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221Â Â A P P E N D I X C Summary of State Flood Systems Table C1. Summary of state flood systems. State Topic area Description Alabama Monitoring/warning The Alabama Department of Transportation Intelligent Transportation Systems Strategic Business Plan states that ALGO Advanced Traffic Management System provided for Montgomery, Mobile, and Birmingham County is a software that manages ITS equipment, including closed circuit television, digital message signs, vehicle detectors, and road weather information systems (Greshman Smith and Partners 2016). Alabama Law Enforcement Agency publishes weather advisories with details of flood predictions determined by NWS (Alabama Law Enforcement Agency 2019). These advisories are real-time updates. Alaska Prediction Three forward-focused case studies were conducted, including an analysis of the increased risk of storm damage at an airport and an analysis and risk associated with thawing permafrost and increased precipitation. It was determined that precipitation in northwestern Alaska is projected to increase by about 15% to 30% based on estimates by the National Climate Assessment. NOAA predicts storm surges of 10 feet or more, with some parts of western Alaska seeing as high as 13-foot surges. To consider possible climate changes and uncertainties, the U.S. Department of Transportation developed a General Process for Transportation Facility Adaptation Assessments (the Process). This is an 11-step framework considering climate change and is used to determined best methods for decision making at the project level (Armstrong and Lupes 2016, FHWA-WFL/TD-16-001). Arizona Monitoring Arizona DOT (ADOT) developed a resilience program, Asset Management, Extreme Weather, and Proxy Indicators Pilot Project (ADOT 2020), with the help of USGS to develop a solution to incorporate extreme weather (i.e., flooding) and climate change into engineering design, management, and long-term planning of roadways. This program analyzes precipitation, flooding, wildfires, wildfire-induced floods, dust storms, rockfalls, slope failures, surface temperatures. Monitoring/warning The Arizona Flood Warning System is an interactive map for users to determine precipitation data (15 min, 30 min, 1 hr, 3 hr, 6 hr, 12 hr, 24 hr, 14 day) and water level (discharge and stage) in tabular and graphical format across the state from precipitation gages provided by contributing agencies (Arizona Department of Water Resources 2019). California Prediction Californiaâs Ocean Protection Council predicts a likely sea level rise of 3.4 feet in 2018, with higher-end and extreme scenarios coming in at 7 feet and 10 feet, respectively. A project has been created to protect the Embarcadero Historic District that welcomes more than 24 million people per year. The project will take approximately 30 years to complete and cost about $5 billion. There is also a smaller project aimed at protecting the San Francisco International Airport that will cost approximately $587 million. The airport is responsible for two-thirds of the regionâs air travel and 95% of its international travel. The airport is expecting up to 36 inches of sea level rise by 2085 according to a Fiscal Feasibility Study from March 2019 (Cardno 2020).
222 Practices for Integrated Flood Prediction and Response Systems ITS device data can be analyzed to provide decisions to be implemented into the QuickMap. Monterey County, California, began using the ALERT (Automated Local Evaluation in Real Time) flood warning network after the Marble Cone fire in 1977. This system is NWSâs communications protocol, which is a reliable and low-cost way to transmit data in real time. The software for the network continues to improve and is being used around the world as environmental monitoring and flood warning systems. Monterey County Water Resources Agency currently is responsible for operating and maintaining the ALERT system, which includes about 50 remote sites throughout major watersheds in the area. The sites provide environmental data, including rainfall, air temperature, and water level, that is used for flood forecasting and monitoring. This data can also be monitored by staff using internet access from any device through a secure interface. This modern web-based system combined with ALERT allows for reliable access to this data even during extreme events. The system is also utilized to monitor reservoirs, rivers, and lagoons in relation to the environment issues and the operation of the Salinas Valley Water Project (Monterey County Water Resources Agency 2019). âReview of State of PracticeâEvaluating the Performance of Transportation Infrastructures during Extreme Weather Eventsâ (Ibrahim-Watkins 2018) states that inundation resulting from extreme storms impacts the quality and performance of pavement through road collapse and increased rehab costs. Currently, the methods used to predict large inundation events are effective in reducing repair costs and increasing safe evacuation because they properly analyze roadways and their pavement conditions. However, there is a need for the creation of more, diverse methods. The paper focused on analyzing the effectiveness of the FHWA Vulnerability Assessment study, the FHWA Vulnerability Assessment Pilot Study in the Virginia coastal region, and the structural performance of roadways after inundation. The review of these components aims to ensure that they are truly good alternatives to combat coastal inundation from climate change factors. The preliminary investigation on Flood Warning Alert Systems found that a lot of states, like California, are in need of a flood alert system that allows them to proactively monitor, assess, and respond to flood disasters in real time (Lissade 2012). In need of information to develop their system, referring to the previously described FloodCast system, CTC & Associates sought further information by contacting states with flood warning systems that focused on predicting infrastructure failure caused by