What is a Watershed?

1
What is a Watershed?

• An area of land, from ridge top to ridge top,
  that collects, stores, and releases water to a
  common point, such as a river or a lake

2
Whats in a Watershed?

• Streams
• Rivers
• Lakes
• Wetlands
• Hills
• Mountains

• Farms
• Cities
• Houses
• Humans
• Animals
• Plants

3
Watershed Components
4
Watershed Processes

• Precipitation
• Evaporation
• Infiltration
• Runoff
• Erosion

5
Impacts on Watershed

• Land Use
• Pollution
• Too much of a good thing
• Point Sources
• Non-Point Sources
• Erosion
• Natural
• Human-accelerated

6
Watershed Study
PHYSICAL Width Water
Color Depth Streambank Bottom Materials Shading
(canopy) Soils/Rocks Flow Temperature Dams Turbidi
ty Flow Alterations
BIOLOGICAL Bacteria Animals Viruses Fish P
lankton Plants Macroinvertebrates Algae
CHEMICAL pH Alkalinity Dissolved
Oxygen BOD Conductivity Toxics Phosphorus
Nitrates Chlorine/Chloride Heavy Metals
7
Water Quality

• Water shed to stream easier to measure
• Water Quality is primarily chemistry
• Quality is a value judgement based on intended
  use
• Drinking water
• Recreation
• Aquatic life

8
Water Quality Parameters

• Temperature
• Dissolved Oxygen
• BOD
• pH
• Alkalinity
• Turbidity/Total Suspended Solids
• Phosphorus
• Nitrate
• Chlorine/Chloride

9
Temperature

• Most aquatic organisms are poikilothermic - dont
  internally regulate their body temp
• The rate of many chemical reactions increases at
  higher temperatures.
• Oxygen solubility ? as temperature ?
• Loss of riparian shading
• Water inputs (Industrial, Groundwater, etc)
• Weather
• ? Turbidity can ? temperature

10
Temperature

• Measure of heat
• Temperature scales
• Equipment
• Data Loggers
• Thermometers

0C
100C
32F
212F
11
Dissolved Oxygen

• Photosynthesis (? DO)
• Atmospheric Re-aeration (? DO)
• Inflow of oxygenated water (? DO)
• Respiration (? DO)
• Biochemical Oxygen Demand (? DO)
• Nitrification (NBOD) NH3 O2 NO3

12
Dissolved Oxygen

• Measure of O2 in water
• BOD is difference in DO after 5 days
• Measures oxygen-consuming waste present in water
• Equipment
• DO meter
• Winkler titration

13
pH

• Organisms have optimal range (6.5 8.5)
• pH controls availability and speciation of many
  chemicals
• Photosynthesis (? pH)
• Respiration (? pH)
• Acid Rain (pH lt 5.6) caused by NOx and SO2
• Industrial Wastewater

14
pH

• Measure of hydrogen ion concentration
• Equipment
• Color indicators
• pH Meter

15
Alkalinity

• Calcium carbonate CaCO3 lime
• Carbonic acid CO2 H2O H2CO3
• Bases (OH-)
• Phosphate (PO43-)
• Wastewater
• Stormwater Runoff

16
Alkalinity

• Measure of acid buffering capacity
• Equipment
• Acid (H2SO4) titration
• pH endpoint (pH 4.5)
• can be measured using
• color indicator or pH meter
• Bromcresol Green-
• Methyl Red changes from
• green to pink at pH 4.5

7.0
pH
4.5
Drops acid added
17
Turbidity/Total Suspended Solids

• Caused by sediment, algae and organic material
• Inhibits plant growth
• Decreases visibility for visual feeders
• Inhibits gill respiration
• Smothers eggs

18
Turbidity

• Measure of light scattering
• Equipment
• Secchi disk
• Turbidity tube
• Turbidimeter

19
Total Suspended Solids

• Measure of solids in water
• Equipment
• Filter funnel
• 1.0 ?m filter
• Drying oven
• Dessicator

20
Nutrients

• Phosphorus and Nitrogen - essential
  macronutrients for plants and animals
• Usually not obtained from air
• Limiting nutrients
• Excess can lead to Eutrophication

21
Phosphorus

• Soluble Reactive Phosphorus (SRP)
• aka orthophosphorus (PO43-), but due to pH, most
  will be HPO42- or H2PO4-
• bio-available P
• Total Phosphorus
• SRP bound phosphorus
• P adsorbs to surfaces of organic inorganics
  (suspended sediment)
• P absorbs into large organic inorganics

22
Nitrogen

• Ammonia (NH3) and nitrate (NO3) are 2 most common
  forms
• Ammonia can be NH3 (toxic) or NH4 (ammonium)
• Nitrate is VERY soluble preferred N source for
  plants.
• Nitrate toxic gt10 mg/L

23
Chlorine and Chloride

• Chlorine (Cl2)
• Doesnt occur naturally
• Used for water treatment
• Good indicator of human impacts
• Chloride (Cl-)
• Naturally present in salts
• Can be an indicator of human impacts

24
Nutrient Measurement

• Colorimetry - Color Change
• Colorimeter quantifies color change