355 exam 1

Question 1

water resource management goals

Answer 1

protecting healthy waters
restoring degraded waters
enhancing socio-economic benefits

Question 2

monitoring waters

Answer 2

PHYSICAL-CHEMICAL ATTRIBUTES INCLUDE WATER TEMPERATURE AND CLARITY,
DISSOLVED OXYGEN AND A VARIETY OF CHEMICAL POLLUTANTS (PESTICIDES,
PHARMACEUTICALS, PLASTICS, ETC.)
* BIOLOGICAL ATTRIBUTES INCLUDE HEALTHY COMMUNITIES OF INSECTS, FISH, ETC.
AS WELL AS SPECIES OF CONCERN (FRESHWATER MUSSELS, CORALS, MARINE
MAMMALS, ETC.).

Question 3

key point for water monitoring

Answer 3

ASSESSMENT REQUIRES AN OBJECTIVE (USUALLY NUMERIC)
BASIS FOR DISTINGUISHING HEALTHY WATERS.

Question 4

clean water act

Answer 4

REQUIRES THAT STATES DEFINE ‘DESIGNATED USES’ FOR
EACH WATERBODY (E.G., ‘SWIMABLE’, ‘FISHABLE’, DRINKING
WATER, SUITABLE FOR AQUATIC LIFE).
* REQUIRES STATES TO ESTABLISH WATER QUALITY
STANDARDS TO PROTECT DESIGNATED USES.
* REQUIRES STATES TO MONITOR WATERS TO IDENTIFY
THOSE WHICH ARE NOT MEETING THEIR DESIGNATED USES
(AND REPORT TO EPA).
* REQUIRES STATES TO IMPLEMENT MEASURES TO MITIGATE
IMPAIRMENTS (I.E., TO ATTAIN WATER QUALITY STANDARDS).

Question 5

CAUSES OF IMPAIRMENT IN VA
WATERS

Answer 5

BACTERIA LEVELS EXCEEDING
WATER QUALITY STANDARDS
WAS THE MOST COMMON
CAUSE FOR IMPAIRMENT
(AFFECTING RECREATIONAL
USAGE AND SHELLFISH
HARVESTING).
* LOW DISSOLVED OXYGEN AND
LOW PH WERE COMMON
WATER QUALITY ISSUES AS
WELL AS PRESENCE OF HG
AND PCB IN FISH TISSUES
(LEADING TO CONSUMPTION
ADVISORIES).

Question 6

water quality standards

Answer 6

WATER QUALITY STANDARDS ARE DESIGNED TO PROTECT
DESIGNATED USES.
* IF WATER QUALITY STANDARDS ARE NOT MET, THE SYSTEM IS
CONSIDERED IMPAIRED (NOT IN ATTAINMENT OF DESIGNATED USES).
* IDEALLY, THESE SHOULD BE QUANTITATIVE (NUMERIC).
* E.G.,DISSOLVED OXYGEN > 5 MG/L
* NOT: “DISSOLVED OXYGEN SHOULD NOT FALL BELOW LEVELS THAT
CAUSE DELETERIOUS EFFECTS”.
* STANDARDS HAVE TWO COMPONENTS:
* CRITERIA: USUALLY A THRESHOLD VALUE
* APPLICATION: HOW THE CRITERIA ARE ASSESSED (E.G., 30-DAY AVERAGE,
DAILY MAXIMUM, ETC.)

Question 7

water quality standards pt2

Answer 7

DESIGNED TO PROTECT AGAINST DIRECT HARMFUL EFFECTS (E.G.,
TOXICITY) AS WELL AS INDIRECT EFFECTS (SECONDARY EFFECTS
ON WATER QUALITY).
* EXAMPLES:
* DIRECT: DISCHARGE OF TOXIC SUBSTANCES SUCH AS HG.
* INDIRECT: DISCHARGE OF NUTRIENTS WHICH CAUSE ALGAL BLOOMS
THAT LEAD TO LOW OXYGEN.
* WATER QUALITY STANDARDS MUST BE SCIENTIFICALLY
DEFENSIBLE. IF A MUNICIPALITY OR INDUSTRY IS COMPELLED TO
SPEND MONEY TO ATTAIN A PARTICULAR STANDARD, THERE MUST
BE A MEASUREABLE BENEFIT TO HUMAN OR ENVIRONMENTAL
HEALTH.

