Hurricanes are part of living here,” explained Sarah Dupre, a public information officer with the Texas Department of Transportation.

“We’re treating it just like one big storm,” added Rodney Mallet, communications director for the Louisiana Department of Transportation and Development.

Part of Louisiana’s preparations means removing tolls on the Louisiana Highway 1 Bridge to accommodate a mandatory evacuation of Grand Isle, the state’s only inhabited barrier island. The Louisiana DOTD also pre-positioned dozens of school buses and motor coaches in other vulnerable areas throughout south Louisiana to aid with potential evacuations.

By Sunday, Mississippi Department of Transportation crews had removed computerized traffic light controllers from major intersections south of Interstate 10 and set the traffic signals to all-flash mode, noted Katey Roh, a public information officer with the agency. That action protects the controllers from floodwaters, while the controllers “flash mode” helps move potential evacuation traffic better than allowing the signals to run on regular cycles.

Although Mississippi does not have a contraflow plan – a situation in which vehicles travelling on a main road in one direction must use lanes normally used by traffic travelling in the opposite direction – it works closely with Louisiana DOTD’s contraflow plan. That plan uses all northbound and southbound traffic lanes on Interstate 55 and Interstate 59 to evacuate the greater New Orleans area into central and north Mississippi. As of Tuesday morning, neither Louisiana nor Texas had implemented a contraflow plan.

“Contraflow is a last resort,” explained TxDOT’s Dupre. “Right now, our crews are preparing for evacuations, and we have dispatched courtesy patrols to help motorists.”

Those three state DOTs also stressed that personnel and equipment must be pre-staged in relatively safe locations to respond to the most vulnerable, low-lying areas in the wake of a storm’s passage. “The most important thing is to make sure our resources are in the right places,” Mississippi DOT’s Roh said. “We’ve been through a number of storms like this, and we know which areas tend to flood, so our first responders are ready to go.”