Visiting certain Roman Empire sites is more than revealing, it's eye opening. For example, their sewage system engineering set precedent for today's standards. They learned just one rate of slope provided best flushing action to not pool or 'outrun' solid wastes.
https://www.google.com/search?client...te+of+drainage

Certain revisionists might dispute findings, but few are plumbers, pipe-fitters, or other qualified infrastructure personnel.