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Documenting the Summer 2006 Flood

in Otsego County, New York

Overview

Shaded Relief Map of the Upper Susquehanna Basin: stream gages (blue-green icons) that were active in 2006 have a red dot (most gages in Otsego County were decommissioned!)

Introduction

Why study the 2006 flood?

Recurrence intervals

Flood heights

Flood evidence

Data sources

Introduction to the Flood of 2006

In June 2006, a persistent weather pattern brought a couple days of intense heavy rain (“training” of rain storms) to the upper Susquehanna River basin. The result was catastrophic for many people in the area, as they watched flood waters rise, then rise more. Flood waters inundated numerous homes, scoured farmlands and ruined crops, and washed away many highways and bridges. Many channels deposited cobble and boulder size material up onto their banks, and even onto the flood plain. Farm fields in places were stripped of crops and topsoil, and in others were buried under cobbles and gravel. The flood left a lot of debris to mark the high water line, which is still visible in places (as of February 2009).

I arrived in the area in the summer of 2007, and most channels I visited still had some signs from the flood. I found the transport of larger particles over the banks to be an intriguing problem, and I am starting a program to:

 

1) measure flood heights in as many streams as I can before the evidence fades;

2) derive water surface elevations from reconstructed flood heights;

3) document the distribution of cobble and boulder movements during the flood;

4) get a better grasp on the recurrence interval of this kind of event, if possible; and

5) look more closely at flood height and bed roughness, as smooth bedrock-floored sections of streams clearly had lower flood heights than alluvial-covered reaches. This falls right in line with how we think roughness influences stream velocity—namely, rougher beds have higher friction, which slows down the river, and so floods rise higher to transmit the same discharge. See our work on Silver Creek near SUNY Oneonta for an example.

 

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SUNY Oneonta Earth Sciences

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If you are interested in imagery of the flood, here are two places to start:

Here’s a link to Delaware County’s photo record of the event: http://www.co.delaware.ny.us/flood2006.htm.

You can purchase a CD photo journal of the event from Oneonta’s Daily Star.

Floods effects

gravel-bar-debris

 

Photo at right is view downstream of Morris Brook in Otsego County, in Dimmock Hollow. The gravel bar on the right hand side is fresh, and though hard to see, flood debris is trapped against the small tree on the right side of the bar.

 

 

         

 

 

Alluvial-Bedrock-TransitionPhoto at left is a view upstream which shows the alluvial to bedrock transition in Morris Brook (~200 m downstream from the picture above). Bedrock here is flat-lying Devonian sandstone (lots of marine fossils and ripple marks!), which when exposed as the channel floor, is quite smooth. Most erosion of the bedrock is via quarrying of blocks along fractures in the sandstone.

 

 

gravel-bar-debris-field-trip

Image at right shows flood debris and gravel bar on the bank of Morris Brook.

 

 

flood-trimlinePhoto at left shows bedrock-floored channel, and about 2/3 up the bank a light-colored subhorizontal line marks the high water (green begins just above the mark). Clearly, the channel didn’t overtop its banks during this extreme event, and it’s just downstream from the picture above. The smooth channel resulted in higher velocity flow and a lower depth. The stream transported all of the bedload through this section of channel.

 

Page maintained by Les Hasbargen: hasbarle@oneonta.edu
Les is solely responsible for the content of this website
Last modified February 22, 2009

Initiated in Winter 2008