The seminar was very well organized. The class participants were eager to learn; and the material was appropriately presented with a lot of information. Jennifer Andy, Michael Baker Jr. Inc., Moon Township, PA

Storm sewer design requires an understanding of urban hydrology, surface flow hydraulics, inlet hydraulics and pipe flow hydraulics. It also usually requires an understanding of the computer software that is used for analysis. This seminar will provide instruction on how to go through the entire process of designing a storm sewer system. The course will be generally based on the current version of the EPA Storm Water Management Model (SWMM). It will also include other important analyses that are not included in SWMM.

SWMM is a rainfall-runoff computer model used for single event simulation of runoff quantity from primarily urban areas. It was originally developed by EPA in 1971 and is a windows-based public-domain program. The runoff component of SWMM operates on a collection of subcatchment areas that receive precipitation and generate runoff. The routing portion of SWMM transports this runoff through a system of pipes, channels, storage/treatment devices, pumps, and regulators. SWMM tracks the quantity of runoff generated within each subcatchment, and the flow rate and flow depth in each pipe and channel during a simulation period comprised of multiple time steps. There are a number of default values that are inherent in the use of the SWMM model and the reasons to use the default values, or change them, will be discussed. Assumptions inherent in the use of the SWMM model and limitations of the software will also be discussed, along with evaluation of the results. Use of this program will be accomplished through examples and class exercises.

In addition to instruction on the SWMM model, the seminar will include instruction on calculations for gutter flow and the capacity of inlets, including grates and curb openings. This aspect of storm sewer design is often overlooked and can result in a storm sewer system that does not have the intended capacity. It will also include information on the necessity for erosion protection at the outlet of storm sewers and provide guidance on design of this protection.

The basis for any rainfall-runoff model is good rainfall data. This course will discuss a variety of sources of rainfall data, including those available from the National Weather Service.

• Find out the most current information on available precipitation data from the National Weather Service and why it may not be very current or complete
• Learn the basic components of the EPA SWMM model and how to input data into the model
• Learn how to determine if a storm sewer trunk line is adequate
• Learn how to determine if a detention pond and associated outlet structure will reduce the peak flows as required
• Avoid errors in the use of the EPA SWMM model
• Learn why inlets can be one of the most significant components of a storm sewer system
• Learn why riprap or other erosion protection is often necessary at the outlet of a storm sewer system

At the conclusion of the course, you will be able to:

• Select appropriate rainfall values for use in software applications
• Develop appropriate subcatchment data for use in the EPA SWMM model
• Calculate the capacity of inlets in both on-grade and sag locations
• Evaluate the proposed storm sewer trunk line for adequate capacityAssessment of Learning Outcomes

Students' achievement of the learning outcomes will be assessed through problem-solving exercises and through hands-on training with the software.

Participants will receive a CD containing the EPA SWMM software. This is a hands-on computer workshop and participants MUST bring their own laptop computer.

This course is for those involved with the design of storm sewers, including design engineers, technicians, and regulatory officials. The course is technical in nature but the use of the SWMM model requires only basic computer skills.

Time:  8:30am 4:30pm 

DAY 1 

• Introduction and Welcome
• Rainfall Data Sources
• Rainfall input into SWMM  
• Subcatchment Data Input into SWMM  
• Storm Sewer Trunk Line Input into SWMM

DAY 2  

• Detention Pond Capacity and Structure Data Input into SWMM  
• Viewing and Analyzing Output Data from SWMM for Trunk Line Capacity
• Viewing and Analyzing Output Data from SWMM for Detention Pond and Outlet Structure Capacity
• Computing Inlet Capacity for Grates and Curb Openings
• Erosion Protection for Storm Drain Outlets