Question 8

CHALLENGES TO SETTING WQ
STANDARDS

Answer 8

POLLUTANTS ARE COMPLEX
* LETHAL, SUB-LETHAL & INTERACTIVE EFFECTS
* HUMANS ARE COMPLEX SYSTEMS
* MULTIPLE TISSUE TYPES AND ORGAN SYSTEMS
* SENSITIVITY VARIES WITH SEX AND LIFE STAGE
* ECOSYSTEMS ARE COMPLEX
* MANY SPECIES WITH VARYING SENSITIVITY AND VARYING
EXPOSURE
* ETHICS
* TESTING ON HUMANS AND ANIMALS
* DOES “SAFE” = NO EFFECT?

Question 9

CLEAN WATER ACT – PERMITTED POLLUTANT
DISCHARGE

Answer 9

DISCHARGE OF POLLUTANT FROM A POINT SOURCE
INTO WATERS OF THE U.S WITHOUT A PERMIT IS
PROHIBITED.
* ISSUANCE OF A PERMIT REQUIRES PERMIT HOLDER TO
(A) MONITOR POLLUTANT CONCENTRATIONS IN
OUTFALL, AND (B) USE BEST AVAILABLE TECHNOLOGY
TO MINIMIZING POLLUTANT DISCHARGE.
* THE PERMITTED AMOUNT OF POLLUTANT RELEASE IS
BASED ON A TOTAL MAXIMUM DAILY LOAD (TMDL).
* NOT SIMPLY – WHAT IS THE ALLOWABLE AMOUNT
RELEASED FROM THIS SOURCE,
* BUT, WHAT IS THE ALLOWABLE AMOUNT, GIVEN ALL
PERMIT HOLDERS FOR THIS WATERBODY.

Question 10

permittent pollution discharge

Answer 10

DETERMINATION OF THE ALLOWABLE LEVELS OF POLLUTANT
DISCHARGE MUST TAKE INTO ACCOUNT:
a) ALL SOURCES OF THE POLLUTANT CONTRIBUTING TO THE
RECEIVING SYSTEM (INCLUDING POINT AND NON-POINT SOURCES).
b) THE CAPACITY OF THE SYSTEM TO DILUTE OR ASSIMILATE THE
POLLUTANT
c) THE TOXICITY OF THE POLLUTANT. THIS IS DETERMINED FROM
TOXICITY TESTING: EXPOSING TEST ORGANISMS TO POLLUTANTS
THAT ARE BEING RELEASED INTO THE ENVIRONMENT

Question 11

WATERSHED:

Answer 11

A watershed is an area of land
where precipitation collects and
drains off into a common outlet, such
as into a stream.
Surficial topography can be used to
determine direction of flow and
thereby delineate watershed

Question 12

RUNOFF:

Answer 12

PORTION OF RAINFALL
THAT FLOWS FROM LAND TO
WATER VIA SURFACE
(OVERLAND) OR SUB-SURFACE
(GROUNDWATER) FLOW.

Question 13

WATER MOVING ACROSS THE
LANDSCAPE

Answer 13

THE FORCE OF GRAVITY
ACTS TO MOVE WATER
FROM A POSITION OF
HIGHER ELEVATION TO
LOWER ELEVATION.
* THEREFORE, THE
ELEVATION OF WATER IN
THE LANDSCAPE (E.G.,
SURFACE HEIGHT OF A
STREAM OR
GROUNDWATER) CAN BE
USED TO PREDICT ITS
DIRECTION OF FLOW.

Question 14

WATERSHEDS AS UNITS OF THE
LANDSCAPE

Answer 14

DRAINAGE BASINS CONNECT WITH
OTHER DRAINAGE BASINS IN A
NESTED PATTERN, WHICH IN TURN
DRAIN INTO A COMMON OUTLET.

