Circuit top view. Eliminated the breadboard and sautered connections.

Circuit is hidden under the tan. Only tubing can be seen.

Lowest rainfall is in red, second lowest in yellow, and highest in green. This will help the viewer further understand the decrease in rainfall over the decades and allows for each decade to be clearly displayed as the water or “rainfall” duration representing it falls.

Top view.

Rain with corresponding year/LED,

Full, revised circuit.

 Sketch:
 int motorPin = 11;

void setup(){
  for (int thisPin = 3; thisPin < 12; thisPin++)  {
    pinMode(thisPin, OUTPUT);     
  }
  delay(3000);
}

void loop()                   
{
  motorOnThenOff(5200, 5000, 3);
  motorOnThenOff(6300, 5000, 4);
  motorOnThenOff(5200, 5000, 5);
  motorOnThenOff(6500, 5000, 6);
  motorOnThenOff(6000, 5000, 7);
  motorOnThenOff(4600, 5000, 8);
  motorOnThenOff(3500, 5000, 9);
  motorOnThenOff(4400, 5000, 10);
}

void motorOnThenOff(int onTime, int offTime ,int ledNo){  
  digitalWrite(ledNo, HIGH);
  digitalWrite(motorPin, HIGH);
  delay(onTime);              
  digitalWrite(ledNo, LOW);
  digitalWrite(motorPin, LOW);
  delay(offTime);              
}

The video:
https://www.youtube.com/watch?v=bhYiwWps4ug