Surface Runoff and Hydrograph Components Describe runoff drainage patterns Identify stream order Sketch components of a runoff hydrograph Compare how basin features, storm location and direction affect hydrograph properties Compute baseflow and direct runoff volumes Describe steps involved in calculating runoff hydrography from rainfall (will quantify next time) Mays pages 327-334

Runoff drainage patterns B. Dendritic - uniform erosion Rectangular – faults Trellis on folded terrain Trellis on mature coastal plain C. D. From Mays, 2011, Ground and Surface Water Hydrology

Example. What type of drainage pattern does the Logan River watershed exhibit? Dendritic -uniform erosion Rectangular –faults Trellis on folded terrain Trellis on mature coastal plain

Basin order is the highest order branch -- at the outlet) Stream Order 1 = non-branching 2 = only receive 1st order streams Basin order is the highest order branch -- at the outlet) From Mays, 2011, Ground and Surface Water Hydrology

Example. What is the stream order at X, Y 2 X 1 1 2 3 4 5 3 Y CEE 3430

Separating sources of streamflow Dry Wet From Mays, 2011, Ground and Surface Water Hydrology

Effects of basin features on the hydrograph Slope Roughness Storage A B

Effects of storm location and direction on the hydrograph

Effect of Watershed Shape: Which hydrograph is associated with each watershed 1 B 2 3 C

Example. How do the Logan River hydrographs at First Dam for 2009 and 2011 differ? CEE 3430

Example. What is the volume of direct runoff (in mm) from a 120 ha catchment with a baseflow of 0.05 m3/s and the specified discharge hydrograph?

Direct Runoff and Rainfall Excess Time From Mays, 2011, Ground and Surface Water Hydrology

Rainfall – Runoff Analysis From Mays, 2011, Ground and Surface Water Hydrology

Today we… Described runoff drainage patterns Identified stream order Sketched components of a runoff hydrograph Compared how basin features, storm location and direction affect hydrograph properties Computed baseflow and direct runoff volumes Described steps involved in calculating runoff hydrography from rainfall (will quantify next time)