Question 15

A CATCHMENT WATER BUDGET:

Answer 15

INPUTS = OUTPUTS
* INPUTS = PRECIPITATION (RAIN + SNOWFALL)
* OUTPUTS = RUNOFF + ET
* RUNOFF = STREAM + GROUNDWATER
* ET = EVAPOTRANSPIRATION: WATER RETURNED TO THE ATMOSPHERE VIA
TRANSPIRATION BY PLANTS AND EVAPORATION FROM WETTED SURFACES (SOIL, ROADS,
ETC.).
* ET IS TYPICALLY THE LARGEST COMPONENT OF WATER LOSS (50-75%);
HIGHER VALUES FOR WARMER AND DRIER CLIMATES, LOWER VALUES FOR
COOL, HUMID CLIMATES.
* OF THE REMAINING FRACTION (“RUNOFF”), STREAM FLOW TYPICALLY
ACCOUNTS FOR A LARGE PROPORTION OF WATER LOSS (GROUNDWATER
LOSSES ARE SMALL).

Question 16

evapotranspiration

Answer 16

highest rates in vegetated areas because plants increase surface areas.

Question 17

RAINFALL & RUNOFF

Answer 17

Tropical climate:
seasonal variation in
rainfall determines
discharge (little
seasonal variation in ET
where To is similar year-
round).

Question 18

watershed runoff

Answer 18

The amount of water draining from a
catchment is determined by the
area of the catchment and the
amount of rainfall.
When comparing among catchments
of varying size, it is useful to
convert discharge to water yield
(runoff per unit area).
water yield = discharge/area

Question 19

Global-scale variation in
precipitation and river
discharge (as water
yield).

Answer 19

SA receives greatest
rainfall (1600 mm) and
has greatest runoff (700
mm).
* NA, Asia, EU & Africa
have similar rainfall, but
vary in runoff.
* AU has lowest rainfall
(450 mm) and runoff (40
mm).

Question 20

WATER QUALITY AREA

Answer 20

DEPENDENT ON LAND USE IN THE SURROUNDING BASIN.
* FORESTED CATCHMENTS GENERALLY HAVE GOOD WATER QUALITY EXCEPT
WHERE IMPACTED BY ATMOSPHERIC POLLUTANTS (E.G., ACID RAIN).
* AGRICULTURE: ASSOCIATED WITH SOIL EROSION AND SEDIMENT
TRANSPORT INTO STREAMS. ALSO, NUTRIENTS FROM FERTILIZER AND
MANURE APPLICATION, AND AGROCHEMICALS SUCH AS HERBICIDES AND
PESTICIDES.
* URBANIZATION: DISCHARGE FROM INDUSTRY AND WASTEWATER
TREATMENT PLANTS (POINT SOURCES). ALSO, RUNOFF FROM IMPERVIOUS
SURFACES (E.G., LEAD, PETROLEUM PRODUCTS, ETC.).

Question 21

urban dominated sites

Answer 21

ELEVATED CONDUCTIVITY
(EC) DUE TO ROAD SALT
RUNOFF.
* LOW DISSOLVED OXYGEN
AND HIGH OXYGEN DEMAND
(COD).
* HIGH TOTAL NUTRIENTS (TN,
TP) AND DISSOLVED
NUTRIENTS (NH4, NO3).
* HIGH ALGAL ABUNDANCE
(CHLOROPHYLL-A; CHL-A).

Question 22

WHAT IS A STREAM?

