1) (13 points) Determine the evapotranspiration rate in the drainage basin of the Peconic River (Eastern Long Island) by using the hydrologic balance equation and discharge and precipitation data.
a) Download the discharge and
precipitation data for
the Peconic river at Riverhead, and three precipitation stations
in the area: Bridgehampton, Greenport Powerhouse, and Riverhead
Research Farm. The data are in tabulated text format (.TXT). Save
the file and open it in EXCEL. Make sure to save it immediately as
an EXCEL file, e.g. PECONIC.XLSX. Look at a map that shows the location of the
streamgage (Riverhead, Long Island) and current
USGS info about the site
b) (4 points) Plot the discharge rate and the precipitation at Riverhead as a combination diagram with two Y-scales as a function of time. Discharge should be plotted as a line, precipitation as bars. Make sure that the axes are properly labeled. Print the graph.
c) (3 points) Explain in a few sentences the relationship between discharge and precipitation.
d) (3 points) Make the best estimate of total precipitation for the drainage area using the data for the three weather stations. The size of the drainage area is given in the data file.
e) (3 points) Determine the average evapotranspiration
rate for the two given months using the precipitation and
discharge data given. Assume that the groundwater is in steady
state, i.e. there is no change in storage. How much (%) of the
precipitation is lost by evapotranspiration in the basin? (of
course your answer must be in the range of 1 to 100%)
Please describe in a couple of short
paragraphs what we did with the laminar flow table and how the
results relate to Bernoulli law. Look again at the outline
of the exercises we did.
4) (8 points) Weir experiment
a+b) The Google
doc we created on Tuesday contains data
obtained with the Weir experiment in Mudd. Download the
spreadsheet, fill in the missing columns and plot the discharge
rate Q as a function of H (a) and then (b) of H2.5.
Do it with the data of your group only, then all data combined
(you can use different symbols for the different group) .
c)
Draw by hand a fit through the data points in a), what shape
should the curve have?
d)
Data in plot b) should follow a straight line. Make a linear
fit, set the intercept to 0 and determine the slope of the graph
(this is an option when you fit the data with a line). How well
do the data plot on a straight line? What value did you obtain
for the experiments for Cd? (g=9.81 m s-2;
the angle of the weir was 90o). Watch the units!
e) Do you have any explanation for the data points that do not fit the general trend?
5) (8 points) Bernoulli experiment