RAINFALL
Rainfall data was recorded at at two recording stations, the Pacific House station and the Caples station. Reported data is an average of the two.

pH
pH is a measure of the relative concentration of hydrogen ions in solution. a pH of 7 is neutral. Many aquatic organisms have a relatively narrow range of acceptable values.

ALKALINITY
A measure of acid neutralizing capacity. Higher alkalinity results in a better ability of the water to compensate for acidic conditions resulting from acid rain or conifer needles.

CONDUCTIVITY
Conductivity is a measure of the ability of water to pass an electrical current. Conductivity in water is affected by the presence of inorganic dissolved solids such as chloride, nitrate, sulfate, and phosphate anions (ions that carry a negative charge) or sodium, magnesium, calcium, iron, and aluminum cations (ions that carry a positive charge).
Conductivity in streams and rivers is affected primarily by the geology of the area through which the water flows. Streams that run through areas with granite bedrock tend to have lower conductivity because granite is composed of more inert materials that do not ionize (dissolve into ionic components) when washed into the water. On the other hand, streams that run through areas with clay soils tend to have higher conductivity because of the presence of materials that ionize when washed into the water. Ground water inflows can have the same effects depending on the bedrock they flow through.

PHOSPATE
One of the macronutrients, phosphate is essential for plant growth. In concentrations higher than ? phosphate may lead to overgrowth of algae. Natural sources of phosphate include ? and ? . Detergents are the main cause of point source pollution of this chemical.

NITRATE

SULFATE

TEMPERATURE
Water temperature has a direct effect on the biotic community of the aquatic ecosystem. Rainbow trout prefer temperatures between 55o and 60o (Water temperatures between 44o and 50o are necessary for spawning).

DISSOLVED O2
Dissolved oxygen (DO) is reported as parts per million (ppm). Cooler, deeper, faster moving water generally has higher DO levels. Water that is slow, exposed to the sun, or shallow will have lower DO. Water with high nutrient loads (and hence high decomposition) may also have low DO. DO levels greater than 8ppm are usually required to support trout and the macroinvertebrates they feed upon.

FINES
Determined using the pebble count protocol, fines are reported as a percentage of substrate particles smaller than 2 mm in diameter. Accumulation of fines may indicate increased erosion as well as decreased water flows.

D50
Recorded as the diameter at which 50% of the particles are that size or smaller. This value is used as an indicator for channel typing.

D84
Recorded as the diameter at which 84% of the particles are that size or smaller. This value is used as an indicator for channel roughness in flow calculations.

EPT
The combined number of mayfly (E), stonefly (P) and caddisfly (T) taxa found in the sample as a percentage of the total. The number of taxa in each of these macroinvertebrate orders can also be reported separately since each order may respond differently to various impacts.

Aquatic macroinvertebrates are good indicators of stream quality because:

  • They are affected by the physical, chemical, and biological conditions of the stream.
  • They can't escape pollution and show the effects of short- and long term pollution events.
  • They may show the cumulative impacts of pollution.
  • They may show the impacts from habitat loss not detected by traditional water quality assessments.
  • They are a critical part of the stream's food web.
  • Some are very intolerant of pollution.
  • They are relatively easy to sample and identify.

    • CHIRONOMIDAE
    The number of chironomidae taxa found in the sample as a percentage of the total. These midge larvae are indicators of relatively higher nutrient loads, and may be associated with lower water quality.

    HILSENHOFF
    Hilsenhoff Biotic Index
    Only arthropods that require dissolved oxygen for respiration are used in the calculation. Organisms that are most sensitive to low concentrations of dissolved oxygen have low tolerance values, and organisms which have a wide tolerance, have high tolerance values. Organism tolerance values and the BI range from 0 to 10.
    Biotic Index
    Water Quality
    Degree of Organic Pollution
    0.00-3.50
    Excellent
    No apparent organic pollution

    3.51-4.50
    Very good
    Possible slight organic pollution

    4.51-5.50
    Good
    Some organic pollution

    5.51-6.50
    Fair
    Fairly significant organic pollution

    6.51-7.50
    Fairly poor
    Significant organic pollution

    7.51-8.50
    Poor
    Very significant organic pollution

    8.51-10.00
    Very poor
    Severe organic pollution

    USFS BCI
    Taxa are assigned a tolerant quotient from 2 to 108. Taxa assigned low tolerance quotients are found only in high quality unpolluted water and taxa assigned large tolerant quotients are found in severely polluted waters.