Answer 22

HYDROLOGY & PHYSICAL HABITAT
* UNIDIRECTIONAL FLOW ALONG AN
ELEVATION GRADIENT
* HIGH RATIO OF CONTRIBUTING AREA
(LAND) TO STREAM SURFACE AREA
* FORCE OF WATER MOVING DOWNHILL
INTERACTS WITH LOCAL GEOLOGY TO
CREATE AND SHAPE CHANNEL
* WIDTH, DEPTH, SUBSTRATE
COMPOSITION

Question 23

LINKING PHYSICS & BIOLOGY

Answer 23

HYDROLOGY & PHYSICAL HABITAT
* DEFINED BY UNIDIRECTIONAL
FLOW ALONG AN ELEVATION
GRADIENT
* HIGH RATIO OF CONTRIBUTING
AREA TO STREAM SURFACE AREA
* FORCE OF WATER MOVING
DOWNHILL INTERACTS WITH
LOCAL GEOLOGY TO SHAPE
CHANNEL

BIOLOGY
* ADAPTED TO LIFE IN FLOWING
WATER
* DOMINATED BY BENTHIC
PROCESSES
* BIOFILMS COVER SURFACES
(ROCKS, WOODY DEBRIS, ETC.)
* BIOFILMS: A COMMUNITY OF
MICROSCOPIC PLANTS AND
ANIMALS

Question 24

BIOFILMS

Answer 24

AUTOTROPHS (ALGAE) TAKE UP
DISSOLVED INORGANIC NUTRIENTS
(N,P) AND USE ENERGY FROM
SUNLIGHT TO CARRY OUT
PHOTOSYNTHESIS THEREBY
PRODUCING NEW ORGANIC MATTER.
* HETEROTROPHS (BACTERIA, ETC.)
USE ORGANIC COMPOUNDS
PRODUCED BY ALGAE AS THEIR
ENERGY SOURCE. THE BREAKDOWN
OF ORGANIC MATTER RELEASES
INORGANIC NUTRIENTS.

Question 25

RIPARIAN CANOPY & LEAF LITTER

Answer 25

THE PRESENCE OF A RIPARIAN CANOPY IS
IMPORTANT NOT ONLY IN REGULATING THE
LIGHT CLIMATE OF STREAMS, BUT ALSO FOR
PROVIDING ORGANIC MATER INPUTS IN THE
FORM OF LEAF LITTER.
* INPUTS OF TERRESTRIAL PLANT MATERIALS
SUPPORT SECONDARY PRODUCTION IN STREAM
FOOD WEBS.Inputs of organic mater
from outside of the
ecosystem (e.g., from
forest to stream) are
referred to as “subsidies”.

Question 26

GROWTH OF STREAM ALGAE

Answer 26

Effects of light and nutrient availability on
the accumulation of benthic algal biomass
in experimental stream channels. Nutrient
levels are concentrations of SRP (μg/L).
Where there is a loss of canopy shading
and elevated nutrient inputs (e.g., urban
and agricultural streams) excess growth of
stream algae may occur.

Question 27

STORM EVENTS & BENTHIC ALGAE

Answer 27

• STORMS THAT RESULT IN HIGH
  DISCHARGE ARE A FORM OF
  ECOLOGICAL DISTURBANCE
  (SIMILAR TO FIRES AND
  BLOWDOWN IN FOREST).
• INCREASED WATER VELOCITY
  SCOURS ALGAE AND
  SUBSTRATES.
• THEIR RECOVERY FOLLOWING
  DISTURBANCE IS DICTATED BY
  TEMPERATURE, LIGHT AND
  NUTRIENTS.
  FREQUENCY OF STORM
  EVENTS DICTATES THE
  IMPORTANCE OF SCOUR VS.
  GRAZING IN CONTROLLING
  ALGAL ABUNDANCE
• URBAN STREAMS PRONE TO
  FREQUENT DISTURBANCE DUE
  TO IMPERVIOUS SURFACES.

Question 28

LEAF LITTER & AQUATIC
MACROINVERTEBRATES

Answer 28

LEAVES BECOME
WATERLOGGED AND SINK.
COLONIZATION BY BACTERIA
AND FUNGI BEGINS ALMOST
IMMEDIATELY.
* SHREDDERS (AQUATIC
INSECTS) FRAGMENT LEAVES
CREATING MORE SURFACE
AREA FOR BACTERIAL
DECOMPOSERS.

Question 29

SHREDDERS:

Answer 29

FRAGMENT LEAVES CREATING MORE SURFACE AREA FOR
BACTERIAL DECOMPOSERS. CONVERT COARSE PARTICULATE ORGANIC
MATTER (CPOM) TO FINE PARTICULATE ORGANIC MATTER (FPOM).

