Specialty

Grading, drainage and floodplain

Water decides whether the rest of a site works. We do the grading, the storm system, and the modeling that has to stand behind them, including the floodplain work that usually gets subcontracted out.

What the work covers

Design and the analysis that supports it. One firm, so the grading plan and the model it was checked against agree with each other.

A detention basin shaped and graded, with turf reinforcement matting laid over the flow path and an outlet structure in place.
Detention basin, shaped and matted, turf reinforcement over the flow path. Sized to a release rate, not to whatever fit.

Grading and earthwork

  • Grading and drainage plans
  • Cut and fill balance, earthwork quantities
  • Spot elevations, slopes and accessible routes
  • Erosion and sediment control, SWPPP
  • Land disturbance permit support

Storm sewer and detention

  • Inlet sizing and spacing, gutter spread
  • Pipe network design and hydraulic grade line
  • Detention and retention sized to the required release rate
  • Outlet structures and emergency spillways
  • Water quality volume and BMP selection

Hydrology and hydraulics

  • Rational method, NRCS TR-55 and TR-20
  • HEC-HMS watershed models
  • HEC-RAS steady and unsteady flow
  • Culvert and bridge hydraulics
  • Channel design, riprap and scour protection

Floodplain and FEMA

  • No-rise certification for work in a regulatory floodway
  • CLOMR before construction, LOMR after it
  • LOMR-F where the building pad is raised on fill
  • Base flood elevation determination
  • Floodplain development permit support

When people call us

In plain terms, the situations this work exists for.

  • The city will not approve the plan until the site detains its own runoff.
  • The parcel is in Zone AE, or a regulatory floodway crosses it.
  • You want to build inside the floodway and need a no-rise before anyone will review the plans.
  • Water leaves your site onto a neighbor, or arrives from theirs.
  • A lender or insurer wants the structure out of the flood zone.
  • A subdivision needs a drainage report the county will actually accept.
  • An existing basin, culvert or channel no longer carries what it was built for.

What you receive

  • Sealed grading plan, and storm sewer plan and profile
  • Drainage report carrying the calculations behind the plan
  • Model files, so the reviewing agency can check the work rather than trust it
  • FEMA submittal package where the project requires one

Standards Storm design follows the Kansas City Metro APWA 5600 criteria where the jurisdiction has adopted them, land disturbance follows the Missouri Department of Natural Resources permit, and anything touching a mapped floodplain follows the NFIP standards FEMA applies to it.