Chester Watershed Data - MaSFChe04v

Please choose from the following parameters:
Temperature - Dissolved Oxygen - Turbidity - pH - Conductivity - Nitrate - Phosphate - Bacteria

Water Temperature
Water temperature is a very important factor for aquatic life and is one of the most important parameters we test. It controls the rate of metabolic and reproductive activities, and determines which fish species can survive. Temperature also affects the concentration of dissolved oxygen and can influence the activity of bacteria and toxic chemicals in water. Respiration of organisms is temperature-related; respiration rates can increase by 10% or more per 1° C temperature rise. Therefore, increased temperature not only reduces oxygen availability, but also increases oxygen demand, which can add to physiological stress of organisms. Water temperature is affected by air temperature, amount of riparian vegetation, and flow rate. The Alaska Department of Environmental Conservation chronic aquatic life criteria standard maximum for water temperature is 15° C for migration routes and rearing areas, and 13° C for spawning areas, and egg and fry incubation.


Dissolved Oxygen
Dissolved Oxygen (DO) is found in microscopic bubbles of oxygen that are mixed in the water and occur between water molecules. Stream systems produce and consume oxygen. Oxygen enters the water by absorption directly from the atmosphere or by aquatic plant and algae photosynthesis. Oxygen is consumed in the water by respiration of aquatic animals, decomposition of organic matter, and various chemical reactions. Levels of dissolved oxygen are closely related to water temperature; the colder the water, the more oxygen can be dissolved in the water. Therefore, DO concentrations at one location are usually higher in the winter than in the summer. DO levels are also affected by flow rate, the type and number of aquatic organisms, the number of dissolved and suspended solids, and the amount of nutrients present in the water. DO is one of the most important indicators of a water body's ability to support aquatic life. It is essential for the basic metabolic processes of animals and plants inhabiting our rivers and streams. Fish "breathe" by absorbing dissolved oxygen through their gills. When oxygen levels fall too low, fish and many other marine organisms are stressed and cannot survive. The Alaska Department of Environmental Conservation (DEC) chronic aquatic life criteria standard for DO is 7 mg/l in waters used by anadromous fish.


Turbidity
Turbidity, or water clarity, is a measure of how much of the light traveling through water is scattered by suspended particles. Any material mixed and suspended in water will reduce its clarity and make the water turbid. Such materials can come from various sources, both natural and anthropogenic. High turbidity levels can be disruptive to aquatic systems in various ways including: (1) interfering with the passage of light through water (resulting in reduced photosynthetic activity), (2) clogging the gills of some fish species, (3) causing an increase in water temperature since suspended particles absorb more heat (resulting in a reduction of dissolved oxygen since warmer water holds less oxygen), and (4) smothering fish eggs and benthic macroinvertebrates.


pH
pH is a measure of the acidity or alkalinity of a solution and is ranked on a scale from 1.0 to 14.0. Acidity increases as pH gets lower. pH affects many chemical and biological processes in the water. For example, different organisms flourish within different ranges of pH. The greatest variety of aquatic animals prefers a range of 6.5-8.0. This range is the Alaska DEC chronic aquatic life criteria standard for the growth and propagation of fish, shellfish, aquatic life, and wildlife. pH values outside of this range reduce the diversity in the stream because it stresses the physiological systems of most organisms and can reduce reproduction. Changes in acidity can be caused by atmospheric deposition (e.g., acid rain), surrounding rock and soils, and certain wastewater discharges.


Conductivity
Conductivity is a measure of the ability of water to pass an electric current, which is proportional to the nature and quantity of Total Dissolved Solids (TDS) in the sample water. (We also measure TDS but do not report the results here since TDS and conductivity are mathematically related.) 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 is affected primarily by the geology of the area through which the water flows. For example, 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 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. Conductivity may also be affected by anthropogenic sources such as failing septic systems or human-caused runoff.


Nitrate
Nitrogen is required by all organisms for the basic processes of life to make proteins, to grow, and to reproduce. Nitrogen is very common and found in many forms in the environment. Inorganic forms include nitrate (NO3), nitrite (NO2), ammonia (NH3), and nitrogen gas (N2). Organic nitrogen is found in the cells of all living things and is a component of proteins, peptides, and amino acids. Nitrogen is continually recycled throughout the environment in its various forms in the “Nitrogen Cycle�. Nitrate, nitrite, and ammonia are common forms of nitrogen in water.
Sources of nitrates include wastewater treatment plants, runoff from fertilized lawns and croplands, outhouses and failing septic systems, animal wastes, acid rain deposition, and industrial discharges that contain corrosion inhibitors. Excessive concentrations can be harmful to humans and wildlife. Together with phosphorus, nitrogen concentrations in excess amounts can lead to eutrophication, causing dramatic increases in aquatic plant growth and changes in the types of plants and animals that live in a water body. The Alaska DEC water quality standard for drinking water is 10 mg/L of nitrates.


Phosphorus
Phosphorus is an essential nutrient for the plants and animals that make up the aquatic food web. Since phosphorus is a nutrient in short supply in the typically clay-rich soils of Southcentral Alaska and in most fresh water, even a modest increase in phosphorus can set off a whole chain of undesirable events in a water body. There are many sources of phosphorus, both natural and human. These include soil and rocks, wastewater treatment plants, runoff from fertilized lawns and croplands, outhouses and failing septic systems, animal manure, runoff from disturbed land areas, drained wetlands, water treatment, and commercial cleaning chemicals.
Phosphorus may exist in an inorganic or organic form and may be in a dissolved or particulate phase. There are various types of tests for measuring the different forms in which phosphorus can exist. We measure total orthophosphate using the EPA-approved ascorbic acid method, often used in volunteer water quality monitoring programs for screening purposes. We report our results as mg/L of phosphorus, although this value is not derived from a total phosphate value but rather from our measurement of total orthophosphate.


EColi Bacteria
Coliform bacteria are generally pretty harmless by themselves. In fact, water may contain coliforms from a variety of sources besides sewage. However, the presence of high levels of coliform bacteria and, in particular, of fecal coliforms (graphed here) suggests that sewage is possibly being discharged into the water. Sewage discharges raise the level of nutrients in the water and can cause phytoplankton blooms. Worse, sewage contains organisms that cause disease, including pathogenic bacteria, viruses, protozoans, and parasites. For example, certain species of pathogenic bacteria can cause typhoid fever, dysentery, and cholera.


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