flooding. Additionally, a literature search was conducted on flood alert systems and related topics. A highlight of their findings is that several states use or have used the commercial system called BridgeWatch. Other states also seem to be developing their own flood alert systems if they do not already have one. In general, states seemed to be unaware of commercial vendors other than BridgeWatch and were unaware that any existed internationally. Response âDOT Stormwater Research Summaryâ (Currier et al. 2020) presented at the 2020 Transportation Research Board Annual Meeting was conducted with support of the Office of Water Programs at Sacramento State. The presentation reviews projects that were selected from a TRID search from 2017 through the present. These projects were categorized into seven relevant topics, including (a) asset management, cost, and multi-benefit; (b) best management practices (BMPs) and drainage system maintenance; (c) BMP modeling and tools; (d) BMP performance, design, and evaluation; (e) cold-weather studies and de-icing agent impacts; (f) watershed scale; and (g) stormwater characterization. Monitoring/warning The Commercial Wholesale Web Portal by Caltrans is the system that provides information on the 150 weather, visibility, and environmental in-field ITS devices updated every minute throughout the 12 districts (Caltrans 2020). With the portal, the Colorado Monitoring/warning Flood Threat Bulletin (FTB) is a webpage created by the Colorado Water Conservation Board that updates users daily on the current weather (forecasts by Dewberry) and flood conditions of the date through detailed meteorological data and
Summary of State Flood Systems 223Â Â descriptions. The bulletin provides Daily Flood Threat, Flood Threat Outlook, and State Prediction Maps. The FTB is updated from May 1 through September yearly (Colorado Water Conservation Board 2020). The Colorado Water Conservation board consists of the Governorâs Flood Task Force and Water Availability Task Force. F2P2 is a program run by the Colorado Mile High Flood District (MHFD) with Boulder County, National Hydrologic, from April 15 through September 30. The program provides a public interactive ArcGIS Webmap created by MHFD, NWS, and ArcGIS showing live stream gages (major, moderate, minor flood, action storage, no flooding, etc.), alert real-time (past 1 hour), stream gages (major, moderate, minor flooding, etc.), alert system status (in or out of service), storm attributes (tornado vortex signature, hail size, etc.), NWS watches warnings and advisories (blizzard warning, avalanche, etc.), and radar loop (snow, rain, etc.) (Urban Drainage and Flood Control District 2020). Delaware Prediction DelDOT Gateway is a DelDOT interactive map with 28 layers, including prediction of Sea Level Rise (SLR) that shows mean higher water, 0.5 meters, 1.0 meters, and 1.5 meters (DelDOT 2020). The Strategic Implementation Plan for Climate Change, Sustainability and Resilience for Transportation describes Delawareâs development of a strategic plan to promote resilience and sustainability in its transportation system. The goals of the plan are the goals of Executive Order 41, which is described as the roots of the initiative. The goals include reduction of greenhouse gas emissions, an increased resilience to climate change, and avoiding or minimizing flood risk due to SLR. FEMAâs Hazus risk assessment tool can be used to model extreme scenarios and identify and address vulnerabilities. The U.S. Department of Homeland Security also has a National Infrastructure Protection Plan (NIPP) that aims to enhance protection of the nationâs key resources and critical infrastructure to build a safer, secure, and more resilient America. NIPP also has a Risk Management Framework to help identify any key resources and critical infrastructure (DelDOT 2017). Monitoring/warning Delaware has a statewide flood monitoring system of 10 hydrology gages with real- time water levels by Delaware Department of Transportation (DelDOT), Integrated Transportation Management System, Delaware Department of Natural Resources and Environmental Control, Delaware Emergency Management Agency, USGS, and University of Delaware. Data are collected and sent to DelDOTâs website and app. Data are also stored for future analysis of weather events (DelDOT 2020). The Delaware Coastal Monitoring System is an alert system used to provide information to planners, emergency managers, and others about future coastal events. The primary objectives of the system are to alert the public through text or email up to 48 hours in advance of an extreme event, to provide access to real-time meteorological and hydrologic conditions, and to provide potential flood inundation maps, road elevation profiles, and tidal surge predictions (Delaware Geological Survey 2019). Florida Prediction Sea level rise, storm surge, and inland flooding were analyzed for Hillsborough County, Florida. USACEâs SLR projection methodology was used along with tide gage data and sea level trends from the NOAA Center for Operational Oceanographic Products and Services. The GeoPlan Center developed the Sea Level Scenario Sketch Planning Tool. Storm surge was analyzed using NOAA models where the height of the storm surge is determined on the basis of historical, hypothetical, or predicted hurricanes while accounting for many other factors. Storm surge with sea level rise was also developed using SLOSH depth with the Sea Level Rise Tool developed by the Tampa Bay Regional Planning Council. Inland flooding was looked at using official 100-year floodplain maps. FEMAâs official Digital Flood Insurance Rate Map was obtained for information on local flood zones, base flood elevation, and floodway status for a particular location. Hot spots were also determined according to the countyâs Engineering and Construction Service Section, on the basis of multiple factors. The team used FHWAâs vulnerability assessment framework in a GIS platform to conduct its assessment on transportation assets (DeFlorio et al. 2014, FHWA).
