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Storm, Sanitary and Water Supply Networks

Guide to adding elements to your Storm and Sanitary networks

Written by Allsite Support

Allsite.ai extended data is automatically added to pipes and structures on creation.

Level AI factors in the storm and sanitary networks if "Servicing Enabled" in the run, this will project minimum pipe grades up the roads from existing manholes/pipes and any lift stations / outlets into lots. PUBLIC PARK and PUBLIC DRAINAGE type lots are excluded from this analysis. This sets a 'floor' for the design accounting the minimum pipe clearances under roads/pervious.

Service AI takes the existing connections and designs the catchments and networks as per the subnet (sub network)'s configured.

Network / Part Library

Select the network for storm and sanitary via drop-down - this is where the pipes and structures created by Service AI will be put. This dropdown is mirrored on Allsite.ai.

When structures and pipes are added for in these networks they will get property data automatically assigned indicating whether a storm / sanitary node.

Via the Allsite.ai you can then set the part family to use Storm and Sanitary pipes and various structure types. This informs Service AI the parts to select from. If no part family is selected the family that was used for any existing pipes/structures and/or family with the most part sizes is selected.

Networks to design on the Service AI settings chooses which of Storm, Sanitary and Water Supply a run designs; all three are on by default. Clear a network to leave its existing assets untouched by the run.

Water supply network and part families

Water supply is designed as a Civil 3D pressure network only. It has no ribbon dropdown: choose its network and part families on the Services (Water Supply) settings, under Civil 3D.

  • Water network - the pressure network the results are added to. It is optional: with none selected, the results go into the drawing's only pressure network, or into a new one called Water Network.

  • Pipe part family - the pressure pipe family Service AI picks sizes from.

  • Fitting and appurtenance part families - one family for each of JUNCTION, VALVE, HYDRANT and PRESSURE REDUCING VALVE. All four are required: without one, every node of that type is dropped when the results load.

The drawing needs a pressure parts list, which comes from the drawing template (a Civil 3D pressure-pipe template such as the AWWA or metric water templates). See Running a Service AI Model for the rest of what water supply needs.

Pipe sub types

Service AI fills in a pipe's Sub Type when the results load; its Type stays PIPE. Mains are left with no sub type.

Sub Type

What it is

Network

LATERAL

A building lateral: the service pipe from the main to a lot.

Storm, Sanitary, Water Supply

LEAD

A short pipe from the main to a hydrant, or from a catchpit to the main.

Water Supply, Storm

Leads and laterals get no long section.

Storm/Sanitary Settings

Below are the storm, sanitary and water supply settings configurable in your Allsite.ai project, grouped by category.

The values a new project starts with are a starting point, not a recommendation. Set your organisation's own standards in a template project and every new project created from it inherits them.

Network placement

Three drawings of storm, sanitary and water supply network placement. Top, a plan of one block: a road reserve with two lots on each side, and six numbered reference lines for what an offset distance can be measured from - parcel front, corridor extent, curb, road centerline, parcel side and parcel rear. Three mains are drawn in one arrangement the table can produce: storm on the low-side curb with two road inlets on it, water supply off the high-side curb, and sanitary off the high-side lots' rear boundary. Each lot is marked with the boundary its connection point sits on, or with a surface discharge arrow across its frontage. Middle, two details of the same stretch of road with the main on the centreline: with both storm inlet switches off, inlets fall where flow capacity and the maximum inlet spacing require them and the pair's leads end at one manhole on the main; with both switches on, inlets sit only where a lot side boundary meets the road edge and each lead saddles onto the main with no manhole. Bottom, a schematic of a custom primary path: one line drawn through a reserve, with a sanitary main offset to the left of the drawn direction, a water supply main offset to the right, and a blank storm offset leaving storm off the line.

