Ponds, earth ponds and waterfalls

Liner pond

You enter the length, width, depth and shape. The liner needed is (length + 2 depths + 2 × 0.5–0.75 m) × (width + 2 depths + 2 × 0.5–0.75 m): the allowance anchors the edges. The same area of geotextile goes under the liner, with a sand bed on the bottom. The edge is stones on geotextile. The system picks the pump, filter and UV by water volume.

Waterfall and stream

Waterfall flow is worked out from the spillway width: about 100–250 l/h for every centimetre. 0.1 m is added to the waterfall height for every metre of hose, and the pump is chosen from that. For a stream the system works out the liner, a double layer of geotextile and gravel in the bed. It also tells you how much water drains into the pond when the pump is off and how much evaporates in a summer week.

Preformed shell

PE shells (400, 500 and 1000 l) are set into a pit with a 15 cm margin on a sand base. They are only 0.4–0.6 m deep, so they do not suit overwintering fish: Lithuania needs at least 1 m, as ice reaches 40 cm.

Earth ponds and rules

- An unlined pond is an artificial water body. It needs no permit, but a pond over 0.1 ha, or a pond of any size in the karst region, must be reported to the environmental and geological authorities (Water Law art. 16).

- On drained land a pond needs the municipality's approval. So does any digging deeper than 0.7 m (Law on Special Land Use Conditions art. 92).

- The excavated soil may not be sold — it stays on the plot.

- The 5 m distance from the plot boundary is known only from secondary sources, so it is shown as an unverified rule.

- Water separated from the ground by a liner or shell is not a water body (Water Law art. 3 para. 11).

- No Lithuanian norm for child safety was found — the system suggests a fence or a grate.