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FE 423 - Watershed AnalysisLecture 1a - Overview
Finn Krogstad
UW Forest Engineering
http://students.washington.edu
Early Regulations• Case-by-case evaluation of roads, harvests,
and locations
• Still dominates forest management today
Watershed Analysis
APPROACH - basin specific•where are the hazards•what are they sensitive to•will they reach the stream•are there sensitive reaches•are vulnerable fish there•do inputs exceed background
Watershed Analysis
PROBLEMS•Massive expert time•Site-by-site investigation •Stop being watershed specific•Site, not landscape plans•Is plan A worse than plan B?
EACH POINT HAS UNIQUE:
• Vegetation• Soil• Slope• Aspect• Upslope Area• Distance to Stream• Management
‘DOWNHILL’ IMPACTS
• Saturating Hillslopes• Erosion Runoff Filtering• Stream Flow Volumes• Stream Width & Depth• Sediment Supply• Fish Habitat
WE NEED1a. Data for each point in the watershed1b. Calculate processes at each point2a. Sum outputs from upslope area2b. Sum ‘delivery costs’ to stream
)(,
),(awatershedyx
a yxOutputQ )(
),(aflowpath
a yxFF
Spreadsheets - The Most Powerful Scientific Tool Ever Developed
1. Bring in data
2. Run calculations
3. Display results
Originally was:
Programming for Accountants
GRID: the Spreadsheet for Landscapes
1. Bring in spatial data (soils, vegetation, topography, )
2. Run equations
3. Display results
ArcView: not just pretty pictures
Watershed Analysis: in GRID
•data for each point•calculation at each point•… along path to the stream•accumulating upstream inputs•accumulating different inputs•compare management plans
Gridding the World
SCHEDULETuesday Thursday
Grid Basics overview spatial data
digital topography surface functions
grid algebra grid functions
Grid Hydrology Exam I flow direction
flow accumulation path length
euclidian/costpath vehicular traffic
wildlife movement Exam II
Grid Watersheds mass wasting surface erosion
hydrology channels
riparian fish
Finals Week Final Exam
OVERVIEW
• why - spatial approach • what - downhill in GIS• when - schedule• where - OSB 111• how -• who -
SYLLABUSInstructors: Finn Krogstad, Peter Schiess
Grading:FE423: three exams (33% each)FE523: three exams and a project (25% each)
Lectures: Tuesday & Thursday, 9:30-11:20, in OSB 111 (except first day in AND 302)
Exams:Each exam will include an in-class and a take-home part. The in-class part is open book, open note, pencil-and-paper discussion of grid-based solution of watershed problems. The take-home part which will require solution of problems.
Practice Problems:Each lecture will include a set of problems to provide hands-on experience in the grid-based approach to solving watershed problems. These problems are not handed in, but the exams will look much like these problems, and will assume that students have completed all problems.
READINGS• Hard copy of the online help
Cell Based Modeling with GRID
• People without ArcView experienceGetting to know ArcView GIS
• Another view of Spatial AnalystExtending Arcview GIS
• Some Hydrology and GeomorphologyWater in Environmental Planning, Watershed Analysis Manual (WFPB)Geomorphology (Chorley, et al)
OVERVIEW
• why - spatial approach • what - downhill in GIS• when - schedule• where - OSB 111• how - syllabus• who -
Why Watershed Analysis in GRID?
PROBLEMS• not a survey class: an approach, not ‘facts’• learning GIS: requires work• existing software: more accurate ‘black boxes’
ADVANTAGES• quantitative approach: actually ‘say something’• insight into process: applicable to many issues• GIS skills: applicable to other types of problems
Discussion Problems:for Thursday, try and be ready to discuss the following
Make a spreadsheet that will estimate the peak flow Q5=.157*A.9*Pa1.35*F-.21 for a five year storm in Region XII, using a table of road crossings with their respective contributing area A, percent forest cover F, and annual rainfall Pa.
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