Ambient water includes water from sources such as lakes, streams and springs. While ambient water may relate to groundwater or drinking water, it is different in some crucial ways. Science Moab talked to Arne Hultquist, who is responsible for testing the ambient water quality in Grand and San Juan Counties in Utah, including Mill and Pack creeks. Hultquist is the watershed coordinator for Grand and San Juan counties and has been in the water quality field for over 30 years.
Science Moab: You are obviously very involved in testing water quality in these two counties. What does this entail?
Hultquist: My mission is to sample ambient water quality only. The city of Moab and the Grand Water & Sewer Service Agency are both partners of mine. I have nothing to do with the testing of the drinking water, and not necessarily groundwater quality. I focus on streams, lakes, and other ambient sources like springs.
Science Moab: Why test the ambient water from streams, lakes, and springs? What are you looking for?
Hultquist: The state is required by the Clean Water Act to test a portion of their waters to see if they meet ‘beneficial uses.’ The beneficial uses are a setup for whether the water itself is a potential source for drinking water, play, recreation, fisheries, or irrigation – or all of the above. In a desert community, it is sometimes tough to meet those minimal standards. It’s a challenge to keep water below 70 degrees Fahrenheit in the desert. For a cold water fishery, for instance in Mill Creek above the BLM boundary, coldwater fish have had to acclimate to warmer water.
Remember, humans are much larger animals than fish: our drinking waters generally have less restrictive standards than the coldwater and warm water fishery standards do. The other thing to remember with fish is that they don’t live in an average condition, they live in an instantaneous condition. They have to live in whatever they’re dealing with, whereas as humans [can] drink water from different sources. The point is that…the fish are much more susceptible to changes in those [chemical and heavy metal] concentrations than we are.
Science Moab: What are some of the main challenges in local ambient water that you find?
Hultquist: In our area, we generally have temperature as an issue, which really is a physical property, not a contaminant. The other one that can be an issue is dissolved oxygen. Fish are very susceptible to both. We do have issues throughout southeastern Utah with total dissolved solids. That’s the amount of solids and the amount of salt in the water, which goes along with low water flows and fairly salty soils. We do see higher total dissolved solids in southeastern Utah than you would find in more northern latitudes where waterflow is plentiful.
The only other constituent we find, which is naturally occurring, is selenium. Selenium is found in some of the soils around here, and especially Mancos Shale. In general, the higher the total dissolved solids, the higher the selenium. For humans, the consumption standard is 50 micrograms per liter. Whereas for juvenile fish, the standard is 4.7 micrograms per liter. So in terms of human consumption of those waters, the amount of selenium is nowhere near [concerning] levels. It’s when we look at the health of juvenile fish that we have an issue with selenium occuring in our waters.
Science Moab: Are there any other issues with our region’s ambient water that we should be concerned about?
Hultquist: We do have an issue with the E. coli bacteria in Spanish Valley and in Moab. Once you get into the urbanized area, E. coli levels increase due to manmade factors. The solutions to E. coli [contamination] are challenging to implement. Things that we can do are fencing cattle and keeping horses away from streams. We can put dog waystations throughout the county, especially by trails. We’ve asked for help from the Utah Division of Water Quality to do a study on the source of E. coli. This should be everyone’s concern and responsibility. Not one individual group or cause.
Science Moab: How does Grand County water compare with other towns in the Colorado Plateau?
Hultquist: As far as drinking water goes, we have some of the best drinking water in the state–a very high quality drinking water in Spanish Valley, which includes the city of Moab. It’s better than Green River, Blanding, Bluff and Monticello. Castle Valley’s another story. Depending upon where your well is, you could either have very good drinking water or horrible drinking water that you wouldn’t even want to drink.
As far as ambient water, we are fortunate there also. Although Pack Creek does have total dissolved solids in it, it’s nowhere near as salty as some of the other creeks in the southeast region that cannot be used for irrigation. Although Pack Creek does exceed state water quality standards only 10% of the time, no one that’s using Pack Creek for irrigation is having problems with their crops.
Science Moab: Why does Moab have such excellent drinking water?
Hultquist: The GWSSA distributes culinary water that is forced from the La Sal Mountains where it enters the groundwater and stays relatively uncontaminated until it is either drawn, or appears as springs in the lower Spanish Valley.
Science Moab is a nonprofit dedicated to engaging community members and visitors with the science happening in Southeast Utah and the Colorado Plateau. To learn more and listen to the rest of Arne Hultquist’s interview, visit www.sciencemoab.org/radio. This interview has been edited for clarity.
