Clear Creek near Golden, CO
Clear Creek is an important tributary of the South Platte River and provides water for several municipalities, including Golden and Westminster. A reconstruction (1685-1987) was first developed for Clear Creek in 1999 by Connie Woodhouse for the City of Westminster. An updated reconstruction (1635-1987) was developed by Woodhouse in 2003 for Wright Water Engineering, consultants for Coors Brewing Company, which obtains water for its brewery from Clear Creek. The latest reconstruction (1566-2002) was developed by Woodhouse and Jeff Lukas, for the City of Westminster. The calibration period includes the extreme drought year of 2002. This reconstruction is shown here.
References:
Woodhouse, C., and J. Lukas. Tree-ring reconstruction of Clear Creek annual streamflow, 1566-2002. Report to City of Westminster, August 2006.
Methods
A forward stepwise regression procedure was used to calibrate the observed flows with a pool of potential predictors consisting of 21 tree-ring chronologies from Colorado (both east-slope and west-slope). The residual chronologies, with the low-order autocorrelation removed, were used. Five predictor chronologies were selected by the stepwise procedure for the reconstruction model. Validation statistics were computed using a leave-one-out (cross-validation) approach.
Predictors: Van Bibber Update (CO), Dillon (CO), McPhee-Dolores (CO), Cochetopa Dome (CO), Chokecherry Canyon (CO)
| Statistic | Calibration | Validation |
| Explained variance (R2) | 0.70 | |
| Reduction of Error (RE) | 0.66 | |
| Standard Error of the Estimate | 27,439 AF | |
| Root Mean Square Error (RMSE) | 28,316 AF |
(For explanations of these statistics, see this document (PDF), and also the Reconstruction Case Study page.)
Figure 1. Scatterplot of observed and reconstructed Clear Creek annual flow, 1912-2002.
Figure 2. Observed (black) and reconstructed (blue) annual Clear Creek annual flow, 1912-2002. The observed mean is illustrated by the dashed line.
Figure 3. Reconstructed annual flow for Clear Creek (1566-2002) is shown in blue. Observed flow is shown in gray and the long-term reconstructed mean is shown by the dashed line.
Figure 4. The 10-year running mean (plotted on final year) of reconstructed Clear Creek flow, 1566-2002. Reconstructed values are shown in blue and observed values are shown in gray. The long-term reconstructed mean is shown by the dashed line.
