| Natural channel design stream restoration is used in the Catskill Mountains of NY to prevent stream bank erosion from polluting NYC's water supply and to improve stream habitat. Patterns of hyporheic exchange flow (HEF) around seven in-channel stream restoration structures in Batavia Kill were examined using stream and streambed temperature amplitude analysis and simulation of hydraulics with computational fluid dynamics (CFD). The results show how CFD simulation of open channel, porous media hydraulics can be used to predict how in-channel restoration structure designs affect HEF patterns. Stream temperature monitoring in Gooseberry Creek examined how channel morphology may influence stream temperature. Based on this work, the model Heat Source was modified to better predict stream temperature changes on small habitat-unit scales in streams with very heterogeneous land cover and morphology. The new model better predicted measured stream temperatures on average, based on Pearson correlation coefficient, Nash-Sutcliffe efficiency and root-mean-square error. |
