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Nonpoint Source Environmental Parameters

The following parameters are currently being collected by watershed groups throughout Indiana. Each parameter has a list of analytical methods and descriptions to assist projects in selecting the method best for each monitoring program.

Core Parameters

At a minimum, all 319/205j funded water quality monitoring programs are required to collect data for the following core parameters:

Additional Parameters

Funding may be available for collecting additional parameters, if needed:


Nitrates are a form of nitrogen, which is found in several different forms in terrestrial and aquatic ecosystems. These forms of nitrogen include ammonia (NH3), nitrates (NO3), and nitrites (NO2). Nitrates are essential plant nutrients, but in excess amounts they can cause significant water quality problems. Together with phosphorus, nitrates in excess amounts can accelerate eutrophication, causing dramatic increases in aquatic plant growth and changes in the types of plants and animals that live in the stream. This, in turn, affects dissolved oxygen, temperature, and other indicators. Excess nitrates can cause hypoxia (low levels of dissolved oxygen) and can become toxic to warm-blooded animals at higher concentrations (10 mg/L) or higher under certain conditions. The natural level of ammonia or nitrate in surface water is typically low (less than 1 mg/L); in the effluent of wastewater treatment plants, it can range up to 30 mg/L.

Sources of nitrates include wastewater treatment plants, runoff from fertilized lawns and cropland, failing on-site septic systems, runoff from animal manure storage areas, and industrial discharges that contain corrosion inhibitors. Nitrates from land sources end up in rivers and streams more quickly than other nutrients like phosphorus. This is because they dissolve in water more readily than phosphates, which have an attraction for soil particles. As a result, nitrates serve as a better indicator of the possibility of a source of sewage or manure pollution during dry weather.

NPS Parameter lists for AIMS:
  • Nitrogen, Ammonia Colorimetry Continuous Flow
    • EPA 350.1
  • Nitrogen, Ammonia Water by Selective Electrode
    • SM 4500NH3D
  • Nitrogen, Ammonia ISE
    • EPA 350.3
  • Nitrogen, Ammonia Water Using Phenate Method
    • SM 4500NH3F
  • Nitrogen, Nitrate + Nitrite Cadmium Reduction Automated
    • EPA 353.2
  • Nitrogen, Nitrate + Nitrite Cadmium Reduction Manual
    • EPA 353.3
  • Nitrate, converted from N to NO3 by calculation (Hoosier Riverwatch 2005)
    • WaterWorks Test Strips #480009
  • Nitrogen, Nitrate Automated Cadmium Reduction
    • SM 4500NO3
  • Nitrogen, Nitrate Colorimetry
    • EPA 352.1
  • Nitrogen, Nitrate ISE
    • SM 4500NO3D
  • Nitrogen, Nitrate Cadmium Reduction
    • SM 4500NO3E
  • Nitrite, converted from N to NO2 by calculation (Hoosier Riverwatch 2005)
    • WaterWorks Test Strips #480009
  • Nitrogen, Nitrite Cadmium Reduction Automated
    • EPA 353.2
  • Nitrogen, Nitrite Colorimetry
    • SM 4500NO2B
  • Nitrogen, Nitrite Spectrophotometer
    • EPA 354.1
  • Nitrogen, Total Kjeldahl Colorimetry
    • EPA 351.2
  • Nitrogen, Total Kjeldahl
    • SM 4500NORGC
  • Nitrogen, Total Kjeldahl
    • SM 4500NORGB
  • Nitrogen, Total Kjeldahl ISE
    • EPA 351.4
  • Nitrogen, Nitrate + Nitrite Nitrogen, Nitrate + Nitrite
    • EPA 353.1


Both phosphorus and nitrogen are essential nutrients for the plants and animals that make up the aquatic food web. Since phosphorus is the nutrient in short supply in most fresh waters, even a modest increase in phosphorus can, under the right conditions, set off a whole chain of undesirable events in a stream including accelerated plant growth, algae blooms, low dissolved oxygen, and the death of certain fish, invertebrates, and other aquatic animals.

There are many sources of phosphorus, both natural and human. These include soil and rocks, wastewater treatment plants, runoff from fertilized lawns and cropland, failing septic systems, runoff from animal manure storage areas, disturbed land areas, drained wetlands, water treatment, and commercial cleaning preparations.

