Biological Resources of the
Delaware River and Related
Environmental Issues
Kenneth J. Wagner, Ph.D
0:20
Background for K. Wagner
• Born and raised in the Delaware River (DR) basin
(New Jersey, across the river from Philadelphia)
• Escaped to NH for college (Dartmouth); extradicted in
1977 to Trenton for state service
• Four years with NJDEP, including monitoring work
on the DR, during which Ken lived 300 ft from the
DR at Washington’s Crossing
• Escaped again, to NY for grad school (Cornell) – not
yet recaptured
• 23 years of water resource consulting, based in New
England, but working all over, including in DR basin
0:50
Background for DRBC
• The Delaware River Basin Commission was formed in
the early 1960s through multi-state and federal
agreement, putting management of the watershed under
an authority other than individual states or feds
• Representatives of each state and US government sit on
the commission and make decisions
• Withdrawal and discharge permits are issued by DRBC
• DRBC staff conduct studies and make recommendations
• Scientific, economic and political elements all rolled into
a watershed approach to water resource management
2:50
Background for DRBC
Addresses issues in:
• 13,539 square miles
• 236 watersheds
(HUC 11)
• 4 states: DE, PA,
NJ, NY
• 42 counties
• 838 municipalities
• 25 congressional
districts
• 2 EPA Regions
• 5 USGS offices
4:00
Background for DRBC
• The DRBC has a
recent plan with key
result areas
• Recognizes the
complications and
interactions
associated with
water resources and
watershed activities
• Implementation is
always a challenge
5:00
Biological Groups of Interest
• Periphyton – attached algae
• Aquatic Plants – emergent or submergent vascular
plants
• Benthic Macroinvertebrates – bugs and other aquatic
invertebrates
• Fish – best known stream biota
• Reptiles and Amphibians – snakes, turtles, frogs,
salamanders with strong link to water
• Birds and Mammals – water dependent species
Some are more “charismatic” than others…
6:50
Periphyton
• Photosynthetic plants or bacteria growing
attached to some substrate
• Affected by substrate, light and water quality
• Limited water quantity effects; mainly presence
and velocity
• Most often used as water quality indicators
8:25
Periphyton
• Shifts among groups are meaningful;
some field assessment possible with
training
• Requires lab techniques for best
quantity measurement
• Microscopic analysis of algal types is
very useful, but requires considerable
training and equipment
8:50
Aquatic Vascular Plants
• Provide food and shelter for many other groups
• Types and density usually determined by substrate and
light; only a few use water as a nutrient source
• Water quantity impacts related to presence of adequate
water and flows that may destabilize community
• Patchy distribution over space and time expected;
recovery from disturbance is fairly rapid
10:15
Aquatic Vascular Plants
• Hot button issue is invasive species
• Native species may be replaced by invaders, altering
ecology
• Not all new species are invasive, and not all native
species are non-nuisances
• Yet invasive species represent a major ecological and
economic threat
11:40
Benthic Macroinvertebrates
• Invertebrate fauna living among the substrate materials
• Typically feed on algae, terrestrial inputs (e.g., leaves)
or each other
• Sensitive to substrate and water quality
• React to a lesser degree to water quantity; mainly
presence and velocity
• Sensitive to food resources; especially periphyton,
drifting particles and leaf packs
• Mussels are the most threatened among benthic
invertebrates, and are affected by both water quantity
and quality issues
15:10
Benthic Macroinvertebrates
• Insects, Annelids, Crustaceans and Molluscs are the
main groups
16:05
Benthic Macroinvertebrates
• Abundance is important, although hard to characterize
• Shifts among groups are very meaningful
– EPTs vs. Chironomidae
– Similarity indices
– Functional feeding groups
Distribution of Individuals among Feeding Groups
700
600
# of individuals
Total Collectors
500
Total Shredders
Total Filter Feeders
Total Scrapers
400
Total Predators
Total Parasites
300
Total Detritovores
200
100
0
Station 1
Station 2
Station 3
Station 4
Station 5
17:40
Fish
• Vertebrate biota with wide variety of forms and
ecology
• Consume some algae, mostly invertebrates,
often each other
• Sensitive to cover (substrate, vegetation, banks),
water quantity (depth, velocity), and water
quality (especially oxygen and temperature)
18:20
Fish
• Types of fish present usually linked to water
quality
• Amount of fish present usually linked to
physical habitat and by extension to water
quantity – but this may not always be true
18:45
Fish
• Primary groups include salmonids (trout),
cyprinids (minnows) and centrarchids
(bass/sunfish)
19:20
Fish
kg fish/ha
40
30
Fish biomass in OC -1
20
10
0
Nov-98 May-99 Sep-99 Jun-00 Sep-00 Jun-01 Sep-01 Jun-02 Oct-02
Date
Fish biomass in OC -2
80
kg fish/ha
• Shifts among groups
are very meaningful
– Trout vs. other
species
– Fluvial specialists
vs. fluvial
dependents vs.
