Area water managers were informed this morning that the Albuquerque Bernalillo County Water Utility Authority will shut down its diversion of water from the Rio Grande for use in the municipal drinking water system, switching over to groundwater pumping to meet municipal needs.
The reason is low flows in the river. Albuquerque is constrained by a 2004 “biological opinion” from the U.S. Fish and Wildlife Service, which requires the municipal utility to shut down to minimize impact on the endangered Rio Grande Silvery Minnow.
The water Albuquerque diverts – when we’re diverting – is half water from our San Juan-Chama Project transbasin diversion (Colorado River water!) and half native water. We then kinda sorta return the native water to the river via the wastewater treatment plant. The idea is that half of it we consumptively use by dumping the Colorado River water on our lawns and trees, while the native water we run down the sink, clean up, and return to the river – an accounting exercise intended to leave the river whole.
The creates a weird bonus in the short run for the river when this happens, because now we pump groundwater to meet all those needs, and then dump some of that into the Rio Grande, thereby increasing the river’s flows in the short run.
Last summer, for a brief period of time, that pumped groundwater/wastewater was the only thing keeping the Rio Grand wet through the southern end of the Albuquerque reach,.