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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)

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Biological Resources of the Delaware River and Related Environmental Issues

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Biological resources of the delaware river and related environmental issues

Biological Resources of the Delaware River and Related Environmental Issues

Kenneth J. Wagner, Ph.D

Background for k wagner


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

Background for drbc


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

Background for drbc1


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

Background for drbc2


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

Biological groups of interest


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…




  • 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




  • 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

Aquatic vascular plants


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

Aquatic vascular plants1


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

Benthic macroinvertebrates


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

Benthic macroinvertebrates1


Benthic Macroinvertebrates

  • Insects, Annelids, Crustaceans and Molluscs are the main groups

Benthic macroinvertebrates2


Benthic Macroinvertebrates

  • Abundance is important, although hard to characterize

  • Shifts among groups are very meaningful

    • EPTs vs. Chironomidae

    • Similarity indices

    • Functional feeding groups

Biological resources of the delaware river and related environmental issues



  • 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)

Biological resources of the delaware river and related environmental issues



  • 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

Biological resources of the delaware river and related environmental issues



  • Primary groups include salmonids (trout), cyprinids (minnows) and centrarchids (bass/sunfish)

Biological resources of the delaware river and related environmental issues



  • Shifts among groups are very meaningful

    • Trout vs. other species

    • Fluvial specialists vs. fluvial dependents vs. habitat generalists

Biological resources of the delaware river and related environmental issues



  • 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)

Reptiles and amphibians


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

Birds and mammals


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

Key delaware river bio resources


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

Key delaware river bio resources1


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

    • (

Key delaware river bio resources2


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

Key delaware river bio resources3


Key Delaware River Bio-Resources

  • Macroinvertebrates - saltwater

    • Horseshoe crab decline prompted harvest restrictions

    • Shellfish harvest restrictions due to WQ

Key delaware river bio resources4


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

Key delaware river bio resources5


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

Key delaware river bio resources6


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

Key delaware river bio resources7


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

Key delaware river bio resources8


Key Delaware River Bio-Resources

Non-support from pH, mercury, PCB and bacteria

Key delaware river bio resources9


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

Key delaware river bio resources10


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)

Delaware river issues


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

Delaware river issues from plan


Delaware River Issues (from plan)

Upper Region Water Supply System

Delaware river issues from plan1


Delaware River Issues (from plan)

From DRBC Plan ppt:

Central Region

• Comprehensive watershed


• Environmental education

• Regional water supply &

land use planning

• Fish habitat & water quality

• Recreation & flow mgmt

• Power generation

• Partnerships

Notes from Experience:

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

This is an area of more active development and land use conversion (agric to residential); heightened competing uses is expected

Delaware river issues from plan2


Delaware River Issues (from plan)

Notes from Experience:

Poor water quality is an overriding consideration in this area

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

  • From DRBC plan ppt:

  • Lower Region

  • Adequate supply, suitable quality

  • TMDLs & water quality standards

  • Salinity impacts: industry, drinking water & the estuary

  • Watershed planning

  • Tourism & recreation

  • Navigation

  • Partnerships, coordination & stewardship

Delaware river issues from plan3


Delaware River Issues (from plan)

Lower Region Water Supply System (includes Central and Lower from issues summary)

Delaware river issues1


Delaware River Issues

  • From DRBC Plan ppt:

  • Bay Area Issues

  • Non-point source issues

  • Water supply enhancement options

  • Science-based regulations

  • Watershed-based planning & management

  • Collaboration

  • Salinity impacts

  • Wetlands & oyster habitat

Notes from Experience:

WQ impacts on shellfish, water supply, and recreation remain primary concerned, not really emphasized in the list on the left

There is ongoing effort and controversy on the science-based regulation of key contaminants, along with pollutant trading

Water quantity is less an issue here

Example hoffman springs project


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

Hoffman springs project


Hoffman Springs Project

Hoffman springs project1


Hoffman Springs Project

36 cfs

0.3 cfs

Average daily flow is 1.7 cfs

4.0 cfs

Hoffman springs project2


Hoffman Springs Project

Hoffman springs project3


Hoffman Springs Project

Relationship of flow to fish biomass

Hoffman springs project4


Significance = 0.013

R2 = 0.82

Hoffman Springs Project

Relationship of pool availability to fish biomass

Hoffman springs project5


Hoffman Springs Project

Hoffman springs project6


Hoffman Springs Project

East Stream – change in pool area from 2004-05 storm

Hoffman springs project7


Hoffman Springs Project


  • 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)

Overall conclusions and tips


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

Overall conclusions and tips1


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

Overall conclusions and tips2


Overall Conclusions and “Tips”

  • When evaluating a possible withdrawal, consider:

    • Where does it occur relative to known bio-resources?

    • 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

Delaware River Bio-Resources

Questions and Comments?

Get good info before reacting; it is easy to be mislead!

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