Sewers: catalogue

Gravity sewers: hydraulics, headspace air and sulfide (SWMM .inp reader). How the pieces fit together: Sewers. Every application is set up the same way; see Using noodl.

Import from noodl.apps.sewer. The full reference, with every parameter, is in the API reference.

Set-up

Build the model and its starting state and inputs.

Name	What it does	How to call it
build_model	Assemble the sewer model and return (model, state, drivers).	build_model(net, *, storage=False, air=None, quality=None, species=('bod', 'sulfide'), f_air=0.02, f_i=0.000749, c_s=1.0, leak_area=0.0008, leak_cd=0.6, fans=(), coupling='pingpong', scheme='implicit', dt_storage=None, iterate_tol=None, iterate_max=None, outfall_stage=None, iterate_flow_tol=None)
initial_drivers	build_model's driver template (copied), then values by name (see noodl.refs.drivers_from), e.g. by outfall and species name.	initial_drivers(model, *, values=None)
initial_state	All-zero state, dispatching on each layer's quantity (the app convention).	initial_state(model, drivers=None, *, values=None)

Network components

Descriptions of the physical objects a network is built from.

Name	What it does	How to call it
DynamicWaveOptions	SWMM 5.2.4's dynamic-wave [OPTIONS] that change the physics, with SWMM's defaults (project.c:841-880). head_tolerance and max_trials are SWMM's own iteration controls, and the defaults of build_dynamic_wave_model's (iterate_tolerances; docs: "Iteration and convergence").	DynamicWaveOptions(routing_step=20.0, inertial_damping='partial', normal_flow_limited='both', surcharge_method='extran', min_surface_area=None, head_tolerance=None, max_trials=None, variable_step=0.0, minimum_step=0.5, lengthening_step=0.0, lengthening_routing_step=None, force_main_equation='H-W', allow_ponding=False)
Orifice	An orifice (SWMM [ORIFICES], dynamic wave only) from node u to node v: a "side" (vertical) or "bottom" (horizontal) opening of shape "circular" (height its diameter, m) or "rectangular" (height and width, m), its crest crest_height (m above u's invert, SWMM's CrestHt), discharge coefficient discharge_coefficient (-, SWMM's Cd) and a flap_gate (closes on flow from v to u, with SWMM's ARMCO head loss on forward flow). It starts fully open; control rules (ControlSet) move it, close_time (hours, SWMM's CloseTime) being the time they take to move it through its full opening (0: at once). order is the line of the input file (SWMM's link index order). Flow follows link.c::orifice_getInflow (noodl.apps.sewer.structures).	Orifice(name, u, v, orientation, shape, height, crest_height, discharge_coefficient, width=None, flap_gate=False, close_time=0.0, order=0)
Weir	A weir (SWMM [WEIRS], dynamic wave only) from node u to node v. kind is "transverse" or "sideflow" (a rectangular opening width m wide), "v_notch" (a triangle width m wide at the top) or "trapezoidal" (bottom width m, side_slopes the left and right side slopes, horizontal per vertical); its opening is height m tall above the crest crest_height (m above u's invert). discharge_coefficient is SWMM's Cd in SI units (m^0.5/s, the flow Cd L h^1.5, Cd L^0.83 h^1.67 sideflow, Cd s h^2.5 V-notch, in m and m3/s), end_discharge_coefficient a trapezoid's end triangles' Cd (SWMM's Cd2), end_contractions the number of end contractions (SWMM's EndCon), can_surcharge SWMM's CanSurcharge (above the opening the weir flows as an orifice; else its head is capped at the opening height) and flap_gate as for Orifice. It starts fully open (control rules set its crest). Flow follows link.c::weir_getInflow (noodl.apps.sewer.structures).	Weir(name, u, v, kind, height, width, crest_height, discharge_coefficient, side_slopes=(0.0, 0.0), end_contractions=0.0, end_discharge_coefficient=0.0, can_surcharge=True, flap_gate=False, order=0)
Outlet	An outlet (SWMM [OUTLETS], dynamic wave only) from node u to node v, its crest crest_height m above u's invert, with a rating ("functional", a, b) for q = a h^b (m3/s, h in m) or ("tabular", heads, flows) (m, m3/s; SWMM's RATING curve, heads strictly increasing, held at the end flows outside them). h is the upstream depth above the crest (SWMM's /DEPTH, the default) or, with head_difference, the head across the outlet (/HEAD). flap_gate closes it on flow from v to u. Flow follows link.c::outlet_getInflow (noodl.apps.sewer.structures).	Outlet(name, u, v, crest_height, rating, head_difference=False, flap_gate=False, order=0)
Pump	A pump (SWMM [PUMPS], dynamic wave only) from node u (its inlet, a manhole) to node v. kind is SWMM's pump type: "type1" (PUMP1 curve: flow steps with the inlet node's volume), "type2" (PUMP2: steps with the inlet depth), "type3" (PUMP3: flow against the head delivered, v minus u), "type4" (PUMP4: continuous in the inlet depth), "type5" (PUMP5: the variable-speed PUMP3, head divided by the squared speed setting) or "ideal" (no curve: the pump takes its inlet node's inflow). curve is (x values, flows) in SI (x in m3 for type1, m otherwise; flows m3/s; x strictly increasing); an ideal pump has none. The pump starts ON (initial_on, SWMM's Status), switches OFF when its inlet depth falls below shutoff_depth (m) and back ON above startup_depth (m); 0 disables either. Control rules can switch it and set its speed (ControlSet). order is the line of the input file (SWMM's link index order).	Pump(name, u, v, kind='ideal', curve=(), initial_on=True, startup_depth=0.0, shutoff_depth=0.0, order=0)
