Track: Water Distribution, Wastewater, Sewer
Rainfall Quantity Analysis from a Watershed Perspective: Using the Virtual Rain Gauge
Jesse M. DayRichard Walker , Kathleen Leo, P.E., Rizwan Hamid, E.I.
As required by an EPA Consent Decree, the Miami-Dade Water and Sewer Department (MDWASD) has implemented a hydraulic computer model to reduce sanitary sewer overflows. MDWASD operates more than 900 sewer pump stations and has a total treatment capacity of 317 million gallons per day at its three wastewater treatment plants. In order to quantify the impact of major rainfall events, MDWASD is using NEXrad technology to estimate rainfall. The Virtual Rain Gauge (VRG) by WSI uses filtered satellite NEXrad imagery to estimate the amount of rainfall within a 2 x 2 kilometer area. A grid system GIS coverage was established for MDWASD that yielded 256 "virtual" rain gauges. The information from the VRG is updated every fifteen minutes and downloaded to a database. The VRG grid is "joined" with the rainfall database, which allows quantitative impact analysis of individual rain events for the entire system or specific regions within the system. With the information provided by this analysis, the accuracy of total quantities required to be transmitted to the wastewater treatment plants is greatly improved, and operational considerations can be planned to eliminate sanitary sewer overflows.
Jesse M. Day
Post, Buckley, Schuh and Jernigan, Inc.
2001 N.W. 107th Avenue
Miami, FL 33172-2507
USA
Telephone: (305) 592-7275 ext. 505
Fax: (305) 599-0448
E-mail: 11729@pbsj.com