[GRASS-user] plz help..grass question

[Mohsin]

I am new to Grass and need your help. I am doing a course and I will be
grateful if you can advise me on the following question and where to start. 
Thanks for your time.
_________________________
As the GIS engineer at a consulting firm, you are to find  and assess the
hazard risk of a debris flows in a watershed in the NC database.
The minimum variables to be used for hazard assessment, alone and in
combination, are:
i. valley slope (longitudinal upstream of the area to protect, which you can
extract using the appropriate GIS function you have used in lab; use 100 m
and 1000 m upstream)
ii. geology of the valley (measure of vulnerability to sudden slope
failure/erosion events e.g. silt soil is more erodible, as are sedimentary
rocks; you may use a buffer distance of approx. 500 m from the river axis
outwards to the left/right banks, and uplsope areas).
You need to detail very clearly your specific: catchment, crossing, source
maps, and criteria of hazard valuation. For credit, your answer should guide
the reader on all logical steps you take sequentially using GRASS. Note:
Include a mention of all the material that you would use to support your
answer; e.g., maps, layers, queries, tables, etc.
SOLN A (less than 50%) steps (only general delineation, used 1 page
description):
1. Select the basin correctly but didn't make sure your base map has
reasonable elevation resolution.
2. Didn't select correct cell coordinates [X,Y] to extract basin
3. Determine slope but didn't make sure DTM had enough resolution – e.g.
6m).
4. Didn't compute stream power P=pQS or similar measure for flow hazard
5. Didn't check rock type in the buffer zone, only in the general catchment.


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