Influence of Climatic Variables on the Hydrology of a Montane Wetland

The effect of climatic and abiotic factors on the water quality of Oliver Creek in the Cloud Peak Wilderness Area of the Bighorn Mountains were studied by an international team of U.S. and Scottish high school students in the summer of 2000. Monitoring of atmospheric and stream conditions were performed over a three-week period in late June and early July. To fully understand the processes that encompass and surround a stream environment, it was necessary to study a wide variety of aspects relating to the stream ecosystem. Given the Oliver Creek's source, snow melt, studies were completed on the chemical aspects of snow melt, groundwater, and the stream. Factors such as snow, the riparian vegetation and soil environment, and weather patterns were studied to determine their influence on the stream.

Instruments to measure and record air temperature, relative humidity, wind speed and direction, incoming and outgoing radiation, and precipitation were positioned in the upper catchment area of the stream. In addition, transects of piezometers to study ground water properties were positioned across the valley floor. Physical characteristics of the stream including channel width, depth, and sinuousity, composition of substrate, and velocity and flow rate were determined. The stream banks were evaluated for steepness of slope, evidence of erosion, and percentage bare soil.

Physical-chemical assessment of the stream was performed using the tests of the National Sanitation Foundation's Water Quality Index (WQI) along with alkalinity and conductivity. Biological assessment of the benthic macroinvertebrate population was done using the indicator organisms of the Pollution Tolerance Index (PTI), with the Sequential Comparison Index (SCI) providing information on diversity and relative abundance.

Observed stream properties/behaviors were subdivided into three study areas: (1) factors producing changes in water quality parameters, (2) evaluation of load movement and substrate stability, and (3) fluvial transmission of a precipitation event. Information on Oliver Creek, located within the Bighorn National Forest, were provided to the U.S. Forestry Service to add to their limited data base of information for this part of the Cloud Peak Wilderness Area.