PROJECT FEATURE

RA led the City of Dayton Parallel Intercepting Sewer Project which includes over 22,000 lineal feet of intercepting sewer along the Great Miami River ranging in size from approximately 6’ x 6’ to over 6’ by 12’. The scope of work included environmental permitting, hydraulic modeling, survey and basemapping, design, risk analysis, utility coordination and cost estimating.  

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The survey included over 5,000 feet along the river including structure location and gps, topographic survey and critical depths in and around the Great Miami River.  RA also performed bathometric surveys at the siphon locations and at locations where the proposed new sewer encroaches on the river. 

 

The City of Dayton has selected a replacement strategy that accomplishes the replacement in four phases (A through D) along with the addition of multiple junction chambers.  Because Phase A was to begin the project, RA served as the lead in developing the initial alignment for the entire project, technical team coordination and development of the hydraulic grade line.  We utilized a risk mitigation-based framework to coordinate the team activity and solve potential issues that could impact the project.  The design team worked together to identify and rank the issues while the collective team experience was leveraged to plan and mitigate these issues.

 

The interceptor was designed as a gasketed box culvert with a low flow channel (chevron).  Using gaskets as the primary sealing measure for box sections is a relatively new concept in Ohio.  The boxes were designed for anti-floatation as the sewer is located in the river corridor and is at risk of floatation during high river conditions.  

 

Since the sewer parallels the existing interceptor, large junction chambers were used to equalize flows as well as provide locations where the flows could be diverted from one interceptor to the other when maintenance is required.  Design modifications to three siphons were also completed to re-align the flow into the new interceptor. 

 

In addition, RA designed over 1,600 LF of 36” PCCP water main that needed to be relocated to make room for the proposed intercepting sewer in the area.