224 Practices for Integrated Flood Prediction and Response Systems Idaho Monitoring The Idaho Department of Transportation attributes the success of its successful flood monitoring systems to BridgeWatch and the Idaho Transportation Board Scour Committee. More information about the practices of Idahoâs DOT is included in Chapter 4. A Temperature-Based Monitoring System for Scour and Deposition at Bridge Piers (Carpenter et al. 2017, FHWA) explains that the leading cause of bridge failure in the United States is scour because it compromises the bridgeâs structural stability. Yearly or bi-yearly streambed surface elevations may not provide accurate representations of the scour risk at bridges due to factors (water flow conditions, local sediment transport) that may cause fluctuation in these elevations. This project tests a low-cost, simple methodology to continuously monitor streambed elevation changes that uses the natural oscillations of stream water temperature as a tracer. The method was tested on five bridges in five different watersheds in Idaho and was determined to be robust. Illinois Monitoring/warning Using a deterministic approach, âAn Evaluation of Transportation Network Robustness against Extreme Flooding: A GIS Based Approachâ (Kermanshah and Derrible 2017) analyzed the ability of the New York City and Chicago transportation networks to withstand extreme flood events. To model what an extreme flood event may resemble in these cities, roadways within the FEMA 100-year floodplains were removed from the simulation. This removal then factored into the calculation of the number of trips completed found using GIS properties, travel demand modeling data, topological information, and Longitudinal Employer-Household Dynamics data. This simulated extreme flood demonstrated that both New York City and Chicago have high edge betweenness centralities within the floodplains. However, despite key bridge closures in New York City, data show that Chicago is more susceptible to being damaged by extreme flood events. Iowa Prediction Iowa DOT claims that BridgeWatch has allowed it to conduct successful flood prediction modeling. The Iowa Flood Centerâs flood prediction and Iowa Flood Information System have also contributed to Iowa DOTâs success. More information on Iowa DOTâs practices is included in Chapter 4. Flooding, particularly in the coastal areas, is predicted to increase in severity due to climate change, which threatens the stability, lifespan, and maintenance cost of roads and bridges. âAn Integrated Framework for Risk and Resilience Assessment of the Road Network under Inland Floodingâ (Zhang and Alipour 2019) analyzes the vulnerability of a regionâs transportation infrastructure through running networkwide topologic assessments and flow-based risk assessments. Each of these analysis methods then works collectively to assess the potential vulnerabilities of a road segment sample when faced with 2-, 50-, 200-, and 500-year storm events. The results of this project demonstrate that there is an increased likelihood of road closures and poor network and transportation performance with larger, more intense storm events. The goal of this project is to create a framework that will provide insight on infrastructure improvement strategies for future developments in the sample cities of Iowa City and Cedar Rapids. âFHWA Climate Resilience Pilot Program: Iowa Department of Transportationâ (Claman and Lupes 2015) worked to improve transportation network resilience to storm events. In Iowa, this program is used to help evaluate the vulnerability of bridges and roads to river flooding. This study involved collecting data on vulnerable assets and climate, modeling streamflow, estimating future floods, and analyzing the credibility of the results. These findings will then be integrated into BridgeWatch, which is used to monitor the overtopping of bridges and roadways. BridgeWatch will be used in conjunction with USGS gages and NEXRAD to alert engineers when bridges should be closed due to incoming storms or the likelihood of failure. Projected streamflow statistics were integrated with Iowa DOTâs bridge and roadway asset infrastructure database to assess vulnerability. The rating curves were developed using USGS gage data, when available, or USGS regression equations. NOAA Stage IV precipitation analysis was used to obtain accurate streamflow simulation. It is noted that the online USGS climate projection rainfall data sets are cumbersome. However,
Summary of State Flood Systems 225Â Â the main challenge is to figure out how to analyze multiple climate scenarios in a justifiable mannerâbecause the existing design process is also cumbersomeâwhile using multiple streamflow data series at a single location. The main recommendation is to ensure that DOTs incorporate flexibility in their design analysis (C. Anderson et al. 2015, FHWA SPR HEPN-707). Real-Time Flood Forecasting and Monitoring System for Highway Overtopping in Iowa is currently research in progress related to Iowa DOTâs flood monitoring and forecasting. Since 2006, Iowa DOT has used BridgeWatch to send alerts if there is a rainfall event or if stream gages indicate flooding potential at scour critical bridges. It is looking to use a similar system to provide alerts for when highways are overtopping because of flooding. The study includes attempting to interface the prediction of the hydrological model with BridgeWatch and information from sonic sensors developed by Iowa Flood Center. University of Iowaâs CUENCAS hydrological model will be used for flood forecasting to better predict flood overtopping on roadways. Iowa Flood Centerâs hydrological model for the entire state uses real-time rainfall events along with forecast resultant peak flows near basins in Iowa. The predicted flood discharge from this model can then be integrated with BridgeWatchâs stage/discharge relationship to provide real-time warnings to maintenance staff before overtopping occurs. Iowa Flood Center also developed sensors for bridge sites that can provide real-time stage/discharge data. In a smaller basin, these can be used to provide real- time warnings for the overtopping of highways by integrating the data into the BridgeWatch system (Mantilla and Krajewski 2015). The hydrological model CUENCAS had been used to predict flooding in small tributaries in the Squaw Creek basin in Iowa. This model had only been verified for large-scale models as of the beginning of the project. The goal of this project is to eventually develop a reliable real-time flood forecasting system to produce actionable results for those maintaining roadways during extreme flood events. This hybrid system will combine real-time observations at multiple locations from sonic sensors with a hydrological model for the river network. The CUENCAS model was coupled with a one-dimensional hydraulic model, like HEC-RAS, to compare the results with information collected from the sonic sensors. It was determined that the predictions of the hydrological model at internal locations are as accurate as predictions made at the basinâs outlet (Krajewski and Mantilla 2014, FHWA). Monitoring/warning WeatherView is an interactive map by Iowa Department of Transportation that reports live weather conditions with data from Automated Weather Observing Systems and RWIS (Appendix F). Reports include pavement temperatures, camera images, NWS watches and warnings, and forecasts (30 hoursâforecast for each hour). The Iowa Flood Information System (IFIS) allows web-based access to flood-related information, visualization, and application (Iowa Flood Center 2019). The website provides easy access to links of flood alerts, stream conditions, river communities, and inundation maps. A Google Mapsâbased interface shows the state of Iowa and the locations of stream sensors, which are color-coded depending on their stage (e.g., action, flood), as presented in Figure C1. Figure C1. IFIS interface (Iowa Flood Center 2019).