Manhole	A manhole: invert and ground elevations (m), a constant lateral inflow (m3/s), for storage its surface_area (m2), and SWMM's surcharge_depth (SurDepth, m >= 0): how far dynamic-wave routing lets the water rise above the full depth before the manhole floods (kinematic and steady routing ignore it). initial_depth is SWMM's InitDepth (m >= 0), the water depth the dynamic wave starts from (0 lets SWMM average the depths of the attached conduits, DynamicWaveHydraulics.initial_state). A storage curve makes it a SWMM storage unit (dynamic wave only). ponded_area is SWMM's Aponded (m2 >= 0): with DynamicWaveOptions.allow_ponding a flooded junction with a positive one stores the water above its full depth over that area instead of losing it (dynamic wave only; not for a storage unit). A storage unit also has SWMM's evaporation_factor Fevap (-, >= 0: the fraction of the potential evaporation rate it loses over its surface area) and an exfiltration (Exfiltration) into the soil (dynamic wave only; both need SewerNetwork.climate or subcatchment hydrology for the evaporation rate and the conductivity adjustment).	Manhole(name, invert, ground=None, inflow=0.0, surface_area=None, surcharge_depth=0.0, initial_depth=0.0, storage=None, ponded_area=0.0, evaporation_factor=0.0, exfiltration=None)
Outfall	An outfall, where the network discharges: its invert elevation (m).	Outfall(name, invert, kind='free', stage=None, flap_gate=False, tide=None, series=None, stage_series=None)
Pipe	A conduit from manhole u to v: length and diameter (m), Manning's n and bed slope (m/m). inlet_offset and outlet_offset (m) are the heights of the pipe invert above the invert of its u and v node (SWMM's link offsets).	Pipe(name, u, v, length, diameter, n, slope, inlet_offset=0.0, outlet_offset=0.0, barrels=1, max_flow=None, initial_flow=0.0, flap_gate=False, flap_gate_reversed=False, xsect=None, loss_inlet=0.0, loss_outlet=0.0, loss_average=0.0, transect_length_factor=1.0, culvert=0, seepage=0.0)
SewerNetwork	A gravity sewer: manholes, pipes, outfalls. Kinematic-wave and steady routing need a dendritic network (one outgoing pipe per manhole); dynamic-wave routing allows loops and flat pipes.	SewerNetwork(manholes, pipes, outfalls, routing='kinematic_wave', notes=<factory>, geometry='analytic', dynamic_wave=DynamicWaveOptions(routing_step=20.0, inertial_damping='partial', normal_flow_limited='both', surcharge_method='extran', min_surface_area=None, head_tolerance=None, max_trials=None, variable_step=0.0, minimum_step=0.5, lengthening_step=0.0, lengthening_routing_step=None, force_main_equation='H-W', allow_ponding=False), orifices=(), weirs=(), outlets=(), inflows=None, pumps=(), controls=None, climate=None)
Transect	One [TRANSECTS] entry (transect.c), SI. stations (m, across the section, with the X1 station multiplier applied) and elevations (m, with the yFactor offset applied); left_bank, right_bank (m, station multiplier applied) end the overbanks; n_left, n_right, n_channel the Manning n values SWMM holds when it validates the transect (transect_validate: the main channel's, as stored, is the conduit's roughness) and length_factor the ratio of the main channel to the flood-plain length (Lfactor, X1 field 8). SWMM scales the channel's n by sqrt(length_factor) in the tables and the conduit's roughness likewise (link.c::conduit_validate), and divides the conduit's length by length_factor (conduit_getLength).	Transect(name, stations, elevations, left_bank, right_bank, n_left, n_right, n_channel, length_factor=1.0)
Xsect	A conduit's cross section as SWMM reads it ([XSECTIONS]), SI.	Xsect(kind, geom=(), transect=None, curve=None)
Adjustments	[ADJUSTMENTS]: monthly evaporation (added to the rate, in/day or mm/day), rainfall and conductivity (multipliers, 12 each).	Adjustments(evaporation=(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0), rainfall=(1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0), conductivity=(1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0))
CurveNumber	SCS Curve Number infiltration (CURVE_NUMBER): curve_number (clamped to 10..99, as SWMM does) and dry_time (s), the time for the soil's storage to regenerate; the obsolete conductivity of the file's line is not used by SWMM and is not kept.	CurveNumber(curve_number, dry_time)
Evaporation	Potential evaporation of the subcatchments ([EVAPORATION]): kind constant or monthly (monthly holds the 12 monthly rates, in/day or mm/day) or timeseries (series: dates in s since START, rates in/day or mm/day, a step function), dry_only allows evaporation only when it is not raining and recovery the optional monthly factors of RECOVERY that scale the soil recovery of the infiltration models.	Evaporation(kind='constant', monthly=(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0), series=None, dry_only=False, recovery=None)
