Integrated Web-Based Automated Radar Acquisition, Flow Monitoring and Real-time Hydraulic and Hydrologic Modeling for Flow and Flood Forecasting in Toronto, Ontario and Erie County, New York

The paper describes the development of a web-based, automated radar and flow data acquisition system based on the real-time PCSWMM.NET platform. Two applications are presented:

1. The Erie County Department of Environment and Planning/Division of Sewerage Management (DSM), initiated development of a web-based tool to significantly improve flow forecasting. This web-based tool, known as the Real Time Flow Monitoring System and Hydraulic Model, allows County staff to obtain up-to-the-minute status of sanitary sewer flows and operation within the District 6 trunk collection system. In addition, it allows modeling of what if scenarios regarding new flows, capital improvements and modifying operations rules. Ultimately, the DSM anticipates expanding this system during the next three years to incorporate all of the County’s sewer districts, which serve more than 300,000 customers and contain 1,000 mi. (1,600 km) of sewers, 87 pumping stations, seven treatment facilities, and five overflow retention facilities.
2. The Toronto and Region Conservation Authority (TRCA) with Computational Hydraulics Int. (CHI) developed computer tools for automating NEXRAD radar data acquisition and processing the data to provide both real-time and historical rain-gage calibrated radar-rainfall data for flood forecasting for the TRCA watersheds and surrounding area.

The automated web-based applications accomplished the following tasks:

(i) Acquire Buffalo (KBUF) public NEXRAD data on a continuing near-real time basis. Data acquisition may be either automatic or initiated manually.

(ii) Transform radar intensity readings for each sampling period into rainfall depths over subwatersheds or catchments. The application takes as input any GIS shapefile containing watersheds of any configuration, and generates rainfall depths over each subwatershed/catchment.

(iii) Export the list of rainfall depths on both a sampling interval basis and a continuous basis, where each additional sample is appended to a record of the rainfall depths previously recorded (creating a real-time hyetograph).

(iv) Simply calibrate to rain gauge data by inclusion of an offset or ratio modification factor to be applied to radar-derived rainfall depths.
(v) Allow simplified operation wherein a single control (one click operation) is used to initiate data acquisition, read in a pre-selected GIS shapefile containing subwatershed and catchment information, and generate the output file in a format amenable to further use by hydrologic models and GIS visualization tools, as well as the standard PCSWMM rainfall input format.

(vi) Operate on archived NEXRAD data spanning a user-selected time frame, and after processing return a rainfall intensity time series for the subject time frame.

The customized PCSWMM.NET software provides automated real-time storm tracking and forecasting, and leveraging of the additional existing data analysis, GIS, and hydrologic/hydraulic modelling capabilities.

Presented herein are the key elements involved in developing the web-based model, how these elements were integrated, and examples of how this system can be used to optimize drainage and collection system operations and improvements. This paper details the approach and outlines the steps involved in using the developed methodology for surface flood forecasting in urban areas.