226 Practices for Integrated Flood Prediction and Response Systems âScour Management in Iowa Using Modified HYRISKâ (Morshedi et al. 2018) discussed a tool, HYRISK, that was developed by FHWA to prioritize bridges based on scour level. Modifications on components, like soil erodibility and cost calculations, were made to this tool so bridge scour could be specifically analyzed in Iowa. A sample of 30 bridges was used to compare this newly modified HYRISK tool with the original tool, where these bridges were ranked according to risk and compared between both tools. Results of the study of the 30 bridges predicted future necessary construction that Iowa DOT will have to do, such as abutment and pier protections. âClimate Change Impact on Highway Bridges: Flood-Induced Bridge Scourâ (Fioklou and Alipour 2017) also analyzed the costs and benefits of five potential countermeasures to decrease the risk of bridge failure from scour in an old Iowan pilot study on U.S. 30 over the South Skunk River. Response As a part of its weather-responsive management strategies, Iowa DOT redesigned its 511 traveler information map. In an effort to reduce flooding impacts on the public and to provide better flood-related data to travelers, Iowa DOT improved upon its traditional closure icons and added painted lines to show the extent of closures, construction, and other applicable events (FHWA 2020a). Kansas Monitoring/warning The Kansas Department of Transportation (KDOT) Transportation Operations and Management Center is the department that provides flood warning to the public through activation of the traveler information system (KDOT 2020). Flood information is given through the automated flood warning system, which has water level gages and flood prediction algorithms. The emergency broadcast system is activated when a flood is possible. Developing a Bridge Scour Warning System explains that the monitoring of bridge scour presents multiple challenges for bridge owners, including state DOTs, because it can be difficult to detect below water level. It was determined that a systematic statewide system for monitoring scour-capable events at bridges across the state would be the most beneficial. Even though the tools used are public domain, the use of these resources would require staff overhead to ensure reliability and timely bridge closures and inspections (Young 2016). Kentucky Prediction The Kentucky Transportation Center and the Kentucky Transportation Cabinet worked together to assess the flooding vulnerability of the National Highway System (NHS) in âAssessing Transportation Assets for Vulnerability to Extreme Weather and Other Natural Hazardsâ (Blandford et al. 2018). Using proximity indicators, the areaâs risk of hazards like flooding, sinkholes, landslides, and earthquakes was analyzed. Data were collected using a variety of sources, including (a) USGS peak ground acceleration for earthquakes, (b) FEMA flood mapping for 100-year floodplain, (c) Kentucky Geological Surveyâs GIS data on the possibility of karst presence for determining sinkhole potential, (d) historical climate data from Midwestern Regional Climate Center, (e) keypad exercise and flood mapping workshops, and (f) Kentucky Geological Surveyâs landslide inventory database. All of these data were then placed in GIS to help communities find highway segment vulnerabilities and to rank vulnerable segments of the NHS at a district level. Monitoring/warning GoKY is Kentucky Transportation Cabinetâs interactive map providing users information on weather activity, traffic delays, alerts, DMS, and cameras. The map also provides information on snowfall interpolation (Kentucky Transportation Cabinet 2020). Louisiana Monitoring USGS HydroWatch is an interactive map of USACE river gages, USGS HydroWatch devices, movable bridges, and water body locations (LA DOT 2020). Maryland Current status of flood event Major hurricanes to hit the United States between 2017 and 2018 have caused much damage to areas because of their intense rainfall. Steps need to be taken to mitigate the impacts of intense rainfall events in order to decrease urban flooding. Even though local governments are primarily responsible for mitigation of urban flooding, there is no clear definition of responsibilities between federal, state, regional, local, and tribal governments for stormwater management of urban flooding. Urban flooding has become a growing source of social disruption, economic loss, and housing inequality. No agency is responsible for overseeing federal support for urban flood mitigation
Summary of State Flood Systems 227Â Â activities at the federal level. Additionally, effective ways of communicating risks to those located in urban flood-prone areas have not been provided by the government. In fact, many public officials and unaffected members of the public generally do not know the social and economic impacts of urban flooding. Many people who live and work in these urban flood areas do not understand that they can take steps to significantly reduce their propertyâs vulnerability. Many of these people also lack the support and resources to carry out these actions. Lastly, data are not readily available or shared with local researchers, decision makers, or residents (Galloway et al. 2018). Prediction Maryland State Highway Administration (SHA) looked at the vulnerability of assets to climate stressors, including increase and decrease in precipitation, sea level change, and more. They aimed to develop approaches to address these risks, as well as to make recommendations to improve highway resilience. LiDAR information from the state and Hazus modeling were used to develop predictive models. Vulnerability assessment for bridges was determined using the U.S. Department of Transportationâs Vulnerability Assessment Scoring Tool and for roadways using the Hazard Vulnerability Index. It was determined that sea level change, storm surge, and increased precipitation would have the greatest impact on