A survey of flood warning sensor network operational and maintenance practices across the United States

Communities employ flood sensor networks to mitigate flood risks, enhance drainage infrastructure, and reduce associated fatalities. This study explores four primary research questions aimed at improving the understanding and effectiveness of flood sensor network operations managed by government entities. Specifically, it addresses: (i) the critical challenges these organizations face in managing and maintaining these networks, (ii) the impact of various communication protocols on network performance and reliability, (iii) the ways in which data from flood sensor networks can guide infrastructure improvement projects, and (iv) the variation in operational scale of flood sensor networks across different types of government organizations. We interviewed 18 government agencies via Microsoft Teams in the United States that own and operate flood sensor networks to gain insights into their daily operations. These agencies operate in a hierarchical structure, which can be categorized as functional or divisional. The factors influencing the operation of flood sensor networks emerged as organizational structure, equipment, data storage and management, personnel, scale of operation, and funding. Real-time monitoring and capital improvement projects were the predominant uses of sensor data. Amongst the interviewees, 53 % of the agencies actively issue local warnings through diverse media, 37 % provide technical expertise in decision-making during flood emergency operations. The versatility of sensor data is highlighted by its application in flood forecasting (32 %), traffic operations (32 %), and dam operations (26 %). As with most engineering operations, adequate funding and maintenance are necessary for sustainability. Data indicated that the sensor maintenance was performed by agency employees or hired consultants/contractors. Agencies using employees recorded monthly travel ranging between 75 and 1700 miles, with a median of 300 miles. Annual operational costs ranged between $55,000 to $1.5M USD, and annual maintenance costs between $25,000 to $602,000 USD. These sensor operations are funded from diverse sources, including taxes, service fees, bonds, and grants. This research, with its valuable insights into flood monitoring and management, plays a crucial role in informing future strategies for optimizing the effectiveness and reliability of flood sensor networks.