Mod10 11 part1

Module 10/11Stream Surveys

Stream Surveys – February 2004Part 1 – Water Quality Assessment

Developed by: Updated: U5-m21a-s2

Objectives

Students will be able to:• describe techniques used to determine dissolved oxygen.• list factors that influence high turbidity and suspended

solids in streams.• explain methods used to determine total suspended solids.• evaluate the relationship between total suspended solids

and turbidity.• identify methods used to determine water clarity in streams.• assess habitat degradation by determining the degree of

sediment embeddedness in a stream.• analyze the impact of dissolved salts, pH and temperature

on streams.• describe accepted sampling methods used in stream

surveys.


Stream assessments

• Water quality• Habitat• Hydrologic• Biological • Watershed


Water quality parameters


Water Quality Parameters

• Dissolved oxygen• Suspended sediments (TSS) and turbidity• Specific conductivity (EC)• alkalinity• pH• Temperature• Major ions

• All of these parameters are presented in greater detail in Module 9 – Lake surveys


Dissolved Oxygen


DO – importance and reporting

• Oxygen is produced during photosynthesis and consumed during respiration and decomposition.

• Generally < 3 mg/L is stressful to aquatic life.• Units of measurement are:

• Concentration: mg/L = ppm; concentrations range 0.0 to 20 mg/L

• % saturation – used to determine if water is fully saturated with oxygen at a particular temperature


DO – techniques

• Probe types and measurement techniques:• Winkler titration• Amperometric (polarographic) method, most

commonly usedhttp://www.lumcon.edu/education/StudentDatabase/gallery.asp

http://www.lumcon.edu/education/StudentDatabase/gallery.asp


DO – probes

• Most common sensor is the temperature compensated polarographic membrane-type (amperometric)• Temperature sensitive (but virtually all are

compensated).• The probes actually consume O2 as they work so

measurements require moving water using either a built-in stirrer (typical in multiparameter sondes and BOD probes) or “hand jiggling” during the measurement.

• in situ sensors are prone to fouling by algal/bacterial slimes and by silt in streams.


DO probes and meters

• The WOW units use either Hydrolab or YSI multiprobe datasounds, but there are many others


Sedimentation/siltation

• Excessive sedimentation in streams and rivers is considered to be a major cause of surface water pollution in the U.S. by the USEPA


Measures of sedimentation

• Suspended sediments

• Turbidity

• Embededdness


High turbidity and suspended solids

• Caused by many factors including: • soil erosion• domestic and industrial wastewater discharge • urban runoff• flooding• algal growth due to nutrient enrichment • dredging operations • channelization • removal of riparian vegetation and other stream

bank disturbances


Total suspended solids and turbidity

• Both are indicators of the amount of solids suspended in the water • Mineral (e.g., soil particles)• Organic (e.g., algae, detritus)

• TSS measures the actual weight of material per volume of water (mg/L)

• Turbidity measures the amount of light scattered

• Therefore, TSS allows the determination of an actual concentration or quantity of material while turbidity does not


Measuring TSS

1. Filter a known amount of

water through a pre-washed,

pre-dried at 103-105 oC, pre-

weighed (~ + 0.5 mg) filter

2. Rinse, dry and reweigh to

calculate TSS in mg/L (ppm)

3. Save filters for other analyses

such as volatile suspended

solids (VSS) that estimate

organic matter


Total suspended solids - method

What type of filter to use?


Calculate TSS by using the equation below

TSS (mg/L) = ([A-B]*1000)/C

where

A = final dried weight of the filter (in milligrams = mg)

B = Initial weight of the filter (in milligrams = mg)

C = Volume of water filtered (in Liters)

Total suspended solids


TSS

• Range of results and what the results mean• Example:

Suspended solids concentrations at Slate Creek WA average 150.8 mg/l with a range of 50 to 327 mg/l. It is generally desired to maintain total suspended solid concentrations below 100 mg/l.


•Turbidity measures the scattering effect suspended particles have on light•inorganics like clay and silt•organic material, both fine and colored

•plankton and other microscopic organisms

•Transparency or turbidity tubes

Even small amounts of wave action can erode exposed lakeshore sediments, in this case a minepit lake from northeastern Minnesota. Guess the mineral mined here.

