Expert map

Flooded Valley

Info

Flooded Valley is an Expert map added in version 18.0 in May 2020, together with Bazaar. A huge dam runs down the middle of the map from top to bottom. One side holds a reservoir of water, the other side is a dry valley with rocks and land. The track runs along the top of the dam.

Path

Bloons enter from the top and the bottom of the dam at the same time and walk along it to the opposite end, so every round sends two groups past each other on one straight path. There are two entrances and two exits, and the path is about 10 seconds long for a red bloon. You cannot place towers on the sloped dam itself.

Line of sight and high ground

The dam is the main obstacle. Towers placed on the low ground of the dry valley cannot see over it. The rocks on the dry side are high ground: towers placed on them can see the track, although many need extra range to reach it. In version 23.0 the smaller rocks near the dam were raised so towers such as Sharp Shooter and Plasma Accelerator can see the path from there, while Missile Launcher and above still cannot. Aircraft like Heli Pilots and Monkey Aces ignore the problem entirely. The reservoir side has no such issue, so water towers have an easy time.

The flooding secret

There are two panels on the dry side of the dam. Click each panel five times to open them, then press the upper button and then the lower button before the panels close, so both turn green. A third button appears in the middle. Paying $5,000 to "remove" it opens the dam and floods the valley, turning everything except the highest ground into water. Non-amphibious towers on the low ground are sold automatically, except Sun Temples and True Sun Gods. Ice Monkeys and Mermonkeys can stay. Most players never use this, since the water side already has plenty of room.

How it compares

Flooded Valley has a lot of water, similar to Spice Islands, but the dam makes land towers awkward. It is easier than the multi-lane Expert maps, but the CHIMPS start is notoriously tight because almost nothing can reach the track in the first rounds. Like other Expert maps, it unlocks after you have won on 20 different maps.

How to beat Flooded Valley

Why this map is hard

Flooded Valley is not a multi-lane nightmare, but it fights you on placement. Bloons come from both ends of the dam at once, so the path has two "fronts" and no single end to defend. On the dry side, the dam blocks line of sight for anything on low ground, which rules out many of the best land towers unless they sit on the rocks. On the wet side, water towers are free to work, which is why most strategies are built around Subs, Buccaneers and Admiral Brickell.

The opening in CHIMPS is the hardest part. Very few cheap towers can reach the track at all, and a Monkey Sub is effectively the only way to survive rounds 6 and 7. After that, your defence must cover two flows of bloons going in opposite directions on a short path.

Best towers

Monkey Sub: the mandatory CHIMPS opener and a strong core all game. 2-0-2 Advanced Intel Subs with Heat-tipped Darts handle the early and mid game, 2-0-4 First Strike handles blimps, and a 2-5-0 Sub Commander buffs a whole fleet.
Monkey Buccaneer: 3-2-0 Destroyers for the mid game, 0-5-2 Pirate Lord for blimps, and 5-x-x Carrier Flagship late. A Flagship's deck lets you place land towers on it.
Ice Monkey (0-3-0 Arctic Wind): Arctic Wind freezes nearby water into ice that land towers can be placed on. Put it on a Carrier Flagship or by the shore, and Carrier Flagship plus Arctic Wind becomes a famous combo here for opening up land placement.
Heli Pilot and Monkey Ace: they ignore the dam completely. A 2-0-4 Comanche Defense or a Spectre gives strong damage from the dry side.
Sniper Monkey: the elevated rocks at the back of the dry side are good spots for Snipers, which have infinite range once they can see the track.
Spike Factory with Perma-Spike: with a Village and Alchemist buffing its range, a Perma-Spike can still reach the middle of the dam.
Mermonkey: amphibious and can be placed in the water, which makes it one of the few Magic towers that works well here.
Towers with homing attacks: since most towers hit the path from the side, seeking projectiles waste less pierce.