habitat generalists
Non-Trout
Brown Trout
Brook Trout
70
60
Non-Trout
Brow n Trout
Brook Trout
50
40
30
20
10
0
Nov-98 May-99 Sep-99 Jun-00 Sep-00 Jun-01 Sep-01 Jun-02 Oct-02
Date
Spring, 2002
12
Frequency
10
8
6
4
2
0
40
50
60
70
80
90
100 110 120 130 140 150 160 170 180
Length bin (mm)
Fall, 2002
12
10
Frequency
• Shifts within groups
are very meaningful
– Size distribution
(length or weight)
– Growth rate (age
vs. length or
weight)
– Condition factor
(length vs. weight,
evidence of
parasites and
disease)
Fish
8
6
4
2
0
40
50
60
70
80
90
100 110 120 130 140 150 160 170 180
Length bin (mm)
Brook trout, OC-1 by season
180
Fall
Spring
Standard weight
160
140
120
Weight (g)
20:30
100
80
60
40
20
0
0
50
100
150
Length (mm)
200
250
300
21:10
Reptiles and Amphibians
• Most forms are dependent on water during at least part
of life cycle
• “Hibernation” over winter creates vulnerability
• National trends in decline: pollution, habitat loss, disease
or other cause (or all of the above)?
• Many protected forms; requires site specific knowledge
of populations when planning projects
22:10
Birds and Mammals
• River is a source of food for many forms, shelter for
some
• Water dependent bird species are highly visible and
popular
• Water dependent mammals have variable “appeal”
• Greater range and less complete dependence complicates
impact analysis
23:20
Key Delaware River Bio-Resources
• Periphyton
• Used as WQ indicators; NWQA
project, Limbeck and Smith 2007
• Generally indicate good quality in
most of DR basin
• Upper DR less rich, less diverse,
less pollution tolerant, and more
indicative of clean conditions than
Lower DR, which is indicative of
elevated nutrient levels
• Some evidence of siltation and
substrate instability
Limbeck & Smith. 2007. Pilot Study:
Implementation of a Periphyton Monitoring Network
for the Non-Tidal Delaware River. DRBC, Trenton, NJ
26:15
Key Delaware River Bio-Resources
• Aquatic vascular plants
• Submergent Valisneria, Elodea, Potamogeton
represent most biomass in Upper DR; reduced
over a decade (1989-1997) presumably by
reduced ammonia in discharges
• Emergent Nuphar, Peltandra, Pontederia,
Zizania, Typha and Phragmites represent most
biomass in Lower DR; sequesters up to 10%
P, <1% N in marshes
• Invasive species threats not quantified
(http://www.state.nj.us/drbc/public.htm)
28:10
Key Delaware River Bio-Resources
• Macroinvertebrates - freshwater
• Used as WQ indicators around discharges for
compliance and to classify streams
• 8 species of mussels protected
Federally endangered Dwarf
Wedge Mussel
29:35
Key Delaware River Bio-Resources
• Macroinvertebrates - saltwater
• Horseshoe crab decline prompted harvest
restrictions
• Shellfish harvest restrictions due to WQ
30:40
Key Delaware River Bio-Resources
• Fish
• Major recreational resource – Versar creel
census, state tributary surveys
• Freshwater, saltwater, anadromous, catadromous
fish present and important
• Economic driver – recreational and commercial $
can be huge
• Political driver - fish don’t vote, but fishermen do
• Habitat used as a surrogate for fish abundance in
instream flow studies
32:25
Key Delaware River Bio-Resources
• Versar 2003 Delaware River Creel Census, for
PA FBC
• 7.5 month period, 120,000 angler trips, 2/3
non-tidal, 1/3 tidal
• Shad, herring, striped bass were primary
species, catch down from a decade ago, but
perceived to be due to lower effort
• Trout and bass from Upper DR
not discussed, but also significant
• Catch and release practices dominate
33:10
Key Delaware River Bio-Resources
• Upper DR coldwater fishery
• Discharge from Cannonsville Reservoir
creates coldwater conditions for 27 miles
• Another 50 miles of “coolwater” fishery; esp.
