Real-world elements: OpenStreetMap roads and rivers, and area names. The main S01/S02 → S03 → S04 routes follow connected river geometry. Sensor and pump house locations are examples, not a verified DBKL/JPS asset inventory.
Synthetic elements: rainfall on 7–13 September 2026, catchment areas, drainage/pump capacities, bed elevations, river dimensions, base flows and travel delays. Each date is an independent event starting at 14:00; conditions do not carry over to the next day.
Modelled water network
- Rainfall → runoff after surface losses → runoff storage → travel delay → local drainage storage.
- Drainage storage → parallel gravity and pump discharge → drainage travel delay → the named receiving river.
- S01 Gombak and S02 Klang → S03 confluence → S04 downstream → model outlet boundary.
- Levels and surface flooding are derived from stored volumes. Water exceeding capacity remains in storage and assumed overflow areas; it is retained when thresholds are exceeded.
The calculation time step is 30 seconds; the display is sampled every 5 minutes. Animation speed does not change the calculation. All transfers track volume, including water travelling between nodes.
Pumps and receiving rivers
Pumps switch on and off automatically based on storage depth, with separate start and stop thresholds. The 50% setting limits capacity; 0% represents failure. Delivered flow is limited by available water and an assumed pump curve based on head difference. Pumped water enters the receiving river and can increase downstream flow.
Gravity flow uses assumed head differences and one-way valves. This storage model does not solve actual backwater effects or dynamic-wave hydraulic equations. Pump coordinates, drainage connections and dashed lines represent model links, not verified pipe routes or catchment boundaries.
Demonstration station thresholds
The unit m indicates depth above an assumed riverbed. This is not an official JPS gauge level. Station thresholds vary with assumed bankfull depths. Area colours: normal <5 cm; alert 5–<10 cm; warning 10–<20 cm; danger ≥20 cm.
Volume balance
Initial water + rainfall + boundary inflow = node storage + water in transit + surface losses + boundary outflow. Assumed upstream base flows are 3.0 m³/s at S01 and 4.5 m³/s at S02.
Before operational use
Replace assumptions with verified pump/sensor inventories, drainage dimensions, catchment boundaries, topography, level datums and rainfall/level data. Calibrate and evaluate the model before using it for flood forecasting, operational instructions or safety decisions.
METMalaysia / data.gov.my · Forecast & warning API ↗METMalaysia · Thunderstorm warnings, valid for up to 6 hours ↗JPS · Water level data and categories ↗EPA SWMM · Runoff & hydraulic modelling reference ↗© OpenStreetMap contributors · ODbL ↗This is not an implementation of the SWMM engine. The basic map and all simulations work offline. The optional detailed map requires an internet connection. No personal data is collected and no notifications are sent.