Streams 101: Stream Basics & Planning for Flood Resiliency

Hudson Estuary Watershed Resiliency Project
www.hudsonestuaryresilience.n Building Long-term Resilience to Exteretme Weather and Climate Change in the
Hudson Estuary Watershed
Streams 101: Stream Basics & Planning
for Flood Resiliency
A program of Cornell Cooperative Extension in partnership with the NYS DEC Hudson River Estuary
Program, NY Water Resources Institute and Cornell University with support from the NYS Environmental
Protection Fund.

www.hudsonestuaryresilience.net
Resiliency Project
An initiative of Cornell Cooperative Extension of
Columbia-Greene, Dutchess and Orange Counties in
partnership with the NYS DEC Hudson River Estuary
Program, NY Water Resources Institute and Cornell
University with support from the NYS Environmental
Protection Fund.

Hudson Estuary

The area of land
in which all
precipitation
(rain, snow, etc.)
that falls on it
drains to a
common
waterway, such
as a stream,
lake, estuary,
wetland, aquifer,
or even the
ocean.
4
What is a Watershed?

Hudson
Watershed
• Hudson River
watershed is 13,390
square miles in size.
• Includes parts of NY,
VT, MA, CT and NJ.
• Land of abundant
freshwater
resources.
• More than 16,000
miles of streams
Hudson
Estuary Watershed

What is Resiliency?
The ability to plan for, withstand,
and recover from severe events
- without suffering permanent loss
of functions, devastating damage,
diminished productivity or
decreased quality of life.
signsofpolitics.blogspot.com/2009/03/around-and-about-resilience.html

Flood Outreach and Education
http://www.hudsonestuaryresilience.net/

Outline
• Why are we here?
• Causes of increased flooding in our
municipalities
•A closer look at what is happening in our
streams
• How we are impacting streams (and
making flooding worse)
• Solutions and Resources

Why we are here… Catskill, NY Aug. 28, 2011
Albany, NY
alloveralbany.com
Albany, NY August 5, 2014

Where Are We: NFIP? NYS, 11/10 NYS 8/12 NYS, 3/13 U.S., 1/13
Policies 162,965 167,455 176,000 5.6 million
Premiums $147 Million $157 Million $170 million $3.6 billion
Coverage $38.6 Billion $41.4 Billion $42 billion $1.3 trillion
Claims to Date 84,825 105,674 162,504 2.0 million
Claim
Payments
$631 Million $1.2 Billion $3.1 Billion $45.5 billion
National NFIP
Program Debt
$18.8 billion before Sandy. $9 billion more?
•Prior to 2005, Program was largely self supporting.
•Policy structure not set up to handle catastrophic losses.
•Fund was never capitalized.
•1% of policies represent 1/3 of all claims.
•Congress wants program to be on a sounder financial footing.
•It will take years to pay off debt.
Slide credit: Bill Nechamen, NYS DEC, Floodplain Management Section

Why is this happening?
• Increased precipitation
• Land use changes

Our climate is changing
Temperature changes from 1991-2012 compared to the 1901-1960 average
(and compared to the 1951-1980 average for Alaska and Hawai‘i). NOAA NCDC / CICS-NC

Era of Extreme Weather
Precipitation changes are
occurring now.
The map shows percent
increases in the amount
of precipitation falling in
very heavy precipitation
events (defined as the
heaviest 1% of all daily
events) from 1958 to
2011 for each region.
Source: National Climate Assessment,
2014

Say it isn’t so!
Northeast Regional Climate Center, 2003
Cornell Bulletin 1009, July 1966

N. Hamilton St., City of Poughkeepsie
Beacon Train Station

Land Use

Impervious Surfaces
• Materials like cement, asphalt, roofing, and compacted soil
that prevent water from seeping/percolating into the ground.

Stormwater
runoff

www.hudsonestuaryresilience.n Building Long-term Resilience to Exteretme Weather and Climate Change in the
As Impervious Surfaces increase…
• Infiltration
decreases
• Surface
Runoff
increases

Human Impacts on Stream Stability
Roadways, culverts
& ditches
Change in
Land Cover
Floodplain Development
Dams & Diversions

What in the World Are We To Do?
• We live in close proximity to streams
and rivers.
• Much of our infrastructure is
vulnerable to flood damage.
• Many of our streams have unstable
reaches due to flooding &/or
development.
• Extreme precipitation events are
increasing the likelihood of flooding.
• We having a growing population and
therefore a demand for more
development.

Stream Science & Flood Resiliency
Luna Leopold
Dave Rosgen

What’s happening in our streams?
• Causes of increased flooding in our municipalities
• A closer look at what is happening in our streams
• Back to Basics
• What is a Floodplain
• How Energy Moves Through a Stream
• Streams Move More than Water
• How we are impacting streams (and making
flooding worse)

Back to Basics: The Water Cycle
Precipitation
Infiltration
Evaporation
Condensation

The Effects of Land Use on Watersheds & the
Precipitation
Infiltration
Water Cycle
Evaporation
Condensation

or Base Flow
Parts of a Stream
Bankfull Flow: is associated with the flow
that just fills the channel to the top of its
banks and at a point where the water begins
to overflow its banks onto a floodplain.
Stream Channel: the physical
confine of a stream (river)
consisting of a bed (stream bottom)
and stream banks (stream sides).
Base Flow: low flow or dry weather
flow. The component of streamflow
that comes from ground-water
discharge into streams.

