new hampshire fluvial geomorphology assessments...new hampshire fluvial geomorphology assessments...
Post on 13-Jun-2020
8 Views
Preview:
TRANSCRIPT
New Hampshire Fluvial Geomorphology Assessments
Shane Csiki New Hampshire Geological Survey
New Hampshire Department of Environmental Services UMass Fluvial Geomorphology Workshop, Amherst
October 25, 2012
Assessment Objectives
• Fluvial Erosion Hazard (FEH) program • Geomorphic and aquatic organism passage
compatibility of stream crossings • Large woody debris jams for potential effects
of infrastructure • Site-specific assessments after flood events • Holistic understanding of river condition and
health • Integrated Watershed Management
FEH
FEH
FEH
• Emphasis on field photographs and use of GPS units to capture features
• Number of points on cross-sections
• Valley wall verifications • Option for more
detailed cross-section collection
Enhanced Large Woody Debris (LWD) Protocol
• Density of LWD • Qualification: - position in, or suspended
over bankfull width of channel
- Min L = 6 feet - Min D (wide) = 1 foot - Min D (6 feet from wide
end) = 0.5 foot
• GPS location • Root mats or
embeddedness in channel
L D
D
Enhanced Large Woody Debris (LWD) Protocol
• Volume of each piece – frustulum of a paraboloid
Culvert Assessments
Culvert Assessments NH Protocol – similar to Vermont, with
incorporated components from Mass.
Added For AOP – - Flow conditions (survey) - Depth/velocity in culvert
- Emphasis on
upstream/downstream/ reference bankfull widths - Crossing condition
Post-Flood Event Geomorphic Assessments
•Site visits in support of assessing flood and damage for determination of public safety risks
•Qualitative
•Examination of existing bed and bank condition and how it will impact flow, and determination of feedbacks upon bed/bank condition based upon new flow patterns
•Objective: Collation of photographs and assessment evaluation into reports provided to emergency response, stream permitting and funding assistance determinations
top related