Water Resources

1
Water Resources

• LaDon SwannMississippi-Alabama Sea Grant
  Consortium
• Auburn University

2
Water Resources

• Water sources
• Water quality
• Water quantity

Inadequate water quality causes more losses than
any other problem!
3
Water Sources

• Springs
• Wells
• Rivers, lakes and streams

• Surface
• Groundwater
• Municipal

4
Springs

• Advantages
• constant temperature
• few or no predators
• no pathogens
• Disadvantages
• pumping cost if not gravity fed

5
Wells

• Types
• pumped
• artesian
• Advantages
• no predators
• no pathogens
• Disadvantages
• high dissolved gasses
• like N2 and CO2
• low O2

6
Rivers, Lakes and Streams

• Advantages
• large volumes
• inexpensive
• Disadvantages
• contaminates
• predators
• excessive nutrients

7
Surface

• Advantages
• inexpensive
• Disadvantages
• contaminates
• draughts or floods
• 5-7 acre watershed
• per surface acre
• of water

8
Groundwater

• Advantages
• inexpensive
• few/no predators
• Disadvantages
• hard to drain
• buildup of organics
• removal of fish

9
Municipal

• Advantages
• very high quality
• no predators
• no pathogens
• Disadvantages
• disinfectants
• chlorine
• chloramines
• expensive

10
Water Quality

• Daily or weekly tests

• Semi-annually or annually

11
Daily or Weekly

• Dissolved oxygen
• Nitrogen compounds
• ammonia
• nitrite
• nitrates
• pH
• Alkalinity
• Hardness

• Carbon Dioxide
• Temperature
• Hydrogen sulfide
• Total suspended solids
• Chlorine

12
Dissolved Oxygen

• Importance
• highest cause of mortality
• Solubility
• variables
• temperature (-)
• elevation (-)
• salinity (-)
• Safe levels
• greater than 5 mg/L

13
Nitrogen Compounds

• Types
• dissolved gas
• ammonia
• ionized
• un-ionized
• nitrite
• nitrate

14
Ammonia

• Ammonia (NH3) results from the breakdown of fish
  feed, and waste
• Two forms
• Ionized (NH4)
• Unionized (NH3).
• Unionized ammonia concentration is a function of
  pH and temperature
• Chronic exposure of 0.06 mg/L in the unionized
  form is toxic to warm water species such as
  catfish

15
Nitrite

• Nitrite (NO2-) is the intermediate product in the
  breakdown of ammonia to nitrate (nitrification)
• Nitrite levels greater than 0.60 mg/L or 10 times
  higher than the toxic threshold for unionized
  ammonia is toxic to fish

16
Nitrate

• Nitrate (NO3-) is the final breakdown product in
  the oxidation of ammonia
• Nitrate is relatively nontoxic to fish at
  concentrations up to 3.0 mg/L

17
Nitrification

• Requires 3 moles oxygen to convert one mole of
  ammonia to nitrate
• Nitrification is an acidifying reaction

18
Relationships
19
pH

• Measure of the hydrogen
• ion concentration
• 1-14 scale
• less than 7 acidic
• greater than 7 basic
• Safe range
• 6.5-9

20
Carbon Dioxide
CH2O (food) O2 ? CO2 H2O

• Sources
• bi-product of respiration of
• fish and phytoplankton
• wells
• carboniferous rock
• Removal
• intense aeration
• buffers
• calcium carbonate
• sodium bicarbonate

21
Alkalinity

• Alkalinity is the capacity of water to buffer
  against wide pH swings
• Acceptable range 40-400 mg/L

Bicarbonate CO2 H2O ? H HCO3-
Carbonate HCO3- ? H CO3-
Effects of calcite lime
CaCO3 CO2 H2O ? Ca2 2HCO3-
Dolomite CaMg(CO3)2 yields 4HCO3-
22
Alkalinity
Bicarbonate pK1 6.3 Carbonate pK2 10.4
Relationship Between pH and Various Carbonate
Ions.
23
Hardness

• Hardness if the measure of divalent cations
• calcium
• magnesium
• Hardness is used as an indicator of alkalinity
  but hardness is not a measure of alkalinity
• magnesium or calcium sulfate increases hardness
  but has no affect on alkalinity
• Recommended hardness levels

24
Hydrogen Sulfide

• Source
• well water
• inadequate filtration
• shift from aerobic to
• anaerobic breakdown
• of wastes
• Removal
• intense aeration

25
Total Solids

• Types
• suspended
• settleable
• Sources
• runoff
• uneaten food
• feces

• Safe levels
• less than 1,000 mg/L
• Removal
• filtration
• settling chambers

26
Chlorine

• Disinfectant
• municipal water
• to clean tanks and equipment
• Safe levels
• less than 0.3 mg/L
• Removal
• intense aeration
• sodium thiosulfate
• 1 mg/L for every mg/L chlorine
• sunlight

27
Temperature

• Effects
• metabolic rate doubles
• for every 18oF increase
• Influences spawning
• Influences growth
• Fish Categories
• warmwater
• coolwater
• coldwater

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Warmwater Species

• Food fish species
• channel catfish
• tilapia

29
Coolwater Species

• Food fish species
• hybrid striped bass
• yellow perch
• largemouth bass

30
Coldwater Species

• Food fish species
• rainbow trout
• Atlantic salmon
• coho salmon

31
Dissolved Gasses

• Problem gasses
• nitrogen
• maintain less than 110
• CO2
• maintain less than 10 mg/L
• Problem sources
• wells and springs
• leaky pipes

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Semi-annual or Annual

• Cadmium
• Copper
• Iron
• Ferrous
• Ferric
• Lead
• Manganese

• Mercury
• Phosphorus
• Toxins
• Zinc
• Ozone

33
Water Quantity

• Ponds
• Raceways
• Cages
• Recirculating aquaculture systems

34
Ponds

• Minimum requirement
• 26 gal./min. per surface acre
• Rational
• to fill spawning ponds
• to replace evaporation
• to refill ponds after
• harvesting

35
Raceways

• Minimum requirement
• 500 gal./min.
• Rational
• constant water
• exchange
• high densities
• 15-20 lbs./gal./min.

36
Recirculating Aquaculture Systems

• Minimum requirement
• varies depending on
• size of system
• enough water for 10
• exchange per day
• Rational
• needed to backflush filters
• during harvesting
• emergencies