Hydrology and Stream Flow Analysis its a fresh water ecology lab I’ve attached both the instruction sheet and the answer paper which will includw the graphs and describtion or answer for each please I want the excel file too to be attached Hydrology Lab Answer sheet
Hydrology is the study of water over and under the earth’s surface, and it encompasses
the hydrologic cycle—the processes that move water between various water storage
compartments and back again. Water is probably the most important factor that shapes the land,
and flow regimes are, of course, an important factor that influences the structure and function of
aquatic ecosystems. Consider for instance a headwater stream that receives surges of water from
a precipitation event. Flow regime in these streams is more “flashy” compared to larger rivers.
The organisms that make up the community in headwater streams should be expected to differ
from those in a larger river, which have less extreme flow regimes. Hydrology is also a complex
science with specific courses devoted to its content, so this emphasizes the need for
interdisciplinary approaches to watershed ecology and management.
Discharge (Q) is the most fundamental measurement in the study of water flow. It
measures the volume of water passing a given cross-section of stream channel per unit time
(m3/s, gal/min, ft3/s, cfs, etc.). The flow of water in a stream channel also has energy, i.e., the
capacity to do work, in that it can pick up and/or move material downstream. The ability of the
given discharge to do this work is a measure of stream power. Power depends on slope and
determines the distribution and character of sediment on the stream bed, which in turn influences
the distribution and abundance of aquatic organisms.
The objective of today’s lab is to explore some content in the field of hydrology by
working with flow data from this USGS Website (http://waterdata.usgs.gov/nwis/rt). Please visit
this website to get a feel for the kind of information that is available for the U.S., WV, or for
your home state. By understanding the nature of surface water flow, we can gain insight into
how human activities alter hydrologic regimes, often to the detriment of biota.
Problem Set #2: Hydrology and Stream Flow Analysis
Answer all question in the provided answer sheet
ACTIVITY #1: Discharge (Q) and Rating Curve
One way stream ecologists determine Q is by the area-velocity approach. Briefly,
average stream velocity (ft/s, m/s) recorded using a flow meter is multiplied by cross-sectional
area (ft2, m2) of the stream channel. This gives the volume of water passing through an
imaginary plane across the stream channel (ft3/s, m3/s) (see Fig.1 below). To be of much value,
discharge data should be recorded frequently to understand the variation in flow. This, of course,
is time consuming using the area-velocity approach, and furthermore, it can be dangerous or
impossible at high flows. Therefore, gauging stations (Fig. 1 below) have been set up at a
number of locations to continuously measure and record river stage heights. Discharge can then
be estimated from a rating curve once actual discharge measurements have been determined at
Go to the USGS website link for real-time flow data. Click on the state of WV. Select
several of the stations to view their daily stream flow conditions. Note the recent real-time data
and the hydrograph. Now, look at the hydrograph for the station at Big Sandy Creek (In Mon
River basin) at Rockville, WV (the northern most station in Preston County). In the blue box
detailing the available data for this site, select to view data beginning on 2018-01-16 and ending
Question 1 (6 PTS.): How does the slope of rising limbs of high flows compare to the
slope of falling limbs? Copy and paste the hydrograph as part of question one. Interpret the
meaning of this flow pattern. (Hint: you can create a good graph to copy by clicking Stand-alone
Next, click on another site of your choice to retrieve station information, click summary
of all available data for this site. In the “Available data for this site” drop-down box under the
station code and name, select “Surface-water: Field Measurements.” Look at the data available,
specifically Inside or Outside Gage (Stage) height and discharge (discharge is sometimes listed
as “stream flow”). Make sure that the site you choose has a fairly long record of measurements
(at least 20 years), and download it for analysis in EXCEL. To do this, click on “Reselect
Output Format” and then check “tab separated data” at about the middle of the page under
“Choose Output Format.” Finally, click “submit” to retrieve it. You will have to type the
extension “.xls” (measurements → measurements.xls) on the file after it is downloaded. Be sure
to remember where on your disk you saved the file. Then, open the file in EXCEL (you may
have to adjust column widths to see all the data).
Question 2 (8 PTS): Create a plot of stage (y-axis; use either inside or outside gauge
height or the one with the most data entries) as a function of discharge (x-axis). Fit the data
with the best trend line, and place the equation of the line and R2-value on the graph. Define
stage. What is the value (or purpose) to constructing a rating curve? (hint: think prediction)
ACTIVITY #2: Flow regime analysis
(a) Discharge and Basin Area:
On the USGS site, select the state of WV. Next to the picture of WV click “Statewide
Streamflow Table” link. When the page loads, scroll down to the Monongahela River basin.
What should follow is a series sites in the Monongahela basin, including all of the rivers falling
within the Cheat River basin, that have gauging stations that record flow data. About five of
these sites have good long term flow data. Download the annual stream flow statistics for each
of the following sites (directions follow):
1) Dry Fork at Hendricks,
2) Blackwater River at Davis,
3) Shavers Fork Below Bowden,
4) Cheat River Near Parsons, and
5) Big Sandy Creek at Rockville.
