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--- wiki:protection_forest_calc [2018/07/16 09:22] – sebastian
+++ wiki:protection_forest_calc [2020/11/27 11:28] (current) – katharinalapin
@@ Line 3: / Line 3: @@
 ==== General description: ====
-The following model is an approach to delineate areas where the biotic ecosystems (forests) contribute to the mitigation of natural hazards and the protection of human assets from hazardous natural processes. At the Alpine-wide scale, this has been done by combining separate regional models for avalanches, rock-falls and water channel relevant processes. The models use topographical information derived from the 25m EU DEM and statistically derived threshold values identified by earlier projects and assessments (performed in all Alpine countries) to model potential avalanche and rock-fall release and transition zones. **The flowchart below** describes in detail the calculation procedure to derive the developed indicators per local administrative units (LAU2) of the Alpine Space.
+The following model is an approach to delineate areas where the biotic ecosystems (forests) contribute to the mitigation of natural hazards and the protection of human assets from hazardous natural processes. At the Alpine-wide scale, this has been done by combining separate regional models for avalanches, rock-falls and water channel relevant processes. These models where created building on methods developed by the [[http://193.170.148.89/enfin/projects_proalp.html|ProAlp Project]] (Bauerhansel et al. 2009) and [[http://unigis.sbg.ac.at/files/Mastertheses/Full/1500.pdf|Voigt (2010)]]. The models use topographical information derived from the 25m EU DEM and statistically derived threshold values identified by earlier projects and assessments (performed in all Alpine countries) to model potential avalanche and rock-fall release and transition zones. **The flowchart below** describes in detail the calculation procedure to derive the developed indicators per local administrative units (LAU2) of the Alpine Space.
 ==== Input data ====
-  * DEM (slope, slope-length, flow direction, watershed, plan curvature, contour lines) * Land Cover * River Network * Land Cover * River Network
+  * DEM (slope, slope-length, flow direction, watershed, plan curvature, contour lines)
+  * Land Cover
+  * River Network
 ==== Calculation processes ====
-**Avalanche release and Transition zones**
+Avalanche release and Transition zones
 **(1) Calculate potential avalanche release areas:**<font inherit/inherit;;windowtext;;inherit>Select all areas with a slope between 28° and 55°, a plan curvature between -2 and 0.2, a forest land-cover and if there is no better information on potential snow-accumulation available above an altitude threshold (Bauerhansel et al 2009).</font>
@@ Line 18: / Line 20: @@
 **(3) Calculate avalanche cost path:**<font inherit/inherit;;windowtext;;inherit>The cost path represents the easiest way down a slope following the highest elevation differences from one raster pixel to the next. In Arc GIS this can be accomplished with the tool (cost path) using the Flow-Direction as Cost Backlink raster and the DEM as Cost Distance Raster.</font>
-**(4) Calculate energy line angle for every release area:**<font inherit/inherit;;windowtext;;inherit>The energy line,</font><font inherit/inherit;;windowtext;;inherit>or</font><font inherit/inherit;;windowtext;;inherit>generalized</font><font inherit/inherit;;windowtext;;inherit>gradient</font><font inherit/inherit;;windowtext;;inherit>, represents the angle of the connecting line from the release point and the outer edge of the run out zone of a mass movement with the horizontal plan. (Bauerhansel et al 2009)</font>
+**(4) Calculate energy line angle for every release area:**<font inherit/inherit;;windowtext;;inherit>The energy line,</font><font inherit/inherit;;windowtext;;inherit>or</font><font inherit/inherit;;windowtext;;inherit>'generalized</font><font inherit/inherit;;windowtext;;inherit>gradient</font><font inherit/inherit;;windowtext;;inherit>'</font><font inherit/inherit;;windowtext;;inherit>, represents the angle of the connecting line from the release point and the outer edge of the run out zone of a mass movement with the horizontal plan. (Bauerhansel et al 2009)</font>