Best heroes

Admiral Brickell: the reservoir is full of water towers for her to buff. Naval Tactics doubles their attack speed, she gains camo detection at level 7 and Mega Mine handles blimps.
Psi: his attacks reach any bloon and do not care about the dam.
Silas: his ice platforms let land towers stand on water, which is a big help in Primary Only and other restricted modes.

Easy and Medium

Start with a Sub in the reservoir so its range touches the bottom entrance, then a second Sub for the top half. Place Brickell, keep building 2-0-2 Subs, and add a Destroyer. Camo for round 24 is easy with a 0-0-2 Dart on a spot that sees the track, or by waiting for Brickell's level 7. That setup carries you through Medium.

Hard

Add a First Strike Sub before round 40, a Pirate Lord in the 60s and a Heli or Spectre from the dry side. If you want land towers in the middle, build a Carrier Flagship and an Arctic Wind Ice Monkey for extra ground.

CHIMPS

Rounds 1 to 6: place a 0-0-0 Monkey Sub on the bottom half of the reservoir so its range just touches the bottom entrance. It may take a couple of tries to find the spot. If a red bloon or two leaks at the top, quickly add a second Sub on the top half. This Sub start is the only reliable way to beat rounds 6 and 7.
Rounds 7 to 15: second and third Subs, then take them to 2-0-0. Place Admiral Brickell in the reservoir between them.
Before round 24: get camo coverage for your Advanced Intel Subs, either with a 0-0-2 Dart on a spot with sight of the dam or by getting Brickell to level 7.
Before round 28: 2-0-2 Subs for leads.
Rounds 30 to 50: a 3-2-0 Destroyer and a 2-0-4 First Strike Sub before round 40.
Rounds 50 to 80: build a 0-5-2 Pirate Lord and a 2-5-0 Sub Commander. Use Naval Tactics on rounds 63, 76 and 78.
Rounds 80 to 100: aim for a Carrier Flagship, add an Arctic Wind Ice Monkey if you want land towers like an Alchemist or Village on the ice, and stack more First Strike Subs. Save Mega Mine and First Strikes for 98, 99 and the BAD. A Beast Handler with Giant Condor also works well here, because the dam is short and the Condor can carry blimps back along the path.

Impoppable

The same water route works with more economy. Farms fit comfortably on the dry side, which does not need line of sight. See our Impoppable guide.

Restricted modes

Primary Only: hard because few primary towers reach the track from land. Silas's ice, Admiral Brickell or Obyn Greenfoot help a lot, and so does a Pontoon.
Magic Monkeys Only: start with a hero or a Mermonkey. Ninjas are weak without a Pontoon or Silas, but Bloon Sabotage is still useful.
Military Only: Subs, Buccaneers, Helis, Aces and Snipers are all allowed, so it plays almost like a normal game.

Dangerous rounds on this map

Rounds 6 and 7: the CHIMPS opener can fail here without a well-placed Sub.
Round 24: one camo green.
Round 28: six leads.
Round 40: the first MOAB.
Rounds 63 and 76: ceramic rushes coming from both ends of the dam.
Round 78: rainbows, ceramics, a BFB and camo ceramics.
Round 90: camo regrow fortified leads and three DDTs.
Rounds 95, 98 and 99: DDTs and fortified blimps.
Round 100: the BAD.

The BTD6 Master YouTube channel has video guides for Flooded Valley.

Frequently asked questions

How do you flood Flooded Valley?

Click each of the two panels on the dry side five times, press the upper button and then the lower button so both turn green, then pay $5,000 on the middle button that appears.

Is flooding Flooded Valley worth it?

Usually not. It costs $5,000, sells most land towers on low ground, and the water side already has plenty of room.

How do you start Flooded Valley CHIMPS?

Place a 0-0-0 Monkey Sub on the bottom half of the reservoir so its range touches the bottom entrance, and add a second Sub at the top if anything leaks.

Why can't my towers hit bloons on Flooded Valley?

The dam blocks line of sight for towers on low ground. Put them on the rocks, use aircraft or water towers, or freeze the water with an Arctic Wind Ice Monkey.