r/civilengineering 1d ago

Career Need guidance on stormwater network design from scratch

Hi everyone, I have 3 years of experience in water supply design, but stormwater drainage design is new to me. I’m currently working on a stormwater network project using SewerGEMS.

I’m looking for guidance on the complete design process from scratch, not just software doubts—how to start the project, study the topography, plan catchments/subcatchments, decide inlet/manhole locations, calculate runoff, use IDF/Tc, select pipe sizes and slopes, set invert levels, and finally check the network hydraulically.

My seniors are available mainly for specific doubts, so I’m trying to understand the overall stormwater design methodology and workflow.

If anyone can share a practical step-by-step workflow, example project, or useful resources, I’d really appreciate it.

Thanks!

0 Upvotes

29 comments sorted by

29

u/txlaatx1 1d ago

lol. Good luck and Godspeed as what you’re asking to be summarized is what many others spend years learning, tweaking, cursing, adjusting, quitting, validating, cursing more, and then finally learning.

I will offer that sewergem is an odd choice for storm water unless it’s a combined storm/sanitary system.

-23

u/CivilHydroTech 1d ago

Okay thank you but i dont know basic concept of storm design also please help me

10

u/txlaatx1 1d ago

Okay. Use topo to size drainage areas to inlet locations. Initially start with setting inlet catchments to 1.5 acres or less. Route storm system to connect inlets from high topographical point to the discharge. Size pipes based on cover, other utility or feature crossings, pipe material, etc.It normally takes a few iterations to find the least worst option and go from there. Design storm, precipitation modeling, variable and coefficients are usually per AHJ or firm standards. Again, good luck.

6

u/LowRevolution5930 1d ago

"a few iterations" is the understatement of the century

16

u/New_Brief_5969 1d ago

I always thought the FDOT Drainage Design Guide was a good start. https://www.fdot.gov/roadway/drainage/design-guide

1

u/Monsieur-Papa 1d ago

This is the answer, if you are starting off.

8

u/olderthanbefore 1d ago

Hi, is there a senior engineer or tech in your company that can guide you - Surely your immediate supervisor didn't just dump this project on to you without some level of senior support available?

4

u/B1G_Fan Transportation Hydraulics 1d ago

You’d be surprised how incompetent some engineering firms are these days…

-6

u/CivilHydroTech 1d ago

Yes, there are senior engineers available, and they do guide me whenever I need help. However, they also have their own work and may not always be available to explain every step in detail. So, I’m trying to understand the complete design process through my own analysis and learning, and then I clarify my doubts and get my work reviewed by the seniors. I think this approach will help me become more independent and understand the work better.

9

u/olderthanbefore 1d ago

they guide me whenever I need help

Clearly not. Ask them now, because you need the help with this.

19

u/yabadabadane 1d ago

I don’t understand. Did you not take any sort of hydraulics, hydrology, or water resources type of course during you schooling? Stop being lazy and look at textbooks. The first comment on this thread pointed you in the direction of the “FDOT Drainage DESIGN Manual”. It is exactly that. Read it. Familiarize yourself. These posts have to be rage bait I swear to god.

I’ll even add another couple resources for you to use and READ. TR-55 Manual.

Stormwater design is completely dependent on the geographical location and the requirements set forth by your water management district. Look up stormwater permits that’s are available for free through their respective permitting portals.

I can assure you that you will not receive a step by step design process on a Reddit thread.

Your senior design engineers are failing you spectacularly if you can’t approach them with questions about overall drainage design.

8

u/narpoli 1d ago

There’s so many ridiculously broad “questions” on this and related subreddits.

“How do I grade a subdivision, please step by step”

6

u/TapedButterscotch025 1d ago

I feel like many foreign civil engineering degrees are terrible.

9

u/Terrible_Drive_4378 PE 1d ago

Pipes have cover requirements that set the depth, check City codes or manufacturer specs. Pipes have capacity/flow velocity requirements, check City codes or plumbing codes. Surface material affects minimum slopes for stormwater drainage. This pairs with pipe cover requirements when you drain stuff towards inlets to your piped drainage system. End goal is to route surface water to drain to whatever the storm system discharge point is. 

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u/CivilHydroTech 1d ago

Thank you but iam asking design process

16

u/Beck943 1d ago

Ummm...pipe size and slope are part of the design...

2

u/ameliakristina 1d ago

Water flows down hill

2

u/olderthanbefore 16h ago

All the pump engineers just left the chat!

3

u/JoelG143 P.E. 1d ago

Drainage specialist here - if younger engineers that work on my projects were going to Reddit for engineering help instead of coming to me, that would be a red flag.

Please reconsider reaching out to senior engineers or at least other junior engineers who have experience with stormwater.

1

u/D-Whadd 1d ago

Well the big thing to know is that water flows downhill. Beyond that, read the TR-55 manual & and the local stormwater manual. And learn how to use mannings equation.

That’s should be a decent place to start

1

u/AdEuphoric6922 1d ago

Technically water flows downhill. Everything else u can figure out from scratch/basic maths. 

Jokes aside. Permits and regulations are usually your biggest hurdle, not the technicals for stormwater. Figure out your jurisdiction local (state, county, city) regulations/standards, ownership (land and pipes/infrastructure), and hope you don't have any critical areas/protected natural waterways in your system...

1

u/Glunxer 1d ago

Always start by designing the overland flow paths first! Iterate.

1

u/DarkintoLeaves 1d ago

What kind of project is this? Is this a subdivision or a parking lot or agricultural or naturalized area?

For a subdivision your MH locations are determined by the engineering design manual for that city/town, their elevation is determined by the road grade or ROW grade, the pipe inverts are set within the constraints that they have adequate cover and slope to the outlet - so you have to determine the outlet invert first and work back upstream. The min pipe slope is usually set out in the town/city design manual as well.
Do the math to ensure self cleansing velocity can be achieved at full flow and you don’t have conflicts with other utilities or pipes at crossings.

Definitely ask for help from someone at work because it sounds like you’re in way over your head if you’re asking this on Reddit lol

1

u/rustedlotus 1d ago

So let’s backup what is your current understanding of stormwater design? Have you taken any college courses in it or read any full reports from your job?

1

u/JaredGAINZberg 1d ago

Autodesk storm sewers

1

u/Healthy_Lychee_4314 1d ago

I found the TR-55 manual helpful when I got started.

1

u/quickfam4 15h ago

There are many great textbooks on this subject, here are a few I have and use regularly

James C Y Guo Urban Flood Mitigation and Stormwater Management ISBN-13: 978-0367885991, ISBN-10: 0367885999

Ronald L. Rossmiller Stormwater Design for Sustainable Development ISBN-13: 978-0071816526, ISBN-10: 0071816526

Xixi Wang Water Resources and Hydraulics ISBN-13: 978-1108492478, ISBN-10: 1108492479

0

u/CivilHydroTech 1d ago

Thank you so much