All early flood warning systems (FEWS) work with gauges and communications systems to collect and distribute hydro-meteorological measurements in real-time. The objective is to allow the authorities to take action before the flood reaches critical places. The FEWS of the lower Salado River basin, Argentina, were established after the flood of Santa Fe city in 2003. Frequent loss of information due to communication problems with the repository site increases the operational vulnerability of the network. First, the document analyses the flood frequency of the region using known statistical distributions. Then, it offers a low-cost solution to the loss of information problem based on an interface that transmits in parallel the network data through an electronic bypass without interfering with the FEWS satellite communication system. The tests carried out along three stations show the interface proved efficient in transmitting data via WiFi or mobile communications in real-time. The results establish a one-to-one data correspondence when the satellite system and the redundant system are active. The interface is based on low-cost single-board computers and routers. The variety of commercial sensors tested makes the developed interface portable to similar situations, and the savings achieved – maintenance cost – are significant.