- Groundwater quantity and quality: This vital sign refers to the monitoring of groundwater level and chemistry (including contamination). Monitored parameters include groundwater level and volume, pH, temperature, conductivity, trace organic compounds and metals. Samples for analysis are obtained through purging and sampling groundwater wells.
- Reservoir elevation. Lakes that are hydrologically managed (i.e., water impounded by a dam) will have fluctuating water levels that can potentially affect lake food webs and ecosystem function. Therefore, changes in water surface elevation and storage capacity, as well as water inflow and discharge should be part of the long-term monitoring of reservoirs.
- River invertebrate assemblages. The composition of an invertebrate assemblage can be a useful indicator of water quality; and may change in response to the presence of exotic species, as well as changes in sedimentation rate, nutrient loading, composition of predator population, and climate. Two methods can be used to identify and document change: (1) comparing the species of a measured assemblage structure with species that may be indicative of a particular water quality condition (e.g., Stribling et al. 1998), and (2) using multivariate analysis to compare a predicted invertebrate assemblage structure to a measured structure (e.g., Hawkins et al. 2001, Lewis et al. 2001).
- Hydrology of springs and seeps (cold and hot): This vital sign includes documenting the location, volume, duration, and seasonality of flow of springs and seeps. Parameters are quantified by calculating physical/geometric metrics (i.e., water depth [maximum, minimum, average]; site length, and width) and discharge (flow quantity, duration, and peak) at each spring or seep.
- Stream flow/discharge: Stream flow is the measure of the flow of water in a stream at a specific time relative to (1) watershed routing mechanisms and water quality, (2) watershed land-use activities, and (3) natural and point-source discharges within the watershed. Stream discharge (Q) is defined as the unit volume of water passing a given point on a stream or river over a given time. It is typically expressed in cubic feet per second (cfs) or cubic meters per second (cms) and is based on the equation: Q = A*V, where A is the cross-sectional area of the stream at the measurement point and V is the average velocity of water at that point.
- Water chemistry: Information from monitoring water chemistry is used to evaluate water quality with respect to stressors such as atmospheric deposition, nutrient enrichment, and inorganic contaminants. The following parameters and ions are usually monitored: alkalinity, ammonia, bicarbonate, carbonate, calcium, chloride, fluoride, trace metals, nitrate, pH, potassium, silica, sodium, sulfate, total dissolved solids, total suspended solids, total nitrogen, and total phosphorous. In streams, concurrent discharge measurements allow data to be presented as mass flow (e.g., g/hr).
- Algal species composition and biomass: Algal species composition refers to the kinds of species present in a body of water. Algal biomass refers to the combined mass of the species. Certain species can indicate changes in water column nutrient input or water temperature. Algal composition is measured by examining algal assemblages, whereas algal biomass can be measured using chlorophyll ? concentrations or Secchi disk water clarity measurements.
- Escherichia coli (E. coli): The presence of E. coli in a water sample is an indicator of fecal contamination. This bacterium can cause gastrointestinal distress and illness in humans and can be contracted by drinking contaminated water or by swimmers recreating in contaminated swimming areas. Determination of E. coli contamination is based on the density of the indicator organism in a water sample. The EPA requires that the concentration of E. coli in a water sample be no more than a geometric mean of 126 E. coli per 100 ml of fresh water, or 260 E. coli per 100 ml for any single sample.
- Exotic aquatic species community structure and composition: Introduced exotic aquatic species can affect the ecosystem dynamics of a water body and negatively impact naturally occurring native biota in affected systems. Monitoring the distribution (geographical location), abundance (number at each sampling location), and spread of exotic species can help managers understand the potential environmental consequences of these organisms. Introduced exotic species of concern include fish (e.g., kokanee [Oncorhynchus nerka] in Crater Lake and brook trout [Salvelinus fontinalis] in western montane lakes and streams), as well as invertebrates (e.g., the New Zealand mud snail [Potamopyrgus antipodarum]).