smallmouth bass, but some trout
• Mainly rainbow and brown trout in DR, but
many brook trout in tributaries, esp.
headwaters
34:40
Key Delaware River Bio-Resources
• Commercial eel fishery
• Catadromous eels live in freshwater in
spring/summer, return to saltwater to spawn in
the fall
• Caught in eel weirs, an old native american
technique
• Worldwide food market
35:30
Key Delaware River Bio-Resources
Non-support from pH, mercury,
PCB and bacteria
36:10
Key Delaware River Bio-Resources
• Reptiles and amphibians
• 5 reptiles and 4
amphibians on protected
list; bog turtle is prime
example
• Bog turtle habitat
widespread in DR
corridor, prefer open
(non-forested) wetlands
• May overwinter in
undercut banks or areas
prone to flood/drought
37:00
Key Delaware River Bio-Resources
• Birds and Mammals
• Many water birds are resident
• Major resource for migratory birds
• Water dependent mammals common: beaver,
muskrat, otter; bears and deer common in
river corridor (esp scenic designated area)
• Multiple bird species have come off protected
list as a result of DR programs (Eagle, Great
Blue and Little Blue Heron, Cliff Swallow)
38:10
Delaware River Issues
From DRBC Plan ppt:
Upper Region
•Funding for strategic watershed
planning
•Stream buffers
•Basin transfers & efficiency
•Support for local planning
•Flow management
•Fisheries & Recreation
•Special Protection Waters
program
Notes from experience:
Ecological integrity
starts with the
headwaters; the further
up in the watershed the
withdrawal, diversion or
discharge, the more
contentious it will be.
There is an ongoing
effort to upgrade
tributary classifications
for better protection of
resources
39:40
Delaware River Issues (from plan)
Upper Region Water Supply System
40:15
Delaware River Issues (from plan)
From DRBC Plan ppt:
Notes from Experience:
Central Region
Aside from protection of small
tributaries (see Upper DR issues),
improving the main river corridor
to extend scenic status and
related benefits has been
proposed
• Comprehensive watershed
management
• Environmental education
• Regional water supply &
land use planning
• Fish habitat & water quality
• Recreation & flow mgmt
• Power generation
• Partnerships
This is an area of more active
development and land use
conversion (agric to residential);
heightened competing uses is
expected
41:30
Delaware River Issues (from plan)
From DRBC plan ppt:
Notes from Experience:
Lower Region
Poor water quality is an
overriding consideration in
this area
•Adequate supply, suitable
quality
•TMDLs & water quality standards
•Salinity impacts: industry,
drinking water & the estuary
•Watershed planning
•Tourism & recreation
•Navigation
•Partnerships, coordination &
stewardship
Many established industrial
uses and navigation will
collide with recreational uses
if WQ improvements are
made
Salinity intrusion with
reduced freshwater flow is a
primary supply concern
43:00
Delaware River Issues (from plan)
Lower Region Water Supply System (includes Central
and Lower from issues summary)
43:25
Delaware River Issues
From DRBC Plan ppt:
Notes from Experience:
Bay Area Issues
WQ impacts on shellfish,
water supply, and recreation
remain primary concerned,
not really emphasized in the
list on the left
•Non-point source issues
•Water supply enhancement
options
•Science-based regulations
•Watershed-based planning &
management
•Collaboration
•Salinity impacts
•Wetlands & oyster habitat
There is ongoing effort and
controversy on the sciencebased regulation of key
contaminants, along with
pollutant trading
Water quantity is less an
issue here
44:25
Example: Hoffman Springs Project
• Water withdrawn from headwater springs in
Lehigh County of PA
• Permit issued by DRBC with input from PADEP
• Questions regarding impacts on downstream fish