NPS Parameter lists for AIMS:
  • Orthophosphate
    • EPA 365.2
  • Orthophosphate, (Hoosier Riverwatch 2005)
    • Chemetrics Kit K 8510, SM 4500P C and ASTM D51582
  • Phosphorus ascorbic acid reduction
    • EPA 365.1


Stream flow, or discharge, is the volume of water that moves over a designated point over a fixed period of time. It is often expressed as cubic feet per second (ft3/sec). The flow of a stream is directly related to the amount of water moving off the watershed into the stream channel. It is affected by weather, increasing during rainstorms and decreasing during dry periods. It also changes during different seasons of the year, decreasing during the summer months when evaporation rates are high and shoreline vegetation is actively growing and removing water from the ground. August and September are usually the months of lowest flow for most streams and rivers in most of the country……Flow is a function of water volume and velocity. It is important because of its impact on water quality and on the living organisms and habitats in the stream. Large, swiftly flowing rivers can receive pollution discharges and be little affected, whereas small streams have less capacity to dilute and degrade wastes.

Stream gauging is a technique used to measure the discharge, or the volume of water moving through a channel per unit time, of a stream. The height of water in the stream channel, known as a stage or gage height, can be used to determine the discharge in a stream. When used in conjunction with velocity and cross-sectional area measurements, stage height can be related to discharge for a stream. If a weir or flume (devices, generally made of concrete, located in a stream channel that have a constant, known shape and size) is used, mathematical equations based on the weir or flume shape can be used in conjunction with stage height, negating the need for velocity measurements.

NPS Parameter lists for AIMS:
  • Flow 2 transects and a time of travel
    • EPA Volunteer
  • Flow Open-Channel Flow by Acoustic Means
    • ASTM D4408
  • Flow Open-Channel Flow Measurement by Area Velocity & cross sectional area USGS
    • ASTM D3858
  • Flow rating Curve measuring Height
  • Flow using USGS Gauging Station with stream height
    • USGS
  • Flow WidthDepthVelocity Roughness Coef (Hoosier Riverwatch 2005)
    • WDV Roughness Coef
  • Water Levels Recording Devices
    • ASTM D5413B
  • Water Levels Remote Interrogation online or Telephone
    • ASTM D5413C
  • Water Levels Nonrecording Devices
    • ASTM D5413A


The visual stream assessment is used to record field team observations of catchment and stream characteristics that are useful for data validation, future data interpretation, ecological value assessment, development of associations, and verification of stressor data. The observations and impressions of field teams are extremely valuable. Thus, it is important that these observations about stream characteristics be recorded for future data interpretation and validation.

NPS Parameter lists for AIMS:
  • Habitat Evaluation Index, Citizen Qualitative (Hoosier Riverwatch 2005)
    • CQHEI
  • Habitat Qualitative Habitat Score, IDEM Assessment Branch


The stream system both produces and consumes oxygen. It gains oxygen from the atmosphere and from plants as a result of photosynthesis. Running water, because of its churning, dissolves more oxygen than still water, such as that in a reservoir behind a dam. Respiration by aquatic animals, decomposition, and various chemical reactions consume oxygen….DO levels fluctuate seasonally and over a 24-hour period. They vary with water temperature and altitude. Cold water holds more oxygen than warm water (Table 5.3) and water holds less oxygen at higher altitudes. Thermal discharges, such as water used to cool machinery in a manufacturing plant or a power plant, raise the temperature of water and lower its oxygen content. Aquatic animals are most vulnerable to lowered DO levels in the early morning on hot summer days when stream flows are low, water temperatures are high, and aquatic plants have not been producing oxygen since sunset.

