DESIGN IN CONTEXT

Hyperlocal Solutions
Underground flood capture

Buried storage, treatment and deep wells beneath an open public ground.

Below the surface

Two 4,000 m³ storage fields buffer the storm. Treatment and four deep wells release treated water to the receiving aquifer.

8,000 m³main storage fields

50 L/streatment design rate

Engineering cutaway of the proposed underground storage and treatment

Engineering cutaway · proposed underground works

PROPOSED WORKS · MODELLED SCENARIO

MODELLED STORM

How the storm develops

Watch water accumulate across the local study area while the proposed system captures flows from the ground and nearby streets.

Rain has stopped107 mm over the first 3 hours

Time since rainfall began3 h 15 min

Cumulative water captured7,366 m³

Modelled depths at five-minute intervals. Brown outline: proposed site boundary; grey shapes: obstacles. Study assumptions: Technical notes.

0.05–0.15 0.15–0.30 0.30–0.60 0.60–1.00 ≥1.00 m

Saved surface-water depth at 3 hours 15 minutes with the proposed works

WITH PROPOSED WORKS · INSTANTANEOUS DEPTH

N ↑

600 × 600 m · 1 m source grid · Esri, Vantor, Earthstar Geographics and GIS User Community

THE SAME STORM, WITH AND WITHOUT WORKS

Flooding with and without the works

107 mm in 3 hours
600 × 600 m study area

Modelled flooding without works — Peak depth · pale blue 0.15–0.30 m · blue 0.30–0.60 m · dark blue 0.60–1.00 m · navy ≥1.00 m

Modelled flooding with proposed works — Same depth colours · depths below 0.15 m hidden · peak-depth maps, not end-time snapshots

STORAGE HANDLES THE BURST. WELLS WORK MORE SLOWLY.

Where the captured water goes

Modelled results · first 3 h 15 min
Proposed system

01

Capture

7,366 m³

From 7 pond grates
and 7 street pits

→

02

Store

7,022 m³

Held in the plant
at the selected time

→

03

Treat

364 m³

Passed through
the filter

→

04

Feed the aquifer

330 m³

Entered the modelled
aquifer screens

These are different stages of the same water. Storage is an inventory at the selected time; capture, treatment and screen transfer are cumulative flows. They must not be added together.

76% of plant storage

Captured water through the storm

3 h 15 min · 7,366 m³

Rain beginsRain ends at 3 h3 h 15 min

THE COMPLETED SURFACE

Proposed surface use

Buried units preserve space above. Inspection covers, servicing routes and load limits remain part of the design.

Proposed layout. Access zones must remain clear; areas above structures have load limits. See Technical notes.

Proposed completed surface over the underground works, with source-date site imagery

Proposed surface · site imagery, flush inspection covers and edge facilities

70%of the ground classed
as fully usable open space