How are data collected

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How are data collected transmitted?
Stage is the easiest data to collect. It is the
height of the water surface above a reference
elevation. Users of streamflow data find it
necessary to have discharge information about a
stream. Discharge is the volume of flow passing a
specified point in a given interval of time and
it is usually measured in cubic feet per second
(cfs).

• Image and information from http//www.state.nj.us
  /drbc/gage/gageshp.htm

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Questions from Flood Frequency Analysis

• Why 2 peak flows in the same calendar year?
• Do the peak flows appear to occur at a particular
  time of year? If so when?
• Excel, , decimals, wrap text
• How are measurements made? gt How do stream gages
  work?

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Stage gt Discharge

• Discharge is usually estimated from
  stage/discharge relations known as rating curves.
  
• In order to develop a rating curve, USGS field
  personnel must visit a gaging station to measure
  river discharge and compare it to the stage.
• A Current Meter is the instrument that is
  frequently used to perform discharge
  measurements. Year after year, discharge and
  stage data are gathered in the field, sometimes
  as often as once a month. Over time, a
  stage/discharge rating curve is gradually
  developed. Unfortunately, rating curves are never
  fully complete due to the constant changes
  occurring in rivers and streams.

Example of a Current Meter http//water.usgs.gov/p
ubs/circ/circ1123/
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• The width of the stream is divided into a number
  of increments
• the size of the increments depends on the depth
  and velocity of the stream.
• The purpose is to divide the section into about
  25 increments with approximately equal
  discharges.
• For each incremental width, the stream depth and
  average velocity of flow are measured.
• For each incremental width, the meter is placed
  at a depth where average velocity is expected to
  occur.
• That depth has been determined to be about 0.6 of
  the distance from the water surface to the
  streambed when depths are shallow.
• When depths are large, the average velocity is
  best represented by averaging velocity readings
  at 0.2 and 0.8 of the distance from the water
  surface to the streambed.
• The product of the width, depth, and velocity of
  the section is the discharge through that
  increment of the cross section. The total of the
  incremental section discharges equals the
  discharge of the river.

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Developing a Rating Curve

• USGS makes over 60,000 discharge measurements
  each year.
• The more unstable the river bed the more often
  measurements need to be made.

Image from http//water.usgs.gov/pubs/circ/circ11
23/collection.htmlHDR9
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Uses of Streamflow Data

• Enhancing the public safety by providing data for
  forecasting and managing floods
• Characterizing current water-quality conditions
• Determining input rates of various pollutants
  into lakes, reservoirs, or estuaries
• Computing the loads of sediment and chemical
  constituents
• Understanding the biological effects of
  contamination
• Delineating and managing flood plains
• Operating and designing multipurpose reservoirs
• Setting permit requirements for discharge of
  treated wastewater
• Designing highway bridges and culverts
• Setting minimum flow requirements for meeting
  aquatic life goals
• From http//water.usgs.gov/pubs/circ/circ1123/ove
  rview.htmlHDR4

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Uses of Streamflow Data

• Monitoring compliance with minimum flow
  requirements
• Developing or operating recreation facilities
• Scheduling power production
• Designing, operating, and maintaining navigation
  facilities
• Allocating water for municipal, industrial, and
  irrigation uses
• Administering compacts or resolving conflicts on
  interstate rivers
• Defining and apportioning the water resources at
  our international borders
• Evaluating surface- and ground-water interaction
• Undertaking scientific studies of long-term
  changes in the hydrologic cycle
• From http//water.usgs.gov/pubs/circ/circ1123/ove
  rview.htmlHDR4

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Possible Letter to a Legislator MA, RI, NY

• http//waterdata.usgs.gov/ma/nwis/rt
• This national network is the principal tool used
  to measure surface-water supplies in each state.

9
Water Quality
10
Clean Water a Billion Growth Industry

• The calcium scaling in a water cooling pipe is
  one example of the industrial casualties on
  display in the lab's lobby.
• From http//www.nytimes.com/2004/02/15/business/y
  ourmoney/15water.html?pagewanted2th

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Growth/Development in Colorado
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Waste water flow into CT River How bad?

• January - 55 mgal in one day flowed largely
  untreated, into the CT River from the Cromwell
  (Mattabesset) waste water treatment plant
• How does this compare with the flow in the river?
• cubic foot of water contains 7.48 gallons

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(No Transcript)
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• 1cf 7.48 gallons
• 55,000,000gallons
• 7,352,941 cf
• How much water passed by the outflow area?
• cfs 60 s/min 60 min/hr 24 hr/day
• If cfs 30,000 then
• Cf/minute 1,800,000
• Cf/hr108,000,000 hr
• Cf/day 2,592,000,000

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Hectares Available - roughly

• Earth surface area 51 billion hectares
• 13.1 billion hectares not covered by ice or water
• 8.9 billion hectares ecologically productive
  cropland, permanent pastures, forests and
  woodland.
• 1.5 billion hectares occupied by large deserts
• 1.2 billion hectares semi-arid areas
• 1.5 billion includes grassland not used for
  pasture, wasteland (includes 0.2 billion hectares
  built up areas)

16
Ten Simple Steps to ReducingYour Family's Global
Warming Impact

• Union of Concerned Scientists http//www.ucsusa.or
  g/greatlakes/glsolutionsperson.html