Hydraulic network

Hydraulic entities

Connection rules

• Coincident vertices connect. Two pipes sharing a vertex (within the connection tolerance, 0.05 m by default) form a node. A pipe ending in the middle of another is joined by an automatic tee. Emitters, valves, pumps and devices placed on a pipe split it.
• The valve separates the worlds. Everything downstream of a zone valve belongs to that zone; the mainline runs from the supply to the valves. Zone items do not connect to mainline items without a valve between them.
• Tapes and laterals must not touch across zones. Since coincident vertices connect, the ends of tapes in neighbouring blocks must stay apart (a service strip between blocks), or the two zones will be calculated as one. The design check warns about unconnected items, pipes crossing without a junction and dead ends.
• Laterals are lumped. In the graph each lateral becomes a sequence of nodes with aggregated emitters (up to 100 nodes per lateral by default, adjustable), which keeps the calculation fast even with hundreds of emitters per line.
• Valve-in-head stations are scheduled like valves. A head on the mainline opens when its station runs. System flows list the stations next to the zone valves and pivots; a station some flow lists runs only in those flows, at its nominal pressure, and one that no flow lists runs in every flow (and is reported). The controller wires each station like a valve, the solenoids of its heads in parallel.
• Wires follow their own graph. Wire routes do not touch the hydraulic network: each valve reached from a controller along the routes gets a station (the nearest valve is station 1) and a station conductor of its own; all of them share the common conductor along the routes. A master valve opens with every zone, on output 0.

Generators

• Lateral block (B): polygon, direction, lateral spacing, offset of the first one, lateral with emitters or tape, submain position (start, centre, end), valve (position and model), valve stub length, names. If a line, polyline, contour line or spline is selected when the dialog opens it can act as a guide: the laterals follow the curve (parallel to a contour line or a curved boundary) and are clipped by the polygon. The submain runs through the feed point of every row on the chosen side, stepping inside the field where a row does not reach that line (an L-shaped field); rows the polygon cuts in several pieces (a U-shaped field, a curved row clipped in two) are fed by branches joined to it, so every lateral is connected. Rows farther from the guide than the radius of its bends, or round a sharp corner of it, are rounded or cut and the block says so. Its Longest lateral section works out how long a lateral can run from its inlet before the flow of its emitters varies more than allowed (10 % by default, the usual rule; about 20 % of pressure for sprinklers), uphill and downhill, on the slope of the ground fitted over the block (level without terrain), inside the pressure window of the emitter and the velocity limit, for the tape or the emitter and lateral pipe chosen; it says what limits it and warns when the longest lateral of the drawing exceeds it.
• Sprinkler grid (AH): polygon, sprinkler and nozzle, spacings, square or triangular pattern, direction and design pressure.
• Densogram (Zone → Densogram, DENS): map of the water applied by the sprinklers and micro-sprinklers as they are drawn (position, arc, orientation and, after a design, the pressure of each one), with Christiansen CU, low-quarter DU, scheduling coefficient (mean over the driest 5 %) and dry spots, measured inside every irrigated area against its own mean (a lawn of sprays next to one of rotors is judged separately); the measured radial profile of a nozzle when the catalogue has one, else a triangular, elliptical or uniform profile; an optional wind (speed and direction) that drifts the water downwind; cell size, zones; the map is drawn on the canvas and the grid exports to CSV. The scheduling coefficient takes the driest contiguous window of 5 % of the area, and Design → Agronomy → Uniformity in the field shows the depth of one event of the programme instead of the rate (Agronomy and irrigation scheduling).
• Submain position envelope (FE): for every selected lateral, paints in green the stretch where the submain can feed it while keeping the pressure window, taking the terrain into account.

Automatic design (Design → Automatic design)

Each tool shows its result after a pause, in steps with their progress and Cancel, and generates it as one undo step. The islands of an irrigated area and the closed shapes selected inside its outline (a pond, a shed, a well) are exclusions: laterals, rings and heads go round them, and the blocks have net areas. SUBDIV and LAYOUT have the same longest lateral as the block generator (SUBDIV fills its length with Use the computed limit; LAYOUT sets it against the longest path of the routed zones); the routed zones never share a valve between areas of different water use (hydrozones), and their pipes stay inside the outline of the lot.