Urban Hierarchy

Urban hierarchy of El Salvador is analyzed using readily available statistics and data derived from recent studies. Out of 262 municipal capitals, only those having larger urban population are subject to the analysis. The PNODT study classifies municipal areas into four classes: A for urban core of municipal capital including its spillover area, B for large settlement or population center in dominantly rural area, C for other settlements in dominantly rural area, and D for village/hamlet in strictly rural area (PNODT Primer Informe Parcial - Diagnóstico Sistema Urbano y Poblamiento 6. Demografia e Información Básica Municipal, June 2002). Only 61 municipalities with an urban population of Class A over 10,000 are selected for the analysis. Of these, nine are considered to constitute the core of the San Salvador metropolitan region (SSMR) with a total population of 1,352,037 and at the top of the urban hierarchy (Tier I).

The remaining 52 urban centers are analyzed with respect to potentials to serve various urban functions expected at different tiers of the hierarchy. Five criteria are used. The size of population is used to represent agglomeration economies. Population density indicates certain aspect of efficiency for urban services. The average annual rate of population increase over 1992-2000 is used to reflect economic dynamism. The urbanization ratio of each municipality is taken to see effectiveness of urban services. To reflect social aspects in the analysis, an index defined by a recent GTZ study is used (PROMUDE/GTZ, Propuesta de una Tipología de Municipios para El Salvador). This is a composite index defined by combining various factors related to the quality and levels of urban services, and called unfulfilled basic needs index (INBI). All the data are given in this table.

All the urban centers are classified into five ranks for each index as shown below to normalize the evacuation by different indices for comparison.

Rank

Population

Population density (/km²)

Population growth (% p.a.)

Urbanization ratio (%)

INBI

Over 100,000

40,000-99,999

20,000-39,999

12,000-19,999

Below 11,999

Over 1,000

400-999

200-399

100-199

Below 99

Over 9.0

5.0-8.9

3.5-4.9

2.0-3.4

Below 1.9

Over 80

60-79

40-59

20-39

Below 19

8-25

26-33

34-39

40-47

Over 48

The overall rank of any urban center is determined by simply adding ranks by different indices. Based on the overall ranking, the 52 urban centers are categorized into four tiers: rank 5 to 10 for Tier II (seven urban centers), rank 11 to 15 for Tier III (13 urban centers), rank 16 to 19 for Tier IV (22 urban centers), and rank over 20 for Tier V (10 urban centers). More urban centers may need to be defined for Tier V.

This simple analysis on the existing urban hierarchy indicates that the Eastern Region is poorly served by urban centers. Even a top ranked center of San Miguel is at Tier III. For the Eastern Regional development, urban functions need to be strengthened. Therefore, a few urban centers in the Eastern Region are ranked up to a higher tier, respectively, and San Miguel is designated as the regional center at the top of urban hierarchy. The results, illustrated in Figure, appear to be well balanced with respect to spatial coverage of different parts of the Eastern Region.

The urban hierarchical analysis may be conducted with more detailed data. The present analysis indicates, however, that urban centers are well distributed throughout the Eastern Region but their functions are weak. Functions to be strengthened for urban centers at different tiers will be clarified in the subsequent stage of the study.