Marylandâs assets (Maryland SHA 2014, FHWA). Monitoring The Global Flood Monitoring System at the University of Maryland is an experimental system funded by NASA. It uses real-time TRMM Multi-Satellite Precipitation Analysis (TMPA) and Global Precipitation Measurement (GPM) Integrated Multi- Satellite Retrievals for GPM precipitation data as inputs. The system uses a quasi- global hydrological runoff and routing model at 1/8-degree resolution. Flood thresholds are derived from surface water storage statistics, and flood intensity estimates are based on 13-year retrospective models with TMPA as an input (Wu 2019). Massachusetts Prediction âA Hierarchical Approach for Prioritizing Adaptation Needs for Roads and Bridges Exposed to Coastal Flooding in the Broad Sound Area of Coastal Massachusettsâ (Barankin et al. 2018) looks to improve vulnerability assessment approaches, especially indicator-based approaches, through decreasing unpredictable/irrational decisions with a type of adaptation planning. The Hierarchical Approach addresses the limitations of the indicator-based assessments through the generation of a list of ranked vulnerability assessment indicators that are adaptable for various storm event scenarios. Exposure was determined using a model of the 100-year flooding event taken from the Massachusetts Coast Flood Risk Model. In a case study, Massachusetts DOTâs project team used the ADCIRC (advanced circulation) hydrodynamic model along with the SWAN (simulating waves nearshore) model to simulate storm-induced waves in agreement with hydrodynamics. They call this model the Boston Harbor Flood Risk Model (BH-FRM), which was determined to be good at simulating important coastal storm impacts. The BH-FRM was able to identify potential flood locations and determine flood entry points and pathways. Scenarios were developed to simulate sea level rise along with the impact of hurricanes and norâeasters for the time periods selected. A Monte Carlo statistical approach was used to develop depth of flooding information for tens of thousands of locations, flood pathways and sources, detailed time-varying inundation maps, and the probability of flooding in the future. It was recommended that high-resolution hydrodynamic modeling be used in heavily populated areas with critical transportation infrastructure. Additionally, GIS was deemed a very powerful software, but there are many challenges, including complexity and lack of expertise. The team also emphasizes the importance of considering the timing of the storm relative to the tidal cycle. They also recommend not relying solely on automated digital data because local conditions cannot always be captured by them (Miller and Lupes 2013, FHWA). Michigan Prediction Michigan Department of Environment, Great Lakes, and Energy (EGLE) conducts hydrologic analysis and calculates flood and low discharges for the state of Michigan. MiSWIM is an interactive map of hydrologic information by EGLE displaying environmental monitoring, beach/river E. coli, fish contaminant, USGS gage stations, high flow, low flow, wastewater discharges, nonpoint source grants, septage haulers, lakes and streams/rivers, valley segments, cold-water streams, natural rivers, reports,
228 Practices for Integrated Flood Prediction and Response Systems fish stocking information, and fish species (Department of Environmental Quality & Department of Natural Resources 2020). Discharge data and information are provided from the Flood Discharge Database run by the Michigan Department of Environmental Quality. Minnesota Monitoring In MnDOT Flash Flood Vulnerability and Adaptation Assessment Pilot Project (B. Anderson et al. 2014, FHWA), flood risk within Minnesota was evaluated using FHWAâs Climate Change and Extreme Weather Vulnerability Assessment Framework to improve the resiliency of transit systems currently vulnerable to flooding. This framework is presented in Figure C2. MnDOT identified 1,819 state assets within the Truck Highway System that were vulnerable to flooding. Each of these assets was given vulnerability scores based on sensitivity, exposure, and adaptive capacity metrics found using GIS analysis, hydraulic analysis, MnDOT databases, and work sessions. These scores then allowed MnDOT to rank its assets from tier 1 to tier 5, with tier 1 being the most vulnerable to flooding and tier 5 being the least vulnerable to flooding. Figure C2. FHWAâs Climate Change and Extreme Weather Vulnerability Assessment Framework (FHWA 2012). Mississippi Prediction âFlood Vulnerability Rating (FVR) for Sustainable Bridge Management Systemsâ (Durmus and Uddin 2017) offers a geospatial decision support system that prioritizes bridges particularly vulnerable to flooding because the current bridge management system framework lacks vertical underclearance criteria. This system will use a FVR system (1 being catastrophic risk and 6 being very low risk), which will account for bridge top elevation. This report studied approximately 270 bridges across Mississippi. Results from the analysis of the life cycle demonstrate that the cost was 59.3% cheaper if the bridge had preplanned bridge hardening rather than no hardening. âAnalyses of Storm Surge Induced Flood Risk in Coastal Areas of Mississippiâ (Thomas et al. 2017) examines the storm surge flooding vulnerability of the Mississippi Gulf Coast with the goal of finding a method to analyze and predict potential future flooding in order to improve area resilience. The flooding risk was analyzed by using spatial risk distribution on GIS and statistical and regression analysis of average daily traffic (ADT), surface elevation, hurricane surge data, property loss due to flooding, the areaâs max flooding height, and population census. The maximum surge elevation data were then calculated using these components and previous research data from ADCIRC, FEMA, and the National Hurricane Center. The results show that direct loss coverage and the maximum flooding height were seemingly linked.
