ASTM D6146-97(2012)
(Guide)Standard Guide for Monitoring Aqueous Nutrients in Watersheds
Standard Guide for Monitoring Aqueous Nutrients in Watersheds
SIGNIFICANCE AND USE
The user of this guide is not assumed to be a trained technical practitioner in the water quality field. The guide is an assembly of the components common to all aspect of watershed nutrient monitoring and fulfills a need in the development of a common framework for a better coordinated and a more unified approach to nutrient monitoring in watersheds.
Limitations—This guide does not establish a standard procedure to follow in all situations and it does not cover the detail necessary to meet all of the needs of a particular monitoring objective. Other standards and guides included in the references describe the detail of the procedures.
SCOPE
1.1 Purpose—This guide is intended to provide general guidance on a watershed monitoring program directed toward the plant nutrients nitrogen and phosphorus. The guide offers a series of general steps without setting forth a specific course of action. It gives assistance for developing a monitoring program but not a program for implementing measures to improve water quality.
1.2 This guide applies to waters found in streams and rivers; lakes, ponds, and reservoirs; estuaries; wetlands; the atmosphere; and the vadose and subsurface saturated zones (including aquifers). This guide does not apply to nutrients found in soils, plants, or animals.
1.3 Nutrients as used in this guide are intended to include nitrogen and phosphorus in dissolved, gaseous, and particulate forms. Specific species of nitrogen include: nitrate, nitrite, ammonia, organic, total Kjeldahl, and nitrous oxide. The species of phosphorus include total, total dissolved, organic, acid-hydrolyzable, and reactive phosphorus as described in (2)
1.4 Safety—Health and safety practices developed for a project may need to consider the following:
1.4.1 During the construction of sampling stations:
1.4.1.1 Drilling practices during monitoring well installations,
1.4.1.2 Overhead and underground utilities during monitoring well drilling,
1.4.1.3 Traffic patterns/concerns during sampling station installation,
1.4.1.4 Traffic patterns/concerns during surveying sampling station locations and elevations,
1.4.1.5 Drilling through materials highly contaminated with fertilizers, and
1.4.1.6 Installing monitoring equipment below the soil surface.
1.4.2 During the collection of water samples:
1.4.2.1 Using acids for sample preservation,
1.4.2.2 Sampling during flooding events and ice conditions,
1.4.2.3 Traffic on bridges,
1.4.2.4 Condition of sampling stations following flood events,
1.4.2.5 Sampling of water or soils, or both, highly contaminated with fertilizers,
1.4.2.6 Conditions of sampling stations resulting from vandalism,
1.4.2.7 Adverse weather conditions, and
1.4.2.8 Transporting liquid samples.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D6146 − 97 (Reapproved 2012)
Standard Guide for
Monitoring Aqueous Nutrients in Watersheds
This standard is issued under the fixed designation D6146; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Various forms of nitrogen and phosphorus are plant nutrients, both naturally occurring and
manmade, that can threaten water resources. Nutrients that run off or infiltrate through the soil profile
canresultinunfishableandunswimmablestreams,lakes,andestuaries,andunsafesurfaceandground
water used for drinking. High concentrations of nitrate in drinking water are a threat to young infants,
and surface waters can suffer from algal blooms, fish kills, and unpalatable and unsafe water for
swimming and drinking. Nutrients are also added to watersheds via chemigation.
This guide recommends a process for developing and implementing monitoring projects for
nutrients in a watershed. It follows Guide D5851 with more specifics applicable to watersheds and
nutrients. These guidelines are presented for use in the nationwide strategy for monitoring developed
by the Intergovernmental Task Force on Monitoring (ITFM). The nationwide monitoring strategy is
an effort to improve the technical aspects of water monitoring to support sound water quality
decision-making. It is needed to integrate monitoring activities more effectively and economically to
achieve a better return of investments in monitoring projects (1).
Guide D6145 is offered as a guide for monitoring actual and potential nonpoint and point source
pollution within a watershed. The guide is applicable to surface water and ground water resources,
recognizing the need for a comprehensive understanding of naturally occurring and manmade impacts
to the entire watershed hydrologic system.
1. Scope forms. Specific species of nitrogen include: nitrate, nitrite,
ammonia, organic, total Kjeldahl, and nitrous oxide. The
1.1 Purpose—This guide is intended to provide general
species of phosphorus include total, total dissolved, organic,
guidance on a watershed monitoring program directed toward
acid-hydrolyzable,andreactivephosphorusasdescribedin(2).
the plant nutrients nitrogen and phosphorus. The guide offers a
series of general steps without setting forth a specific course of
1.4 Safety—Health and safety practices developed for a
action.Itgivesassistancefordevelopingamonitoringprogram
project may need to consider the following:
butnotaprogramforimplementingmeasurestoimprovewater
1.4.1 During the construction of sampling stations:
quality.
