Warm Springs Ducks Unlimited Pond 



Climatic setting. The net annual precipitation balance for the 

 Warm Springs DU pond (from the MAPS database) is -20 inches, 

 placing the site mid-range in evaporative intensity when compared 

 to other sites of the intermontane basins. Mean monthly 

 precipitation for the Anaconda climatic station shows a broad 

 summertime maximum. The 3-year running average of annual 

 precipitation was below the long-term average from 1986 through 

 1992. In 1993 (the year prior to sampling), precipitation exceeded 

 the long-term average by about 8 inches. Regionally, precipitation 

 totals in 1994 were below average. 



Geologic setting. The WET75 site is underlain by alluvial fan 

 sediments deposited by Warm Springs Creek. Fan sediments are 

 relatively thin (a few tens of feet) and are underlain by valley- 

 fill sediments of Tertiary age. Recent surficial sediments in the 

 Warm Springs Creek area are pervasively contaminated with mineral 

 processing wastes. Shallow water table depths and ground-water 

 discharge from shallow flow systems characterize the lower Warm 

 Springs Creek fan near the WET75 site. Discharge from a deep- 

 circulating geothermal flow system also occurs nearby, supporting 

 the local hot springs. 



Hydrologic type. The Ducks Unlimited pond is a depression of 

 unknown origin in the Warm Springs fan sediments, seasonally(?) 

 intersecting the water table surface. The wetland is augmented by 

 water imports diverted from Warm Springs Creek. The water body 

 does not appear to have a surface outlet but is inferred to 

 discharge to the shallow ground-water system under at least some 

 conditions. 



Basin characteristics. The DU pond has a minimal natural surface 

 catchment but is believed to receive ground-water recharged over 

 a broad area, as well as diverted Warm Springs Creek water. The 

 depth of the small water body is uncertain and has been subject to 

 modification to meet wildlife habitat objectives. 



Water chemistry. The DU pond contains dilute calcium- 

 sulf ate/bicarbonate water with moderately low alkalinity and basic 

 pH. Mineral equilibria indicate slight oversaturation with 

 carbonate phases. Ammonium, nitrate, and phosphorous 

 concentrations rank mid-range with respect to sample sites in the 

 intermontane valleys. (Phosphorous concentrations are low, 

 however, in comparison to other sites lacking surface water 

 outflow. ) The total organic carbon concentration was among the 

 lowest sampled. 



Trace element concentrations in the water column were generally 

 low. Iron and arsenic concentrations ranked toward the lower end 

 of the ranges shown for western sites. The copper and aluminum 

 concentrations ranked mid-range within the site class, and most 

 other trace elements analyzed occurred at concentrations below 



