System Wide Model


Hamilton County approved a new “rule” related to hydraulic modeling of MSD’s sewer system.

View MSD's comments on the proposed rule.

View comments from national modeling experts on the proposed rule.

View the independent review of MSD's model.

















In 2003, MSD completed a three-year project to develop a hydraulic model of the sewer system. One of the largest models constructed at the time, the System Wide Model provides MSD with an extraordinary tool to evaluate existing and projected conditions within the sewer collection system. The model was vetted by the U.S. EPA, Ohio EPA and Ohio River Valley Water Sanitation Commission (ORSANCO).

An independent review of the model, conducted in February 2016 by an internationally recognized expert, found that MSD's model still exceeds applicable industry standards.

What is a Hydraulic Model?

A hydraulic model is a computer-generated replication of the sewer system that can simulate the movement of flow through a piped network. Hydraulic models are a fundamental tool used in the planning and designing of sewer projects and to measure compliance with MSD's federal Consent Decree.

The image below is an example of the output from the flow simulation. Within MSD's service area, sanitary sewers 12" and larger, and combined sewers, 18" and larger are included in the System Wide Model.

Profile of flow model using DHI's Mike SWMM

What are the Benefits?

Overloaded pipes can create a myriad of problems. Sewer backups and overflows present some of the more severe problems attributed to overloaded pipes. The causes are often extremely complex in nature and therefore difficult to both understand and resolve. The System-Wide Model provides the means to view flow levels and velocities, and surcharge conditions in many areas of the sewer network all at the same time. By making changes to the computerized model, "what if” scenarios are developed to simulate proposed system modifications prior to construction. In addition to determing the impact to the immediate area, these simulations allow for the evaluation of downstream impacts to determine the best holistic design solution.

The benefits of the model do not stop there. As development continues at a rapid pace throughout many parts of Hamilton County, the need increases to extend the sewer system. Well-informed decisions can be made when determining the impact of the added flow to the downstream system and to the receiving treatment plants.

Contact Us

Report a Sewer Backup:
(513) 352-4900 24/7 or online

Customer Call Center:
(513) 352-4900 24/7

Project Customer Service:
(513) 557-3594

Development Services:
(513) 244-1330

Media Inquiries:
(513) 557-7095


MSD Mailing Address:
1600 Gest St.
Cincinnati, Ohio 45204

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