Sediment production in Tuni lake catchment due to climate change

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Seiki Kawagoe, Vanesa Vera San Andres Major University, Bolivia

1 Sediment production in Tuni lake catchment due to climate change (Proyecto Grande/Erosión y Sedimentación) Ramiro Pillco Zolá &, Seiki Kawagoe, Vanesa Vera San Andres Major University, Bolivia Fukushima University, Japan rami_lund992hotmail.com Sendai, October 20th of 2012

2 Content: Motivation Objective Target area Image processing Derivation of erosion and dynamic zones Preliminary Conclusions

3 Motivation Glacier landscape environment 1- Rock fragmentation 2- Rockslide??? 4- Erosion from glacier melting 3- Rock mass movement

4 Motivation In such as environment we would like to understand the basis and prioritize the most important forms and sediment production areas, principally based on physical catchment characteristics

5 Based on this work, the aim is to establish a sediment monitoring production program, with a perspective of sediment transport assessment into the glacier lakes in Bolivia (Tuni & Condoriri reservoirs)

6 (METHOD) (VERIFICATION) SEDIMENT PRODUCTION ANALYSIS UMSA GEOGRAPHICAL CHARACTERITICS ANALYSIS FUKUSHIMA UNIVERSITY TIME PERIOD CLIMATE ANALYSIS SEDIMENT PRODUCTION MODEL UMSA Ver. FUKUSHIMA Ver.

7 Target area Bolivia La Paz The glacier catchments are part of Cordillera Real (between 68º 5' 47'' WL and y 16º 5' 47' SL), above average elevation of 4200 m. Lake Tuni Condoriri Total area of the system is 75 km2. Lake Titicaca La Paz Huayna potosi The catchments includes natural and artificial regulations.

Target area Slope systems: (Turner, A.K., & Schuster, R.L., 1996) Includes debris cones and close to river valley. The tills and moraines are just downstream of the glaciers.

8 Target area Slope systems: (Turner, A.K., & Schuster, R.L., 1996) Includes debris cones and close to river valley. The tills and moraines are just downstream of the glaciers. Periglaciers: The slope systems are placed between the glaciers and preglaciers zones (low temperatures, firns, favorable for the physical and chemical motorization of the rocks).

9 Target area Geology and topography: Presence of structural elements (failures, synclines) The catchments have step topography, with strong elevation changes in a small area.

10 Image processing Vegetation map - Cover map - Soil use map The image processing assumes the criteria of combining the unsupervised classification and the rectification process. Unsupervised classification was made by IKONOS 2006 (UMSA) and the temporal classification by LANDSAT TM (FUKUSHIMA) There were defined seven different groups of cover (water, bare soil, debris, rocks, vegetation, slopes, snow cover)

11 Image processing Classification of cover Image Rectification (by Ikonos)

The increase of vegetation cover is more

12 Image processing 2009glacier area 2003glacier area 1996glacier area 2009vegetation area 2003vegetation area 1996vegetation area Rock area Soil area The increase of vegetation cover is more intensive and the decrease of glacier cover is lower (by Landsat TM)

13 Image processing Area(km 2 ) Glacier Vegetation Y=-0.096(X-1986) R=0.860 Y=0.2443(X-1986) (Huyna) R=0.895 Area(km 2 ) Area(km 2 ) Glacier Year (Tuni) 4 Vegetation Y=-0.033(X-1986) R=0.822 Y=0.038(X-1986) R= Glacier Year (Condoriri) 8 Vegetation Y=2.25(X-1986) R= Y=-1.953(X-1986) R= Year

14 Image processing Glacier geomorphology There was reconstructed the glacier retreat map, in order to identify landforms produced by this, for example introducing moraines and cirques glaciers, etc. (shapes developed by E. Ramirez, 2006) Digitization of 1:50000 scale map SERGOTECMIN was use to extract important structural elements and in order to interpret the geomorphologic units based on the panchromatic IKONOS IMAGE 2006.

15 Visible Geomorphology BIG AREA OF PERIGLACIER GLACIER PREGLACIER

16 Map of Geomorphology Horns Glaciers Moraines Fleecy Rocks Debris Bofedales Tills Glacier Cirques Glacier Tongue Failure

17 Derivation of erosion and dynamic zones There were used the following input information developed in above: Coverage map Slope map Dynamic zones/unstable zones

18 Derivation of erosion and dynamic zones Dynamic zones/unstable zones

19 Derivation of erosion and dynamic zones Dynamic zones/unstable zones

20 Derivation of erosion and dynamic zones a) Erosion map based on slope map model The largest area has about 15 % of slope Reduced area has about 45 % of slope The potential area of erosion is limited to slope between 15 and 45%

Condoriri & Tuni the potential productive areas limited to the dynamic zones In the

21 Derivation of erosion and dynamic zones b) Erosion map based on DEM, cover map and dynamic zones map We have different erosion behavior over the three catchments: In Condoriri & Tuni the potential productive areas limited to the dynamic zones In the Huayna catchment the potential productive area is limited to sloping area 15 and 45%

22 Preliminary Conclusions In Tuni and Condoriri the existence of periglacier zone includes a wide presence of dynamic zones (rockslide); oppositely in Huayna zones are very limited and close to the glaciers. The potential sediment production over the area highly is related to the dynamic zones (rockslide) and to high sloping surface. Properly the erosion due to ice melting is included in the areas of high slope and needs to be estimated at glacier tongue. It will be developed a join work of geographical detail result (UMSA) and time scale variation result (FUKUSHIMA).

23 Thanks for your attention!!!!

THE ACTION OF GLACIERS

Surface processes THE ACTION OF GLACIERS Glaciers are enormous masses of ice which are formed due to accumulation, compaction and re-crystallisation of the snow deposited in very cold regions (the majority