MSc thesis in GIS "ANALYSIS OF HYDROLOGICAL EROSION RISK FOR THE ST. MARY BASIN, MONTANA, USA"

1. ANALYSIS OF HYDROLOGICAL EROSION RISK FOR THE ST. MARY BASIN, MONTANA, USA Silvia Vittozzi Master di 2° Livello in “GIS e telerilevamento per la pianificazione Geoambientale” UNIVERSITA’ DEGLI STUDI DI ROMA “ROMA TRE” 30 Giugno, 2008

2. THE PURPOSE OF RESEARCH IS TO ESTIMATE THE MOST EXPOSED AREAS TO SOIL EROSION IN THE UPPER ST. MARY BASIN, MONTANA, USA 12/10/2009 2

3. WATERTON-GLACIER INTERNATIONAL PEACE PARK Source: www.wikipedia.org 3

4. Hydrology Saskatchewan River watershed. Source:www.wikipedia.org St. Mary River Km 200 Oldman River Km 362 South Saskatchewan Km 1,392 kilometers Upper Old Man River watershed; in the South of the map, the affluent St. Mary river. Source: www.uoguelph.ca 12/10/2009 4

5. THE SOIL Isbasicforall life’s form. Encloseselements: biological mineral Is a naturalresource itneed long timetobecreated (geologicalages!) Itneedtobeconserved 12/10/2009 5

6. Soilerosionby water RAINFALL causesrills and sheeterosion Fonte: Marco AcutisDiProVe, marco.acutis@unimi.it, www.acutis.it 12/10/2009 6

7. SOIL LOSS CAUSED BY WATER Depend on: amount and intensity of rainfall and runoff. land cover which reduce the direct forces of rainfall susceptibility to erosion (texture, composition,…) topography of the landscape as described by slope length, steepness and shape. Artificial conservation practices (terracing, canalizations) and land use. THE GIS IS A POWERFUL TOOL WHICH CAN MANAGE TOGETHER ALL THESE ELEMENTS 12/10/2009 7

8. DEM resolution 10 m Fonte : USGS 12/10/2009 8

9. Mosaic of Natural-Color Aerial Photos, 2005These photos are in MrSID format and Montana State Plane coordinates, units meters, datum NAD83. Source: U.S. Farm Services Agency National Agricultural Imagery Program (NAIP). 12/10/2009 9

10. 20 % Subalpine fir Engelmann Spruce 15 % Cliff/Talus Sparse Vegetation 16% Dwarf-shrub/Herbaceous Complex Dry - Mesic Source photos: USGS-NPS, 2007 12/10/2009 10

11. USLE = UNIVERSAL SOIL LOSS EQUATION Long terms (annual) In a determinate area In this case: Upper St. Mary watersheed A standard methodtomapthe potentialrisk and erodibilityofsoil 12/10/2009 11

12. USLE Itwasconceived: In USA In 1978 Wischmeier and Smith (USDA) For the field. Subsequently was applied also at not only agricoltural areas 12/10/2009 12

13. USLE A = R * K * LS * C * P A = potentialmeanannualsoil loss R FACTOR = rainfallfactor K FACTOR = soilerodibilityfactor LS FACTOR = topographicfactor C FACTOR = land cover factor P FACTOR = conservationpractices (terracing) 12/10/2009 13

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16. THE USLE MAP It show: The Potentialerosion The areaswhere rise RILL EROSION and SHEET EROSION UNITA’ In English Units: tons /hectar/year DATUM: NAD83 12/10/2009 16

17. Shape file ottenutodallaclassificazione del data set: Vegetation Map - Waterton-Glacier International Peace Park Vegetation Mapping Project. USGS-NPS 1999 Glacier National Park- 12/10/2009 17

18. MEASURE UNITS Conversion of USLE factor values to U.S. customary measure units. Source: Wall et al, 2002. 12/10/2009 18

20. DATUM : WGS72

21. PRISM Group (Parameter-elevation Regressions on Independent Slopes Model) climate mapping 12/10/2009 19

23. NAD1927 12/10/2009 20

24. LS FACTOR LUNGHEZZA DEL VERSANTE (length) È un indice espresso sulla base di una condizione standard di: 9 ° di pendenza e 22 m di lunghezza = Distanza compresa tra il punto in cui si origina lo scorrimento ed il punto in cui si ha una deposizione di materiale trasportato, per una diminuzione della pendenza. PENDENZA del versante (stepness) è espressa in GRADI Definition of slope length (Renard, et al. 1987) 12/10/2009 21

25. Metodo Shulze (1995) Formula per calcolare la lunghezza: L = where: 22.1 = misura standard dellalunghezza del versante m = = esponenterelativo al rapportoerosionedaflusso e da rainfall Where: β = Where: SD = slope in degree ʎ = - 3.0S + 100 for S < 25% ʎ = 25 for S ≥ 25% where: S = slope gradient in percent 12/10/2009 22

26. Metodo Shulze (1995) ʎ = A A = con (S ≥ 25,25,(5*(-3))+100) β = B3 B3 = B1/B2 B1 = sin (SD div deg) B2 = 0.0896(3*(pow(B1,0.8)) + 0.56) m = M M = B3/(1+B3) L = pow(A/22.1,M) LENGTH Formula per calcolare la lunghezza del versante: procedimento con rastercalculator: 12/10/2009 23

27. Metodo Shulze (1995) St = 10.8 sin (SD div deg) + 0.03 for S < 9% St = 16.8 sin (SD div deg) – 0.50 for S ≥ 9% St = 3.0 [sin(SD div deg)]0.8 + 0.56 for slope lengths < 5m Con raster calculator: S2 = con (SD < 9,(10.8*B1) + 0.03,(16.8*B1) – 0.5) S3 = con (L < 5,(3*(pow(B1,0.8)) + 0.56,S2) STEEPNESS Dopodichèsicalcolal’indice del fattoretopograficomoltiplicando la lunghezza per la pendenza del versante: LS = S3 * L SL FACTOR Formula per calcolare la pendenza del versante secondo queste condizioni: 12/10/2009 24

28. DATA SOURCES Landuse USGS-NPS 1999 Glacier National Park Vegetation Map - Waterton-Glacier International Peace Park Vegetation Mapping Project. Shape file, NAD 83 . 12/10/2009 25

30. Altezza di cadutaPercentuale di suolo ricoperto dalla canopy 12/10/2009 26

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32. C-factor for permanent pasture and woodland Source: Wischmeier and Smith, 1978. 12/10/2009 28

33. C Factor per territoriallostatonaturale e foreste Source: Wischmeier and Smith, 1978. 12/10/2009 29