Question 30

GRAZERS:

Answer 30

SCRAPE ALGAE AND BACTERIA FROM LEAVES AND OTHER
SURFACES.

Question 31

COLLECTOR-FILTERERS:

Answer 31

CAPTURE FPOM DERIVED FROM TERRESTRIAL
(LEAF LITTER) AND INTERNAL (ALGAE) SOURCES.

Question 32

PREDATORS

Answer 32

EAT OTHER INVERTEBRATES

Question 33

STREAM DRAINAGE NETWORK

Answer 33

STREAM ORDER: NUMBERS ASSIGNED
BASED ON BRANCHING PATTERNS.
1ST ORDER = ‘HEADWATER’ STREAMS
(MAY BE EPHEMERAL)
2-4 ORDER: SMALL STREAMS OF
INCREASING FLOW.
>5TH ORDER: RIVERS OF VARYING SIZE
WITH INCREASING STREAM ORDER,
STREAMS GET LARGER (GREATER
DISCHARGE, ALSO WIDER). WITH
GREATER WIDTH, THERE IS LESS
RIPARIAN SHADING – LESS LEAF LITTER
INPUTS, BUT MORE SUN FOR ALGAE.

Question 34

RIVER CONTINUUM CONCEPT

Answer 34

Predictable changes in invertebrate functional feeding
groups arise from longitudinal variation in organic
matter inputs.
Headwater streams (low light, high leaf litter):
* shredders - take large food (leaves) and produce fine
particulate organic matter
* collectors - spin nets or use setae to collect FPOM
Middle order streams (more light):
* scrapers - feed on biofilms
Large order streams (more light, lower water velocity)
* collectors - collect FPOM from upstream and locally
produced phytoplankton

Question 35

HOW STREAMS WORK: FOOD WEB PERSPECTIVE

Answer 35

GREEN FOOD WEB: HERBIVORES FEED ON
ALGAE AND ARE IN TURN FED UPON BY
PREDATORS
* BROWN FOOD WEB: DETRITIVORES FEED
ON LEAF LITTER AND ARE FED UPON BY
PREDATORS
IN STREAMS, EXTERNAL INPUTS OF OM
(LEAF LITTER) MAY BE MUCH LARGER
THAN INTERNAL PRODUCTION (ALGAE)

Question 36

SOURCES OF ORGANIC MATTER TO
STREAMS

Answer 36

AUTOCHTHONOUS (INTERNALLY-DERIVED): PRIMARY PRODUCERS IN
STREAMS, PRINCIPALLY BENTHIC ALGAE.
* ALLOCHTHONOUS (EXTERNAL INPUTS): TERRESTRIAL PLANT
PRODUCTION THAT IS EXPORTED TO STREAMS IN DISSOLVED (DOM)
AND PARTICULATE (POM) FORMS.
* ALTHOUGH AUTOCHTHONOUS OM IS MORE LABILE, ALLOCHTHONOUS OM
IS QUANTITATIVELY DOMINANT, PARTICULARLY IN FORESTED STREAMS
WHERE THE RIPARIAN CANOPY CONTRIBUTES LEAF LITTER AND
SUPPRESSES BENTHIC ALGAE PRODUCTION.

Question 37

Stream Monitoring Parameters

Answer 37

Physical: streamflow (discharge), temperature.
 Chemical: basic water quality attributes (pH, dissolved oxygen) as well as a wide
range of micropollutants (metals, herbicides, pharmaceuticals, etc.).
 Biological: harmful bacteria (E. coli) as well as community-based metrics that are
indicators of biological integrity (aquatic insects & fish).

Question 38

Physical Properties: Streamflow

Answer 38

In urban environments, the presence of impervious surfaces (roofs, pavement)
prevents infiltration of rainwater into the ground and results in rapid runoff.
High runoff during storm events results in unnaturally high streamflow
conditions. These cause stream bank and bed erosion.
Erosion of bed and bank materials results in high mortality of fish and aquatic
insect communities, and results in the export of sediment to downstream areas
(lakes, estuaries).

