I&I Investigation and Reduction

City of Blytheville, Arkansas

Horner & Shifrin completed smoke testing and GIS mapping for the City's sanitary sewer system.


Pollution Management Inc. and the City of Blytheville, AR retained Horner & Shifrin to complete an extensive smoke testing of the entire sanitary sewer system including I&I investigation involving structure inspection, condition assessment, and video inspection of selected portions of the system. In addition, GIS asset collection and website deployment were included in the scope of work. H&S developed a secure web-based GIS application and database of system attributes (location, sizes, physical condition, etc.) and performed data migration of existing sewer system drawing files into the GIS system. The team conducted survey-grade GPS survey of 200+ structures including manholes, pump stations, air release valves, and valve vaults. Survey data was integrated into the GIS to create a District wide sewer map and integrated with online aerial data. H&S conducted approximately 200+ detailed manhole inspections utilizing NASSCO standards to collect physical dimensions, structural conditions, and sources of possible I/I. Mobile devices linked to the web-based GIS were used to collect all data, inspection notes, and photographs in real-time providing up to the minute data and status of structures. Utilization of real-time data allowed for additional coordination with PMI and City staff to coordinate additional efforts in the event of extreme I&I situations.

H&S conducted smoke testing on over 500,000 linear feet of gravity sewer lines. Public and private defects and possible I/I locations were documented and entered into the GIS database system. Mobile devices linked to the web-based GIS were used to collect location, data, and photographs of defects in real-time. Specific sewer reaches were identified, a sub-consultant CCTV crew gathered additional detail from visual pipe inspections and the CCTV inspection video and PDF reports were added to the web-based GIS to provide direct access for PMI and the City staff to the data.





Blytheville, Arkansas

Year Completed


Innovation. Agility.
Reliability. Horner & Shifrin.