CAPE Members’ Work Recording Rainfall

What if the rain fell and there was nobody to record it? Few people likely ever think about the importance of recording rainfall and maintaining records, but for the CAPE members in the Records Unit of Water Resources Division, it’s their job. Across Los Angeles County, a network of 274 rain gauges exists, 126 of which are automated ALERT (Automatic Local Evaluation in Real Time) types and 148 of which are manually read by local agencies and citizen volunteers. In the case of the automated stations, the gauges report in real time and the manual stations are recorded daily and reported on a monthly basis. Maintaining this data is something that the County of Los Angeles has been doing since the 1900s and it provides a vital service on many fronts. First, the data is shared with the hydrology section which uses it to develop hydrologic standards and procedures used by County engineers for the design of the flood control drainage system. Rodney Brown, a CAPE member from the Records Unit explains, “If the storm drains are too small, it presents a safety hazard in that the drain could surcharge and flood peoples’ homes. If the storm drain is too large, taxpayer money is wasted in designing and building something that is larger than needed.” Another application of the precipitation data is in storm water recapture. By posting the rainfall on the internet, County employees at the spreading grounds can be prepared to capture any storm water that is released from upstream dams so that it can be conserved instead of wasted; an important ability in a drought stricken region. Finally, rainfall data saves lives. In coordination with the National Oceanic and Atmospheric Administration, the ALERT system is a critical decision tool that aids in the issuance of flash flood warnings. Taking all this into account, it’s safe to say that it’s a good thing County engineering technicians are there to record the rain when it falls.