Question 39

Runoff as a cause of impairment in urban streams

Answer 39

Urban streams have a “flashy”
hydrograph (rapid changes in
water level & discharge) due to
runoff from impervious surfaces.
Consequences: stream erosion
and incision.
Example: water level in Reedy
Creek.

Question 40

Urban stream syndrome

Answer 40

High discharge
during storm events
 Channelization &
incision
 Homogenization of
habitat & Reduced
biodiversity
 Loss of ecological
function

Question 41

Physical Properties: Temperature

Answer 41

Human activities can alter stream temperature both directly (e.g., discharge of
heated effluent, loss of riparian shading) and indirectly (via rising air
temperatures).
These may cause stream conditions outside of thermal tolerance for aquatic
organisms.

Stream shading provided by
mature, young and post-burn
forest.
Loss of shading may arise from
timber harvesting or clearing of
land for agriculture or
development.

Question 42

Physical Properties: Conductivity

Answer 42

A measure of the ability of water to carry an electrical charge.
Conductivity is directly related to the amount of dissolved substances in
water.
Elevated conductivity in streams is often an indicator of pollution

Question 43

Road salt

Answer 43

Road salt runoff results in
elevated levels of stream
conductivity and chloride
following snowfall events in city
of Richmond.
Salinization of freshwaters is a
widespread problem: impacts
on aquatic life, drinking water
sources.
How to balance human risk
(safe roads) and ecological
harm?

Question 44

Physical Properties: Dissolved Gases

Answer 44

Dissolved oxygen is an important water quality attribute as many
species are intolerant of low oxygen conditions.
Oxygen concentrations in water are determined in part by
temperature (solubility).
Low oxygen conditions in
streams may be indicative of
organic matter pollution (e.g.,
sewage).
Organic matter is decomposed
by bacteria which consume
oxygen in the process.

Question 45

Dissolved Oxygen

Answer 45

Wastewater treatment plants and other
industries may discharge effluent that
when released into the environment
causes oxygen depletion.
COD = chemical oxygen demand. Presence
of reduced chemical compounds (e.g., NH4)
results in oxygen consumption as these are
oxidized (e.g., NO3).
BOD = biological oxygen demand. Dissolved
and particulate organic matter that is
decomposed resulting in oxygen
consumption by bacteria.

Question 46

Stream Monitoring: Chemical Properties

Answer 46

A long list of potential chemicals of interest.
 Naturally occurring substances that may be present in excess amounts: e.g.,
sediments, mineral nutrients (nitrogen, phosphorus), trace metals (Al, Zn, Cu).
 Man-made compounds that do not naturally occur in the environment: PCBs,
herbicides, pesticides, pharmaceuticals, microplastics.

Question 47

Biological Monitoring: Bacteria

Answer 47

Escherichia coli (E. coli) - a coliform bacterium found in the lower intestine of warm-
blooded organisms. Most strains are harmless, but its presence in the environment
is indicative of fecal contamination.
 The presence of E. coli poses a hazard to human health, particularly in drinking
water, but also through recreational contact.
 Sources include sewage, urban runoff (pet waste & wildlife) and agricultural runoff
(livestock operations).
 Water samples are incubated under specific conditions to determine the number of
colony forming units (cfus).

Question 48

urban streams and water quality

Answer 48

In cities which
have combined
sewer systems,
rain events result
in the release of
wastewater to the
environment.

Question 49

e. coli

Answer 49

E. Coli levels exceeding 126
cfu are considered unsafe
for recreational contact.

Question 50

Stream Monitoring: Biological Indicators

Answer 50

Poor water quality results in a loss of biodiversity as sensitive species are unable
to survive and reproduce and communities become dominated by tolerant species.
 Biota are often used as indicators of water quality: diverse, balanced communities
of stream insects and fish are indicative of good water quality conditions.

