This is a post for World Water Day. See more posts about transboundary water at Cr!key Creek.
For the past two years, my intro Earth Science students have been doing a project monitoring one of our local rivers. On the one hand, it’s just another stream, small enough for students to safely wade into it with a current meter. On the other… it’s our town’s water source, and every drop of it is promised at least once, for irrigation, for municipal water supplies, for fish, for electricity, for a treaty between the US and Mexico.
The Florida River (Flor-EE-da, the Spanish word for “flowery”) is, in some ways, a microcosm of water use in the Rockies. It’s fed by snowmelt in the Weminuche Wilderness, in an area of Precambrian granite that was explored for mining, but didn’t produce much. The water is stored behind a dam at about 8000 feet above sea level, and released little by little in summer, when irrigation in both the ranches and the city increases water demand. After the water leaves the reservoir, some of it goes through a canal, over a drainage divide, and into the city reservoir for Durango. Some of that water evaporates, some trickles into the groundwater that feeds the Animas River, and some goes through the city’s sewage treatment plant (and then into the Animas). Other water gets used for irrigation in the Florida River basin. A lot of the irrigated land sits above a perched water table between the Florida and Animas Rivers, and provides groundwater for household wells in the unincorporated county.
When the Florida River joins the Animas, its water is considerably more salty than when it left the wilderness. My class has some good discussions about this – does evaporation of the irrigated water increase the concentration of salt, or are we looking at salt that comes from the local rocks? (One of the tributaries is called Salt Creek. We haven’t tried to find out why.) That water goes on to New Mexico, where the water is used for more agriculture and more city water, and then to the San Juan River, and the Colorado River at Lake Powell, and on and on through the Grand Canyon and Lake Mead and water taps in Las Vegas or irrigation in the Imperial Valley or, maybe, across the border into Mexico. Maybe the lettuce in your salad was watered with recycled Colorado snowmelt.
Until this past summer, I wasn’t much of a participant in this cycle (except at work). I lived out of town, in an unirrigated area on the edge of the next drainage basin to the east. I got my water from a community well drilled into fractured low-permeability rock, and I think that water had a pretty short cycle from nearby snowmelt to our well. The well ran dry every so often, so we tried to use as little water as possible for drinking, short showers, dishes, and occasionally laundry. I killed our tiny patch of lawn through neglect and unwillingness to water, and did all my landscaping with rock and cheatgrass.
But last summer I moved into town, into a house with city water. Now I have a lawn, and neighbors. The lawn is small, and most of the other plants are drought-tolerant, but still… I have a lawn. And I water it, a couple times a week in the evening during the peak of summer heat. And I’m thinking of planting a small garden and growing spinach, lettuce, zucchini, and pumpkins (so I won’t get in trouble with the kid for waiting too long before Halloween). We have to pay a water bill, but the costs are hidden with the costs of garbage and sewer. It’s not the obvious feedback that I got from a dry well. And with the water bill comes confidence that the water will not be shut off, even though the city’s water rights are junior to the agricultural users downstream, and even though my part of the Colorado River basin has to make sure that enough water goes past Lee’s Ferry to satisfy the Colorado River Compact.
There’s a new reservoir being built in town – the Animas-La Plata project, which will pump water out of the Animas River and store it in a valley above the river, to be released when necessary. The reservoir is supposed to supply water to the Southern Ute and Ute Mountain Ute tribes, whose water rights should be senior to all of ours. In practice, the city of Durango has its eye on the water. Will the reservoir make it that much easier to ignore the ongoing drought?
We’re legally obligated to share our water with several tribes, five states, and one country. But even in a fairly eco-conscious community, I’m not sure that most people understand what that might imply.