Trenchless technology has opened up a world of opportunities for cost-effective wastewater infrastructure rehabilitation and life extension for the City of Nampa, Idaho.
By being open-minded and willing to consider new technologies, the city can effectively maintain its system on time and on budget and add more projects to its capital improvement program than it could complete using dig-and-replace methods.
“Once we discovered trenchless technology, we couldn’t help but realize and recognize the cost savings and the time savings,” says Michael Creager, collection system technician II. “That’s not to mention the reduction in inconvenience to neighborhood residents. All in all, it’s a phenomenal deal compared to open-trench.”
Consistent maintenance
Nampa, population 82,000 (industrial customers create a population equivalent of 225,000), lies in a high desert region. Recent years have brought an inflow of new residents, expanding the wastewater collection system to EPA Class 4 level with more than 300 miles of sewer main, 12 lift stations and 6,000 manholes. Most mains are concrete, 6 to 42 inches.
Nampa has an established preventive maintenance program of cleaning and CCTV inspection, using an in-house crew with two Model 2100 combination trucks by Vactor Manufacturing, and two inspection rigs from CUES Inc. The inspection and cleaning crews work together on a two-and-a-half-year cycle through the system which is divided into sections.
To stay focused and organized, Nampa uses OASIS software by Hydrologics Inc. along with its ESRI GIS system to track and analyze cleaning and inspection. Unlike many cities that set up monthly or yearly goals, Nampa sets daily goals, scheduling some mainline cleaning, inspection and lift station maintenance tasks every day.
Although several of the city’s CCTV operators are certified in the NASSCO Pipeline Assessment and Certification Program (PACP) coding system, the city still uses its own coding on the grounds because it is less time-consuming for operators and does not compromise data quality.
Since some parts of the collection system are more than 100 years old, maintenance could only carry the system so far, and many components were nearing the end of their life cycles. So the hunt began for cost-effective rehabilitation methods that would offer the best return on investment and the least disruption to the community.