Measuring turbidity


Turbidity

• Field turbidity measurements are made with • Turbidimeters (bench meter for discrete samples)• Submersible turbidity sensors (Note - USGS

currently considers this a qualitative method)

Hydrolab turbidity probe


Turbidity - Nephelometric optics

• Nephelometric turbidity estimated by the scattering effect suspended particles have on light

• Detector is at 90o from the light source


Turbidity – units and reporting

• Nephelometric Turbidity Units (NTU) standards are formazin or other certified material

• JTU’s are from an “older” technology in which a candle flame was viewed through a tube of water

1 NTU = 1 JTU (Jackson Turbidity Unit)


Turbidity - standards

• Top - a range of formazin standards

• Bottom –the same NTU range using a clay suspension


Turbidity

• Range of results and what the results mean• Ex: Salmon Creek Watershed (OR/WA border)

TMDL for turbidity is: "Turbidity shall not exceed 5 NTU over

background turbidity when the background turbidity is 50 NTU or less. Or more than a 10% increase in turbidity when the background turbidity is > 50 NTU”.


How do turbidity and TSS relate?


TSS vs Turbidity relationship

TSSTurbidity

Yearly average

Summer range (May-Oct)

Winter range (Nov-Apr)

Cedar River 3.61.1

0.6-5.00.4-1.2

3.5-6.21.0-2.0

Newaukum Ck 5.72.4

1.6-5.10.7-1.5

7.5-8.83.1-4.0

Springbrook Ck 19.822.0

8.0-26.013.0-44.0

6.7-44.013.0-35.0


Water clarity – transparency tubes



• Used in streams, ponds, wetlands, and some coastal zones

• Analogous to secchi depth in lakes: a measure of the dissolved and particulate material in the water



• Useful for shallow water or fast moving streams bodies where a secchi would still be visible on the bottom

• It is a good measure of turbidity and suspended sediment (TSS)

• Used in many volunteer stream monitoring programs


Horizontal secchi

• Newer method – all-black disk viewed horizontally


Embeddedness

• Measure of fine sediment deposition in the interstitial spaces between rocks

• High embeddedness values indicate habitat degradation

• Visual assessment used to estimate the degree of embeddedness


Embeddedness – cont.

• The stream-bottom sediments to the top right provide spaces for fish to lay eggs and for invertebrates to live and hide.

• Excess erosion has deposited fine grained sediments on the stream bottom to the bottom right. There are no spaces available for fish spawning or for invertebrate habitat.


Embededdness – visual assessment

• Embeddedness: General guidelines• 0% = no fine sediments even at base of top

layer of gravel/cobble• 25% = rocks are half surrounded by sediment• 50% = rocks are completely surrounded by

sediment but their tops are clean• 75% = rocks are completely surrounded by

sediment and half covered• 100% = rocks are completely covered by

sediment


Specific electrical conductivity = EC25


EC25 - importance

• Cheap, easy way to characterize the total dissolved salt concentration of a water sample

• For tracing water masses and defining mixing zones • Groundwater plumes• Stream flowing into another stream or into a lake or

reservoir


EC25 – units and reporting

Principle of measurement

• A small voltage is applied between 2 parallel metal rod shaped electrodes, usually 1 cm apart

• Measured current flow is proportional to the dissolved ion content of the water

• If the sensor is temperature compensated to 25oC, EC is called “specific” EC (EC25)


EC25 - units

• What in the world are microSiemens per centimeter (µS/cm)?

• Units for EC and EC25 are mS/cm or μS/cm @25oC. The WOW site reports it as EC @25oC (in μS/cm).

• Usually report to 2 or 3 significant figures (to + ~ 1-5 μS/cm)

• More details can be found in Module 9


EC25

• EC25 values in streams reflect primarily a combination of watershed sources of salts and the hydrology of the system• wastewater from sewage treatment plants and

industrial discharge • wastewater from on-site wastewater treatment and

dispersal systems (septic systems and drainfields) • urban runoff • agricultural runoff • acid mine drainage • atmospheric inputs


Snowmelt runoff example


pH

Image courtesy of USGS at http://www.usgs.gov/


pH – importance in aquatic systems

• The pH of a sample of water is a measure of the concentration of hydrogen ions.

• pH determines the solubility and biological availability of chemical constituents such as nutrients (phosphorus, nitrogen, and carbon) and heavy metals (lead, copper, cadmium, etc.).


pH - reporting

• pH can be measured electrometrically or colorimetrically (pH paper) BUT ONLY the former technique is approved by the EPA and USGS for natural waters.

