§ Project · Town of St. Michaels, MD

Chester Park / North Street Drainage Improvements

Scope

Town-wide drainage analysis for a historic Eastern Shore community. Drone photogrammetry and LiDAR-derived terrain feed a 2D HEC-RAS model of the town drainage network — flood extents, velocities, and hydraulic bottlenecks mapped at neighborhood scale to surface solutions compatible with the historic streetscape.

Assignment. Chester Park and the North Street corridor are older, low-lying neighborhoods on flat clay soils with shallow groundwater, where undersized drainage leaves residents with recurring street and yard flooding after ordinary storms. Under a U.S. EPA Section 319(h) grant administered by the Center for Watershed Protection, AMP was retained to diagnose the drainage system town-wide and develop a program of voluntary private-property retrofits, conveyance improvements, and conservation landscaping.

Work performed. In a single mobilization AMP surveyed several hundred inlets, pipes, culverts, and outfalls with RTK GNSS — elevations, sizes, materials, photographs, and condition — and flew the neighborhood under Part 107 with RTK ground control. The resulting Civil 3D surface supports a town-wide HEC-RAS 2D model showing where water collects. From the model, AMP developed four town-scale alternatives — swales and green infrastructure, piped conveyance, a hybrid of the two, and full curb-and-gutter with stormwater management — plus retrofit concepts for individual private lots, including rain gardens and small-lot gravel wetlands suited to clay soils.

Deliverables to date. A structure inventory and browser dashboard, in use by the Town. Progress updates to the Town and the Center for Watershed Protection. A concept plan set covering the four alternatives. The community-meeting presentation. The concepts are the basis of the implementation-phase grant application now in preparation.

Dodson Avenue in one take · 46 sFrom the drone survey to the roadside rain garden and inlets in the Dodson Avenue right-of-way, in one continuous move. The closing scene is a concept visualization, not a final design.

Services delivered

Drone photogrammetry survey
LiDAR terrain model
2D HEC-RAS modeling of the town drainage network
Flood-extent, velocity, and bottleneck mapping at neighborhood scale
Phased improvement recommendations

Capture. Process. Analyze. Model.

Drone orthophoto of the Chester Park and North Street neighborhoods, St. Michaels — 01 · CapturePart 107 orthophoto with RTK ground control.

Oblique 3D point cloud of St. Michaels with ground points in yellow and contours in magenta — 02 · ProcessLow-pass surface points (yellow) and contours (magenta).

Elevation-shaded terrain surface of the St. Michaels study area — 03 · AnalyzeCivil 3D surface, usable across all design software.

HEC-RAS 2D maximum-depth map over the St. Michaels orthophoto, darker blue deeper — 04 · ModelHEC-RAS 2D depth; darker blue is deeper.

Chester Park / North Street, St. Michaels — existing conditions, 2026.

Practices modeled for the community meeting

A whole residential lot seen from above: a one-story house, a lawn with a small flowering rain garden beside the house, a sidewalk, and a curb inlet at the street — Backyard Rain Garden
A 15 x 10 ft rain garden about 13 ft from the house: 3 in mulch, 6 in planting media, 10 in No. 57 stone and a 4 in underdrain. Water ponds up to 6 in, then overflows through a grated outlet and a pipe to the curb inlet and the public storm drain.
Rain
Ponding
Soaks into the stone
Overflow grate
Public storm drain
Illustrative — not to scale. Design guide only; not a substitute for project-specific profiles and sections.

A whole residential lot seen from above: a one-story house, a lawn with a small planted gravel wetland and its grated outlet beside the house, a sidewalk, and a curb inlet at the street — Backyard Submerged Gravel Wetland
A 15 x 10 ft planted gravel wetland with no forebay. Inflow drops onto a stone strip, moves through stone that stays wet 4 in below the soil, and leaves over a J-hook inside a grated outlet, piped to the curb inlet and the public storm drain.
Inflow
Stone strip
Wet stone
J-hook outlet
Public storm drain
Illustrative — not to scale. Design guide only; not a substitute for project-specific profiles and sections.

A whole residential lot seen from above: a one-story house, a lawn with a shallow grass swale running from the downspout to a curb cut, and the street, with no sidewalk — Grass Swale to a Curb Cut
A 6 ft wide, 6 in deep grass swale from the downspout across the yard to a curb cut, where a short concrete apron carries the water through the grass strip and into the gutter. Shown without a sidewalk; a sidewalk crossing would need a covered chase under the walk.
Downspout
Grass swale
Curb cut
Gutter
Illustrative — not to scale. Design guide only; not a substitute for project-specific profiles and sections.

A whole residential lot seen from above: a one-story house, a lawn with a square grated yard inlet set flush in the grass, a sidewalk, and a curb inlet at the street — Yard Inlet
A 3 x 3 ft precast yard inlet with a cast-iron grate, set flush in a shallow dish in the lawn. Roof runoff leaves the downspout onto a splash block, sheets across the lawn with the yard runoff, and ponds briefly at the grate before dropping in. Gutter flow enters the public curb inlet.
Roof and downspout
Splash block
Sheet flow across the lawn
Yard inlet
Public storm drain
Illustrative — not to scale. Design guide only; not a substitute for project-specific profiles and sections.

Working under a similar jurisdictional review?

Tell us where the site sits — response within two business days from the Professional Engineer of record.

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PE · MD #49353 · VA #66472 · DE #28440 · NV #027358