Recap of the Conference of Science & Management on the Colorado Plateau & Southwest Region

biennialThe Flagstaff Chapter represented AHS during the 13th Biennial Conference of Science & Management on the Colorado Plateau & Southwest Region, October 5–8, 2015, at the High Country Conference Center in Flagstaff. Information about AHS was presented in our newly acquired tabletop display.

We are pleased to report that many attendees, including students and faculty, dropped by our booth and picked up information about AHS. A number of AHS members attended this conference and both Paul Whitefield (NPS) and Don Bills (USGS) gave oral presentations.

We were pleased to see a strong AHS presence at the conference.

Restoring Heiser Spring at Wupatki National Monument

paulWhitefieldWHITEFIELD, M.P., Resources Management Division, Flagstaff Area National Monuments, 6400 N Highway 89, Flagstaff, AZ 86004, USA, paul_whitefield@nps.gov

Abstract: Heiser Spring is fed via a local perched aquifer in the Moenkopi Formation, and is among the few sources of reliable surface water within Wupatki National Monument. Prior to Anglo settlement, the spring was utilized by Native Americans. Beginning in the early 20th century, Heiser Spring was sequentially relied upon as the primary water supply for a ranching homestead, an early archeological field camp, and a Depression era labor camp. The NPS purchased the homestead tract in 1950, and developed it into an operations facility and employee housing area. As a cumulative result of post-Anglo settlement use and development, Heiser Spring is among the most severely degraded natural features within the national monument. Between 1990 and 2002, the NPS phased out operations near the spring and removed most structures. The 2002 General Management Plan proposed formally abandoning operations area and restoring the springs to a more natural condition. Restoration planning was completed between 2007 and 2009, and restoration tasks were implemented during 2009 and 2010 by the NPS and partners under cooperative agreements. The total project area is 12 acres, and notable accomplishments include: removal of 2¼ tons of abandoned infrastructure and debris, demolition and removal of the four primary water diversion structures, closure of ⅓ mile of access road, herbicide treatment of 2½ acres of invasive camelthorn plants (Alhagi maurorum Medik.), and “dry-land” revegetation treatments on 1.35 acres. Follow-up actions since 2010 include: continued herbicide treatment of invasive camelthorn, continuous water table monitoring, and qualitative monitoring with repeat photographs and field observations. An overview will be presented on Heiser Spring and the restoration effort, including hydrogeology, history, reference conditions, restoration objectives, regulatory compliance, implementation, monitoring, and recovery of the area since 2010.

Monitoring and evaluation of the effects of natural, legacy, and current uranium mining water resources in the Grand Canyon Region of northern Arizona

donBillsBILLS, D.J., USGS, Arizona Water Science Center, Flagstaff, AZ, 86001, djbills@usgs.gov

Abstract: The Grand Canyon Region contains high-grade uranium ore hosted in geologic features called breccia pipes. The exploration and extraction of uranium ore from breccia pipes that are mineralized can pose potential risks to humans and biota of the region. From 2009 to 2013, the USGS has conducted regional water-chemistry studies to develop better baseline water-chemistry characterizations of the regional aquifers and other water-bearing zones in the region. This information is needed to better characterize regional water chemistry and changes in water chemistry of water resources exposed to unmined, mined and reclaimed, and actively mined orebodies. Currently, dissolved uranium in groundwater is about 5.0 μg/L or less regionally, except in proximity to uranium ore bodies where concentrations can be higher than 100 μg/L. Most of the higher uranium concentrations occur within a mile or two of naturally exposed ore bodies or ore bodies that have been mined and reclaimed, or left exposed since the 1970s and 1980s. USGS scientists are actively collecting the data needed to determine whether mining increases or changes uranium concentrations relative to natural levels. There is no evidence currently to link present-day mining activity to changes in local or regional water chemistry. The current discharge of total uranium in the Colorado River from the Grand Canyon Region have concentrations of 4.0 μg/L or less resulting in a total annual load of uranium delivered to Lake Mead of about 30 to 40 tons. This results in little if any impact to drinking water supplies to the Lower Colorado River States. Ongoing activities include additional data collection and monitoring to expand base-line water-chemistry characterization, monitoring to better understand temporal trends, and evaluation of the geochemistry of springs and nearby reclaimed mines. This study and ongoing activities also support ongoing biological assessments in the region.

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