The Tale of the Tape

1
The Tale of the Tape

• Measuring Pond Surface Area and Volume for
  Stocking and Chemical ApplicationsBilly
  Higginbotham
• Professor and Extension Wildlife and Fisheries
  Specialist
• Texas Cooperative Extension

2
How Big is Your Pond?

• Its a 2,000 yard pond.
• My ponds pretty small.
• Its about an acre, I guess.
• My ponds real big.

3
Why Measure?

• Surface area
• Fish stocking
• Carrying capacity
• A few chemical applications
• Volume - most chemical applications

4
What Do I Measure?

• Surface area in acres
• Volume in acre-feet

5
So What is an Acre?

• 1 surface acre 43,560 square feetEquivalent
  to a square 209 x 209 a circle 235
  across

6
How Do I Measure Surface Area?

• Pace it off
• Tape measure
• Range finders
• Aerial photos
• Geographic Information Systems (GIS)

7
Determining Surface Area

• Three basic pond shapes
• Square or rectangular
• Triangular
• Circular
• (or a combination of 2 of the 3)

8
Area of a Square or Rectangle
Length
Width
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An Acre-foot of Water is

• 1 surface acre 1 foot deep
• 43,560 cubic feet
• 326,000 gallons

10
Determining Pond Volume

• Pond Volume surface area (acres) x
• average depth (feet)

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How Do I Measure Depth?

• Guess!
• Depth finder
• Calibrated rope and anchor
• Calibrated pole

12
Measuring Pond Depth

• Take at least 2 perpendicular transects
• Begin at one bank with zero and end with zero
• The more transects and depth soundings taken, the
  better your depth estimate becomes
• Average depth is always LESS than you suspected
  BM (Before Measuring)!

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Measuring Depth

x
x
x
x
x
x x x x x x x x x x
x x x x x x x x x x x x x x x x x
x
x
x
x
x
x
x

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Determining Average Depth

• Average depth sum of soundings
• (feet) ? number of soundings
• Transect 1 - 0,2,3,6,6,8,7,5,3,1,0
• Transect 2 - 0,1,1,1,3,4,8,6,6,4,1,0
• 76 feet ? 23 3.3 feet

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Determining Average Depth

• If you do not include zeros
• Transect 1 - 2,3,6,6,8,7,5,3,1
• Transect 2 - 1,1,3,4,8,6,6,4,1
• 76 feet ? 19 4.0 feet

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Determining Surface Area in Acres

• Square or Rectangular Pond
• Length (ft.) x Width (ft.) ? 43,560Acres

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Determining Surface Area in Acres

• Square or Rectangular Pond
• Length (ft.) x Width (ft.) ? 43,560Acres
• Example Pond is 200 x 350 70,000 square
  feet
• 70,000 ? 43,560 1.6 surface acres

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Determining Volume in Acre-Feet

• Square or Rectangular Pond
• Example pond is 200 x 350 70,000 square
  feet
• 70,000 ? 43,560 1.6 acres
• Average depth 3.2 feet
• 1.6 acres x 3.2 feet 5.1 acre-feet of water

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Determining Surface Area in Acres

• Triangular Pond1/2 base (ft.) x height (ft.) ?
  43,560 acres

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Area of a Triangle
Base
Height
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Determining Surface Area in Acres

• Triangular Pond1/2 base (ft.) x height (ft.) ?
  43,560 acres
• Example pond is 200 along the dam x 500
  to upper end
• 1/2 (200 x 500) ? 43,560 1.1
  surface acres

22
Measuring Depth
x
x x x x x x x x x
x
x x x x x x
x x
x
23
Determining Volume in Acre-Feet

• Triangular Pond
• Example pond averages 4.2 feet deep and is 200
  along the dam x 500 to upper end
• 1/2 (200 x 500) 50,000 ? 43,560
• 1.1 surface acres
• 1.1 surface acres x 4.2 feet
• 4.6 acre-feet of water

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Determining Surface Area in Acres

• Circular Pond ? x (radius)2 ? 43,560 acres
  ? is the ratio of the pond circumference to the
  pond diameter and approximates 3.14The pond
  radius is 1/2 of the pond diameter

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Determining Surface Area in Acres

