streams 101: stream basics & planning for flood resiliency

Hudson Estuary Watershed Resiliency Project

www.hudsonestuaryresilience.netBuilding Long-term Resilience to Extreme Weather and Climate Change in the

Hudson Estuary Watershed

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.

Streams 101: Stream Basics & Planning

for Flood Resiliency


www.hudsonestuaryresilience.net

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.


Resiliency Project



Hudson Estuary



4

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.

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




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

What is Resiliency?



Flood Outreach and Education

http://www.hudsonestuaryresilience.net/

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

alloveralbany.com

Albany, NY

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

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

Precipitation changes are

occurring now.



Say it isn’t so!

Northeast Regional Climate Center, 2003

Cornell Bulletin 1009, July 1966



Beacon Train Station

N. Hamilton St., City of Poughkeepsie



Land Use

http://www.contech-cpi.com/images/state/chichester rd 4.jpg

http://www.contech-cpi.com/images/state/chichester rd 4.jpg



Impervious Surfaces

• Materials like cement, asphalt, roofing, and compacted soil

that prevent water from seeping/percolating into the ground.



Stormwater

runoff


www.hudsonestuaryresilience.netBuilding Long-term Resilience to Extreme 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

Dams & Diversions

Floodplain Development



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)




Precipitation

Infiltration

Evaporation

Condensation

Back to Basics: The Water Cycle



Precipitation

Infiltration

Evaporation

Condensation

The Effects of Land Use on Watersheds & the

Water Cycle



or Base Flow

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.

Parts of a Stream

Base Flow: low flow or dry weather

flow. The component of streamflow

that comes from ground-water

discharge into streams.

Stream Channel: the physical

confine of a stream (river)

consisting of a bed (stream bottom)

and stream banks (stream sides).



Types of Flows

Base Flow

Bankfull

Flood



or Base Flow

Riparian: the area between land and

flowing surface water.

Parts of a Stream

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

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/

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



Upland Stream Type: Step - Pool

Adapted from Applied River Morphology, Dave Rosgen, 1996

Dissipating Energy Naturally



Deposition on the inside

of meander bend.

Erosion on outside

of meander bend.

Lowland Stream Type: Riffle – Pool & Meander Bends

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

Unstable Streams will Evolve to Return to a Balanced State

Human Caused

OR

Natural



Stream Channel EvolutionUpland - 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


www.hudsonestuaryresilience.netDoes Dredging help flooding?



Berms



Channel Straightening

48

Shorter distance means a

steeper slope

A steeper slope increases

velocity

A steeper slope increases

erosion on the streambank

and bed

400’ Straightened

Channel

500’ Meandered

Channel



Human Impacts on Stream Stability

Roadways, culverts

& ditchesChange in Land Cover

Dams & Diversions

Floodplain Development

What Can We Do?!!!



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 roofs bio-infiltration swalesGreen

Infrastructure

rain garden

porous pavement

Slide credit: Dr. Allison Roy

Solutions & Resources:• 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

Solutions & Resources:• 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 InfrastructureBridgesCulverts

Roadside Ditching

Solutions & Resources:• 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/

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 AcknowledgementsLower 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 CountiesLiz LoGiudice, Audrey Kropp, Ron

Frisbee, Marilyn Wyman

518 622-9820 x 33

[email protected]

CCE Orange CountyRosemarie Baglia

(845) 344-1234

[email protected]

CCE Dutchess CountyCarolyn Klocker, Neil Curri, Camille

Marcotte, Sean Carroll

(845) 677-8223 x135

[email protected]

Cornell UniversityShorna Allred

(607)255-2149

[email protected]

Hudson River Estuary ProgramScott Cuppett

(845) 256-3029

[email protected]

NYS Water Resources InstituteChristina Tonitto

(607) 252-6825

[email protected]

mailto:[email protected]






streams 101: stream basics & planning for flood resiliency

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