Ask a water-resources engineer where the time goes on a municipal drainage study and the answer is rarely the hydrology. The models are fine. HydroCAD does what HydroCAD does. The hours disappear in the assembly line that runs before the model opens and in the reconciliation that runs after it closes. Six friction points come up over and over in conversations with stormwater engineers.
1. Pulling site data from three federal sources
Soils from the NRCS Web Soil Survey. Land cover from the National Land Cover Database. Elevation from the 3D Elevation Program. Three portals, three formats, three exports that have to be clipped to the same subarea polygons before anything can be computed. None of it is engineering. All of it is hours.
2. Computing weighted curve numbers by hand
Once the soils and land cover are assembled, someone builds the composite curve number for each subarea: intersect the polygons, weight by area, document the assumptions. It is arithmetic with a paper trail, done in a spreadsheet, and redone every time a delineation moves.
3. Translating the ordinance into design criteria
The jurisdiction’s stormwater ordinance is a PDF. The design-storm recurrence intervals, water-quality volume formulas, detention rules, and BMP siting constraints are in there somewhere, spread across sections that were amended at different times. Someone reads the whole thing and builds the criteria table, and someone else later hand-checks the worksheet against it.
4. Reconciling Civil 3D against the hydraulic model
The pipe network exists twice: once in Civil 3D, once in SewerGEMS. Inverts, rims, diameters, and pipe types drift between the two as the design iterates. Finding the mismatches means comparing exports invert by invert, and a missed mismatch surfaces at the worst possible time, in review.
5. Building the modeling worksheet
The curve numbers, times of concentration, and design storms have to land in whatever format the modeling tool imports. Reformatting a spreadsheet so software will accept it is nobody’s idea of engineering, and it is on the critical path of every study.
6. The hand-check at the end
After all of it, a licensed engineer checks the assembled inputs against the ordinance and against the source data, because their seal is on the result. That check is the one step that should never be automated away. The problem is that everything upstream of it arrives messy, so the check takes longer than it should.
The pattern
Five of the six are clerical. One is judgment. A drainage-study workflow that automates the assembly and leaves the judgment where it belongs gives the engineer a draft to review in minutes instead of a pile to build in hours. That is the design principle behind the stormwater workbench prototype: every value cited to its source or flagged for review, nothing under a seal without independent engineering review.
If your team loses afternoons to steps 1 through 5, the fastest way to find out whether they are automatable in your shop is a 30-minute scoping call. The intake is at vernonmcintosh.com/start.