Development of Rdii Hydrographs and Their Rainfall Relationships Using Scada

Abstract

The Miami-Dade Water and Sewer Department (MDWASD) is the 5 th largest water and sewer utility in the United States. MDWASD, inclusive of the municipalities it serves, has a very complex wastewater collection and transmission system consisting of over 2000 pump stations, 1000 miles of force mains, and 4000 miles of gravity sewers. A Peak Flow Management Study, which includes the construction of a hydraulic computer model of this system, was mandated as part of an EPA settlement agreement. As part of this agreement, MDWASD was required to install supervisory Control and Data Acquisition (SCADA) telemetry on all of the pump stations it owns. Presently, SCADA is installed on 85% of the stations. MDWASD has recognized the benefit of SCADA as a long-term, data collection, system. This data proved useful when MDWASD reviewed major storm events during 1998 and 1999 to quantify rainfall dependent infiltration and inflow (RDII) and to determine the relationship between rainfall and RDII. This paper presents the MS Access application developed to quantify the individual pump station's RDII response. Spreadsheet applications were first employed but the volume of data overwhelmed the spreadsheet capacity. MS Access was chosen because of its availability and ease of use. Novice MS Access users can implement this application and customize it at will. Once RDII is quantified in a digital database format, a myriad of relationships can be developed. The biggest advantage to this application to the engineering community is that the RDII can be quantified, related to rainfall, and documented for pre-and post-rehabilitation analyses.