In words: an offset distance is measured from one of six lines — the road centreline, the curb, the corridor extent, or a parcel's front, side or rear boundary. Road side then decides which side of the road the main favours: Low or High by ground level, Left or Right with respect to the direction the road alignment was drawn, Both for one main each side, Centre, or a compass quarter such as North East. A lot's connection setting picks which boundary its tie-in point sits on — front, rear, either, or one per building — or replaces the pipe with a surface discharge point that sheds to the road channel instead. Storm road inlets have two switches of their own, described in the table below. A custom primary path is a line you draw where no road corridor puts a main, through a reserve or across open space: each line carries its own storm, sanitary and water supply offset distance, positive to the left of the direction you drew it and negative to the right, 0 putting the main on the line itself, and a blank offset leaving that network off the line. It is additional to the mains the road corridors already produce, so a path drawn along a road that declares the same network produces two. The arrangement in the diagram is one of many the table can produce, not a recommended one.

Setting

Description

Network

Network placement

Desired network paths within the road corridor and parcels — an offset distance measured from the road centreline, curb, corridor extent, or a parcel's front, side or rear boundary, plus the Road side the main favours.

All

Maximum lots on a single feed

The most lots a water supply main may serve from a single feed. Service AI adds loop mains along the water supply network paths until a break in any one main cuts off no more than this many lots. It also puts every hydrant on a loop and adds any loop under 100 m (328 ft) that gives a lot a second feed. 0 turns off every loop main, the hydrant and short loops included, and leaves the network a tree.

Water supply

Hydrant placement parameters

Where hydrants may sit across the road reserve: the feature the offset is measured from (curb, road centerline or corridor extent), the offset distance, and the Road side. For the curb and the corridor extent a positive offset is away from the road centerline; for the centerline it is to the left of the alignment direction. Every road takes this row as its hydrant defaults and can override it (see Road Settings). Vehicle crossings and service laterals are trimmed out of the hydrant line before hydrants are placed.

Water supply

Hydrant design distance

Every lot must have a hydrant within this distance, measured along the road reserve. Service AI places hydrants until every lot is covered.

Water supply

Default normal lot pipe connection

Default pipe connection method for NORMAL-category lots (surface single/multiple discharge point [storm], piped front, piped rear, or piped front or rear).

Storm, Sanitary

Default Normal Lot Water Supply pipe connection

Default water supply connection for NORMAL-category lots: piped front, piped rear, piped front or rear, or piped front each building (the default, which gives each building its own service lateral). No connection leaves the lot off the water supply network, unless the lot sets its own connection.

Water Supply

Align inlets with lot side boundaries

Places road inlets only where lot side boundaries meet the road edge, and at intersections, so inlets line up with the boundaries. Off, inlets are placed where flow capacity and maximum inlet spacing require them.

Storm

Allow inlet leads to saddle onto the main

Lets each road inlet connect to the main with a lead that saddles onto the pipe at the closest point, with no manhole at the junction. Off, an inlet lead must end at a manhole: the inlets of a pair share a manhole placed on the main at the most downstream of the two.

Storm

Hydrant design

These settings drive the hydrant sizing model: Service AI checks that the water supply network can deliver the fire flow at any single hydrant while still holding the residual pressure everywhere else.

Setting

Description

Network

Hydrant fire flow

Fire flow drawn at a single hydrant in the hydrant sizing model. Imperial projects show flow in gallons per second, so divide a requirement given in gpm by 60.

Water supply

Residual pressure under fire flow (head)

Minimum pressure, as head of water, to hold at every node while the fire flow is drawn at one hydrant.

Water supply

Fire flow duration

How long the fire flow must be sustained. Reported with the hydrant model and used for storage checks.

Water supply

Coincident demand factor under fire flow

Multiplier on average daily building demand in the hydrant model, so the fire flow is drawn on top of maximum-day demand.

Water supply

Cover

All of these are measured downward from the ground surface to the top of the pipe, and they form an ordered ladder — each minimum must be shallower than its matching maximum, and every maximum must stay shallower than the maximum network cover, the single hard limit no pipe may cross. Settings that were previously labelled “depth” are now labelled “cover” — they have always been the same measurement.

