Automatic Waterfall

// https://www.youtube.com/channel/UCaXI2PcsTlH5g0et67kdD6g  //
// Automatic waterfall //
// By MOHD SOHAIL //

const int trigPin = 2;  //trig pin of ultrasonic sensor

const int echoPin = 3;  //echo pin of ultrasonic sensor

const int relay = 5;   // output pin for relay, relay is low level triggered

long duration;
int distance;

int led1 = 8;
int led2 = 9;
int led3 = 10;
int led4 = 11;
int led5 = 12;
int led6 = 13;

void setup() {
  
pinMode (5,OUTPUT);
pinMode (8,OUTPUT);
pinMode (9,OUTPUT);
pinMode (10,OUTPUT);
pinMode (11,OUTPUT);
pinMode (12,OUTPUT);
pinMode (13,OUTPUT);

pinMode (trigPin,OUTPUT);
pinMode (echoPin,INPUT);
Serial.begin(9600);
}

void loop() {

digitalWrite(trigPin,LOW);
delayMicroseconds (2);

digitalWrite(trigPin,HIGH);
delayMicroseconds (10);
digitalWrite(trigPin,LOW);

duration = pulseIn(echoPin,HIGH);
digitalWrite(trigPin,HIGH);

distance = duration*0.034/2;

Serial.print("Distance: ");

if (distance <=70)
{
digitalWrite(5,LOW);
{
  digitalWrite(8,HIGH);   
  delay(2000);
  digitalWrite(9,HIGH);   
  delay(2000);
  digitalWrite(10,HIGH);   
  delay(2000);
  digitalWrite(11,HIGH);   
  delay(2000);
  digitalWrite(12,HIGH);   
  delay(2000);
  digitalWrite(13,HIGH);   
  delay(2000);
  digitalWrite(8,LOW);   
  delay(2000);
  digitalWrite(9,LOW);   
  delay(2000);
  digitalWrite(10,LOW);   
  delay(2000);
  digitalWrite(11,LOW);   
  delay(2000);
  digitalWrite(12,LOW);   
  delay(2000);
  digitalWrite(13,LOW);   
  delay(2000);
} 
digitalWrite(8,HIGH);   
  digitalWrite(9,HIGH);  
  digitalWrite(10,HIGH);   
  digitalWrite(11,HIGH);   
  digitalWrite(12,HIGH);   
  digitalWrite(13,HIGH); 
delay(10000); 
}                                          // to make lamp on
else
{
digitalWrite(5,HIGH); // to make lamp off
digitalWrite(8,LOW);   
  digitalWrite(9,LOW);   
  digitalWrite(10,LOW);   
  digitalWrite(11,LOW);   
  digitalWrite(12,LOW);   
  digitalWrite(13,LOW);   
delay(500);
}
}