The tour of Zagunao villages revealed clear patterns in the way human settlement has evolved and sustained itself in the watershed. Recognizing these patterns, the BE Lab was better able to identify the constraints and degrees of freedom available for innovative settlement form. Taoping is located at latitude 31°33’ north, longitude 103°26’ east, at the point where the Zagunao River flows out of Li County to join the Min River at Wenchuan. Taoping’s elevation, at approximately 1500 meters (4921 feet) above sea level, is the lowest point in Li County. The highest peaks of the Upper Min watershed, some of which are also in the Zagunao Watershed, are 4500–5100 meters or about 14500 feet above sea level. In this low-latitude region with extreme differences in elevation and steep and narrow valleys, the highest valleys are typically the most lushly vegetated. Rainfall actually decreases at the lower elevations. Higher locations are thus favored for self-sufficient agriculture, but suffer from inaccessibility.
Settlements at the bottom of the valley have greater accessibility, but are dependent on streams and springs for water, and so locate where small tributaries join with the Zagunao River. These villages are typically situated on rocky outcroppings above the streams, for protection against the mud and rock flows that occur when landslides dam up the streams. (The friable rock, steep slopes and minimal vegetation of the main river valleys make landslides a frequent occurrence.) The small alluvial flatlands that these flows create along the main river course are the chief locations for agricultural fields in low valley villages. Taoping, located is at the junction of the Zagunao River and the tributary Zengtou stream, is typical of these villages. Figure 5 shows this relationship clearly.
Overall, population throughout the region was historically relatively stable and somewhat evenly distributed between high and low valley settlements, or indeed high valley populations were larger, due to the greater capacity in high valleys for subsistence agriculture. Road improvements through the main river valleys during the last quarter-century or so have brought changes to this balance. Improved accessibility
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Survey and Design Work in Taoping