1.4.1.1 Drilling practices during monitoring well
installations,
1.2 Thisguideappliestowatersfoundinstreamsandrivers;
lakes, ponds, and reservoirs; estuaries; wetlands; the atmo- 1.4.1.2 Overhead and underground utilities during monitor-
sphere; and the vadose and subsurface saturated zones (includ- ing well drilling,
ing aquifers). This guide does not apply to nutrients found in
1.4.1.3 Traffic patterns/concerns during sampling station
soils, plants, or animals.
installation,
1.4.1.4 Traffic patterns/concerns during surveying sampling
1.3 Nutrients as used in this guide are intended to include
station locations and elevations,
nitrogen and phosphorus in dissolved, gaseous, and particulate
1.4.1.5 Drilling through materials highly contaminated with
fertilizers, and
This guide is under the jurisdiction ofASTM Committee D19 on Water and is
1.4.1.6 Installing monitoring equipment below the soil sur-
thedirectresponsibilityofSubcommitteeD19.02onQualitySystems,Specification,
face.
and Statistics.
1.4.2 During the collection of water samples:
Current edition approved June 15, 2012. Published July 2012. Originally
approved in 1997. Last previous edition approved in 2007 as D6146 – 97 (2007).
1.4.2.1 Using acids for sample preservation,
DOI: 10.1520/D6146-97R12.
2 1.4.2.2 Sampling during flooding events and ice conditions,
The boldface numbers given in parentheses refer to a list of references at the
end of this standard. 1.4.2.3 Traffic on bridges,
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6146 − 97 (2012)
1.4.2.4 Condition of sampling stations following flood 3. Terminology
events,
3.1 Definitions:
1.4.2.5 Sampling of water or soils, or both, highly contami-
3.1.1 For definitions of terms used in this guide, refer to
nated with fertilizers,
Terminology D1129 and Guide D5851.
1.4.2.6 Conditions of sampling stations resulting from
3.2 Definitions of Terms Specific to This Standard:
vandalism,
3.2.1 aquifer—a geologic formation containing water, usu-
1.4.2.7 Adverse weather conditions, and
ally able to yield appreciable water.
1.4.2.8 Transporting liquid samples.
3.2.2 ground water—that part of the subsurface water that is
1.5 This standard does not purport to address all of the
the saturated zone. (D653, D18)
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.2.3 nonpoint pollution—a condition of water within a
water body caused by the presence of undesirable materials
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. from diffuse locations with no particular point of origin.
1.6 This international standard was developed in accor-
3.2.4 vandose zone—the zone of soil located between the
dance with internationally recognized principles on standard-
surface and the water table that is not saturated.
ization established in the Decision on Principles for the
3.2.5 watershed—all lands enclosed by a continuous hydro-
Development of International Standards, Guides and Recom-
logic surface drainage divide and lying upslope from a speci-
mendations issued by the World Trade Organization Technical
fied point on a stream. (D4410, D19)
Barriers to Trade (TBT) Committee.
2. Referenced Documents
4. Significance and Use
2.1 ASTM Standards:
4.1 The user of this guide is not assumed to be a trained
D515 Test Method for Phosphorus In Water (Withdrawn
technical practitioner in the water quality field.The guide is an
1997)
assembly of the components common to all aspect of water-
D653 Terminology Relating to Soil, Rock, and Contained
shed nutrient monitoring and fulfills a need in the development
Fluids
of a common framework for a better coordinated and a more
D1129 Terminology Relating to Water
unified approach to nutrient monitoring in watersheds.
D1357 Practice for Planning the Sampling of the Ambient
4.2 Limitations—This guide does not establish a standard
Atmosphere
procedure to follow in all situations and it does not cover the
D1426 Test Methods for Ammonia Nitrogen In Water
detail necessary to meet all of the needs of a particular
D1739 Test Method for Collection and Measurement of
monitoring objective. Other standards and guides included in
Dustfall (Settleable Particulate Matter)
the references describe the detail of the procedures.
D3370 Practices for Sampling Water from Closed Conduits
D3590 Test Methods for Total Kjeldahl Nitrogen in Water
5. Monitoring Components
D3856 Guide for Management Systems in Laboratories
Engaged in Analysis of Water
5.1 A watershed monitoring program of nutrients is com-
D3858 Test Method for Open-Channel Flow Measurement
prised of a series of steps designed to collect nutrient data to
of Water by Velocity-Area Method
achieve a stated objective. The purposes of monitoring may be
D3867 Test Methods for Nitrite-Nitrate in Water
several and include: analyzing trends, studying the fate and
D4410 Terminology for Fluvial Sediment
transport of nutrients, defining critical areas, assessing
D4448 Guide for Sampling Ground-Water MonitoringWells
compliance, measuring the effectiveness of management
D4696 Guide for Pore-Liquid Sampling from the Vadose
practices, testing for sufficient levels, making wasteload
Zone allocations, testing models, defining a water quality problem,
D4700 Guide for Soil Sampling from the Vadose Zone
and conducting research (3).
D5092 Practice for Design and Installation of Groundwater
5.1.1 Monitoringtoanalyzetrendsisusedtodeterminehow
Monitoring Wells
water quality is changing over time. In some cases baseline
D6145 Guide for Monitoring Sediment in Watersheds
monitoring is included as the early stage of trend monitoring.