NPS Parameter lists for AIMS:
  • Oxygen, Biochemical Carbonaceous Ultimate UcBOD
    • SM 5210C
  • Oxygen, Biochemical Demand Carbonaceous cBOD
    • EPA 405.1
  • Oxygen, Biochemical Demand 5 Day BOD
    • EPA 405.1
  • Oxygen, Biochemical Demand 5 Day BOD
    • SM 5210B
  • Oxygen, Biochemical Demand BOD (Hoosier Riverwatch 2005)
    • Chemetrics DO Kit K7512
  • Oxygen, Biochemical Ultimate UBOD
    • SM 5210C
  • Oxygen, Chemical Demand COD
    • ASTM D1252B
  • Oxygen, Chemical Demand COD Colorimetry
    • EPA 410.4
  • Oxygen, Dissolved in ISE Membrane Electrode Hydrolab & YSI
    • SM 4500OG
  • Oxygen, Dissolved Percent Saturation, (Hoosier Riverwatch 2005)
    • CHEMetrics DO Kit, K 7512
  • Oxygen,Dissolved Percent Saturation, Membrane Electrode YSI & Hydrolab
    • SM 45000G
  • Oxygen, Dissolved (Hoosier Riverwatch 2005)
    • CHEMetrics DO Kit, K 7512 ASTM D88887
  • Oxygen, Dissolved Modified Winkler HACH OX-2p
    • EPA 360.2 M
  • Oxygen, Dissolved Winkler Technique
    • EPA 360.2
  • Oxygen, Dissolved Winkler Technique
    • SM 4500OC
  • Oxygen, Dissolved ISE Membrane Electrode Hydrolab & YSI
    • EPA 360.1


pH is a term used to indicate the alkalinity or acidity of a substance as ranked on a scale from 1.0 to 14.0. Acidity increases as the pH gets lower. pH affects many chemical and biological processes in the water. For example, different organisms flourish within different ranges of pH. The largest variety of aquatic animals prefers a range of 6.5-8.0. pH outside this range reduces the diversity in the stream because it stresses the physiological systems of most organisms and can reduce reproduction. Low pH can also allow toxic elements and compounds to become mobile and "available" for uptake by aquatic plants and animals. This can produce conditions that are toxic to aquatic life, particularly to sensitive species like rainbow trout. Changes in acidity can be caused by atmospheric deposition (acid rain), surrounding rock, and certain wastewater discharges.

NPS Parameter lists for AIMS:
  • pH
    • EPA 150.1
  • pH
    • SM 4500H
  • pH Continuous Monitoring
    • EPA 150.2
  • pH Paper
    • EPA 9041A
  • pH Test Strips (Hoosier Riverwatch 2005)
    • Water Works pH strips


The rates of biological and chemical processes depend on temperature. Aquatic organisms from microbes to fish are dependent on certain temperature ranges for their optimal health. Optimal temperatures for fish depend on the species: some survive best in colder water, whereas others prefer warmer water. Benthic macroinvertebrates are also sensitive to temperature and will move in the stream to find their optimal temperature. If temperatures are outside this optimal range for a prolonged period of time, organisms are stressed and can die…..Causes of temperature change include weather, removal of shading streambank vegetation, impoundments (a body of water confined by a barrier, such as a dam), dis-charge of cooling water, urban storm water, and groundwater inflows to the stream.

NPS Parameter lists for AIMS:
  • Temperature, of Water by Thermometer Swirl 2 minutes under surface (Hoosier Riverwatch 2005)
    • Thermometer
  • Temperature, of Water by Thermometer
    • SM 2559B1
  • Temperature, Thermister Hydrolab & YSI
    • SM 2550B2
  • Temperature, Thermocouple
    • EPA 170.1


Turbidity is a measure of water clarity how much the material suspended in water decreases the passage of light through the water. Suspended materials include soil particles (clay, silt, and sand), algae, plankton, microbes, and other substances. These materials are typically in the size range of 0.004 mm (clay) to 1.0 mm (sand). Turbidity can affect the color of the water.

Higher turbidity increases water temperatures because suspended particles absorb more heat. This, in turn, reduces the concentration of dissolved oxygen (DO) because warm water holds less DO than cold. Higher turbidity also reduces the amount of light penetrating the water, which reduces photosynthesis and the production of DO. Suspended materials can clog fish gills, reducing resistance to disease in fish, lowering growth rates, and affecting egg and larval development. As the particles settle, they can blanket the stream bottom, especially in slower waters, and smother fish eggs and benthic macroinvertebrates.