• Now through 10+ years of monitoring
• Applied site-specific model of flow-habitat-fish
abundance to one stream segment
• Variability with overall flow regime evident, but
impact of withdrawal not discernible
• Changing habitat appears to be a major factor
46:05
Hoffman Springs Project
46:55
Hoffman Springs Project
36 cfs
0.3 cfs
Average daily
flow is 1.7 cfs
4.0 cfs
48:45
Hoffman Springs Project
Juvenile (<150 mm TL)
35
30
25
20
15
10
5
0
Nov-98
May-99
Sep-99
Jun-00
Avg WUA Without Withdrawal/100
Sep-00
Jun-01
Sep-01
Avg WUA With Withdrawal/100
Jun-02
Oct-02
Biomass (kg/ha)
Adult brook trout (>=150 mm TL) OC-1
35
30
25
20
15
10
5
0
Nov-98
May-99
Sep-99
Jun-00
Avg WUA Without Withdrawal/100
Sep-00
Jun-01
Sep-01
Avg WUA With Withdrawal/100
Jun-02
Oct-02
Biomass (kg/ha)
51:20
Hoffman Springs Project
Relationship of flow to fish biomass
Fall Total Brook Trout
kg/ha = 7.748 (cfs) + 7.42
Significance = 0.119 R2 = 0.275
Fish Biomass (kg/ha)
40
2003
30 kg/ha
Class A
level for
brook
trout
30
1999
1998
20
2000
2001
2005
10
2004
2002
2006
2007
0
0
0.5
1
1.5
Mean Summer Flow (cfs)
2
2.5
52:55
Hoffman Springs Project
Relationship of pool availability to fish biomass
Total trout biomass vs. % areal pool habitat in OC1
Biomass (kg/ha)
40
2003
30
2004
20
1999
2005
10
2007
2006
0
0
Significance = 0.013
R2 = 0.82
10
20
% pools
30
54:10
Hoffman Springs Project
54:20
Hoffman Springs Project
East Stream – change in pool
area from 2004-05 storm
54:50
Hoffman Springs Project
CONCLUSIONS
• Ontelaunee Creek headwaters support a thriving
trout population; water quality is suitable,
although certain human activities represent a
threat
• Natural variability in flow impacts fish
abundance; withdrawal may have a negative
influence during dry periods, but any such effect is
masked by the larger natural pattern
• Factors other than flow affect fish abundance;
management for more or bigger fish could be
accomplished with habitat manipulation (pools)
56:20
Overall Conclusions and “Tips”
• DR has a lot of valuable biological resources and
represents an economic driver (commercial and
recreational) as a result
• Water quality and water quantity are linked and
must both be considered in management decisions
• Some of the desirable features of DR are a result
of human actions (e.g., coldwater fishing due to
deep water releases from constructed reservoirs);
it is not a system “apart from humans”
• Undesirable features center on pollutant inputs
and consumptive water withdrawals; the further
upstream these occur, the greater the impact
57:35
Overall Conclusions and “Tips”
• While all bio-resources deserve consideration, fish
are the pivotal resource; they have measurable
value, no where else to go, and the community
may not recover quickly after damage
• Protected species represent the greatest regulatory
“hook”; approval of a project becomes much more
difficult if protected species may be impacted
• While the DRBC has political shortcomings, it is a
highly appropriate institution by virtue of its
watershed focus, and offers a single point of
contact and defined process for evaluating
projects and making management decisions
59:00
Overall Conclusions and “Tips”
• When evaluating a possible withdrawal, consider:
• Where does it occur relative to known bioresources?
• When does it occur relative to the needs of
specific biota?
• What is the magnitude of withdrawal compared
to the range of possible flows at the point of
withdrawal?
• What other factors mitigate or exacerbate any
impact of the withdrawal?
• What economic and socio-political drivers are
important in addition to biological impacts?
Delaware River Bio-Resources
Questions and Comments?
Get good info before reacting; it is easy to be mislead!