Exfiltration	The seepage of a storage unit into the soil below it (SWMM's [STORAGE] exfiltration fields, exfil.c): the saturated hydraulic conductivity Ksat (m/s) and, for SWMM's modified Green-Ampt model, the capillary suction head (m) and the maximum initial moisture deficit initial_deficit (-, IMDmax). With initial_deficit == 0 (the single Ksat form always) the rate is Ksat times the monthly conductivity adjustment, whatever the depth; with a positive one it follows the Green-Ampt model at the storage depth. us_units says whether the file was in US units, which decides the one place SWMM reads an area in the wrong unit (losses.StorageLosses).	Exfiltration(conductivity, suction=0.0, initial_deficit=0.0, us_units=True)
GreenAmpt	Green-Ampt infiltration (GREEN_AMPT or MODIFIED_GREEN_AMPT): suction the capillary suction head (m), conductivity the saturated hydraulic conductivity (m/s) and initial_deficit the initial moisture deficit (fraction of the upper zone's volume, 0 to 1). modified selects SWMM's modified method (a new event does not reset the moisture deficit while the rain stays below the conductivity).	GreenAmpt(suction, conductivity, initial_deficit, modified=False)
Horton	Horton infiltration ([INFILTRATION] HORTON or MODIFIED_HORTON).	Horton(f0, fmin, decay, dry_time, max_volume=0.0, modified=False)
Hydrology	The hydrology of a SWMM file: gages, subcatchments, evaporation and adjustments, on the calendar that starts at start and lasts total_duration s, with the runoff steps wet_step and dry_step (s; wet_step already lowered to the smallest rain interval, SWMM's gage_validate, and dry_step raised to it). us_units says whether the rain and evaporation values of the file are in inches (else millimetres). ignore_rainfall is SWMM's IGNORE_RAINFALL. rdii is the file's RDII (rdii.Rdii; its unit hydrograph sets read rain gages, which SWMM then counts as used), or None.	Hydrology(gages, subcatchments, start, total_duration, wet_step=300.0, dry_step=3600.0, us_units=True, evaporation=Evaporation(kind='constant', monthly=(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0), series=None, dry_only=False, recovery=None), adjustments=Adjustments(evaporation=(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0), rainfall=(1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0), conductivity=(1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0)), ignore_rainfall=False, rdii=None)
RainGage	A rain gage with a time series ([RAINGAGES] TIMESERIES): series holds the rainfall in the file's rain units (in or mm per interval, or per hour) at the dates (s since the simulation START) of its entries, kind is intensity, volume or cumulative and interval the recording interval (s). snow_factor (SWMM's snow catch deficiency factor) multiplies snowfall only and is 1 here (there is no snowfall).	RainGage(name, series, kind='volume', interval=3600.0, snow_factor=1.0)
Subareas	A subcatchment's [SUBAREAS] line: Manning roughness n_imperv and n_perv, depression storage s_imperv and s_perv (m), pct_zero (percent of the impervious area with no depression storage), route_to (outlet, impervious or pervious) and pct_routed (percent of the routed subarea's runoff that goes to the other subarea). Any number may be a torch scalar.	Subareas(n_imperv, n_perv, s_imperv, s_perv, pct_zero=25.0, route_to='outlet', pct_routed=100.0)
Subcatchment	A subcatchment ([SUBCATCHMENTS] with its [SUBAREAS] and [INFILTRATION] lines).	Subcatchment(name, gage, outlet, area, pct_imperv, width, slope, subareas=None, infiltration=None, outlet_is_subcatchment=False, n_perv_pattern=None, storage_pattern=None, infiltration_pattern=None)
Rdii	The RDII of a SWMM file: sets (UnitHydrographSet) and inflows (RdiiInflow, one per node). ignore is IGNORE_RDII. A set that no [RDII] line names still advances the rain gage (SWMM processes every set), so it stays here.	Rdii(sets, inflows, ignore=False)
RdiiInflow	An [RDII] line: the node that receives the RDII of the unit hydrograph set unit_hydrograph over the sewershed area (m2; a torch scalar allowed).	RdiiInflow(node, unit_hydrograph, area)
UnitHydrograph	One triangular unit hydrograph (SHORT, MEDIUM or LONG) of a month: response ratio r (the fraction of the rainfall that becomes RDII), time to peak t and recession ratio k (hours; the base is t * (1 + k)) and the initial abstraction ia_max (rain depth, in or mm), ia_recovery (depth per day) and ia_initial (the depth used at the start of the run). Any number may be a torch scalar.	UnitHydrograph(r=0.0, t=0.0, k=0.0, ia_max=0.0, ia_recovery=0.0, ia_initial=0.0)
UnitHydrographSet	A [HYDROGRAPHS] set: the rain gage it reads (None when the file gives none) and responses, twelve months (January first) of three UnitHydrograph (short, medium, long).	UnitHydrographSet(name, gage, responses)

