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99Â Â The responses provided by 48 DOTs give valuable insight into state practices related to the flood prediction and response systems. The case example interviews conducted with seven state DOTs provide more details on the concerns and effective practices for addressing the flood monitoring, prediction, warning, and response systems. On the basis of the work carried out in this synthesis, the following general conclusions can be made. Summary â¢ Advancements and integration of relational database systems, real-time data collection tool technologies (e.g., LiDAR, gages), flood prediction models, data processing and visualiza- tion software (e.g., GIS), and data sharing platforms (e.g., USGS National Water Information System, NWS River Forecast Center) have made substantial contributions to the effective management of floods. â¢ Various FHWA initiatives (e.g., Sustainability Resilience Pilot Program, Every Day Counts) paired with investments in national programs (NOAAâs NWM and USGSâs NWIS) reflect the importance of an effective and accurate flood modeling and management system. â¢ Interviews with case example states demonstrated that the close relationship among the state DOT divisions (e.g., Hydraulics Design, Asset Management), and between the state DOT and other state and federal offices (e.g., FEMA, Department of Natural Resources), is a key factor in a successful flood prediction and response system. A close working relationship with USGSâs gage program, particularly the rapid deployment gages, has proved helpful to several states. Furthermore, a coordinated and updated asset inventory document that is accessible to the key state DOT staffs is a method applied to keep the state DOT informed. â¢ The survey indicated that slightly more than half of DOTs (25 of the 48 DOTs) reported that they consider their integrated system for flood prediction and response system successful. Common plans or initiatives that have contributed to successful systems are the use of USGS gages, the importance of communication between agencies, and BridgeWatch. â¢ On the basis of the 43 DOTsâ responses, approximately half of state DOTs reported using USGSâs NWIS for flood monitoring, and the majority of the DOTs indicated that they use federal stream gages as an instrument and tool for flood monitoring. The other most common instruments and tools DOTs use for flood monitoring are federal rain gages, non- federal stream gages, and GIS. Most DOTs indicated visual inspection as the most common tool used in determining the extent of flooding severity. â¢ The DOTs provided information on risk thresholds that trigger action. Common responses from DOTs indicated that the NWS issues the warnings and parameters that DOTs apply to issue a flood warning. According to a self-ranking, the most important information used in statesâ flood warning systems is observed stream stage, observed stream inundation, and bridge scour. C H A P T E R 5 Conclusions and Knowledge Gaps
100 Practices for Integrated Flood Prediction and Response Systems â¢ DOT survey results showed that for flood prediction methods, a hydrologic/hydraulic model was identified as the most common type of flood prediction model used by DOTs. For the platform/model of the flood prediction model, most DOTs reported that the flood prediction model is produced by a federal agency (e.g., USGS, FEMA, NOAA, NWS, USACE, Bureau of Reclamation). â¢ The survey showed that the most widely used communication tools and methods to alert the public in response to flooding events are radio, social media (e.g., Facebook, Twitter, Insta- gram), television, signs, and 511 systems. For communicating and working with other state agencies when responding to flooding events, direct calls and emails, agency sharing (i.e., homeland security, police), and emergency operations centers were identified practices and approaches applied by the DOTs. Email lists, conference calls, and an emergency manage- ment center were identified as frequently applied in DOT internal communication systems that are structured to respond to flooding events. â¢ Many DOTs reported cooperation from local agencies in the state, adequate state resources (in staff and funding), and a continuous public awareness campaign regarding the emergency response and warning systems as key factors and attributes that have led to the success of flood response systems. The most common methods used to facilitate emergency response systems were identified: (a) frequent coordination meetings among the stakeholders, (b) involvement of the FHWA division office or other FHWA assistance, and (c) a committee established to oversee and contribute to effective emergency response initiatives. â¢ Many DOTs indicated state resources (staffing, funding, turnover), data, and technical exper- tise as common issues (limitations, constraints) in implementing a flood prediction model and a flood warning system. Reported challenges and weaknesses in implementing a successful flood monitoring system were state resources (staffing, funding, turnover), data coverage (e.g., lack of stream gages), and local resources (staffing, funding, turnover). Knowledge Gaps and Future Research On the basis of the work carried out in this synthesis, the following information gaps and future activities are suggested: â¢ Although hydrology and hydraulic modeling challenges differ depending on land cover and physiographic region, there is a need to improve real-time flood model predictions, especially for backwater flow conditions and other hydrologically complex areas (i.e., snowmelt flood- ing or king tides). â¢ The need for advancements in data collection (e.g., bridge scour) was a key issue for most of the states interviewed. There is a need to understand the required resolution of data needed (e.g., issues with the stream network without the monitoring gages or low-frequency monitoring) and data continuity (e.g., for identifying hydrodynamics). â¢ There is currently an inundation of the amount of data due to the current data revolution period. To be able to leverage information wealth, it is critical to integrate data across differ- ent data formats, types, resolutions, and qualities. Therefore, research is needed to address difficulties and challenges in facilitating database sharing and integration (e.g., incorporating disparate data types). There is also a need to share and incorporate heterogeneous data between agencies and states, as well as stakeholders. Spatial-temporal databases would better facilitate data sharing, modeling, and analysis of the flooding risks and impacts on the trans- portation infrastructure. â¢ Investigating methods are needed for further integration of developed BridgeWatch software into the state DOTâs real-time monitoring system while overcoming various issues associated with data format, type, resolution, and quality. Furthermore, an investigation is needed to
Conclusions and Knowledge Gaps 101Â Â determine an optimal warning-level setting for a range of scenarios to minimize false alarms, because the degree of false alarms varies according to local hydrology and hydraulics. â¢ Urbanization and land development result in more frequently observed intense runoff events. The highly dynamic nature of these areas makes flood prediction particularly chal- lenging. To better mitigate the impacts of intense runoff events, research is needed to better predict the downstream impacts of urbanization and land development.