TEACHING THE HYDROLOGIC AND GEOMORPHIC SIGNIFICANCE OF DRAINAGE BASINS AND DISCHARGE IN PHYSICAL-GEOGRAPHY

Drainage basins, stream discharge, and sediment discharge are fundamen tal concepts in physical geography, and they play an integral part in other cognate disciplines. To enhance student understanding of water a nd sediment discharge there needs to be an integration of field-based monitoring exercises with classroom exercises using readily available (published) discharge data from water resource agencies. This paper ou tlines two groups of exercises. The first set of exercises involves a combination of field-based monitoring and associated laboratory analys is, and they include the following worked examples for Manoa Stream, O ahu, Hawai'i: 1) discharge measurement using the velocity-area techniq ue, 2) measurement of suspended sediment concentration, and computatio n of suspended sediment load, yield and erosion rates for a drainage b asin, and 3) determination of channel hydraulic parameters. The second set of exercises was developed for students who are not able to condu ct field monitoring. These may also be used by students who have compl eted field discharge monitoring. These exercises focus on readily avai lable daily discharge data for several drainage basins in Hawai'i, and worked examples include: 1) developing annual stream discharge hydrog raphs for drainage basins of different size, 2) comparing river regime s of local systems to global models, and 3) developing flow-duration c urves for different drainage basins. Utilization of real-world dischar ge data allows students the opportunity to explore relationships and t o grasp the underlying controls on discharge variation from drainage b asins. These are important aspects in developing an understanding of w ater and sediment linkages within environmental systems.