Group 3.pptx

INTERPRETATION OF STREAMFLOW DATA ROWENA B. LAURENTE

IMPORTANCE OF STREAMFLOW DATA For water supply plans - to determine how much water is available in different locations to assure that there is an adequate water supply even during periods of drought. Engineering design - For building reservoirs, bridges, roads, culverts and treatment plants Flood planning and warning

TYPES OF STREAMFLOW DATA  WATER YEARS  HYDROGRAPHS

 MEAN ANNUAL RUNOFF

WATER YEAR What is a Water Year? Due to meteorological and geographical factors, the definition of the water years varies; the United States Geological Survey defines it as the period between October 1st of one year and September 30th of the next. The water year is designated by the calendar year in which it ends, so the 2010 water year (USGS) started on October 1, 2009 and ended on September 30, 2010.

Used to compare precipitation from one water year to another.

HYDROGRAPH A hydrograph is a graph showing the rate of flow (discharge) versus time past a specific point in a river, channel, or conduit carrying flow. The rate of flow is typically expressed in cubic meters or cubic feet per second (cms or cfs).

The hydrograph below shows rainfall and streamflow for a single day for Peachtree Creek at Atlanta, Georgia (USGS station number 02336300).

MEAN ANNUAL RUNOFF The average amount of water that flows down a particular river, per year, expressed either as a depth (in millimeters) of water spread evenly across the entire drainage basin, or as a volume (in cubic meters) of water flowing past a given point.