What this is
The storm sewer network — the pipes, channels, flumes, and inlets that carry rainwater from streets and neighborhoods out of the city. Every line with its material, size, slope, and elevation.
Why it matters to you
Storm sewers are why your street doesn’t become a river in a downpour. When they fail, you get flooding — and the flood doesn’t care about property lines. This dataset is how engineers find where the weak points are: an undersized pipe, a too-gentle slope, a line in the wrong material. For homeowners in flood-prone areas, knowing where the storm infrastructure is (and reading its size and slope) explains a lot about why water behaves the way it does on your street.
How to read this data
- Material — what the pipe is made of. Old materials corrode faster; this field is a first clue to a line’s age and health.
- Nominal Size — the pipe’s diameter. This is the capacity number: bigger pipes move more water.
- Slope — the gradient as a percentage. Water flows because of slope — too little and the pipe silts up, too much and it scours.
- Upstream / Downstream Invert — the elevation of the pipe at each end. Compare them and you get the drop that drives the flow.
Try it yourself
Find the storm line nearest your home and note its size and slope. Next heavy rain, watch where the water actually goes — then see if your observations match what the data says the system should do. That’s field-checking, and it’s how the pros do it.