That the Navajo nation's agricultural project. It uses only surface water from Navajo Dam on the San Juan River. Their is a system of canals and pumps that deliver it to the fields. Infiltration from the irrigation dissolves minerals in the soil and seepage enters the deep arroyos that bisect the flat surface fields. This salty water enters the San Juan River and is transported down stream to Lake Powell and further. Nothing here releases significant methane.
Also, coal mined for both the Four Corners and San Juan Power plants is from surface mining or dry underground coal seam.
Well then I will have to completely change my system of absolute truth.
Now I believe it is irrefutable that the irrigation water is seeping into the ground and displacing accumulated methane.