Using Risk-Based GIS Modeling Software to Optimize Sewer Renewal Planning
Broomfield, Colorado, USA, December 4, 2009
Rapid population growth and the deterioration of aging infrastructures, some over a century old, are seriously overtaxing sewer systems worldwide. Growing communities continue to expand their sewer systems outward. Renewed interest in urban development and gradual land use changes have resulted in a drastic increase in loads on an older infrastructure that was not designed to sustain these additional flows. Increasingly, these stresses are causing sewer surcharges, backups and failures that directly impact human health and the environment while increasing agency liabilities.
The usual localized, “find and fix as you go” approach is not cost-effective or reliable, and may not even improve overall collection system performance. For alterations and improvements to these systems to be effective and economical, good engineering decisions based on sound analysis procedures will be required. There are guidelines and best practices manuals for sewer renewal planning (e.g., WEF, ASCE, WRc) but without automated software support, their practical application poses massive data processing and management challenges. As a result, sewer renewal planning remains a complex, inexact manual and subjective process.
Recent technological advances in GIS, dynamic modeling and high resolution closed-circuit television (CCTV), allow wastewater utilities to better predict when a sewer pipe is going to fail and quantitatively assess and evaluate the costs and benefits of alternative renewal options for optimal effectiveness. MWH Soft’s CapPlan seamlessly integrates the industry-standard USEPA SWW5 hydraulic sewer network simulator with ESRI ArcGIS geospatial technology and sophisticated decision tree algorithms. The product gives wastewater engineers new power to efficiently process sewer inspection and modeling data, accurately identify pipes with the greatest risk of hydraulic deficiencies and/or structural failure, generate a prioritized list of all pipes requiring rehabilitation, and propose appropriate rehabilitation methods or replacement.