Question 51

Chemical vs. Biological Monitoring

Answer 51

Advantages of biomonitoring:
Aquatic communities can be used to directly assess whether conditions are
suitable for aquatic life.
Biota integrate the effects of stressors over their life span, thereby providing a
longer-term perspective on the suitability of the site to support aquatic life (vs.
spot sample of chemistry).

Disadvantages of
biomonitoring:
Requires skilled taxonomists to
identify fish, insects, algae (not
automated, more difficult to
replicate, more expensive vs.
chemistry).
Does not provide information
on stressors (what is the cause
of the impairment to aquatic
life?).

Question 52

Aquatic Bioindicator Assemblages

Answer 52

Algae: planktonic and attached species used in assessment of lakes and streams,
respectively.
 Benthic macroinvertebrates: bottom-dwelling animals (many are insects) that can be
seen without magnification.
 Fish: long-lived and more mobile (integrate conditions over greater space and time).

Question 53

Metrics used for Bioassessment

Answer 53

Individuals:
 Species-specific tolerance to pollution
 Health: presence of lesions, abnormalities, body condition.
Communities:
 Diversity: number of species present, relative proportions of individuals.
 Functional groups: e.g., insect scrapers, shredders, grazers, predators, etc.
 Number of native vs. invasive species

Question 54

Benthic Macroinvertebrates as Indicators

Answer 54

Maccaffertium- flatheaded mayflies, relatively pollution
intolerant.
 Fast-water specialists (riffles) that cling to hard substrate
and feed primarily by scraping algae (diatoms).
 Disturbance that reduces flow, and sedimentation that
buries rocks and benthic algae are primary stressors.
 DEQ tolerance value is 5.4/10 (pollution sensitive taxa
have values <3).

Question 55

Sampling Stream Fishes

Answer 55

Typically carried out by electrofishing – a
weak current is used to immobilize and
capture fish. Individuals are identified in
the field and released. Generally
harmless, though can cause mortality in
very small fish.
A representative sample of the fish
assemblage is obtained by collecting
from a length of stream with a mix of
habitats (e.g., pools and riffles).

Question 56

Catchment-based management

Answer 56

Cause of impairment: bacteria (from livestock), sediment (erosion), ag chemicals
(fertilizers, pesticides, herbicides).
Install fencing to keep livestock out of streams
Maintain riparian plant buffer to remove pollutants
No-till farming to reduce erosion & sediment transport

Question 57

Catchment-based management: Urban streams

Answer 57

Cause of impairment: bacteria (from sewer overflows), elevated salinity (from road salt),
bed & bank erosion (from stormwater runoff).
Install stormwater retention ponds & rain gardens to capture runoff & promote
infiltration
Eliminate overflows from sewer systems
Restore riparian buffers

Question 58

Catchment vs. in-stream approaches to restoration

Answer 58

Catchment-based approaches have the advantage that they treat the problem at
the source (reduce run-off and pollutants before they enter the waterway). The
challenge is that they are generally very limited in scope relative to the scale of
the problem (can’t fix entire catchment).
Consider a 3-mile stream in an urban setting – many property owners
(private, public, business). What proportion are willing to undertake (pay for)
or allow installation of green infrastructure?
 In-stream restoration can be used to repair degraded stream channels. but will
repairs succeed if proximal causes (livestock, impervious surfaces) are not
addressed?

Question 59

Stream Restoration

Answer 59

Typically focus on the physical template of the stream channel.
 Field of dreams hypothesis: if you build it, they will come (i.e., if stream habitat is
returned to a more natural condition, stream biology and functioning will return).
 How do we measure success?
The goal of restoration is usually not to return the stream to a pristine state
(difficult to achieve in ag or urban setting), but to stabilize the stream to
prevent further degradation (bed and bank erosion).

Question 60

Setting goals for restoration:
What is a stream supposed to look like?

