Establishing a dynamic model of most of Cincinnati's
collection system was an ambitious project.
Yet the forward-looking Metropolitan Sewer District of
Greater Cincinnati (MSDGC) saw this system wide model as the tool that would support
improved sewer system management, including sanitary sewer overflow (SSO) and
combined sewer overflow (CSO) control, planning, and operations.
After more than two years, a diligent team relying on
hundreds of flowmeters is ready to roll out this model, one of the largest of
its kind.
Is the Site Right?
The MSDGC teamed with lead consultant CDM, engineering firm
R.D. Zande and Associates, and other project partners. With 2,000 miles of
MSDGC sewer pipeline to represent and a budget to meet, "our challenge was
to select sites that were consistently accessible, economical to monitor,
yielded 'high-quality' velocity and level data during both dry and wet weather,
and met modeling objectives," explained John Barton, Zande project leader.
For each half of the system, the team identified more than
1,500 representative sites, eliminated nearly half of those as poor monitoring
locations, and finally selected 160 manholes for data collection.
System wide, the site-appraisal process took a full
one-third of the $9 million data collection and evaluation budget.
"Critical site evaluation may not guarantee success, but there's no chance
for success without it," cautioned Barton.
Monitoring Data Poured In
With four field crews monitoring those 160 sites, the
project team needed to standardize instruments and chose American Sigma
flowmeters from Hach Company. These meters utilize submerged depth/velocity
sensors but offer the flexibility of ultrasonic level detection in the few
situations where levels rise above the limits of the submerged pressure
transducer.
Barton further explained that the software inherent in these
meters was easy for them to use. "The crews needed little training to
download meter data to their laptops. The built-in data handling software
actually made it hard to lose data."
The team successfully collected velocity and level
measurements every five minutes from nearly all sites, from January through
June 2001. The entire study was repeated in a similar manner, the following
year, for the second half of the system. MSDGC anticipates finalizing the model
in April 2003.
Proactive Management the Goal
MSDGC project leader Steve Donovan reflected, "The data
collected not only helped identify constraint areas but also allowed us to
calibrate model response to various situations so we can address 'what if'
scenarios. This proactive approach will let us meet higher customer service
expectations and hit the ground running with Best Management Practices in place
when the federal capacity, management, operations, and maintenance (CMOM)
guidelines become regulation."
For more on the MSDGC system wide model, visit
www.msdgc.org/swm.
For additional information, phone 800-635-4567.