Constitutive laws

The relation between the flow through an edge and the potential difference across it.

Name	What it does	How to call it
DynamicWaveConduit	SWMM's dynamic-wave conduit (dwflow.c) with its coefficients frozen for one pass.	DynamicWaveConduit(kind='pipe')
StructureLink	A flow regulator (orifice, weir or outlet) or pump with its flow linearised about the previous pass: q = c0 + g (dp - dp_fed) (m3/s, dp = H1 - H2 in m), then the flap gate's clamp (a pump's, which never flows backwards).	StructureLink(kind)
Headspace	dp = R \|Q\| Q on a headspace edge, with R read from per-edge drivers.	Headspace(length, pipe_positions, *, f_air=0.02, rho_air=1.2041, area_key='sewer.A_air', dh_key='sewer.D_h', dp_transition=1e-08, kind='headspace', learnable=False)

Drives

Terms added to an edge's potential difference (stack, wind, fans).

Name	What it does	How to call it
Drag	Interfacial drag as a Drive: the shear a moving water surface exerts on the air.	Drag(length, pipe_positions, *, f_i=0.000749, c_s=1.0, rho_air=1.2041, v_key='sewer.v', width_key='sewer.T', area_key='sewer.A_air', zero_positions=(), kind='headspace')

Closures

Functions of the state that compute drivers each step (densities, flows, levels).