Two drawings of pipe cover. Top, what cover means: a ground surface with a pipe below it and a dimension running from the surface down to the top of the pipe, not to its centre or invert. Bottom, the four cover bands drawn to depth below the ground surface. Under roads, the band runs from a 3 foot or 1 m minimum to a maximum whose default is 20 feet or 6 m on storm and 14 feet or 4.2 m on sanitary. Other areas runs from a 0.5 foot or 0.2 m minimum to a maximum whose default is 20 feet or 6 m on both storm and sanitary. The preferred band Service AI aims for is drawn as two columns: storm and sanitary run from 4 feet or 1.2 m through a 7 foot or 2 m target to 23 feet or 7 m, and water supply has its own, much shallower, from 3 feet or 0.9 m through a 3.5 foot or 1 m target to 7 feet or 2 m. Building minimum freeboard is the top 3 feet or 1 m below a building. A heavy dashed line at 33 feet or 10 m is the maximum network cover, the hard ceiling no pipe may cross. Water supply carries the minimums, its own preferred band and the ceiling: it has no maximum cover. Every figure drawn is a shipped default that a project can change to another value, given imperial first and then metric.

Water supply has minimum covers and its own, much shallower preferred band, but no maximum cover: a pressurised main holds one depth and only leaves it to clear a clash. Storm and sanitary have both minimums and maximums. Because cover is measured to the top of the pipe, a larger pipe sits deeper for the same cover.

Setting

Description

Network

Road minimum cover / Road maximum cover

Minimum and maximum cover for pipes under roads (from top of pipe); can be overridden per pipe. Water supply has the minimum only. Also informs Level AI.

Min: All · Max: Storm, Sanitary

Other area minimum cover / Other area maximum cover

Minimum and maximum cover for pipes under pervious / other areas (from top of pipe). Water supply has the minimum only. Also informs Level AI.

Min: All · Max: Storm, Sanitary

Preferred minimum cover / Preferred cover / Preferred maximum cover

The cover band Service AI aims for between the hard limits — a preferred minimum, a target, and a preferred maximum. Water supply has its own band, separate from the gravity networks'.

All

Building minimum freeboard

Minimum drop between a building and the pipe (from top of pipe). Also informs Level AI.

All

Maximum network cover

Maximum cover the network can reach (from top of pipe) — increase this if using a deep lift station. Also informs Level AI.

All

Pipes

Setting

Description

Network

Pipe grades / default minimum grade

Table of pipe grade limits by pipe size; the default minimum grade applies to sizes not in the table. Level AI uses the minimum grade for the largest pipe size when assessing serviceability.

All

Grade limits (max + preferred)

Maximum allowable pipe grade, plus the preferred minimum/maximum grades Service AI targets.

All

Pipe length (min / max)

Shortest and longest pipe run allowed between structures — each with an absolute limit and a preferred target.

All

Minimum pipe diameter (private / public)

Smallest diameter allowed for private and public pipes.

All

Minimum catchment area

Minimum catchment area threshold used in sizing.

All

Pipe roughness

Material-specific Colebrook-White wall roughness for capacity/HGL calculations, plus a default roughness for materials not listed. (Manning's n on the Civil 3D pipe is used when the hydraulic method is Manning-based.)

Storm

Structures

Setting

Description

Network

Manhole deflection

How much a pipe run can turn through a manhole: a preferred maximum angle, which is a soft target, and an absolute maximum. The preferred angle must be less than the maximum.

Preferred: All · Max: Storm

Minimum manhole wall distance

Minimum distance from a pipe connection to the manhole wall.

All

Manhole benching type

Benching configuration used for manhole hydraulic checks.

All

Capacity assessment

Setting

Description

Network

Design storm sizing

Up to three design storms — Average Recurrence Interval, duration source (fixed duration in hours if applicable), sizing method (HGL or Flow at Grade; depth to HGL if HGL), and whether to include node headloss.

Include node headloss is off by default. Ticked, Service AI and the capacity workbook take the FHWA HEC-22 access-hole (manhole) energy loss at every manhole for that storm, which raises the HGL upstream of each manhole. Unticked, there is no manhole loss: the HGL runs through each manhole at the level of the pipe leaving it. Saddle connection losses (Saddle head loss K) apply either way.

