Basic Data Analysis for Time Series with R

19 CHRISTOPHER TENNANT/BEN CROSBY WATERSHED DATA

19.1 BACKGROUND AND QUESTION

This data, due to graduate student Christopher Tennant and Professor Ben Crosby of the Idaho State University Geosciences department, is a measure of water flow rates at 12 watersheds in Idaho. The watersheds are contained within three different elevation ranges, representing different types of precipitation (low elevations have precipitation dominated by rain, higher elevations have snow-dominated precipitation, and the mid-elevations have mixed precipitation). The data is in the Tennant folder on the data disk (this data is not in DataMarket):

• Low (rain) elevation: Baker Gulch, Gregory Creek, Rice Creek, Rock Creek.
• Mid (mixed) elevation: Boulder Creek, Little Goose Creek, North Fork Slate Creek, Slate Creek.
• High elevation (snow): Beaver Creek, Frenchman Creek, Salmon River, Smiley Creek.

The final measurement, which was taken for 1054 days (2.89 years) was normalized discharge (the volume of discharge per unit of time divided by the surface area of the watershed). The final units are millimeters per day. Normalized discharge reveals the amount of water contributed per unit area from a drainage basin and provides a convenient measure for comparing water flux from watersheds of different size.

This is a preliminary analysis of the data and the interest is in whether the three regimes behave differently. In the main analysis, an exploration of whether the low and mid-elevations produce different ...