Name	What it does	How to call it
DynamicWaveHydraulics	The dynamic-wave closure: the conduit coefficients, junction surface areas and outfall heads of one pass, from the previous pass's heads and flows.	DynamicWaveHydraulics(graph, net, *, layer='water', quality_layer=None, air=False, air_quality_layer='air_quality')
H2STransfer	Two-film water-to-air H2S transfer, as a Model closure.	H2STransfer(n_nodes, manhole_idx, *, sulfide=1, water_layer='water_quality', air_layer='air_quality', out_pipe=None)
SewerHydraulics	The water side of a sewer, as a Model closure.	SewerHydraulics(net, pipes, manholes, *, storage=False, dt=None, quality_layer='water_quality', air_quality_layer='air_quality', shaft_depth=None, surface_area=None, geometry='analytic', name='sewer')

Reactions

Transformations applied to transported species each step.

Name	What it does	How to call it
OverflowLoss	The contents a flooded junction loses with its overflow (a dynamic-wave quality reaction).	OverflowLoss(n_species, layer='water_quality')
SulfideGeneration	Operator-split Pomeroy-Parkhurst sulfide generation and bulk BOD decay.	SulfideGeneration(*, bod=0, sulfide=1, m_prime=0.00032, m_loss=0.64, k_bod=0.2, out_pipe=None, manhole_idx=None, n_nodes=None, n_species=None)

Sources

Nodal sources and withdrawals.

Name	What it does	How to call it
JunctionStorage	SWMM's junction continuity as a node withdrawal: trapezoidal storage over the step, with a stiff bed below the invert, or no storage at all where the junction is EXTRAN-surcharged, capped by flooding at the junction's top.	JunctionStorage(nodes, bed, bed_area, crown=None, top=None, surchargeable=None, pond_head=None)

Files

Readers and writers of other tools' file formats.

Name	What it does	How to call it
read_swmm_inp	(network, {node: {pollutant: kg/m3}}, {pollutant: {...}}) for path.	read_swmm_inp(path, *, geometry='tabulated')

Other classes

Supporting types.

Name	What it does	How to call it
StorageCurves	The storage area (m2) and volume (m3) of every junction as functions of its depth (m), vectorised over the junctions (no per-junction loop on a pass); a junction with no curve (None) has neither. full_depth (m, per junction) caps the volume (node.c:943-945); a curve whose full volume is negative is refused by name with names (node.c:219-222).	StorageCurves(curves, full_depth, names=None)
RunoffInflows	The lateral inflow of a SWMM model with subcatchments: the hydrology and the file's schedule (InflowSchedule of time series, patterns, dry-weather flow; None if none). It stands where an InflowSchedule does (net.inflows, model.inflow_schedule): start, nodes, driver(names), flows(t), at. driver(names) is the inflow callable of simulate_dynamic_wave (it makes a fresh RunoffModel each time, so every run starts from dry subcatchments). Runoff to a node that is not in nodes of the network (an outfall) is dropped by the reader, as the dynamic wave ignores lateral inflow at an outfall; so is RDII (rdii.py) to a node outside rdii_nodes, which defaults to the nodes of hydrology.rdii. The RDII of the file joins the runoff in the driver, whether or not the file has subcatchments.	RunoffInflows(hydrology, schedule=None, nodes=None, rdii_nodes=None)
RunoffModel	SWMM's runoff computation for a Hydrology, advanced runoff step by runoff step.	RunoffModel(hydrology)
RdiiModel	SWMM's RDII computation for an Rdii under the rain gages, calendar, WET_STEP and rainfall adjustments of a Hydrology. flows(t) is the RDII {node: m3/s} that SWMM adds to the lateral inflow of a routing step that starts t s into the run (sampled at t + 1 ms, as the interface file is read); t must not decrease between calls by more than the record in force (the records are computed in order and kept). records holds {record number: {node: cfs}} for the records with some RDII, a record being RdiiStep long.	RdiiModel(rdii, hydrology)

Functions

Calculations and helpers.