• The electrometric method uses a hydrogen ion electrode.

• pH meters require extensive care in handling and operation.

• Report to the nearest 0.1 standard pH unit


pH – probes

• Field probe types:• Combination probes (e.g.YSI)

• Less expensive; more rugged design• Less precise• Shorter life because reference solution cannot be

replenished

• Separate reading and reference electrodes (e.g., Hydrolab)• Costs more• More precise; faster response time• Allows user maintenance; Teflon junction and electrolyte

can be replaced


pH – probes

• Or, alternatively, a bench or hand-held meter and probe can be used in a fresh subsample if you don’t have a field meter with a pH probe.


Temperature


Temperature importance

• Temperature affects:• the oxygen content of the water (oxygen levels

become lower as temperature increases) • the rate of photosynthesis by aquatic plants• the metabolic rates of aquatic organisms• the sensitivity of organisms to toxic wastes,

parasites, and diseases


Temperature measurement - probes

• Types of probes• Liquid-in-glass• Thermistor: based on measuring changes in electrical

resistance of a semi-conductor with increasing temperature.

thermistor on a YSI sonde


Temperature changes

• Causes of temperature change include:• weather• removal of shading streambank vegetation,• impoundments (a body of water confined by a

barrier, such as a dam) • discharge of cooling water• urban storm water• groundwater inflows to the stream


Temperature changes - continued

Graph showing factors that influence stream temperature, from Bartholow (1989).


Temperature criteria – example

Here’s an example of a temperature TMDL for a California stream


Temperature criteria – cont.


Temperature – summer rain storm

Summer rainfall event

Bump in stream temp (and turbidity)


Other Water Quality Parameters

• Nutrients – nitrogen and phosphorus• Fecal coliforms• Biochemical oxygen demand (BOD)• Metals• Toxic contaminants

• Details on analyzing these parameters are in Module 9 – Lake Surveys


Fecal coliforms

• Pathogens are number one


Water sampling - microbes

• Sterile technique:• Containers must be

sterilized by autoclaving or with gas used to kill microbes

• Take care not to contaminate the container

• Water samplers should be swabbed with 70 % alcohol


Bacteria – E. coli and fecal coliforms

• Fecal bacteria are used as indicators of possible sewage contamination

• These bacteria indicate the possible presence of disease-causing bacteria, viruses, and protozoans that also live in human and animal digestive systems

• E. coli is currently replacing the fecal coliform assay in most beach monitoring programs

See Module 9 for a detailed discussion of measuring pathogens


Water sample collection – grab samples

Grab samples for fecal coliforms are taken with sterile containers


Water sample collection

• A detailed discussion on how to manually collect stream and river water can be found in the USGS Field Manual Chapter 4: Collection of Water Samples

• General considerations:• Sample in the main

current• Avoid disturbing bottom

sediments• Collect the water sample

on your upstream side


Analyte Volume neededchlorophyll >500 mLs

TSS Often > 1 L

total phosphorustotal nitrogenanions

200 to 500 mLs

Dissolved nutrients ~ 100mLsTotal and dissolved carbon ~60 mLs

Metals ~60 mLs

color, DOC ~60 mLs

Suggested sample volumes


Stream sampling– sample labeling

• An unlabeled sample may as well just be dumped down the drain.

• Use good labels not masking tape, etc. Poor labels often fall off when frozen samples are thawed.

• Use permanent markers NOT ball point pens, pencils in a pinch


• A simple sample label with the minimum amount of information needed…

WOW

Tischer Creek 7/26/02 Reach 3

RAW, frozen

Lake sampling – sample labeling

Often, much more information may be needed by the laboratory performing your analyses. You will also need to supply a chain of custody form.

Stream sampling – sample labeling

project Site, date, location

Sample processing and preservation info


Automated stream monitoring


Water sampling - automated

• Automated stream sampling stations provide continuous monitoring of a variety of parameters

• These units are capable of both collecting water samples and measure various water quality parameters


Automated stream samplers

• Flow weighted composites• Flow weighted discrete• Sampling triggered by predetermined set point

such as:• Flow• Precipitation• Any other parameter measured by in-stream

sensors


Automated sampling – Duluth Streams

• These stream monitoring units are not “state of the art” but provide near real-time data for delivery into the data visualization tools

Automotive

Mod10 11 part1