Nogales, Sonora Flood Warning and Modeling Network

The Nogales Early Warning Flood Hazard project has the objective of installing a weather monitoring and stream gage network in critical Mexican headwaters upstream from the U.S. border city of Nogales, Arizona, and to establish a cooperative program between borderlands emergency personnel and managers in the two sister cities that will enable them to jointly monitor, track, and develop strategies for mitigation of floods and associated damage caused by flooding. The United States Geological Survey (USGS) office in Tucson, Arizona, is the lead agency for the project and this work is being done through the United States Consulate office, Nogales, Sonora. Funding and logistical support will be provided by USNORTHCOM Overseas Humanitarian Disaster Assistance and Civic Aid.

For a number of years there have been multiple flooding incidents that have occurred along Nogales Wash which flows from Nogales, Sonora, Mexico into Nogales, Arizona, otherwise known as the Ambos Nogales area. Most recently, in 2007 and 2008, flooding caused extensive damage to downtown businesses in Ambos Nogales. High flows in Nogales Wash damaged the concrete panels lining the channel, and threatened the underlying International Outfall Interceptor (IOI), a large sewer line originating in Mexico that delivers 9.9 million gallons of raw sewage per day to the Nogales International Wastewater Treatment Plant (NIWTP). With the assistance of the US Consulate in Nogales, Sonora and cooperating agencies in the city of Nogales, Arizona, monitoring equipment was shipped across the border and the installation of the system was successfully completed in August 2012 during the waning stages of the summer Monsoon. The National Weather Service (NWS) Weather Forecast Office in Tucson installed equipment to receive the network data with assistance from several cooperators, including the USGS. This network provides the NWS with real-time gage data for an area with limited radar coverage. The Early Warning Flood Hazard System consists of NOAA-specified weather stations, USGS stream gages, and Contrail® Base Station linked with radio and satellite telemetry. An additional secondary independent weather station array using Davis Instruments and Weatherlink software was also initiated. The system is currently delivering data to the internet. The website is planned to be available to the public in the coming months.

The Nogales, Sonora ALERT (Automated Local Evaluation in Real Time) system that is being developed is primarily a real-time flood-threat detection system with the secondary utility of collecting data of environmental, meteorological, and hydrologic value. Technology transfer for this system will include training to install, maintain, and operate the flood detection system itself as well as training to develop the full flood threat detection and forecasting potential out of the project and leverage the secondary environmental, meteorological and hydrologic data for hydro-meteorological modeling and analyses. The final phase of the project will be to support various models, KINEROS2, HEC RAS, WMS (Aquaveo), running in real-time mode at the emergency response facility in Nogales, Sonora. This effort would provide the means to allow forecasters to pinpoint (i.e. provide site specific information) which basins are receiving the heaviest rainfall and determine the timing and magnitude of the predicted event downstream (at the Nogales downtown area, Sonora and in Nogales, Arizona)--in real time. More advanced future applications include using the network to inform coupled surface-water-groundwater models to refine flood forecasting through improved understanding of groundwater-surface-water interactions, to predict movement of contaminants, and to understand the effects of urbanization and flood retention structures on aquifer recharge.