Designing Ponds in Allsite (Level AI)

Ponds are used in Allsite to provide stormwater detention and storage within your site model. Once drawn, Level AI automatically excavates (“digs out”) the pond to meet your specified volume, depth, invert, and side slope constraints, while balancing the overall site grading.

You create ponds from:

Drainage → Pond

This article explains:

How to draw a pond
All pond settings (as shown in Extended Data)
Global pond defaults (Web Settings)
How Level AI excavates and sizes the pond

Drawing a Pond

Select Drainage → Pond
Draw a closed polygon where the pond will be located.
Open Extended Data to configure the pond settings.

The pond is created on the AS-PONDS layer and stored as a pond feature

How Level AI “Digs Out” a Pond

When Level AI runs:

The pond polygon becomes an excavation zone.
The solver determines:
- Bottom level (invert)
- Side slopes
- Storage depth
The finished surface is reshaped using COGO points inside the polygon to:
- Meet either depth or volume targets
- Respect maximum cut and fill
- Respect defined minimum lip level
- Tie smoothly into surrounding grades

Conceptual pond design

Conceptual pond cross-section showing the bottom invert, storage depth, side wall slopes, and the tie-in to the surrounding finished grade.

Conceptually:

The pond has a bottom invert
A defined storage depth
One or more side wall slopes
A tie-in to surrounding finished grade

Level AI adjusts the invert elevation to satisfy the governing constraints (volume, depth, invert control, or drainage limits). A feature line is returned for the lip and the shape is defined by cogo points .

Settings (Defaults in web)

Setting	Description
Target volume	If enabled, applies this target volume to all ponds created in your DWG
Target depth	If enabled, applies this target (storage) depth to all ponds created in your DWG
Target grade	If enabled applies up to 3 different grades of the ponds side slopes (from edge). e.g. If want just a single grade, only specify Grade 1 and leave Grade 1 distance blank, if want to grades, set Grade 1, Grade 1 distance and Grade 2 (leaving Grade 2 distance blank).
Permanent pool depth	If enabled, applies this permanent (dead storage) pool depth to all ponds created in your DWG.
Live storage volume	If enabled, applies this live (active) storage volume, held above the permanent pool, to all ponds created in your DWG.
Slope bottom	If enabled, applies this bottom slope (grade) of the pond floor to all ponds created in your DWG.

Settings (On Pond Feature)

Click on the ponds extended data to set the sizing and grading for each individual pond.

Sizing

There are several ways to size a pond, by a fixed depth or by a target volume.

Setting	Description
Storage depth	Depth Level AI digs the pond to. Leave blank if using a volume target.
Target Volume	If not using a target depth can set a target volume on each pond.
Permanent pool depth	Permanent (dead storage) pool depth retained in the base of the pond, below the live storage. Leave blank if not required.
Live storage volume	Live (active) storage volume provided above the permanent pool.

Grading

You can also put additional grading restrictions on the pond area to control total earthworks allowed.

Setting	Description
Max Cut	Maximum amount of cut allowed in area, leave blank to ignore.
Max Fill	Maximum amount of fill allowed in area, leave blank to ignore
Min Lip Level	Minimum elevation of the lip of the pond.
Min Invert	Minimum elevation of the bottom of the pond.
Side wall Grade and distance	Specify up to 3 different side wall grades and distance (from pond edge) for each pond.
Slope bottom	Bottom slope (grade) applied across the pond floor.

Service AI

Drainage

Setting	Description
Maximum catchment area	Used by Service AI to delineate catchments. This is the total area allowed to drain into the pond.
Max catchment area (impervious)	Used by Service AI to delineate catchments. This inspects the area Impervious regions in the project. Node road lanes are automatically assigned impervious regions.
Max catchment area flow	Used by Service AI to delineate catchments.

Subnets

Used by Service AI to control which storm sub-network the pond connects to. See Creating/Configuring Subnets for details.

Setting	Description
Storm Subnet ID (In)	ID for the ‘pit’ storm sub-network (to control connection). Leave blank to automatically assign (to subnet 1). Set to zero to ignore in analysis.
Storm Subnet ID (Out)	ID for the ‘sink’ storm sub-network (to control connection). Leave blank to automatically assign (to subnet 2). Set to zero to ignore in analysis.