• Circular Pond ? x (radius)2 ? 43,560 acres
• Example Pond is 150 across the middle
  (diameter)
• ? 3.14 and radius 75, so
• 3.14 x (75)2 ? 43,560 0.41 acres

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Area of a Circle
Radius
27
Area of a Circle
Diameter
28
Measuring Depth

x
x x
x x x x x x x x x x x x x x x
x
x x
x x
x
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Determining Volume in Acre-Feet

• Circular Pond
• Example pond averages 3.9 feet deep and is 150
  across the middle (diameter)
• 3.14 x (75)2 ? 43,560
• 17,662.5 ? 43,560 0.41 acres
• 0.41 acres x 3.9 feet 1.6 acre-feet of water

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Pond Math

• My pond is 0.5 surface acres and averages 4 feet
  deep. How much powdered 5 Rotenone do I need to
  apply at the recommended rate of 10 pounds per
  acre-foot of water to kill my fish so I can
  re-stock?

31
Pond Math

• My pond is 0.5 surface acres and averages 4 feet
  deep. How much powdered 5 Rotenone do I need to
  apply at the recommended rate of 10 pounds per
  acre-foot of water to kill my fish so I can
  re-stock?
• 0.5 surface acres x 4 feet deep 2 acre-feet
• 2 acre-feet of water x 10 lbs Rotenone per
  acre-foot 20 lbs of Rotenone needed

32
Pond Math

• Information from Texas Cooperative Extension
  states that I can stock 1,000 catfish per surface
  acre if I feed 5-7 days per week from April
  through October. How many catfish should I order
  for my triangle-shaped pond that is 125 feet
  across at the dam and 200 feet long from the dam
  to the upper end?

33
Pond Math

• Information from Texas Cooperative Extension
  states that I can stock 1,000 catfish per surface
  acre if I feed 5-7 days per week from April
  through October. How many catfish should I order
  for my triangle-shaped pond that is 125 feet
  across at the dam and 200 feet long from the dam
  to the upper end?
• 1/2 b x h 1/2 (125 x 200)
• 12,500 ? 43,560 0.29 surface acres
• 1,000 fingerlings per acre x 0.29 acres 290
  fingerlings

34
Pond Math

• I have a pond that is a rectangle on one side
  connected by a culvert under my driveway to a
  triangular shaped upper end. The rectangle side
  is 100 feet by 150 feet and the average depth is
  6.2 feet. The triangle is 100 feet along the
  driveway and runs up into a neck 75 feet from the
  driveway and average depth is only 3.0 feet. How
  much copper sulfate do I need to apply at 2
  pounds per acre-foot of water to kill the
  filamentous algae covering the entire pond?

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Rectangular Side

• 100 x 150 15,000
• 15,000 ? 43,560 0.34 acres
• 0.34 x 6.2 2.1 acre-feet of water
• 2 lbs of copper sulfate per acre-foot x 2.1
  acre-feet 4.2 lbs of copper sulfate

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Triangular Side

• 1/2 (100 x 75) 3750
• 3750 ? 43,560 0.09 acres
• 0.09 acres x 3 feet 0.27 acre-feet of water
• 2 lbs of copper sulfate per acre-foot x 0.27
  acre-feet 0.54 lbs of copper sulfate

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Spot Treatments

• When fish are important pond resources
• When vegetation covers more than 50 of thepond
• When treatment is required in the summer months
• To spot-treat, applyherbicide to no morethan
  20 of the totalpond surface at weeklyintervals

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Spot Treatment

• I have bushy pondweed growing from the pond
  edge to about 20 feet out around 250 feet of
  shoreline. The water where the weeds are growing
  averages
• 2 feet in depth. How much
• Aquathol Super K do I
• need to buy to treat
• the affected area if the
• application rate is 3ppm
• (13.2 pounds per acre-foot
• of water)?

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Spot Treatment

• 250 x 20 5,000 square feet of area to be
  treated
• 5,000 ? 43,560 0.11 surface acres
• 0.11 acres x 2 feet average depth 0.22
  acre-feet
• 0.22 acre-feet x 13.2 pounds of Aquathol Super K
  per acre-foot
• 2.9 pounds of Aquathol Super K

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Restricted Use Pesticides for Aquatic Applications

• Rotenone
• 2,4-D products

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The End