Smart Pond / Wadi Water Level Control with Home Assistant
Home Assistant monitors the pond water level, pump status and power usage, solar production, dynamic electricity prices and runtime limits. Based on these inputs, it decides whether the groundwater pump should run.
The goal is to automatically maintain the water level by pumping groundwater from my own well, but only when it makes sense to do so.
The pump is switched through a Shelly Plug, which also provides feedback about power consumption and pump status. The waterlevel is measured with an Agara leakage sensor.
Full write-up: - Erve 't Putke
Additional water balance / leakage estimation
After the basic pump control was working, I extended the setup with a simple water balance calculation.
Home Assistant now combines several daily values:
- evaporation data from KNMI (National Weather station in the Netherlands);
- a Penman-based evaporation estimate, derived from the KNMI Makkink EV24 value;
- local rainfall values from my own Netatmo rain gauge;
- the amount of groundwater pumped into the pond;
- the effective catchment area that drains towards the pond.
These values are written into a continuously updated table in Home Assistant and are also published simultaneously on the webpage.
By comparing the effective rainfall input, the pumped water input and the calculated evaporation loss, the remaining difference gives an estimate of the seepage or leakage of the pond bottom. In my case this is expressed as a daily k-value in mm/day and m/day, and also as the amount of water in m³/day that would have to be pumped in if there were no rainfall.
Because the table is updated continuously, the estimate should become more reliable over time. Individual daily values can still fluctuate due to rain distribution, measurement uncertainty and the assumptions about the contributing catchment area, but the longer-term average gives a useful practical indication of the water permeability of the pond bottom.
This makes the system more than just an automatic pump controller: it also becomes a continuously updated monitoring tool for the pond’s water balance.