Total solids are dissolved solids plus suspended and settleable solids in water. In stream water, dissolved solids consist of calcium, chlorides, nitrate, phosphorus, iron, sulfur, and other ions particles that will pass through a filter with pores of around 2 microns (0.002 cm) in size. Suspended solids include silt and clay particles, plankton, algae, fine organic debris, and other particulate matter. These are particles that will not pass through a 2-micron filter….The concentration of total dissolved solids affects the water balance in the cells of aquatic organisms…Higher concentrations of suspended solids can serve as carriers of toxics, which readily cling to suspended particles.

NPS Parameter lists for AIMS:
  • Solids, Suspended Solids Concentration SSC
    • ASTM D 3977 97
  • Solids, Suspended Total
    • TSS SM 2540D
  • Solids, Suspended Total
    • TSS EPA 160.2
  • Solids, Total TS
    • EPA 160.3
  • Solids, Total TS
    • SM 2540B
  • Transparency Secchi
    • Secchi
  • Turbidity Hydrolab or YSI light scattering
    • SM 2130B M
  • Turbidity Nephelometric Turbidity light scattering
    • SM 2130B
  • Turbidity Nephelometry Lab light scattering
    • EPA 180.1
  • Turbidity Transparency Tube
    • Transparency Tube


NPS Parameter lists for AIMS:
  • Chloride Colorimetric Automated Ferricyanide
    • EPA 325.1
  • Chloride Colorimetry Automated Ferricyanide
    • SM 4500CLE
  • Chloride ISE YSI data sonde & Hydrolab
    • EPA 9212
  • Chloride Mercuric Nitrate Titration
    • EPA 325.3
  • Chloride Potentiometry
    • SM 4500CLD
  • Chloride Titration Argentometric
    • SM 4500CLB
  • Chloride Titration Mercuric Nitrate
    • SM 4500CLC
  • Chloride Colorimetric Analysis II
    • EPA 325.2


NPS Parameter lists for AIMS:
  • AFDM Ash Free Dry Mass
    • USGS B352085
  • Chlorophyll a, YSI & Hydrolab with 6025 probe
    • YSI 6025
  • Chlorophyll a, Periphyton & Phytoplankton/Seston Chromatography/Fluorometry
    • EPA 445.0
  • Macrophytes,Distribution and Abundance Quantitative
    • USDOI/USGS B4520

Organic Carbon

NPS Parameter lists for AIMS:
  • Carbon, Particulate Organic
    • POC USGS 440.0
  • Carbon, Total Organic Ultraviolet Oxidation (Hoosier Riverwatch 2005)
    • SM 5310C

E. coli

NPS Parameter lists for AIMS:
  • Coliform, E. coli Membrane Filter Procedure
    • SM 9222B
  • Coliform, E. coli IDEXX Laboratories Method Colilert (35C) (IDEM-E. coli van/ISDH)
    • SM 9223B
  • Coliform, E. coli in Water by Membrane Filtration
    • EPA 1103.1
  • Coliform, E. coli Micrology Laboratory 35C 24h
    • Coliscan Easygel 35C
  • Coliform, E. coli Micrology Laboratory Coliscan Ambient 24-48Hr
    • Coliscan Easygel Ambient
  • Coliform, E. coli m-tek
    • EPA 1603


NPS Parameter lists for AIMS:
  • Pollution Tolerance Index Rating Biologicals, (Hoosier Riverwatch 2005)
    • PTIR
  • Water Quality Index Chemical Monitoring Only (Hoosier Riverwatch 2005)
    • WQI


NPS Parameter lists for AIMS:
  • Macroinvertebrate mIBI, State of Indiana's Rapid Bioassessment Protocol
    • EPA 841-B-99-002 July 1999

Oil & Grease

NPS Parameter lists for AIMS:
  • Oil and Grease
    • EPA 1664
  • Oil and Grease
    • EPA 413.1
  • Oil and Grease
    • SM 5520 C


NPS Parameter lists for AIMS:
  • Specific Conductance, field
    • SM 2510A
  • Specific Conductance, Wheatstone bridge
    • EPA 120.1
  • Specific Conductivity,
    • HACH 8160
  • Specific Conductivity, Field
    • SM 2510B

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