Water Quality

[1]
 Method
Assessing water quality is concerned with predicting, tracking, and determining the symptoms and proximate causes of ecosystem degradation.  There are various metrics used to describe water quality, and none are necessarily exclusive.  Selecting a metric is more or less contingent on upon what one wishes to evidence.  Water quality data can include documentation of physicochemical parameters (such as pH, dissolved oxygen, temperature, suspended materials, stream velocity) and biotic sampling, a semi-quantitative/semi-qualitative method of sampling used to characterize a stream community. Regulation agencies look to the local flora and fauna as bioindicators, organisms shaped by present inhabitat forces, as evidence of these less tangible parameters.  River monitoring is particularly concerned with the sampling of macroinvertebrates.  As instream inhabitants, whose morphology, reproduction, and life history patterns are tethered to their biogeography, the presence or absence of these organisms can speak volumes to the processes and patterns acting upon the entire stream community. 

BMIs as Bioindicators: More at Interpreting Water Quality>>>

Habitat Assessment

Water quality considers many factors:

The condition of stream bottom, the depth and velocity of the water in the stream, day length, temperature, pH, dissolved oxygen, organic nutrients, bacteria, and toxins.   Given that rivers characteristically possess unstable channel and bed morphology, concentrations of these factors naturally vary from stream to stream, from site to site on the same stream, and (accounting for distinct variances in the geology, climate, soil and vegetation of within a watershed) may fluctuate throughout the year (Murdoch).  In order to most accurately determine what is "normal" for body of water, an area has to be tracked over time.  Though in theory, the RCC may postulate a virgin body of water untouched/unaffected by man, rivers tend to indelibly case the happenings within a catchment. Compiling a habitat assessment takes into account the basic anatomy of a river as well as a given stream's natural variation. A full habitat assessment typically considers both abiotic (aforementioned physicochemical parameters) and biotic factors (such as riparian vegetation and benthic macroinvertebrate population) in its compilation.  Biotic sampling as a method of quantifying these biotic interactions is further explained in Interpreting Water Quality and lightly discussed in Lab Methodology.

* This field study's habitat assessment >>>
*Photos of habitat sites sampled in field study [K]>>> [E]>>> [H]>>>

A Typical Lotic Habitat Template [Expanded]

A habitat assessment considers the following values:
Oxygen: expressed as a concentration, oxygen enters the water from the air at the surface of the stream and from aquatic plants and algae via photosynthesis. Oxygen is most readily available to benthic biota as dissolved oxygen. Natural factors affecting dissolved oxygen include temperature, flow, aquatic plants, altitude, dissolved or suspended solids.

Temperature: has a direct effect on metabolic rates as most BMIs are poikilothermic, meaning their temperature varies with surroundings. Temperature fluctuations can also have an indirect influence on metabolic rates and respiration of instream flora and fauna, effecting availability and demand of dissolved oxygen.
Light: influences plant populations and primary production rates, effecting available oxygen and temperature

Riparian Vegetation: represent the influence other instream factors of light, allochthonous organic matter, water chemistry, and physical channel morphology. Riparian vegetation can similarly influence, temperature, light, water chemistry and channel morphology as autochthonous input

Substrate: provides habitat space, refuge, food directly, can determine channel morphology by altering stream flow; when characterizing the stream bead, one would assess substrate type (cobble, gravel, sand, mud) and embeddedness

Flow: considers the volume and velocity of water being profiled
Turbidity: measures the concentration of dissolved nutrients (nitrogen, phosphorus, metals, detergents, and petroleum hydrocarbons) and indirectly, light
pH: specifically measures hydrogen ion concentration; relative proportions are critical to both biological and chemical instream processes

Refs--
     Murdoch, Tom, Martha Cheo, and Kate O'Laughlin. The Streamkeeper's Field Guide: Watershed Inventory and Stream Monitoring Methods. Everett, WA: Adopt-a-Stream Foundation, 1996. Print.
Images:
[1] Personal Illustrations