To do this, click on the “Site Number” for one of the sites. This will take you to realtime data for the site. Note the basin (drainage) area (in square miles) for the site and record it in
the table below. From the “Available data for this site” drop-down box, select “Time Series:
annual statistics.” Check “Discharge, cubic feet per second”, then select your output format as
“Tab-separated data” and “Submit.” Save the file to a known location on your disk with the
“.xls” extension. Repeat this procedure for each of the stations listed. Be sure to give each file
an appropriate name, such as “dry_fork_annual.xls,” so that you don’t confuse sites. When
complete, open the files in EXCEL, and calculate the mean annual discharge over the period of
record (use the command “=average (data range)” in EXCEL). Write down the average annual
discharge for each site in the following table:
Dry Fork at Hendricks
Blackwater River at Davis
Shavers Fork Below Bowden
Cheat River Near Parsons
Big Sandy Creek at Rockville
Basin Area (sq mi)
Ave Annual Q (cfs)
Now that you have basin area (mile2) and mean annual discharge (Q—ft3/s) for each of
the five sites, enter it into EXCEL, and do the following:
Question 3(10 PTS). Re-create the above table in EXCEL. Plot discharge (y-axis) as a
function of basin area (x-axis) for all sites in one figure. Include the best fit trend line (linear)
and the R2-value. What can you conclude about the relation between mean annual discharge and
basin area (refer to your figures and table)?
(b) Mean Flow and Time
Choose another site that interests you, either in WV or another state, and make sure it has
long term data (at least 20 years) and has discharge data. Download the following data for your
location: 1) “Time-series: daily statistics,” 2) “Time-series: annual statistics,” and 3) “Surfacewater: peak streamflow.” Download the data like you did before. For example, click on
“Available data for this site” drop down box and choose “Time-series: daily statistics.” Then,
select “Discharge, cubic feet per second,” and “Tab-separated data”, and then click “Submit.”
For the peak stream flow, you will have to click the “Reselect output format” button first to get
to where you select the data in “Tab-separated data” format. Save the files for analysis in
EXCEL. I suggest naming the files: “your_site_daily.xls,” “your_site_annual.xls,” and
Question 4 (6 PTS). Create a table presenting the name of your site, county, state and
calculated values. Calculated values to report include: the daily, annual, and annual-peak mean
discharges. Again, simply take the average of the numbers in the column labeled “mean_va” (or
“peak_va” for the peak dat.). In EXCEL the syntax is “=average(data_range). Note: annualmean peak flow is the average annual flood.
(c) Rating Curve and Flood Frequency
For your annual peak flow data (your_site_peak.xls), sort the flow (the column labeled
“peak_va”) according to magnitude by using the sort data function in EXCEL. Then rank the
data where the highest flow =1, next highest =2, and so on (write a formula in EXCEL to
automate this rather than doing it manually). Hint: to make things easier and cleaner, you might
want to delete all the other data that is in the file, and leave only 3 columns of data: one with the
date (“peak_dt”), one with the peak discharge (“peak_va”), and one with the gage height
Then calculate the recurrence interval (T) of each peak flow in your record with the
following formula: T = (n+1)/m, where n = the number of years in the record and m = the rank
of that peak flow in the record. This is easily automated in EXCEL and the syntax would be
something like “=(n+1)/C3”, where C3 is the rank for a year of interest. Remember to just
“drag” the formula you have just written down the column to automatically fill in the rest of the
column. Also, calculate the probability of exceedance (P) for each peak flow, which is just the
reciprocal of T. Here, the EXCEL syntax would be “=1/cell_reference_to_T” followed by
dragging the formula down the column.
Question 5 (6 PTS). Make a scatterplot of flood discharge (y-axis) against T and P on
two separate graphs. Fit the data with the best trend line and display the equation and R2 value.
In a sentence or two (or more), interpret the general meaning of these graphs.
(d) Return Period
The mean annual flood (i.e., the average of all the maximum annual discharges in a time
series) should have a recurrence interval of once every 2.33 years. (Hint: you should refer back
to #4, compare average to the return period you just calculated.)
Question 6 (6 PTS). Given your data, where does your average annual flood (from
Question # 4) plot on your graph of recurrence interval (Question # 5). Does it occur at
approximately 2.33 years? If not, what flow does occur at 2.33 years according to your data
(Hint: use your regression equation to get this estimate)?
Question 7 (4 PTS). As a separate question, what is the probability of occurrence (P) for
a 1.5-year and the 20-year magnitude flow in a given year? Use the equation P = 1/T (Hint: do
not over-think this question).
Question 8 (4 PTS). Would you be comfortable extending your data to predict the
discharge that has a return period of 500 years on average (i.e., for a 500-year flood flow, or
even a 200 year flood) if you only have 100 years of flow data? Justify your answer. (Think back
to your ratings curve you made for #2, how accurate was it at high levels of discharge?)
Make your figures look like this.
Example Figure. Flood frequency curve for the Susquehanna River at Marietta, PA. The
extreme outlier represents the flood of June 1972 from Hurricane Agnes. Discharge recorded
(1,080,000 cfs) was affected to an unknown degree by flow regulation and diversions.
Annunal Maximum Discharge (cfs x 1000)
Equation for line of fit
Return Interval (years)
Figure X. Give this an appropriate caption.
Figure 1. Area-velocity approach to calculating discharge (left). Gauging station (right).
For Further Reading
Leopold LB, Wolman MG, Miller JP. 1964. Fluvial processes in geomorphology. W. H.
Freeman and Company, San Francisco, CA.
Leopold LB. 1994. A view of the river. Harvard University Press, Cambridge, MA.
Leopold LB. 1997. Water, rivers and creeks. University Science Books, Sausalito, CA.
Ritter DF, Kochel RC, Miller JR. 2001. Process geomorphology. McGraw-Hill.
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