Transcript Water Quality Monitoring: Data Collection & Analysis

Water-Quality
Monitoring:
Data Collection and
Analysis Strategies
for Designing Program
U.S. Department of the Interior
U.S. Geological Survey
Measuring the
Success of Best
Management
Practices (BMP)
Implementation
presented by Miya N. Barr
Hydrologist/Water-Quality Data Base Administrator
(573) 308-3552
[email protected]
Missouri Water Science Center
Rolla, Missouri
BMP Project Goal
• The most common goal is to
improve the water resources
in the watershed
• How can project success or
failure be measured?
Watershed Natural
Resource Issues
Involves a mix of:
• Ecological, physical, and chemical
variables
• Social, economic, and ethical
issues
Evaluation Strategy
Involves systematic collection
of information about:
• The needs the project should
address
• The most effective ways to meet
those needs
• The extent to which the project met
those needs and project goals
Ways to Measure
Project Success
Evaluation strategy should include
physical and social aspects
of project impacts
• Water-quality monitoring to detect
changes in water quality
• Evaluate change in the human
dimension, i.e., the application of the
project and the impact of the project
on people
Barriers to BMP
Project
Evaluation
• Poor planning
• Failure to collect baseline data to
measure change against
• Selection of ineffective evaluation
methods
• Reliance on single evaluation
method
Barriers to BMP Project
Evaluation, cont’d
• Failure to consider both physical
water-quality parameters and
social/human indicators of change
• Insufficient time, financial resources,
and staff expertise
• Overlooking the obvious, i.e.,
existing data
Physical Indicators of
Water-Quality Changes
Water-Quality Monitoring:
• Water chemistry
• Macroinvertebrates
• Algae
• Fish population
• Habitat measures
Water-Quality
Monitoring
Water chemistry:
• Early planning essential
• Target constituents (nutrients, suspended
sediment, indicator bacteria, etc.)
• Importance of baseline data collection
• Long-term (5-10 years) monitoring may be
necessary
• Monitoring can be costly
• Complicated process; consult the experts
U.S. Geological Survey
Mission
The USGS provides the
Nation with reliable,
impartial information to
describe and understand
the Earth
Purpose of the USGS
Water-Quality Program
To provide a longterm data base so
that the general
water quality of the
hydrologic system
is known to allow
for proper planning
and management of
potential concerns
in the State
Ambient Water-Quality
Monitoring Network Stations:
USGS/MODNR (Missouri Department of Natural Resources)
Federal Program
Water-Quality Stations
National Stream
Quality Accounting
Network (NASQAN)
U.S. Forest Service
St. Louis: USGS/MSD
(Metropolitan Sewer District)
Special Studies: Water-Quality
Monitoring of the East Fork of
the Black River and the Black
River (Taum Sauk project)
Sample Collection
Monthly to biannually by
hydrologic technicians
Typical
Constituents
Measured
• Field parameters
• Nutrients
• Major ions
• Trace elements
• Pesticides
• Indicator bacteria (Fecal coliform and
E. Coli)
Sampling
Goals
• Obtain a representative sample
• Use “clean” sampling and
•
•
processing techniques
Measure unstable physical
properties and chemical constituents
at site
Determine streamflow at time of
sample collection
• Quality-assurance
practices
What is a representative
water-quality sample?
A water-quality sample that
represents the physical
characteristics and
chemical composition of
the flow of a stream at the
sampling point
Sampling Methods of the USGS
Purpose: To obtain a sample that is
representative of the stream cross section
• Weighted bottle
• Equal-width increment
• Equal-discharge increment
Equal Width
Increment
Sampled at equal widths in cross section;
verticals will have different volumes
Sampling
points
Stream
cross
section
Equal Discharge Increment
Sampled at equal discharge increments; each
vertical will have equal volume
Sampling
points
Stream
cross
section
Sampling Equipment
“Isokinetic” and
“Clean”
8-Liter Bag Sampler
“Clean”
Sampling
Techniques
“Clean”
Processing
Techniques
Why are some physical
properties and chemical
constituents measured in the
field?
•
•
•
Unstable and change with time
Preservation is not feasible
Change cannot be accurately
predicted
Field
Measurements
• Temperature
• Specific conductance
• pH
• Dissolved oxygen
• Alkalinity
• Indicator bacteria
Why is streamflow
important?
Chemical constituent concentration
must be related to stream
discharge
• To compute
constituent
transport loads
• To understand
dischargeconstituent
relations
Quality
Assurance
Practices
• Instrument calibration
• Equipment blanks
• Replicate samples
• “Clean” techniques
• National Field Quality
Assurance Program
After Sample
Collection
• Measure field parameters
• Process sample for shipment
to laboratory
• Laboratory analysis
• Retrieve data and review
• Store in data base
Continuous/Real-Time
Water-Quality Monitoring
 Use YSI brand equipment
 Provide customers and public
with web-based, real-time data
(http://nwis.waterdata.usgs.gov)
 Continuous collection of data for
up to five different parameters
simultaneously
 Data stored in USGS database
Real-time
view of
data
Data
updated
hourly
Continuous WQ Monitor
Quality Assurance
 Standard guidelines set by USGS for
installing and calibrating monitors, as well
as reporting monitor data
 Monitor sites visited frequently and data
watched online daily to detect issues
 Calibrations are checked for each
parameter and documented
 Must correct for monitor fouling and drift in
data set
Continuous WQ Monitor
Fouling: Before and After
Ancillary Activities
• Maintain a quality-assurance plan
• Review quality-assurance data
• Maintain data bases
• Participate in National Water-Quality
Assurance program
• Replace and repair sampling and
measuring equipment
• Continuing education
USGS Water-Data
Collection
• Experts in the field
• Continuous methods development
• Standardized sample collection, processing,
and analysis protocols
• Centralized storage of data with links to
other data bases
• Not biased, non-regulatory
• Quality motivated, not profit motivated
Conclusions
• Early planning essential
• Select effective evaluation methods
• Consider both physical water-quality
parameters and social/ human indicators
of change
• Allow sufficient time for monitoring; 5-10
years may be necessary to detect change
Conclusions, cont’d
• Collect baseline data to measure change
against
• Careful selection of target constituents
• Be sure of financial resources;
monitoring is not cheap!
• Monitoring is a complicated process;
consult the experts!