Summary of State Flood Systems 229Â Â Missouri Response Missouriâs Department of Public Safety released a Flood Damage Assessment Packet in 2019 to assist during major floods. The packet contains information on the five steps the local administrator should take following a flood. The packet also explains âThe 50% Ruleâ to assist with substantial damage assessment and contains a sample damage assessment worksheet as a guideline. The FEMA Substantial Damage Estimator (SDE 3.0) is provided as well. Other sample documents (for notices, forms, press releases, and damage determination letters) are also included in the packet. Lastly, the packet provides general National Flood Insurance Program information for reference (Missouri Department of Public Safety 2019). New Jersey Response The Transportation Operations Task Force of the Delaware Valley Regional Planning Commission (DVRPC) meeting noted that New Jersey Department of Transportationâs UAS (unmanned aerial system) current initiatives related to the synthesis include structural inspections, emergency response assessments, traffic congestion management, aerial 3D corridor mapping, and watershed surveys. They use this information for 3D mapping as a less expensive alternative to LiDAR. Gloucester Countyâs UAS Aviation Division uses its drones for search and rescue, damage assessment, situational awareness, and fatal incidents (Transportation Operations Task Force 2019). New York Prediction, monitoring/warning NYSDOT uses NWS flood warnings and BridgeWatch. NYSDOT also uses StreamStats for flood prediction and is working on further developing its StreamStats usage. The practices of NYSDOT are discussed further in Chapter 4. North Carolina Monitoring/warning The North Carolina Department of Transportation (NCDOT) has strong relationships with various agencies that has allowed it to develop and maintain its flood management and response systems. More information on NCDOTâs practices is provided in Chapter 4. After devastating flooding by Hurricane Floyd in 1999, North Carolina established the North Carolina Floodplain Mapping Program, which led to the establishment of the Flood Inundation Mapping and Alert Network (FIMAN). These are both used to provide North Carolina with better management of and response to flood hazards and to provide real-time flood inundation throughout the state, respectively. FIMAN is unique because it is able to provide flood information and storm-specific rainfall using a system of measurement stations that are located throughout the state, rather than creating floodplain maps based on model simulations of probabilistic storm events. The system is also capable of mapping, analyzing, and communicating flood risks in real time (Dorman and Banerjee 2016). Response The Mississippi Department of Transportation (MDOT) announced in a news release multiple closures in Hinds County in anticipation of Pearl River flooding. MDOT also announced that it has taken precautions and staged traffic control devices in areas where it is anticipated that flooding will be encountered. Both changeable and dynamic message boards have been staged in advance of the closures to alert any motorists of conditions ahead. The news release also provided readers with a link to driving safety tips in flood conditions and severe weather, as well as a link to check roadway conditions before traveling (MDOT 2020). Response Hurricane Florence produced record-breaking rainfall across eastern North Carolina and parts of northeastern South Carolina, where over 30 inches of rain was measured in a couple of locations in North Carolina. Over the next few days, record river flooding occurred, destroying and damaging roads, houses, and businesses. A USGS report showed that nine river gages reported flooding that exceeded the 1-in-500-year expected return intervals. The state of North Carolina estimates preliminary damage costs to be $16.7 billion. It has also reported 42 fatalities, 74,563 flooded structures, and 5,214 people rescued from flooding. After the storm, approximately 140,000 North Carolina residents registered for disaster assistance. South Carolina Emergency Management reported $607 million in damages, nine fatalities, 455,000 people evacuated, 11,386 homes with moderate to major damages, and 11 breached or failed dams (Armstrong 2019).
230 Practices for Integrated Flood Prediction and Response Systems Bruce Siceloff, a NCDOT spokesperson, reported that more than 1,000 feet of pavement and protective dunes along the roadway will need to be replaced on NC 12 on Ocracoke Island. NCDOT must present its repair plan to the National Park Service before it can begin working since the Park Service owns the land. NCDOT estimated a cost of $40 million and $5 million, respectively, to clear and repair roads after Dorian. NCDOT expects to spend tens of millions of dollars more once all repairs are complete, since the cost of road repairs has already reached nearly $180 million after Florence. Repair and cleanup costs from storms have reached over $300 million over the past year. This along with the cost of settling hundreds of Map Act lawsuits has left NCDOT in a tough financial situation, forcing the department to delay any new construction projects and to lay off temporary workers (Stradling 2019). North Dakota Prediction Clearpath Weather is the interactive map of sensors across North Dakota, including NDDOT RWIS, NWS, and FAA information. Two-day forecasts are available for select regions providing information on temperature, precipitation, winds, and skies (NDDOT 2020). Ohio Monitoring/warning Development of a Flood-Warning System and Flood-Inundation Mapping in Licking County, Ohio explains that Licking County has experienced flooding that has closed multiple roadways resulting in many consequences, including loss of commerce and safety issues. A flood-warning network was created by upgrading a lake-level gage, reestablishing and adding stream gages to the existing network, delineating the flood- inundation boundaries, and developing an unsteady-flow model for use by NWS. Real- time gage information, flood-forecast predictions, and flood-inundation mapping can be accessed on websites hosted by USGS and NWS. The ability of public and emergency management officials to assess flood conditions will improve with an increase in the availability and amount of publicly accessible streamflow data (Ostheimer 2012, FHWA). Oklahoma Response Decision Support System for Road Closures in Flash Flood Emergencies explains that the southwestern United States is dangerous for people and vehicles entering sudden, isolated thunderstorms, because flash flooding is the number one weather-related killer in the United States. As these flash floods are time sensitive, availability to a computer system that provides quick response and an effective decision support system can save many lives. A novel decision support system was developed to predict threats on roadways and remotely turn on TADD (Turn Around Donât Drown) red lights or gates to close roads during dangerous flood emergencies. The system automatically monitors water depth at remotes sites, so it is capable of sending control signals to these TADD systems. Additionally, the system integrates the newly established Oklahoma Flash Flood Database and GIS Spatial Database. The GIS-based interface will automatically show the areas and roads under flood threats (Collins et al. 2013). Pennsylvania Prediction The stateâs phase one extreme weather vulnerability study evaluates historic vulnerabilities, develops a framework to address the impacts of climate change, and assesses risks and priorities linked to vulnerabilities. To locate areas of historical flooding, the project team used a Road Conditions Reporting System and a stakeholder outreach tool. The Roadway Management System (RMS) was used to map overlays and variables for risk assessment. Pennsylvania Spatial Data Access was used to obtain the digital elevation model and FEMA flood zones and depth grids. Historic and projected climate data were obtained from NOAA websites. Forecast models were developed using projected daily precipitation values from general circulation models through 2099. The team determined that flooding issues are most significant where there are deficiencies in local drainage systems or flooding resulted from tropical storms (Michael Baker International 2017). Monitoring Flood Monitoring for Scour Critical Bridges serves as a reference for Pennsylvania on how to document signs of distress on bridges and approaches that have been or have nearly been overtopped by flood water. It also describes how to coordinate bridge closures, including steps to take before, during, and after a flooding event. Photographs of possible flooding situations and effects are provided for reference (Pennsylvania DOT 2015).