D5851 Guide for Planning and Implementing aWater Moni-
5.1.2 Fate and transport monitoring is conducted to deter-
toring Program
mine whether pollutants move and where they may go.
5.1.3 Water quality monitoring can be used to locate critical
areas within watersheds exhibiting greater pollution loading
than other areas.
5.1.4 Nutrient monitoring may also be used to assess
compliance with water quality plans or standards.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.1.5 Nutrient monitoring may assess the effectiveness of
Standards volume information, refer to the standard’s Document Summary page on
individual management practices in improving water quality
the ASTM website.
or, in some cases, may be used to evaluate the effect of an
The last approved version of this historical standard is referenced on
www.astm.org. entire nutrient management program in a watershed.
D6146 − 97 (2012)
5.1.6 The testing of nutrient levels in water bodies may be attributes for nutrient monitoring objectives are often binary;
used to see if sufficient amounts are present to support certain that is, either the objective is accomplished or not.
aquatic organisms.
5.4 Step 3: Statistical Design—A statistical experimental
5.1.7 Monitoring of receiving water bodies may be used to
design should be stated that is consistent with the objectives of
determine wasteload allocations between point and nonpoint
the monitoring program. Appropriate experimental designs
sources. Such allocations require a thorough knowledge of the
could include: reconnaissance, plot, single watershed, above-
individual contributions from each source.
and-below, two watersheds, paired watershed, multiple
5.1.8 Nutrient monitoring may be used to fit, calibrate, or
watersheds, and trend stations (3). The design selected will
test a model for local conditions.
dictate most other aspects of the monitoring project including
5.1.9 Nutrient monitoring may be used for research ques-
thestudyscale,thenumberofsamplinglocations,thesampling
tions such as the accuracy of different types of samplers in
frequency, and the station type.
collecting a representative sample.
5.4.1 Reconnaissance or synoptic designs may be used as a
5.1.10 Finally, nutrient monitoring may be used to give
preliminary survey where no data exist or to assess the
adequate definition to a water quality problem or determine
magnitude and extent of a problem. This type of sampling
whether a problem exists. Guide for Planning D5851 provides
could be used to identify critical areas as well. A critical area
overall guidance on water monitoring.
is one that is contributing a significant amount of nutrients to
5.1.11 Thisguidesuggestsanddiscussesthefollowingsteps
the water body of interest. Randomization in sampling loca-
in designing a watershed monitoring program for nutrients.
tions may be important for reconnaissance monitoring. Recon-
More detail on each step may be found in (3).
naissance monitoring could be used in a “whole aquifer” study
with well placement located randomly or on a grid basis.
5.2 Step 1: Water Quality Need—The first step is to define
5.4.2 Plot designs have been commonly used in agricultural
the need for nutrient monitoring. The need statement should
experiments for 100 years (4). Plots are generally small areas
include several components: the potential or real water quality
that can be replicated on the land or waterscape. Plots allow
issue requiring attention (for example, eutrophication), the
replication and control of certain variables, such as soil type.
potential water resource use impairment (for example,
Plot designs are analyzed using Analysis of Variance (3).
recreation),thenameoftheactualwaterresource(forexample,
Long Lake), the potential threats or causes (for example,
5.4.3 The single watershed before-and-after approach has
phosphorus), and the potential sources that may cause a
been sometimes used to compare water quality conditions
problem (for example, agriculture) (3). Very often the need is
before a watershed treatment to after. Generally, this technique
toidentifyawaterqualityproblem,butinsomecases,theneed
is not recommended, since the results are confounded with
may be to assess the existing water quality whether a problem
time and climate variables, and should be avoided. For
exists or not. An example of a need statement might be: “The
example, the water quality differences from year-to-year may
lack of recreation in Long Lake is due to excessive eutrophi-
be caused by climate differences not the watershed activity.
cation caused by excessive phosphorus loading possibly from
5.4.4 The above-and-below design is used after a watershed
agricultural sources.”
practice is in place. Sampling is conducted both upstream and
downstream, or in the case of ground water monitoring,
5.3 Step 2: Objectives—The second step in developing a
up-gradient and down-gradient from the activity of interest.
nutrient monitoring program is to define the monitoring objec-
Although this design is not as susceptible to the effect of
tives. The objectives of the monitoring study should address
climate as the single watershed design, the differences in water
the water quality need or problem. An objective statement
quality between the two stations may be partly due to inherent
should include an infinitive verb, an object word or phrase, and
watershed differences such as soils or geology. If monitoring is
some limits on the objective such as the surface or ground
conducted before and after the practice in installed, the design
water resource or watershed boundaries and variables to
would follow the paired watershed approach described below.
monitor. An example of a monitoring objective might be: “To
5.4.5 Ground water monitoring using this approach is re-
determine the effect of implementing agricultural management
practices on phosphorus concentrations in Long Lake.” When ferred to as up-gradient versus down-gradient monitoring.This
is probably the most commonly used strategy in ground water
severalobjectivesareused,ahierarchialapproac
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