 ====   ====
@@ Line 31: / Line 33: @@
 **(****5) Limit avalanche Paths with energy line angle:**<font inherit/inherit;;windowtext;;inherit>Knowing the avalanche path, the energy line angle allows a rough estimation of maximal runout distance. The previously measured events occurred at an ELA of 17° - 47° with the mean 28°. Events with ELA 17° are very improbable. We used this threshold for our approach to consider all possible events. (Bauerhansel et al. 2009, PARAmount Project 2012).</font>
-=== Rock-fall Release and Transition Zones ===
+Rock-fall Release and Transition Zones
 **(6) Calculate potential rock-fall start zones:**<font inherit/inherit;;windowtext;;inherit>Similar to the avalanche release areas, this can roughly be done by selecting all areas with bare-rock land-cover and a slope steeper than 43°. In the Alpine-wide approach we had to use CORINE Land Cover as the input dataset where most rock surfaces are not delineated (because of resolution and minimum mapping width). For that reason, we also included all the areas without vegetation. Depending on the DEM resolution, different slope thresholds should be applied (Berger et al 2010).</font>
@@ Line 59: / Line 61: @@
 **(9) Perform Path Distance ****analysis****to**** calculate maximum runout lengths of falling-rocks**: The threshold of 2250 was used which is approximatly a runout of 250 meters in forested terrain (assuming the same dbh and tree density in all forests). With better information on the tree stands in forests different thresholds could be applied using the Rockfor<sup>NET</sup>   tool, found here: [[http://www.ecorisq.org/rockfor-net-en|http://www.ecorisq.org/rockfor-net-en]] .
-=== Areas relevant for water channels ===
+Areas relevant for water channels
 **(10) Delineate Forest areas with a protective effect for water-channels: **  All areas with an on-surface distance to water channels of between 10m (trees too near to the channel can have negative influence) and 200m and a slope steeper than >20° are potential erosion and mudslide risk zones that could clog up the river. Forests within this zone are thus particularly important in preventing erosion and events.
-=== Supply Indicator creation ===
+Supply Indicator creation
 **(11) Combine areas where forests have a protective function: **By merging all natural hazard zones that already have a forest land-cover, the sites of protection forests are identified. By definition, the protective function of forests exists in all avalanche release and transition zones, rock-fall transition zones and water channel relevant terrain.
-=== Demand indicator creation ===
+Demand indicator creation
 **(12) Calculate natural hazard potential:**Merge the spatial extent of the avalanche and rock-fall transition zones calculated above.
@@ Line 75: / Line 77: @@
 **(14) Calculate protection forest demand index:**Overlay the natural hazard potential and the damage potential areas. This allows one to identify all of the Infrastructure in potential hazard zones that is in need of protection.
-=== Flow indicator creation ===
+Flow indicator creation
 **(15) Backlink intersections of hazard potential and damage potential to release areas:**In the case of avalanches all the transition zones that intersect with infrastructure have to be traced back to the corresponding release area. Using Raster in ArcGIS, this can be done by inverting the DEM and performing a new cost path analysis starting from the intersected damage potential areas. Finally, by combining the avalanche release and transition zones as well as rockfall transition zones that possibly harm infrastructure we are able to identify Object-protecting forest.
-<font 26px/inherit;;inherit;;inherit>**Protection Forest**</font>
+{{:en:protection_forest_flowchart_f1.jpg?nolink&1643x2001|protection_forest_flowchart_f1.jpg}}
-{{:en:protection_forest_flowchart_f1.jpg?nolink&1643x2001}}
+{{:en:test_legens.jpg?nolink&500x297|test_legens.jpg}}
-{{:en:biomassproductionfromgrassland_page_12_1_.jpg?nolink&500x300}}
 <font 18px/inherit;;inherit;;inherit>**Flowchart depicting the procedures used to derive the supply, flow and demand indicators**</font>