Summary of State Flood Systems 231Â Â A presentation by PennDOT on âMonitoring Scour Critical Bridges during Floods for Local Bridge Ownersâ explains the fundamentals of bridge scour and how to categorize how scour critical a bridge is. The presentation goes through the process of how to monitor these critical bridges, as well as how to log the information. It also describes flood alerts and valuable flood alert websites to go to for information. It explains the process on what to do before, during, and after the flooding event, and how to close a bridge, if necessary. The presentation stresses the prioritization of safety during all processes as flood waters can be very dangerous (2015). Response DVRPCâs Transportation Operations Task Force meeting noted the usage of the Pennsylvania Turnpike Commissionâs UAS Program to update aerial imagery (Transportation Operations Task Force 2019). PennDOTâs Asset Management Initiatives include the Transportation Asset Management Plan (TAMP), Pavement Asset Management System (PAMS), and Bridge Asset Management System (BAMS). TAMP requirements include a 10-year cover period for the National Highway System for all pavement and bridge assets regardless of ownership. The plan eventually intends to include other NHS infrastructure and assets on other public roadways. The RMS for PennDOT aims to define and monitor the stateâs highway network and create an inventory of roadway characteristics, features, and conditions. PAMS will be used for cost-effective network planning that aims to predict optimized strategies on the basis of condition data and budget scenarios. This system includes models for forecasting pavement conditions and the ability to predict distress conditions on individual like pavements. BAMS is similar to PAMS because it is a forecasting tool used to better manage bridge assets. It will help select the right repairs at the correct times and predict future bridge conditions according to funding levels. BAMS will also assist in programming to the lowest life-cycle cost and in analyzing PennDOT data sets (PennDOT 2017). South Carolina Prediction âSouth Carolina Flood Inundation Mappingâ is research in progress to determine how to use HEC-RAS two-dimensional rain-on-grid modeling software to provide real-time data maps. It would be possible by leveraging existing data from two Hydrologic Unit Code 8 watershed basins located in South Carolina. This research will take a comprehensive approach in order to predict which roadways and bridges will be inundated and in need of closure during an extreme weather event to ensure the safety of the public (Lamm 2020, FHWA). Response South Carolinaâs Department of Transportation (SCDOT) collaborates with multiple agencies on their flood management systems while aiming to constantly improve communication efforts. SCDOT utilizes BridgeWatch, which provides various benefits to SCDOTâs flood system efforts. SCDOTâs practices are discussed further in Chapter 4. The South Carolina Unit Hydrograph Method Applications Manual provides the latest updates and improvements on the South Carolina Unit Hydrograph Method (Meadows 2020, FHWA). SCDOT has an application spreadsheet that can be used for the South Carolina Synthetic Unit Hydrograph Method. Governor Henry McMaster established the South Carolina Floodwater Commission in October 2018. This commission was a first-of-its-kind attempt to bring together all stakeholders and others in the nonprofit sector to address flooding issues as a team. This is a proactive way to begin mitigating disasters and protecting lives and property (Mullikin 2019). The commission aims to mitigate flooding in South Carolina and lessen its negative impacts on the economy. The state has experienced numerous flooding events in the past few years, increasing its need for a statewide plan to mitigate flooding impacts. The commission has worked to develop both short- and long-term recommendations to mitigate and alleviate flood impacts while emphasizing the communities located along South Carolinaâs coasts and rivers. Its resiliency strategy for the state aims to consolidate resources in order to be costly and strategically effective (South Carolina Floodwater Commission 2019).
232 Practices for Integrated Flood Prediction and Response Systems Texas Prediction TxDOT uses the NWM for flood prediction but is working on improving some flaws within the model. TxDOTâs notable practices include data storage, communication, and well-coordinated emergency management. More information on TxDOT practices is provided in Chapter 4. The Texas Natural Resources Information System (TNRIS) is a data information system containing census data, data related to emergency management, natural resource data, and other socioeconomic data (2020). TNRIS states that it is a âreliable and uniqueâ state resource for both Texas agencies and citizens. TNRIS is able to provide current geospatial data products, training, and education while having over 1 million frames of aerial photography and average monthly data downloads exceeding 1 terabyte. Streamflow Measurement at TxDOT Bridges: Final Report (Maidment et al. 2019) tested NWSâs National Water Model through the installation of 20 radar streamflow gages on bridges on or near Interstate Highway 10. These gages also can help forecast flooding in real time along this route by using water velocity and water level to find stream discharge in the HEC-RAS two-dimensional model. The Kisters big data system was used to process these data and present them on the model. The data were then accessible through the TxDOT Water Data Viewer and TxDOT Bridge Portal. This forecast system is also important because it will help create a foundation for assessing the risk for the regionâs transportation system, portions of which are at high risk of flooding. The Texas State Flood Assessment provides information on the flood risks throughout the state, an estimate of the cost of flood mitigation, a review of responsibilities and roles related to flooding, and a summary of stakeholder views on future flood planning. The main findings include mapping, planning, and mitigation, all of which are main elements for comprehensive flood risk management. It addresses flooding as a serious and potentially life-threatening issue, which emphasizes Texasâs need to assess flood risks, impacts, and mitigation costs at the statewide level (Lake et al. 2019). The âCity of Austin Flood Early Warning System with GCM Inputs to Forecast Inland Flooding Conditionsâ (DeFlorio 2015) used the Flood Early Warning System (FEWS) hydraulic model to predict the conditions of inland flooding in the city of Austin, Texas. This system determined the likely impacts and flood conditions of extreme rain storms that are becoming increasingly common in this area. The North Central Texas Council of Governments created an assessment of extreme weather and climate impacts on infrastructure assets in North Central Texas. It predicted that rainfall would be lower in the winter and summer, but would be disrupted by single storms of stronger intensity. An increase was predicted for the spring with intensified extra-tropical cyclones. In general, there is a likelihood of an increase in the number of days of severe thunderstorms by the end of the century. These predicted storms will likely increase severe flooding and therefore erosion and runoff. FEMAâs 100-year floodplain maps were also used to identify transportation assets vulnerable to flooding in severe precipitation events. Critical roadways were determined by overlaying this floodplain map on the location of assets with high annual average daily traffic per travel lane according to the Mobility 2035 Planâ2013 Amendment. The team recommends the use of three-dimensional models (like LiDAR) to significantly improve the assessment of critical infrastructure vulnerable to severe flooding and make results more spatially explicit and reliable (Winguth et al. 2015, FHWA).