Storm

Load & flow method

Methods used to calculate design loads/flows and to assess pipe hydraulic capacity.

All

Runoff parameters

Manning's n (pervious / impervious), pervious curve number, and SCS D value used in runoff calculations.

Storm

Saddle head loss K

Head-loss coefficient for saddle connections.

Storm

Peaking factors (DWF / WWF)

Dry-weather and wet-weather flow peaking factors.

Sanitary

Network clearances

Two drawings of network clearance. Top, a plan of a storm main, a sanitary main beside it and a water supply main. Horizontal clearance is measured in plan, wall to wall, from a manhole or pit to a pipe or structure it does not connect to: one dimension runs from a sanitary manhole's outer wall to the storm main, another between the walls of a storm manhole and a sanitary manhole. A tee on the water supply main is not checked, because buried fittings such as tees, valves and junctions are not structures. A storm lead crossing the sanitary main is judged on vertical clearance instead. Bottom, a section where a sanitary pipe passes under a storm pipe: vertical clearance is the gap between the two pipe walls, above or below. Both are columns of the network clearance parameters table, one row per pair of networks and ownership classes, up to a pipe size. The defaults for most pairs are 3 feet or 1.0 m horizontal and 1.5 feet or 0.5 m vertical, and storm or sanitary against water supply ships 10 feet or 1.0 m horizontal. A pair with no row, or a blank value, is not checked. The drawing is not to scale.

Setting

Description

Network

Network clearance parameters

Horizontal and vertical clearances between the different networks. Each row applies to a pair of networks and ownership classes, up to a pipe size limit; where several rows cover a pair, the row with the smallest size limit that covers both pipes applies. A pair with no row, or a blank value, is not checked.

Vertical clearance is the gap between pipe walls where one pipe crosses above or below another. A pipe may never pass under a manhole or pit, whatever the gap.

Horizontal clearance is the minimum distance in plan, wall to wall, from a manhole, pit or other chamber to a pipe or structure it does not connect to. Service AI aims to keep both clearances while designing, and the results review flags any shortfall, with a pipe passing under a manhole or pit flagged at the highest priority. Buried fittings such as tees, valves and junctions are not checked, and pipes that cross each other are judged on vertical clearance instead.

All

Overland flow paths

Setting

Description

Network

Saw-tooth overland flow paths on

Master toggle for saw-tooth flow paths. Lets Level AI place the low points on the inlets along any overland flow path whose type is SAWTOOTH INLETS.

Storm

Saw-tooth flow path minimum drainage grade (%)

Minimum grade along a saw-tooth flow path. Level AI works the tooth lengths out from it, so it sets how long each tooth runs. Applies only where the flow path carries no minimum grade of its own.

Storm

Maximum highpoint to highpoint length

Furthest apart two high points on a saw-tooth flow path may be, capping how widely the teeth are spaced.

Storm

Minimum highpoint fall depth

Least fall required away from a high point. Divided by the maximum highpoint to highpoint length to give the flattest grade a saw-toothed flow path may sit at.

Storm

Maximum ponding depth

Deepest ponding allowed when Level AI checks that a saw-tooth flow path drains.

Storm

Hydrology Settings

Rainfall IDF defines the rainfall intensity, duration, and frequency data used for stormwater design.

An IDF curve tells Service AI how intense a storm is expected to be for different storm durations and return periods. Shorter storms generally have higher rainfall intensity, while rarer storms generally have higher rainfall intensity than more frequent storms of the same duration.

Use project-specific rainfall data where available. For United States projects, this may come from sources such as NOAA Atlas 14.

Term

Meaning

Intensity

How hard it rains, usually expressed as mm/hr or in/hr.

Duration

How long the storm lasts, such as 5 minutes, 15 minutes, 1 hour, or 24 hours.

Frequency

How rare the storm is, often expressed as a return period such as 2-year, 10-year, 25-year, or 100-year storm.

Update hydrology data for the project on the Project Properties -> Hydrology Data tab.
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Tip: set up localised hydrology data in your template project for the region that way new projects will all inherit the correct data.

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