var biomes = {
    "riverLand": {
        probability: 0.8,
        tiles: {
          "bambooBush": 0.8,
          "rockCluster": 0.2
        }
    },
    "forest": {
        probability: 0.5,
        tiles: {
          "loneTree": 0.25,
          "rockCluster": 0.75
        }
    },
    "desert": {
        probability: 0.5,
        tiles: {
          "loneTree": 0.25,
          "rockCluster": 0.75
        }
    }
}

var biomes = {
    "riverLand": {
        probability: 0,
        tiles: {
          "bambooBush": 0,
          "rockCluster": 0.2
        }
    },
    "forest": {
        probability: 0.5,
        tiles: {
          "loneTree": 0.25,
          "rockCluster": 0.75
        }
    },
    "desert": {
        probability: 0.5,
        tiles: {
          "loneTree": 0.25,
          "rockCluster": 0.75
        }
    }
}

Set bamboo generation percent to 0 until water is ready