Vermont River Sensitivity Coarse Screen Presented by Roy Schiff, Milone & MacBroom Waterbury, Vermont roys@miloneandmacbroom.com Acknowledgements Jessica Louisos, Jim MacBroom, Milone & MacBroom Evan Fitzgerald and Joe Bartlett, Fitzgerald Environmental Associates Liz Thompson, Vermont Land Trust Mike Kline and Shannon Pytlik, Vermont Rivers Program MA FGM Task Force Meeting November 10, 2014
Vermont River Data Specific site modeling Phase 3 Data interpretation & project ID Corridor Plan Accuracy, Detail, and Cost Field data to perform sensitivity analysis Phase 2 Remote sensing to estimate channel & floodplain setting Phase 1 Erosion and deposition potential based on valley setting Coarse Screen
How close are the 1,608 VLT projects to river and stream channels? 1,800 1,600 1,454 1,472 1,513 1,551 1,591 1,400 1,200 Number of VLT Projects 1,000 800 600 400 290 200 0 20 50 100 250 500 1,000 Distance to Rivers (feet) Source: VLT, 2013
1,400 What is the channel size that VLT projects are located within 50 feet of? 1,293 1,200 1,000 915 Number of VLT Projects 800 600 503 400 232 200 0 159 64 5 0 0 1 2 3 4 5 6 7 8 9 Stream Order Source: VLT, 2013
VT Route 100 Road Embankment Floodplain Incision due to confinement on Tweed River (looking upstream) Killington, Vermont Source: MMI, 2012
Floodplain VT Route 100 Road Embankment Stabilized bed on the Tweed River (looking downstream) Killington, Vermont Source: Fitzgerald Environmental, 2013
Total Stream Power (TSP) [W/m] = *Q*S Specific Stream Power (SSP) [W/m 2 ] = *Q*S / w Source: Bagnold, 1966 Source: Brierley and Fryirs, 2005
Source: Kleinhans and van den Berg, 2010
High-Energy Floodplains Medium-Energy Floodplains Source: Nanson and Croke, 1992
PK2 CSM Calculation Ran USGS StreamStats Batch Processor on 130 Ph1 reach break points PK2 Discharge Drainage Area Calculated mean PK2 CSM Applied mean PK2 CSM by stream order to entire watershed Plotted actual PK2 vs. predicted PK2 Very strong correlation with a few outliers in high elevation reaches and areas with large wetlands Source: Fitzgerald Environmental, 2013
Specific Stream Power Calculation Specific power calculated using Phase 1 Data PK2 CSM based stream power for entire watershed Specific Power = (Specific Gravity of Water*PK2 Discharge*Slope)/Stream Width Source: Fitzgerald Environmental, 2013
Mendon Brook Mendon, VT 9/1/2011
Confinement Increase Natural Confinement = 8.4 Confinement after Developed = 4.5 Confinement Increase = 46%
Wet valley bottom Land Type Associations (TNC, Ferree and Thompson, 2008) Buffered streams by 50 feet
Roaring Branch Bennington, VT 9/1/2011
Source: VTANR, 2011
Slope Change Calculation Receiving stream slope < 5% Slope Change 2 nd order and Calculation larger Intersections with a Δslope >5% and a transition from steep to shallow
Vermont River Sensitivity Coarse Screen
COARSE SCREEN USES Initial site screening to obtain preliminary understanding of risk setting at the valley scale. Indicates the likely dominant river process that could influence the river corridor and valley. Caution against use of coarse screen for specific damage site prediction.
COARSE SCREEN USES Initial site screening when no stream geomorphic data are available. Support findings of sediment departure analysis in river corridor plans to establish restoration and conservation projects. Provide a gateway to more detailed stream geomorphic assessment data and corridor plans. Deposition Coarse Screen River Corridor Plan Sediment Regime Excerpt from Upper White River Corridor Plan Source: Redstart Consulting, 2007
Tyler Branch near Welch Farm Enosburg, Vermont Source: MMI, 2008
COARSE SCREEN USES Gain an understanding of valley setting in conjunction with reach scale geomorphic assessment data. Cannot identify undersized bridges or culverts that can specifically determine the location of the most hazardous area or conservation target. Do not use coarse screen alone for planning.
COARSE SCREEN USES Initial site screening when no stream geomorphic data are available.
Vermont River Corridor Flood Sensitivity Coarse Screen Summary of Uses DO Initial site screening when no other data available. Support findings of sediment departure analysis from existing field data. Obtain preliminary understanding of risk setting at the valley scale. DON T Cannot identify site details that drive risk level. Do not use for specific damage site prediction. Do not use alone for planning. Determine the likely dominant river process in the valley. Help establish restoration and conservation projects. Provide a gateway to more detailed data.
EXTRA SLIDES
Source: Knighton, 1999
COARSE SCREEN USES Initial site screening to obtain preliminary understanding of risk setting at the valley scale that is a function of stream size and watershed location.
Low-Energy Floodplains Source: Nanson and Croke, 1992
River Corridor Planning to understand sediment regimes and equilibrium at the watershed scale: floodplain connectivity storage & transport Identifying Key Attenuation Areas Excerpt from Browns River Corridor Plan Source: Arrowwood Environmental, 2007
Deposition Erosion
Deposition Coarse Screen River Corridor Plan Sediment Regime Excerpt from Batten Kill Corridor Plan Source: Field Geology Services, 2007
Erosion Coarse Screen River Corridor Plan Sediment Regime Excerpt from Batten Kill Corridor Plan Source: Field Geology Services, 2007