Timberborn Reservoir Design: Build Deep to Beat Droughts — The Math Both Factions Need

Quick Start: Build Your First Deep Reservoir in 5 Steps

Before the evaporation maths, here are the five steps that work for both factions from day one. Verified against Timberborn Update 6 — values may change with future patches.

If you’re still setting up your first colony, the Timberborn Beginner’s Guide covers colony fundamentals before diving into advanced water engineering.

1. Find the narrowest channel or valley on your map. Terrain walls provide free depth and free containment — use them. The narrower the opening, the fewer blocks you need to seal it.
2. Anchor the base with dams across the downstream end. Each dam costs 2 logs and blocks 0.5 units of water height per layer.
3. Stack levees vertically on top of the dam base to extend wall height. Each levee tile adds 1.0 unit of blocking height — three stacked levees reach a 3.0-unit wall.
4. Add at least one floodgate. You need a controlled release valve to drain during floods and to feed irrigation channels during droughts. Floodgates adjust in 0.5-unit increments and are available in sizes covering 1, 2, or 3 tiles wide.
5. Position your water pump at the correct depth. Folktails pumps reach 2 tiles deep. Iron Teeth’s Deep Water Pump reaches 6 tiles. Don’t build deeper than your pump range unless you’re using a tiered system or irrigation towers.

Why Evaporation Punishes Wide Reservoirs

Water evaporates at exactly 0.045 units per exposed surface tile per day. That rate stays constant regardless of weather, season, or map difficulty [3].

The mechanism that makes this matter: evaporation is only calculated on the top layer of each water column. A block of water 4 tiles deep loses exactly the same daily surface evaporation as a block 1 tile deep — because the game only reads the topmost tile. The three tiles beneath it are completely shielded [2].

This means going deeper does not reduce your evaporation rate. It increases the total volume of water that evaporation can’t reach. Every tile you add in depth adds storage without adding a single additional exposed surface tile.

By contrast, every tile you add in width adds another exposed surface tile and another 0.045 units of daily loss. I’ve seen colonies wiped mid-drought not by insufficient total water volume, but by having that volume spread across too wide a surface — all of it bleeding away before the floodgates could deliver. On a wide reservoir with 60 exposed tiles, you’re losing 2.7 units per day to evaporation alone before a single beaver drinks.

The Depth vs. Width Numbers

Both reservoir configurations below store 40 units of water. Every difference in the table comes from depth versus width [3]:

The deep 5×2×4 reservoir and the wide 20×2×1 reservoir hold the same 40 units. The deep version loses 0.45 units per day to evaporation; the wide version loses 1.80 units per day — four times as much [3]. Same storage capacity, one-quarter the daily loss, and the deep reservoir uses a quarter of the land footprint.

For a colony of 20 beavers needing roughly 3 units each per day [3], daily colony consumption is 60 units. A wide reservoir adds 1.80 units of overhead on top of that. A deep reservoir adds 0.45. Over a 15-day drought, that’s the difference between losing 27 units to evaporation versus 6.75 units — a 20-unit swing that can decide whether your colony survives.

Faction Design Templates

The maths favour depth. How you implement it depends on which faction you’re playing.

Folktails: Working Around the 2-Tile Pump Limit

Folktails’ standard Water Pump reaches only 2 tiles deep [4]. Build a reservoir 6 tiles deep and your pumps can’t access the bottom four tiles during drought — you’re storing water you can never draw. Three approaches that work within this constraint:

Tier-and-terrace system: Build two reservoirs at different elevations, each no more than 2 tiles deep, connected by a floodgate. During drought, the upper basin feeds the lower by gravity. The result is 2 + 2 = effectively 4 tiles of total accessible depth across two basins, all within pump range. This is the most reliable Folktails design for maps with significant terrain variation.

Minimum-width deep trench: A 3-tile-wide, 2-tile-deep trench holds double the water of a 3-wide, 1-deep trench with zero additional surface area [7]. Keep width at 3 tiles minimum for good evaporation-to-volume balance. Going wider adds surface tiles faster than it adds volume relative to depth.

Irrigation towers for passive depth storage: Folktails’ irrigation towers deliver moisture from water at any depth without needing a pump. A deep excavation acts as a moisture bank even during drought — the water stays in the pit, irrigating surrounding soil passively. Pair this with a shallow pump-accessible reservoir for drinking water, and you’re splitting the load: deep pits handle crop moisture, shallow reservoirs handle colony water.

The Folktails triple floodgate [5] gives finer release control for managing staged flow between tiered basins. Close the upper gate during wet season to fill both basins; open it slowly at drought onset to meter the gravity-fed supply to the lower basin.

Iron Teeth: Canyon-First Design

Iron Teeth’s Deep Water Pump accesses water up to 6 tiles deep from game start [4]. The faction design philosophy follows directly: build down, not out.

Canyon reservoir: Any valley or terrain depression on the map is free depth. Seal the downstream end with a levee wall, let rain fill the canyon over wet seasons, and draw from the full 6-tile depth throughout drought. A 10×3×6 canyon basin holds 180 units and exposes only 30 surface tiles — losing just 1.35 units per day to evaporation. A Folktails player storing the same 180 units in a 2-tile-deep design needs 90 surface tiles and loses 4.05 units per day instead.