Name	What it does	How to call it
build_dynamic_wave_model	Assemble a dynamic-wave sewer and return (model, state, drivers).	build_dynamic_wave_model(net, *, iterate_tol=None, iterate_max=None, relaxation=0.5, acceleration='anderson', memory=5, iterate_flow_tol=None, outfall_stage=None, quality=False, species=('bod', 'sulfide'), scheme='implicit', air=False, f_air=0.02, f_i=0.000749, c_s=1.0, leak_area=0.0008, leak_cd=0.6, fans=())
simulate_dynamic_wave	Run the dynamic wave from state for steps steps, or for duration s.	simulate_dynamic_wave(model, state, drivers, *, steps=None, duration=None, dt=None, inflow=None, outfall_stage=None, record=('water.phi', 'water.q'), diagnostics=None, **solve_kwargs)
tidal_stage	A TIDAL outfall's stage elevation (m) t s into the run (node.c:: outfall_setOutletDepth, node.c:1445-1452): the curve tide of (hour, stage) pairs is read at x = x_first + 24 frac(t / 1 day) (the elapsed time, not the clock time: the simulation's start is not added, so the tide begins at the curve's first hour and repeats every 24 h), by table.c::table_lookup: the first stage at or below the first hour, linear between entries, the last stage beyond the last hour (the curve is not wrapped, so one that stops short of 24 h holds its last stage).	tidal_stage(tide, t)
storage_unit	A SWMM storage unit ([STORAGE]) as a Manhole with a storage curve: invert (m), max_depth (SWMM's MaxDepth, m >= 0: the manhole's ground is invert + max_depth), the surface-area curve (Manhole.storage), SWMM's SurDepth surcharge_depth (m) and InitDepth initial_depth (m), and a constant lateral inflow (m3/s), SWMM's Fevap evaporation_factor and exfiltration (Manhole). Tabular depths and areas are stored as tuples (the manhole is hashable).	storage_unit(name, invert, max_depth, curve, *, surcharge_depth=0.0, initial_depth=0.0, inflow=0.0, evaporation_factor=0.0, exfiltration=None)
air_geometry	(A_air, P_air, D_h) for the headspace above the water surface.	air_geometry(h, diameter)
capacity_flow	Q_max = Q(H_MAX_RATIO D): the largest discharge the ascending Manning branch carries, and the surcharge threshold.	capacity_flow(diameter, roughness, slope)
henry_h2s	Dimensionless Henry constant H = C_gas / C_liquid at absolute temperature (K).	henry_h2s(temperature)
kla_h2s	K_L a in 1/s from the per-hour correlation a (1 + b Fr^2)(S0 V)^(3/8)/d_m.	kla_h2s(slope, velocity, depth, *, a=0.86, b=0.2)
manning_flow	Manning discharge Q = (1/n) A R^(2/3) sqrt(S0) (m^3/s), SI constant 1.0.	manning_flow(h, diameter, roughness, slope)
normal_depth	Manning normal depth (m) for discharge q, batched over pipes and instances.	normal_depth(q, diameter, roughness, slope, *, names=None, tol=1e-14)
pipe_table	One row per pipe of every quantity the hydraulics closure publishes (the model's pipe_columns when it declares them, as a dynamic-wave model does); optionally to CSV.	pipe_table(model, state, drivers, *, path=None)
sewer_steady	The explicit fixed point of transport PLUS reactions (the street_steady pattern).	sewer_steady(model, state, drivers, *, reaction=None, dt=60.0, max_iter=500, tol=1e-12)
to_mg_per_litre	kg/m3 -> mg/L (the factor is exactly 1e3).	to_mg_per_litre(x)
to_ppm	kg/m3 of headspace H2S -> ppm by volume at the headspace temperature (K).	to_ppm(concentration, temperature)
tree_steady	The committed 5-conduit, 6-node fixture (tests/data/sewer/tree_steady.inp).	tree_steady()
unit_factors	(length, flow) for the SWMM FLOW_UNITS keyword flow_units: the metres per length unit (0.3048 for the US system CFS, GPM and MGD, 1 for CMS, LPS and MLD) and the m3/s per flow unit, SWMM's own conversion (units.c). An area converts with length**2. Raises ValueError for an unknown keyword.	unit_factors(flow_units)

Constants and tables

Named values and option tables.

Name	Value
ROUTING_ALIASES	table of 3 entries: STEADY, KINWAVE, DYNWAVE
STORAGE_SHAPES	6 names: functional, tabular, cylindrical, conical, paraboloid, pyramidal
F_AIR_DEFAULT	0.02
F_I_DEFAULT	0.000749
H_MAX_RATIO	0.938