Answer 60

A riffle-pool sequence develops as a stream’s
hydrological flow structure alternates from areas
of relatively shallow, fast-moving water to
deeper, slow-moving water. The sequence
commonly occurs at intervals of from 5 to 7
stream widths.
 Meandering streams tend to develop a riffle-pool
sequence with pools in the outsides of the bends
and riffles in the crossovers between one
meander to the next.
 Habitat diversity fosters biodiversity
Examples of pool vs riffle
fishes
 Fishes and aquatic insects
have specialized habitat
preferences
 Greater habitat diversity
results in greater biodiversity
 Loss of habitat diversity
(urban streams) results in loss
of biodiversity

Question 61

Stream restoration

Answer 61

1 km of stream returned to its floodplain
 During storm events, water exceeds bankfull
capacity and spills into floodplain
 Floodplain inundation slows down the water, more
opportunity for removal of sediments, nutrients
and other pollutants
 Meanders and Pool-riffle structure enhances in-
stream habitat diversity and biodiversity
 Longer transit time of water through the stream
channel allows greater opportunity for nutrient
uptake by benthic biofilm communities.

Question 62

Wilson Creek Restoration

Answer 62

Benefits
Supporting aquatic life designated uses by increasing habitat diversity
to foster greater biodiversity
Enhancement of stream functioning by slowing downstream transport
of water and reducing sediment and nutrient fluxes.
Trapping of particulate matter within the floodplain during storm events.
Greater transient storage within the stream and floodplain allows for
uptake of dissolved inorganic nutrients by biofilms.

Question 63

Managing & restoring urban streams

Answer 63

Changes in stream hydrology
resulting from urbanization:
Before - rainwater infiltrates soil and is
slowly discharged to the stream. Small
peak flows following storm events.
After - impervious surfaces (roads, rooftops)
generate rapid runoff. Large peak flows
after storm events.

Question 64

Managing & restoring urban streams

Answer 64

Flood stage: when stream water elevation
exceeds bankfull capacity.
Before urbanization: water escapes channel
and inundates lateral floodplain areas. This
reduces the force of water and results in
sediment deposition and storage in the
floodplain.
After urbanization: streams become incised,
as bank height increases, water is
prevented from escaping into floodplain.
Erosive force increases resulting in greater
incision and downstream sediment
transport.

Question 65

Restoration of Urban streams

Answer 65

Key challenges: impervious surfaces
generate stormwater runoff.
 High discharge during storm events
causes stream bank and bed erosion
 Channelization & incision results in loss of
habitat complexity and Reduced
biodiversity
 Loss transient storage and floodplain
connectivity reduces ecological function
(sediment trapping and nutrient uptake).

Question 66

Management of Urban streams

Answer 66

Historically focused on getting rid of water
(to prevent flooding).
 Streams were channelized (straightened
and deepened) and sometimes lined in
concrete – designed to convey water
quickly.
 Some streams diverted to underground
culverts to allow for development.
 How to un-do this in an urban setting
(engaging private landholders)?

Question 67

Why is stream restoration controversial?

Answer 67

Not in my backyard: re-grading incised stream banks requires earthmoving,
which often requires removal of riparian trees. Trees are re-planted following
construction, but it may take >20 years for forests to recover. This has led to
opposition from local homeowners (e.g., cancellation of Reedy & Rattlesnake
creek projects in Richmond).
 Does is work? Is there evidence that stream restoration achieves stated
goals (e.g., improving stream biodiversity and ecological functioning)?
 Some projects successful (e.g., Wilson Creek), others not, most are not
monitored.
 Assurance of success if especially important where nutrient reduction credits are
given.

Question 68

Stream restoration in the context of Chesapeake Bay
restoration

Answer 68

The EPA has prescribed a “pollution diet” for the bay, which sets limits on
sediment, N and P inputs.
 States are required to implement mitigation activities to meet their pollution
targets.
 Mitigation activities for point sources (e.g., factories & wastewater treatment
plants) provide quantifiable results (e.g., lbs of N and P removed).
 Mitigation activities for non-point (diffuse) sources do not provide quantitative
results. Examples: stream & wetland restoration, no-till ag, stormwater retention
basins, etc.
 If we give nutrient reduction credits for best management practices (BMPs) that don’t
actually work, then we are not achieving actual nutrient reductions.