Excavated well on flat maps: On maps without natural valleys, dynamite digs depth from flat terrain. A 3×3 excavation 4 tiles below the riverbed creates a 36-unit reservoir that fills naturally from the river and loses only 0.405 units per day. The initial dynamite cost pays for itself after the first drought.

Badwater integration: Iron Teeth’s discharge structures keep contaminated water flowing during droughts, powering water wheels continuously [7]. Build your clean-water reservoir separate from badwater channels, and your power generation continues through the full drought cycle — an advantage Folktails cannot match without the same industrial infrastructure.

On maps with severe drought cycles, veteran players consistently rate Iron Teeth stronger specifically because the 6-tile pump range makes deep storage fully accessible [4]. The Deep Water Pump is not a convenience upgrade — it redefines how much of your stored water is actually usable.

The Structural Toolkit

Dams (2 logs each, 0.5 units of blockage height per layer [5]): Best for broad base construction. Four stacked dams reach 2.0 units of blockage. Low log cost makes them efficient for wide channel spans where you need volume but not height.

Levees (12 logs per official wiki [1]; community guides list 4 logs [5] — verify in your version): Block 1.0 unit of height per tile and stack freely. Beavers and structures can be placed on top of levees — your reservoir wall doubles as a walking platform and building surface. The standard efficient pattern is dams at the base for width, levees stacked above for height.

Floodgates (adjustable in 0.5-unit increments, sizes 1–3 tiles wide [5]): Every reservoir needs at least one. Close before drought starts to retain maximum water. Open partially during drought to release gradually — a fully open wide floodgate on a large reservoir drains it in hours if colony demand is high.

The Water Battery: Combining Reservoir and Tanks

Deep reservoirs manage evaporation efficiently. Water tanks eliminate it entirely — they don’t evaporate and don’t require surface area [3].

A Large Water Tank stores 100 units in a single building. Small Water Tanks store 30 units each (20 logs to build). The tradeoff: tanks require beaver workers to fill and operate, while a reservoir fills passively during rain and runoff.

The reliable drought strategy is a hybrid: a deep natural reservoir acts as your first buffer, covering the early drought days when beavers are still active and filling tanks. When the reservoir runs dry, pre-filled tanks carry you through the rest.

Worked example for 20 beavers facing a 20-day drought:

• Daily consumption: 20 beavers × 3 units = 60 units/day
• Total need: 60 × 20 = 1,200 units
• Deep reservoir (first 10 days): 600 units stored
• Tank buffer (days 11–20): six Large Water Tanks = 600 units

A sealed deep reservoir with levee walls and a single controlled floodgate exit can sustain 30 to 40 beavers through droughts lasting 15 or more days without any tank support [3]. Beyond that threshold, tanks make the difference between a stable colony and a collapse.

Which Strategy Suits Your Playstyle?

FAQ

Does deep always beat wide in Timberborn?

On the evaporation maths, yes — same stored volume, deeper reservoir always loses less water per day [3]. The only practical limit is faction pump depth. Water stored below your pump’s reach is inaccessible during drought, which makes it as good as non-existent when you need it most.

Can I mix dams and levees in the same reservoir wall?

Yes, and it’s the standard approach [5]. Dams cover wide sections cheaply at the base; levees stacked on top add height at 1.0 unit per tile. The hybrid cuts material costs while reaching the wall heights needed for deep storage.

What happens if I build a Folktails reservoir deeper than 2 tiles?

The water stores correctly but your pumps won’t reach below 2 tiles during drought. Any water below that threshold is invisible to your pumping infrastructure. Use the tier-and-terrace system to access 4 tiles of effective depth, or rely on irrigation towers for crop moisture from deep pits.

How many Large Water Tanks do I actually need?

As a rough guide: one Large Water Tank (100 units) covers roughly 3–4 beavers’ water needs for a 10-day drought contribution [3]. Pair tanks with your deep reservoir rather than replacing it — the reservoir fills passively during wet season at zero beaver-labour cost; tanks need workers to fill.

Should I build a reservoir or tanks first?

Reservoir first, always. Water tanks require planks and gears — mid-game crafting materials. A basic deep reservoir built in the first wet season carries your colony until your production chains supply tank construction. Start tanking once your sawmill and gear production are stable and your first reservoir is sealed.

Sources

1. Levee — Official Timberborn Wiki: timberborn.wiki.gg/wiki/Levee
2. Deep Dive: Designing the dynamic irrigation and water systems in Timberborn — Game Developer
3. Timberborn Water Management Guide — The Timberborn Wiki
4. Folktails vs Iron Teeth: Complete Faction Comparison — The Timberborn Wiki
5. Floodgates, Dams & Water Control Guide — The Timberborn Wiki
6. Reservoir placement discussion — Steam Community
7. Comprehensive Timberborn Water Guide — My Gaming Tutorials