Types of Flows
Base Flow
Flood
Bankfull

or Base Flow
Parts of a Stream
Riparian: the area between land and
flowing surface water.
Floodplain: land adjacent to a stream or
river that experiences periodic flooding or
is part of the river during storm
conditions

Riparian Zone/Buffer

Riparian Wetlands
• http://youtu.be/ucb-Y8iipng
Otter Creek Video
http://youtu.be/ucb-Y8iipng

Land Use Impacts on Floodplains,
Riparian Buffers and Wetlands
• Pre and Post Floodplain development

Loss of Floodplain Forests & Wetlands

Why Do Streams Look the Way They Do?
• Topography
• Geology
• Amount of
Water
• Land Use

Streams Move Water
Velocity – speed of water
Discharge – quantity of
water passing a fixed
location or the volume flow
rate
Stream stage – depth of
water
Photo: USGS
http://waterdata.usgs.gov/

Flowing Water Moves Sediment
• As water moves over the land it picks up sediment,
forming the stream channel
• Streams create and maintain their shape and size
themselves, a result of:
• Volume of water
• Amount of sediment
• Type of sediment

Streams Flow in Predictable Patterns

Dissipating Energy Naturally
Upland Stream Type: Step - Pool

Lowland Stream Type: Riffle – Pool &
Meander Bends
Deposition on the inside
of meander bend.
Erosion on outside
of meander bend.
Meander Bends
are a natural way streams
slow the movement of
water or dissipate energy
in flat areas.
Riffle
Pool

Balancing Act
• Streams are said to be in equilibrium or
balance when the volume of water is enough
to transport the available sediment without building up
the channel (deposition) or cutting down the channel
(erosion).

Streams will Respond to Disturbances that
Create Instability
Human Caused
OR
Natural
Unstable Streams will Evolve to Return to a Balanced State

Stream Channel Evolution
Upland - limited floodplain Lowland with floodplain

Further impacting our streams (aka
• Causes of increased flooding in our
municipalities
•A closer look at what is happening in our
streams
• How we are impacting streams (and

Human Impacts on Streams – Flood Response
Flood Response May Cause Stream Instability
Dredging
Berms
Channel
Straightening
Tree Removal

Does Dredging help flooding?

Berms

Channel Straightening
 Shorter distance means a
steeper slope
 A steeper slope increases
velocity
 A steeper slope increases
erosion on the streambank
and bed
48
400’
Straightened
Channel
500’
Meandered
Channel

Human Impacts on Stream Stability
What Can We Do?!!!
Roadways, culverts
& ditches
Change in Land Cover
Dams & Diversions
Floodplain Development

Solutions & Resources:
• Local wetland and riparian buffer
ordinances.
• Stream Corridor Protection
Greenway Guide
• NYS DEC Trees for Tribs plantings
to restore riparian buffers.
• Encourage forest and wetland
stewardship by property owners.
Conservation

Smart Growth / Better Site Design / Low
Impact Development
“Narrow streets with short setbacks … are safer …
use less land, reduce stormwater runoff and cut
construction and maintenance costs…”

Green
green roofs bio-infiltration swales
Infrastructure
porous pavement
rain garden
Slide credit: Dr. Allison Roy
• Zoning techniques to minimize
impervious cover
• Green Infrastructure Greenway
Guide.
• Encourage forest and wetland
stewardship by property owners.

Planning &
Preparedness

Reconsider Land Use Within Floodplains
• Zoning Codes and Overlay
Districts
• Pace Land Use Law Center
Gaining Ground database
• Flooding and Land Use Planning:
A Guidance Document for
Municipal Officials and Planners

Take Stock of Your Infrastructure
Culverts Bridges
Roadside Ditching
• Culvert sizing initiative in the Hudson Valley
• Research & Outreach on Roadside Ditches & Flooding
• Innovations on bridge construction for flood resiliency piloted in
Delaware County
• Post Flood Stream Intervention Training for Highway Personnel

Dams Have an Impact
• Sediment Imbalance
• Spillway Scouring
• Flooding
• Downstream –
Failure
• Upstream - Filling
Solutions:
Research on dams in the Hudson Valley
Dam safety seminars & educational materials
Research and resources on dam removal

Post Flood Response in Streams
Resources:
• Post Flood Stream Intervention
Training
• NYS DEC Post Flood Stream
Intervention Training Manual
• Chemung County Stream
Processes – A Guide to Living in
Harmony with Streams
• Stream Stats
http://water.usgs.gov/osw/streamstats/

Flood Resiliency ~ Take Home Messages
• Streams move water & sediment.
• Streams move in predictable patterns
across the land.
• Streams are dynamic systems that
respond to disturbance.
• Human infrastructure & actions can
cause stream disturbance.
• Recent advances provide tools for
communities to work with streams.
• Communities find pro-active solutions to
flooding.

Partner Acknowledgements
Lower Hudson Coalition of Conservation Districts
NYC Department of Environmental Protection
Natural Resource Conservation Service
USGS NY Water Science Center
NY Extension Disaster Education Network
County Planning Departments
Cary Institute of Ecosystem Studies
Hudson River Watershed Alliance
Hudsonia, Inc.
Trout Unlimited
Local watershed groups
Larry Federman

Hudson Estuary Watershed Resiliency
Project Team
CCE Columbia & Greene Counties
Liz LoGiudice, Audrey Kropp, Ron
Frisbee, Marilyn Wyman
518 622-9820 x 33
eml37@cornell.edu
CCE Orange County
Rosemarie Baglia
(845) 344-1234
rsb22@cornell.edu
CCE Dutchess County
Carolyn Klocker, Neil Curri, Camille
Marcotte, Sean Carroll
(845) 677-8223 x135
cak97@cornell.edu
Cornell University
Shorna Allred
(607)255-2149
srb237@cornell.edu
Hudson River Estuary Program
Scott Cuppett
(845) 256-3029
swcuppet@gw.dec.state.ny.us
NYS Water Resources Institute
Christina Tonitto
(607) 252-6825
ctonitto@cornell.edu

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