Using CBM Produced Water for Irrigation.

Irrigation of crops with water produced from CBM wells can be an effective use of the water if it is managed carefully. As with ANY irrigation of land, there are certain environmental and economic considerations that make it prohibitive as a complete solution.

1. In any irrigation situation, that ground must be treated with minerals that counteract the minerals that will accumulate from the water used in irrigation. Irrigation often works well on sandy soils, uncommon to the Powder River Basin. Farmers, ranchers, or the CBM Operator that are familiar with general irrigation will need to monitor the irrigated soil for proper treatment and mineral balancing. There are costs associated with these treatments and soil management that often are born by the CBM operator. A CBM Operator must first get a soil study, approval from the landowner, proper regulatory permits, and there may be a negotiated damage settlement with the landowner.

2. Irrigation is an expensive treatment option with a large capital outlay. Irrigation involves a large purchase of infrastructure to pipe the water from each well to the location that the irrigation will occur, the purchase of irrigation equipment such as a side-roll, water cannon, center pivot, hand sets, or drip system.

3. Atomization can be considered another form of irrigation utilizing a tall pipe topped by fine-particle spray nozzle for water dispersal. Yet the intent of this method is to obtain high evaporation rates. Unfortunately, this usually causes a higher concentration of minerals and salts to reach the ground, requiring more soil treatment. Currently, no NPDES permit is required for this method.

4. Irrigation can generally only occur during certain summer months, thus, if permitting is obtained, the landowner approves, and the capital is spent on irrigation infrastructure, the produced water can only be discharged with irrigation for a few months of the year. This requires that the water be managed in some other fashion during the winter months or the CBM wells will be shut down during the period when irrigation can not occur.