In the mid-to late 50s, the North Dakota oil industry entrepreneurs drilled commercially producing conventional wells. For nearly 25 years, North Dakota entrepreneurs, with the consent of North Dakota's leaders, ignored the warnings of the American Petroleum Institute.They utilized reserve pits, essentially convenient on site dump grounds. The earliest waste pits were placed wherever was convenient. The pits are sometimes called evaporation pits.They were not.They were percolation pits. Waste dumped in them, byproducts of oil production, chiefly brines, also called saltwater, also called produced water, also called return flows, along with chemicals, have polluted thousands of acres of North Dakota farmland.
In the late 70s, North Dakota regulators required entrepreneurs to utilize pit liners. Hydrologist, Jon Reiten of the Montana School of Mines, has much to say about pits. He declared that it was once a widespread practice to slash the pit liners when the well was retired and the site was reclaimed. The intent of the slash was to create a firm cover over the old reserve pit so that farmers would not get stuck driving machinery across it. The result was what Reiten called "spider webbing." The liquid salt flowed out of the limed pit just as was intended. The old pit ground became firm and passable by the heaviest machinery. The salt poison, however, flowed in a spider web fashon both above and below the surface of the earth sometimes reappearing as much as a mile away and there killing everything.
In North Dakota, the most widespread salt contaminated farm and ranchlands are those that are flat and wet. Eight northern tier counties in North Dakota have widespread pollution of farmlands. In Bottineau County well spacing allowed as many as 16 wells per section. That is four wells per quarter, one well per 40 acres, one pit each or one pit per 80 acres. Reiten calculated that each pit may contain 250 tons of salt, or expressed as a pile of livestoch salt blocks, a pile 25 feet by 25 feet by 18 feet tall. These pit salts leach both laterally and vertically. The leachate salt is called a plume. Pits have overlapping plumes which substantially destroy the farm or ranchland’s productivity, especially during wet and cool periods of time.
The key documents are attached and I provided a short explanation of each document.
The third attachment was written by Len J. Gawel, a PhD whose ideas are outdated. There is better science. The North Dakota Industrial Commission still relies upon the document. In short, the deficiencies are based on unsupportable optimism that ignores leaching of salt and a failure to understand the quantity of salt left behind in the conventional oilfield. Each old pit, on average, contains 250 tons of salt. More recent work by Austin Arabie will show that placement of a web of tiles and collection wells is the better approach. Pumping brines from the collection wells and plunging that salt into the earth is the only permanent remedy.
Ed Murphy reserve pit and brine studies done in the mid 1980's is the fundamental paper for salt contamination of flat and wet productive land in North Dakota. He warns that reserve pits will leach both laterally and vertically especially when wet conditions prevail. The proper remedy to prevent spreading is placement of a dome over the pit and curtain the pit to arrest its leachate.Figure 7 from leachate study of Murphy is an excellent but slightly dated illustration of leaching of salt both laterally and vertically.
Billingsley Oklahoma contamination shows a more sophisticated illustration. There are new insights being developed all the time about movement of contamination plumes. There is much to be learned and saved by testing and modeling. Agricultural consultant Marvin Nelson has made powerful presentations at public hearings and explained the predicament of spreading salt plumes. He has done an admirable job of collecting appropriate legal research. Each zone of contamination has variables depending upon the relief profile of the earth, the quantity of waters flowing or not, and soil types.