Summary of State Flood Systems 233Â Â To determine the vulnerability of transportation assets in central Texas, data were collected and organized in a GIS. Interviews were conducted with local experts to determine the climate variables to include in the vulnerability assessment. The team also used academic research to generate projections using the Weather Research and Forecasting regional climate model. For increased extreme precipitation, the FEWS hydrological model that is currently used by the city of Austin was applied to simulate the future potential flood conditions for critical transportation assets. Vulnerability assessments were conducted using the U.S. Department of Transportationâs Vulnerability Assessment Scoring Tool, which was adjusted later on the basis of feedback from state, regional, and local officials and experts. Lessons learned include the realization that inland extreme weather conditions may differ greatly from those that are faced by coastal communities; this factor should be considered in asset management frameworks and in emergency response plans. Additionally, assets that were identified as critical may not be the most vulnerable, because local and county roads may have a greater sensitivity to extreme weather (Cambridge Systematics Inc. 2015). Warning The winner of the Best Transportation Systems Management and Operations Project was Houston TranStar for its Roadway Flood Warning System. As heavy rainfall is a concern for flooding in the Houston area, Houston TranStarâin coordination with the Harris County Flood Control Districtâs Flood Warning Systemâhas created a real- time flood warning system that alerts travelers in high-risk areas during a rain event. It is noted that this system does not identify flooded roadways, but instead identifies the areas that are at risk of flooding using a comprehensive network of sensors. Travelers are advised to avoid unnecessary trips through these at-risk areas and should be extremely cautious if they do choose to travel in these conditions (Son 2019). A screenshot of the Houston TranStar website is presented in Figure C3. Figure C3. Houston TranStar interface (2020). A Greater Houston Flood Mitigation Consortium (GHFMC) briefing document notes the advanced Severe Storm Prediction, Education, and Evacuation from Disasters Center has developed local flood alert systems for multiple regions, including TxDOT. These systems are capable of using real-time rainfall data from radar to predict flooding in crucial locations. They were specifically developed for end users, but flood predictions and warnings are available to the public online (GHFMC 2018). Response A GHFMC briefing document explains that floodplain regulations should be enacted to protect the health and safety of the public. Any community that is part of the National Flood Insurance Program (NFIP) is required to meet its minimum standards. This requirement applies to all new developments and improved or damaged buildings, but structures that were built before regulations were in place do not need to meet NFIP standards. These regulations are enforced by the city, county, or third-party flood control authority, and are actually enforced by multiple departments in that authority. Flood regulations have three main goals: protecting structures, storing water, and conveying water (GHFMC 2018).
234 Practices for Integrated Flood Prediction and Response Systems Utah Prediction Utah DOTâs Road Weather interactive map includes road condition forecasts, city forecasts, and current conditions (Utah DOT 2020). The current conditions layer includes cameras, weather reports, RWIS, and mountain pass information. The RWIS icon shows information on road surface, weather, and restrictions. The road condition forecast layer includes current, 3â6 hour, 6â9 hour, 9â12 hour, 12â15 hour, 15â18 hour, 18â21 hour, and 21â24 hour forecasts. The city forecast layer shows the city, todayâs forecast, and tonightâs forecast. Monitoring/warning Citizen Reporting is a program through Utah DOT in which roadway users can report on current roadway conditions to enhance coverage of weather on roads (Utah DOT 2020). A visual representation of this change is presented in Figure C4. The Citizen Reporting program is a part of the Utah DOT Weather Operations Program input sources. The public can report roadway issues through Click Nâ Fix. Figure C4. Weather Operations Program data input sources (Utah DOT 2020). Vermont Prediction The Vermont Agency of Transportation (Vtrans) has created a Statewide Highway Flood Vulnerability and Risk Map of bridges, culverts, and embankments along the highway system, which is divided into three interactive maps: flood vulnerability, criticality, and flood risk (Vtrans 2020). The map is marked by low, moderate, high, and no risk or vulnerability to floods. The maps are used for the Transportation Resilience Planning Tool. Vulnerability is calculated and converted to a 10-point scale. Criticality is a blend of the Critical Closeness Access score and modified Network Robustness Index. Risk is an average of vulnerability and criticality scores. Virginia Warning Computational Enhancements for the Virginia Department of Transportation Regional River Severe Storm (R2S2) Model illustrates that flooding caused by changing climatic conditions has major impacts on transportation infrastructure. As climate change continues, it is more critical than ever to begin forecasting potential impacts on transportation infrastructure accurately and quickly. Virginiaâs Department of Transportation has begun addressing this need by creating a flood warning systemâ the R2S2 Model (Morsy et al. 2017, FHWA). Washington Monitoring WSDOT strives to make its flood management systems more proactive than reactive. The DOT uses WatchList for monitoring critical locations during flood events. The practices of WSDOT are discussed further in Chapter 4. Wyoming Prediction WY DOT DayWeather is a map of forecasted weather color-coded in zones by low-, moderate-, and high-impact weather expected (WY DOT 2020).