Smart Irrigation - save water by precisely watering your lawn/garden

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691

Hi,

I started using this integration some days ago. Currently, I have some trouble understanding the use/impact of the drainage rate.

For calculation, I use PyETO, 3 days forecast and data mostly from my Ecowitt weather station.

On a sunny day without rain I see some ET drainage from around -1 to -2 which appears to be OK for my region (Berlin, Germany).

But when I use the proposed/default drainage of 50.8 the bucket is reduces that heavy from the drainage that the EV drainage is almost unimportant.

So Iā€™m a little lost if how the drainage should be used and I hope somebody can help me here.

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692

I can confirm the situationā€¦ the drainage value seems to make the ET calculation obsolete. Need some advice on how to use it.

I remember two values as good start in this thread somewhere ā€¦ sandy or clay soil ā€¦ as I cannot find the corresponding entry ā€¦ does anyone can repeat the figures?

Thanks

693

Hi @reniko and @Monster_D !

According to my knowledge the soil water content is what important for grass. If excess water (like a heavy rain) occured that is where drainage comes into play. Over saturated soil will get the water drained at the rate of its specific drainage (good approx is 50 mm/h). So if you have rain (or irrigation) of 23 mm and the soil can keep approx 10 mm than the above 13 mm will get away in 13/50 hours (~15min). After this water drained away evaporation (ET) is responsible for lower rate of soil water loss influenced by the local weather conditions (wind speed, humidity, temperature). Grass is evaporating and the soil too so the overall rate is dependent on the ratio of plants covering your soil. That is a real complex calculation that has a lots of scientific papers on it.
TLDR: Drainage takes away excess water, evaporation use up the water stored in the soil.

I really donā€™t know how Smart Irrigation calculates with drainage. This should be explained by jeroenterheerdt.

694

Explanation of how drainage rate is used in the calculation is here. How it works | Smart Irrigation

Is looks like, however that the current advise of what value to use is wrong as it diminishes the impact of the et calculation. I need to investigate it, maybe there is a bug. For now, Iā€™d leave it empty or 0 and use it only when you have drainage issues.

695

Hi @jeroenterheerdt !

I might found another bug. I selected the option of current precipitation of Sensor Groups (0. Default Sensor Group - I have only one defined) and the entered entity name disappears on page refresh (Iā€™ve tried to tab out or click outside of the input box, too). Since than the zone irrigation times are not updated. Logs has the following:

2024-09-02 12:02:01.144 ERROR (Recorder) [homeassistant] Error doing job: Task exception was never retrieved (None)
Traceback (most recent call last):
  File "/config/custom_components/smart_irrigation/__init__.py", line 841, in _async_update_all
    self.store.async_update_mapping(mapping_id, changes)
  File "/config/custom_components/smart_irrigation/store.py", line 690, in async_update_mapping
    old.data_last_entry = dict(old.data_last_entry)
                          ^^^^^^^^^^^^^^^^^^^^^^^^^
ValueError: dictionary update sequence element #0 has length 9; 2 is required

Thank you for your support.
Zsolt.