A series of nested and nonnested off-network lakes. Lakes are opaque with black borders and their local catchments are of matching, partially transparent colors. Arrows indicate the direction of hydrologic connection from each lake and its associated catchment. Numbers indicate unique lake identifiers (IDs) and the table shows the FROM-TO connection of each lake ID within the network of lakes. In this example, lakes 1–4 are headwater lakes, i.e., they have no upslope lakes. Lake 5 is downslope of lake 1, lake 6 is downslope of lakes 4 and 5, and lake 7 is downslope of lake 6. Thus, lake 7 is directly and indirectly connected to lakes 1, 4, 5, and 6 and the aggregation of these catchments is its watershed.