Our elders have told us that if the zuzeca sape, the black snake, comes across our land, our world will end. Zuzeca has come – in the form of the Dakota Access pipeline – and so I must fight.

I am Sicangu/Oglala Lakota, born in Rosebud, South Dakota, and writing from the frontline of the movement against the pipeline in Cannon Ball. I have been holding this ground with my Standing Rock Sioux tribe relatives since the spring. I am defending the land and water of my people, as my ancestors did before me.

The $3.8bn pipeline project is proposed to carry approximately 470,000 barrels per day of fracked oil from our Bakken oil fields, 1,172 miles through the country’s heartland, to Illinois. The pipeline will cross the confluence of the Cannonball and Missouri rivers, where it threatens to contaminate our primary source of drinking water and damage the bordering Indigenous burial grounds, historic villages and sundance sites that surround the area in all directions. Those sites that were not desecrated when the area was flooded in 1948 by the construction of the Oahe dam are now in danger again.

I have seen where their machines clawed through the earth that once held my relatives’ villages

This week, I have witnessed pipeline construction tear its way toward the waters of the Missouri river which flow into the Mississippi, threatening to pollute the aquifer that carries drinking water to 10 million people. I have seen where their machines clawed through the earth that once held my relatives’ villages. I have watched law enforcement officials protect the oil industry by dragging away my indigenous brothers and sisters who stood up for our people.

The fact that Energy Transfer Partners, the company behind the pipeline, would use the word “Dakota”, which means “friend” or “ally”, in the name of its project is disrespectful. This pipeline is a direct threat to all Dakota, Lakota and Nakota people, especially our future generations. And we are not the only ones. We know that burning this oil is changing our climate and Indigenous people all over the world are bearing the brunt of the catastrophes that causes.

Tribune police arrested several people protesting the Dakota Access pipeline on a newly constructed roadway to be used in building the pipeline. Photograph: Tom Stromme/AP

This pipeline poses threats strikingly similar to those posed by the now defeated Keystone XL, but has received a fraction of the attention from mainstream media and big environmental groups. On 26 July, we were surprised to learn that the North Dakota permits were approved by the US Army Corps of Engineers to run the pipeline within a half-mile of our reservation. My tribal leaders have said that this done without consulting tribal governments, and without a meaningful study of the impacts it will have. This is a violation of federal law and, more importantly, of our treaties with the US government – the supreme law of the land.

It was my Ina, my mother, who first told me of this struggle. With my Ina, ciye (older brother), and tunwin (aunt) we have joined our Standing Rock relatives to face this new storm. For the past month, we have stood with Standing Rock in solidarity, we have prayed, we have cried, and we have also laughed, even when we thought it impossible to do so.

I never thought I would be on the frontline of a fight like this. I grew up admiring Crazy Horse, Sitting Bull, and my ancestor American Horse, for their courage and leadership in battle against their oppressors. Now I am fighting alongside their descendants, my relatives from all seven tribes, against the very same oppressors.

It saddens me that the government time and time again continues to ravage my people with the same treatment and attitude, only different weapons. But why should be surprised? This is the definition of insanity – to go through the same situations over and over believing the outcome will be different.

This camp was created as a last defense for the water that our communities depend on to survive. I have watched our numbers dwindle down to the single digits, and now we have swelled to over 300 people in just a few days. Hundreds more are on the way right now, as other tribes gather resources to send people and supplies.

This historic battle is bringing the Oceti Sakowin together like nothing has ever before. The Hunkpapa, the tribal band of Standing Rock, are now joined by the Oglala from Pine Ridge, the Sicangu from Rosebud, and relatives from Crow Creek, Cheyenne River, and Yankton, as well as Dine and Ponca relatives from the south, Ojibwe relatives from the Great Lakes, and countless others. From all across the country, tribes are bringing us shelter, food and most importantly, prayers.

To have all this unity of tribes standing together in solidarity before my eyes is a beautiful sight. Our tribes now live together, eat together, and pray together on the front lines.

We are not protesters. We are protectors. We are peacefully defending our land and our ways of life. We are standing together in prayer, and fighting for what is right. We are making history here. We invite you to stand with us in defiance of the black snake.