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Watershed analysis in Guatemala
Including collected and generated data for
Guatemala as well as some basic regional
statistics calculated for the 40 major watersheds.
Maps prepared by the
Spatial Information and Analysis Group, DECRG, World Bank
September 2001
Data sources, too numerous to mention…..sorry!
Municipios
Colours represent
departments, municipal
boundaries shaded in gray.
40 Major Watersheds
Rio Paz
Watershed
LandSat ETM images
Rio Paz
Watershed
Elevation
Terrain Typology
Plains - Greens
Lowlands - Yellows
Hills - Red
Mountains - Grey
High Mountains - White
Land Cover
Forests - Green
Agriculture - Light Yellow
Water - Blue
Other - Pink
Urban - Red
Population Density
Poverty Rate (General)
Low - Green
Medium - Yellow
High - Orange
Critical - Red
Poverty (General)
Population per municipio
classified as being poor
Poverty Rate (Extreme)
Low - Green
Medium - Yellow
High - Orange
Critical - Red
Poverty (Extreme)
Population per municipio
classified as being extremely
poor
Forest / Agri. on Slopes
Forests - Green
Agriculture - Orange
Defining upper watershed areas
5 example methods
1) Use an elevation cut off across the region
2) Split each watershed into 3 based on elevation
3) Derive 3 terrain types (Meybeck) across the region
4) Use a flow length cut off across the region
5) Split each watershed into 3 based on flow length
1) Elevation - Region
Low - Green
Mid - Yellow
High - Grey
2) Elevation - By shed
Low - Green
Mid - Yellow
High - Grey
3) Terrain - Region
Low - Green
Mid - Yellow
High - Grey
4) Flowlength - Region
Low - Green
Mid - Yellow
High - Grey
5) Flowlength - By shed
Low - Green
Mid - Yellow
High - Grey
Comparing the 5 examples
How much land is in each region?
% area in each region
70%
60%
50%
Elev-Region
40%
Elev-Shed
Terrain-Region
30%
Flow-Region
Flow-Shed
20%
10%
0%
Low
Mid
High
Comparing the 5 examples
How many people are in each region?
Population in each region
9,000,000
8,000,000
7,000,000
6,000,000
Elev-Region
Elev-Shed
Terrain-Region
5,000,000
4,000,000
Flow-Region
Flow-Shed
3,000,000
2,000,000
1,000,000
Low
Mid
High
Comparing the 5 examples
How many poor are in each region?
Poor (General) in each region
4,500,000
4,000,000
3,500,000
3,000,000
Elev-Region
Elev-Shed
Terrain-Region
2,500,000
2,000,000
Flow-Region
Flow-Shed
1,500,000
1,000,000
500,000
Low
Mid
High
Comparing the 5 examples
How much forest is in each region?
km2 of forest per region
30,000
25,000
20,000
Elev-Region
Elev-Shed
15,000
Terrain-Region
Flow-Region
Flow-Shed
10,000
5,000
Low
Mid
High
Defining upper watershed areas
There is a lot of variation across the 5 methods
methods 2 and 5 (that split each watershed into 3) consistently
give high values in the high region,
methods 1 and 4 consistently give low values in the high regions
method 3 consistently gives values that lie in between
Taking method 3 as an example….
Defining High / Mid / Low lands
Using Method 3: Terrain Typologies (Meybeck et al. 2001)
Class
Low
Mid
High
Total
Area (km2)
62,175 (57%)
16,958 (16%)
29,297 (27%)
108,429
Agriculture (km2)
30,668 (58%)
9,416 (18%)
12,698 (24%)
52,781
Forest (km2)
27,438 (57%)
5,830 (12%)
15,128 (31%)
48,395
Class
Low
Mid
High
Tot
Population (2000)
2,498,093 (22%)
3,197,987 (28%)
5,694,926 (50%)
11,391,006
Poverty (General)
1,552,135 (25%)
1,187,251 (19%)
3,494,186 (56%)
6,233,572
Poverty (Extreme)
542,990 (21%)
430,058 (17%)
1,621,909 (63%)
2,594,956
Population estimated for year 2000 per municipality, (MAGA / BID)
Poverty rates per municipality from official Guatemala poverty map (SEGEPLAN / World Bank)
Selecting watersheds to analyse
We could remove a certain number of watersheds by
imposing criteria such as
We are only interested in watersheds that have > 20% of there
area classified as ‘high’. Taking method 3 as an example, this
would remove all low lying watersheds
Selected Watersheds
Selected watersheds shaded
in yellow